No GHG Warming Fingerprints in the Sky

For several years I have pored over comments from Kristian (okulaer) and gained understanding from the effort. Here is his recent article on the absence of  “AGW warming” fingerprints in the CERES satellite data.  How the CERES EBAF Ed4 data disconfirms “AGW” in 3 different ways  by okulaer November 11, 2018. Excerpts below with my bolds.  Kristian provides more detailed discussion at his blog (title in red is link)

Background: The AGW Hypothesis

For those of you who aren’t entirely up to date with the hypothetical idea of an “(anthropogenically) enhanced GHE” (the “AGW”) and its supposed mechanism for (CO2-driven) global warming, the general principle is fairly neatly summed up here.

I’ve modified this diagram below somewhat, so as to clarify even further the concept of “the raised ERL (Effective Radiating Level)” – referred to as Ze in the schematic – and how it is meant to ‘drive’ warming within the Earth system; to simply bring the message of this fundamental premise of “AGW” thinking more clearly across.
Then we have the “doubled CO2” (t1) scenario, where the ERL has been pushed higher up into cooler air layers closer to the tropopause:

So when the atmosphere’s IR opacity increases with the excess input of CO2, the ERL is pushed up, and, with that, the temperature at ALL ALTITUDE-SPECIFIC LEVELS of the Earth system, from the surface (Ts) up through the troposphere (Ttropo) to the tropopause, directly connected via the so-called environmental lapse rate, i.e. the negative temperature profile rising up through the tropospheric column, is forced to do the same.

The Expected GHG Fingerprints

How, then, is this mechanism supposed to manifest itself?

Well, as the ERL, basically the “effective atmospheric layer of OUTWARD (upward) radiation”, the one conceptually/mathematically responsible for the All-Sky OLR flux at the ToA, and from now on, in this post, dubbed rather the EALOR, is lifted higher, into cooler layers of air, the diametrically opposite level, the “effective atmospheric layer of INWARD (downward) radiation” (EALIR), the one conceptually and mathematically responsible for the All-Sky DWLWIR ‘flux’ (or “the atmospheric back radiation”) to the surface, is simultaneously – and for the same physical reason, only inversely so – pulled down, into warmer layers of air closer to the surface. This latter concept was explained already in 1938 by G.S. Callendar. Feldman et al., 2015, (as an example) confirm that this is still how “Mainstream Climate Science (MCS)” views this ‘phenomenon’:

The gist being that, when we make the atmosphere more opaque to IR by putting more CO2 into it, “the atmospheric back radiation” (all-sky DWLWIR at sfc) will naturally increase as a result, reducing the radiative heat loss (net LW) from the surface up. And do note, it will increase regardless of (and thus, on top of) any atmospheric rise in temperature, which would itself cause an increase. Which is to say that it will always distinctly increase also RELATIVE TO tropospheric temps (which are, by definition, altitude-specific (fixed at one particular level, like ‘the lower troposphere’ (LT))). That is, even when tropospheric temps do go up, the DWLWIR should be observed to increase systematically and significantly MORE than what we would expect from the temperature rise alone. Because the EALIR moves further down.

Conversely, at the other end, at the ToA, the EALOR moves the opposite way, up into colder layers of air, which means the all-sky OLR (the outward emission flux) should rather be observed to systematically and significantly decrease over time relative to tropospheric temps. If tropospheric temps were to go up, while the DWLWIR at the surface should be observed to go significantly more up, the OLR at the ToA should instead be observed to go significantly less up, because the warming of the troposphere would simply serve to offset the ‘cooling’ of the effective emission to space due to the rise of the EALOR into colder strata of air.

What we’re looking for, then, if indeed there is an “enhancement” of some “radiative GHE” going on in the Earth system, causing global warming, is ideally the following:

OLR stays flat, while TLT increases significantly and systematically over time;
TLT increases systematically over time, but DWLWIR increases significantly even more.
Effectively summed up in this simplified diagram.

Figure 4. Note, this schematic disregards – for the sake of simplicity – any solar warming at work.

However, we also expect to observe one more “greenhouse” signature.

If we expect the OLR at the ToA to stay relatively flat, but the DWLWIR at the sfc to increase significantly over time, even relative to tropospheric temps, then, if we were to compare the two (OLR and DWLWIR) directly, we’d, after all, naturally expect to see a fairly remarkable systematic rise in the latter over the former (refer to Fig.4 above).

Which means we now have our three ways to test the reality of an hypothesized “enhanced GHE” as a ‘driver’ (cause) of global warming.

Three Tests for GHG Warming in the Sky

The null hypothesis in this case would claim or predict that, if there is NO strengthening “greenhouse mechanism” at work in the Earth system, we would observe:

1. The general evolution (beyond short-term, non-thermal noise (like ENSO-related humidity and cloud anomalies or volcanic aerosol anomalies))* of the All-Sky OLR flux at the ToA to track that of Ttropo (e.g. TLT) over time;
2. The general evolution of the All-Sky DWLWIR at the surface to track that of Ttropo (Ts + Ttropo, really) over time;
3. The general evolution of the All-Sky OLR at the ToA and the All-Sky DWLWIR at the surface to track each other over time, barring short-term, non-thermal noise.

* (We see how the curve of the all-sky OLR flux at the ToA differs quite noticeably from the TLT and DWLWIR curves, especially during some of the larger thermal fluctuations (up or down), normally associated with particularly strong ENSO events. This is because there are factors other than pure mean tropospheric temperatures that affect Earth’s final emission flux to space, like the concentration and distribution (equator→poles, surface→tropopause/stratosphere) of clouds, water vapour and aerosols. These may (and do) all vary strongly in the short term, significantly disrupting the normal temperature↔flux (Stefan-Boltzmann) connection, but in the longer term, they display a remarkable tendency to even out, leaving the tropospheric temperature signal as the only real factor to consider when comparing the OLR with Ttropo (TLT). Or not. The “AGW” idea specifically contends, resting on the premise, that these other factors (and crucially also including CO2, of course) do NOT even out over time, but rather accrue in a positive (‘warming’) direction.)

Missing Fingerprint #1

The first point above we have already covered extensively. The combined ERBS+CERES OLR record is seen to track the general progression of the UAHv6 TLT series tightly, both in the tropics and near-globally, all the way from 1985 till today (the last ~33 years), as discussed at length both here and here.

Since, however, in this post we’re specifically considering the CERES era alone, this is how the global OLR matches against the global TLT since 2000:
Figure 5.

This is simply the monthly CERES OLR flux data properly scaled (x0.266), enabling us to compare it more directly to temperatures (W/m2→K), and superimposed on the UAH TLT data. Watch how closely the two curves track each other, beyond the obvious noise. To highlight this striking state of relative congruity, we remove the main sources of visual bias in Fig.5 above. Notice, then, how the red OLR curve, after the 4-year period of fairly large ENSO-events (La Niña-El Niño-La Niña) between 2007/2008 and 2011/2012, when the cyan TLT curve goes both much lower (during the flanking La Niñas) and much higher (during the central El Niño), quickly reestablishes itself right back on top of the TLT curve, just where it used to be prior to that intermediate stretch of strong ENSO influence. And as a result, there is NO gradual divergence whatsoever to be spotted between the mean levels of these two curves, from the beginning of 2000 to the end of 2015.

Missing Fingerprint #2

The second point above is just as relevant as the first one, if we want to confirm (or disconfirm) the reality of an “enhanced GHE” at work in the Earth system. We compare the tropospheric temperatures with the DWLWIRsfc ‘flux’, that is, the apparent atmospheric thermal emission to the surface:

Figure 9. Note how the scaling of the flux (W/m2) values is different close to the surface than at the ToA. Here at the DWLWIR level, down low, we divide by 5 (x0.2), while at the OLR level, up high, we divide by 3.76 (x0.266).

We once again observe a rather close match overall. At the very least, we can safely say that there is no evidence whatsoever of any gradual, systematic rise in DWLWIR over the TLT, going from 2000 to 2018. If we plot the difference between the two curves in Fig.9 to obtain the “DWLWIR residual”, this fact becomes all the more evident:

Figure 10.

Remember now how the idea of an “enhanced GHE” requires the DWLWIR to rise significantly more than Ttropo (TLT) over time, and that its “null hypothesis” therefore postulates that such a rise should NOT be seen. Well, do we see such a rise in the plot above? Nope. Not at all. Which fits in perfectly with the impression we got at the ToA, where the TLT-curve was supposed to rise systematically up and away from the OLR-curve over time, but didn’t – no observed evidence there either of any “enhanced GHE” at work.

Missing Fingerprint #3

Finally, the third point above is also pretty interesting. It is simply to verify whether or not the CERES EBAF Ed4 ‘radiation flux’ data products are indeed suggesting a strengthening of some radiatively defined “greenhouse mechanism”. We sort of know the answer to this already, though, from going through points 1 and 2 above. Since neither the OLR at the ToA nor the DWLWIR at the surface deviated meaningfully from the UAHv6 TLT series (the same one used to compare with both, after all), we expect rather by necessity that the two CERES ‘flux products’ also shouldn’t themselves deviate meaningfully overall from one another. And, unsurprisingly, they don’t:

Figure 14.  Difference plot (“DWLWIR residual”)

Again, it is so easy here to allow oneself to be fooled by the visual impact of that late – obviously ENSO-related – peak, and, in this case, also a definite ENSO-based trough right at the start (you’ll plainly recognise it in Fig.14); another perfect example of how one’s perception and interpretation of a plot is directly affected by “the end-point bias”. Don’t be fooled:

If we expect the OLR at the ToA to stay relatively flat, but the DWLWIR at the sfc to increase significantly over time, even relative to tropospheric temps, then, if we were to compare the two (OLR and DWLWIR) directly, we’d […] naturally expect to see a fairly remarkable systematic rise in the latter over the former (refer to Fig.4 above).

Looking at Fig.14, and taking into account the various ENSO states along the way, does such a “remarkable systematic rise” in DWLWIR over OLR manifest itself during the CERES era?

I’m afraid not …

Four Lines of Evidence Against GHG Warming Hypothesis

The lack of GHG warming in the CERES data is added to three previous atmospheric heat radiation studies.

  1.  In 2004 Ferenc MIskolczi studied the radiosonde datasets and found that the optical density at the top of the troposphere does not change with increasing CO2, since reducing H2O maintains optimal radiating efficiency.  His publication was suppressed by NASA, and he resigned from his job there. He has elaborated on his findings in publications as recently as 2014. See:  The Curious Case of Dr. Miskolczi

2.  Ronan and Michael Connolly  studied radiosonde data and concluded in 2014:

“It can be seen from the infra-red cooling model of Figure 19 that the greenhouse effect theory predicts a strong influence from the greenhouse gases on the barometric temperature profile. Moreover, the modeled net effect of the greenhouse gases on infra-red cooling varies substantially over the entire atmospheric profile.

However, when we analysed the barometric temperature profiles of the radiosondes in this paper, we were unable to detect any influence from greenhouse gases. Instead, the profiles were very well described by the thermodynamic properties of the main atmospheric gases, i.e., N 2 and O 2 , in a gravitational field.”

While water vapour is a greenhouse gas, the effects of water vapour on the temperature profile did not appear to be related to its radiative properties, but rather its different molecular structure and the latent heat released/gained by water in its gas/liquid/solid phase changes.

For this reason, our results suggest that the magnitude of the greenhouse effect is very small, perhaps negligible. At any rate, its magnitude appears to be too small to be detected from the archived radiosonde data.” Pg. 18 of referenced research paper

See:  The Physics Of The Earth’s Atmosphere I. Phase Change Associated With Tropopause

3.  An important proof against the CO2 global warming claim was included in John Christy’s testimony 29 March 2017 at the House Committee on Science, Space and Technology. The text and diagram below are from that document which can be accessed here.

IPCC Assessment Reports show that the IPCC climate models performed best versus observations when they did not include extra GHGs and this result can be demonstrated with a statistical model as well.

Figure 5. Simplification of IPCC AR5 shown above in Fig. 4. The colored lines represent the range of results for the models and observations. The trends here represent trends at different levels of the tropical atmosphere from the surface up to 50,000 ft. The gray lines are the bounds for the range of observations, the blue for the range of IPCC model results without extra GHGs and the red for IPCC model results with extra GHGs.The key point displayed is the lack of overlap between the GHG model results (red) and the observations (gray). The nonGHG model runs (blue) overlap the observations almost completely.

Atmospheric Observations Contradict Global Warming Theory

Update Nov. 13, 2018  H/T Yonason for linking to Blair Macdonald’s discussion of CO2 behavior in the atmosphere.  At the end is a video and link to his paper and website.

This paper just published Has global warming already arrived? by C.A.Varotsos and M.N.Efstathiou (H/T Dennis Bird) Excerpts in italics with my bolds.

Highlights
•  The global warming during 1978–2018 was not more enhanced at high latitudes near the surface.

•  The intrinsic properties of the lower stratospheric temperature are not related to those in the troposphere.

•  The results obtained do not reveal the global warming occurrence.

Abstract

The enhancement of the atmospheric greenhouse effect due to the increase in the atmospheric greenhouse gases is often considered as responsible for global warming (known as greenhouse hypothesis of global warming). In this context, the temperature field of global troposphere and lower stratosphere over the period 12/1978–07/2018 is explored using the recent Version 6 of the UAH MSU/AMSU global satellite temperature dataset.

Our analysis did not show a consistent warming with gradual increase from low to high latitudes in both hemispheres, as it should be from the global warming theory. In addition, in the lower stratosphere the temperature cooling over both poles is lower than that over tropics and extratropics. To study further the thermal field variability we investigated the long-range correlations throughout the global lower troposphere-lower stratosphere region. The results show that the temperature field displays power-law behaviour that becomes stronger by going from the lower troposphere to the tropopause.

This power-law behaviour suggests that the fluctuations in global tropospheric temperature at short intervals are positively correlated with those at longer intervals in a power-law manner. The latter, however, does not apply to global temperature in the lower stratosphere. This suggests that the investigated intrinsic properties of the lower stratospheric temperature are not related to those of the troposphere, as is expected by the global warming theory.

Conclusions

From the analysis presented above the following conclusions could be drawn:

•  The temperature trend shows a decreasing warming from the lower troposphere up to the tropopause level and then reverses to cooling in the lower stratosphere. This trend at the tropopause can be considered almost zero. The latter can not support the increase in the height of tropopause, a fingerprint of global warming.

•  At the lower stratosphere there is a negative temperature trend which is lower over both poles (compared to tropics and extra-tropics) with the lowest value over the North Pole.

•  In the lower and mid-troposphere the temperature trend decreases with height and latitude

The above-mentioned three results do not agree with the global warming theory, namely, the gradual increase of tropospheric warming with latitude.

The DFA and MDFA analyses conducted on the possible association of warming in the global troposphere with cooling in the global lower stratosphere showed the following:

•  The temperature fluctuations in the global troposphere exhibit power-law behaviour with an exponent gradually increasing with altitude reaching the unity at the tropopause.

•  The global lower stratospheric temperature anomalies do not exhibit long-range correlation behaviour. In particular, the lower stratospheric temperature anomalies over tropics obey power-law behaviour, while it is not the case for the low stratospheric temperature anomalies over both poles. This may be attributed to the ozone dynamics in this region.

The two above-mentioned results lead to the main conclusion that the intrinsic properties of the thermal regime in the lower stratosphere are not associated with the thermal regime in the troposphere.In summary, the tropospheric temperature has not increased over the last four decades, in both hemispheres, in a way that is more amplified at high latitudes near the surface. In addition, the lower stratospheric temperature did not decline as a function of latitude. Finally,the intrinsic properties of the tropospheric temperature are different from those of the lower stratosphere.

Based on these results and bearing in mind that the climate system is complicated and complex with the existing uncertainties in the climate predictions, it is not possible to reliably support the view of the presence of global warming in the sense of an enhanced greenhouse effect due to human activities.

Update Nov. 13, 2018

MacDonald’s paper is Reinterpreting and Augmenting John Tyndall’s 1859 Greenhouse Gas Experiment with Thermoelectric Theory and Raman Spectroscopy 

Climate science’s fundamental premise – assumed by all parties in the great climate debate – says the greenhouse gases – constituting less than 2% of Earth’s atmosphere, first derived by John Tyndall‘s in his 1859 thermopile experiment, and demonstrated graphically today by infrared spectroscopy – are special because of their IR (heat) absorbing property. From this, it is – paradoxically – assumed the (remaining 98%) non-greenhouse gases N2 nitrogen and O2 oxygen are non-heat absorbent.

This paper reveals, by elementary physics, the (deceptive) role thermopiles play in this paradox. It was found: for a special group substances – all sharing (at least one) electric dipole moment – i.e. CO2, and the other greenhouse gases – thermopiles – via the thermoelectric (Seebeck) effect – generate electricity from their radiated IR. Devices using the thermopile as a detector (e.g. IR spectrographs) discriminate, and have misinterpreted IR absorption for anomalies of electricity production – between the sample gases and a control heat source.

N2 and O2 were found to have (as all substances) predicted vibrational modes (derived by the Schrodinger quantum equation) at 1556cm-1 and 2330cm-1 respectively – well within the IR range of the EM spectrum and are clearly observed – as expected – with Raman Spectroscopy – IR spectroscopy’s complement instrument. The non-greenhouse gases N2 and O2 are relegated to greenhouse gases, and Earth’s atmospheric thermoelectric spectrum was produced (formally IR spectrum), and was augmented with the Raman observations.

It was concluded the said greenhouses gases are not special, but typical; and all substances have thermal absorption properties, as measured by their respective heat capacities.

Bill Gray: H20 is Climate Control Knob, not CO2

William Mason Gray (1929-2016), pioneering hurricane scientist and forecaster and professor of atmospheric science at Colorado State University.

Dr. William Gray made a compelling case for H2O as the climate thermostat, prior to his death in 2016.  Thanks to GWPF for publishing posthumously Bill Gray’s understanding of global warming/climate change.  The paper was compiled at his request, completed and now available as Flaws in applying greenhouse warming to Climate Variability This post provides some excerpts in italics with my bolds and some headers.  Readers will learn much from the entire document (title above is link to pdf).

The Fundamental Correction

The critical argument that is made by many in the global climate modeling (GCM) community is that an increase in CO2 warming leads to an increase in atmospheric water vapor, resulting in more warming from the absorption of outgoing infrared radiation (IR) by the water vapor. Water vapor is the most potent greenhouse gas present in the atmosphere in large quantities. Its variability (i.e. global cloudiness) is not handled adequately in GCMs in my view. In contrast to the positive feedback between CO2 and water vapor predicted by the GCMs, it is my hypothesis that there is a negative feedback between CO2 warming and and water vapor. CO2 warming ultimately results in less water vapor (not more) in the upper troposphere. The GCMs therefore predict unrealistic warming of global temperature. I hypothesize that the Earth’s energy balance is regulated by precipitation (primarily via deep cumulonimbus (Cb) convection) and that this precipitation counteracts warming due to CO2.

Figure 14: Global surface temperature change since 1880. The dotted blue and dotted red lines illustrate how much error one would have made by extrapolating a multi-decadal cooling or warming trend beyond a typical 25-35 year period. Note the recent 1975-2000 warming trend has not continued, and the global temperature remained relatively constant until 2014.

Projected Climate Changes from Rising CO2 Not Observed

Continuous measurements of atmospheric CO2, which were first made at Mauna Loa, Hawaii in 1958, show that atmospheric concentrations of CO2 have risen since that time. The warming influence of CO2 increases with the natural logarithm (ln) of the atmosphere’s CO2 concentration. With CO2 concentrations now exceeding 400 parts per million by volume (ppm), the Earth’s atmosphere is slightly more than halfway to containing double the 280 ppm CO2 amounts in 1860 (at the beginning of the Industrial Revolution).∗

We have not observed the global climate change we would have expected to take place, given this increase in CO2. Assuming that there has been at least an average of 1 W/m2 CO2 blockage of IR energy to space over the last 50 years and that this energy imbalance has been allowed to independently accumulate and cause climate change over this period with no compensating response, it would have had the potential to bring about changes in any one of the following global conditions:

  • Warm the atmosphere by 180◦C if all CO2 energy gain was utilized for this purpose – actual warming over this period has been about 0.5◦C, or many hundreds of times less.
  • Warm the top 100 meters of the globe’s oceans by over 5◦C – actual warming over this period has been about 0.5◦C, or 10 or more times less.
  • Melt sufficient land-based snow and ice as to raise the global sea level by about 6.4 m. The actual rise has been about 8–9 cm, or 60–70 times less. The gradual rise of sea level has been only slightly greater over the last ~50 years (1965–2015) than it has been over the previous two ~50-year periods of 1915–1965 and 1865–1915, when atmospheric CO2 gain was much less.
  • Increase global rainfall over the past ~50-year period by 60 cm.

Earth Climate System Compensates for CO2

If CO2 gain is the only influence on climate variability, large and important counterbalancing influences must have occurred over the last 50 years in order to negate most of the climate change expected from CO2’s energy addition. Similarly, this hypothesized CO2-induced energy gain of 1 W/m2 over 50 years must have stimulated a compensating response that acted to largely negate energy gains from the increase in CO2.

The continuous balancing of global average in-and-out net radiation flux is therefore much larger than the radiation flux from anthropogenic CO2. For example, 342 W/m2, the total energy budget, is almost 100 times larger than the amount of radiation blockage expected from a CO2 doubling over 150 years. If all other factors are held constant, a doubling of CO2 requires a warming of the globe of about 1◦C to enhance outward IR flux by 3.7 W/m2 and thus balance the blockage of IR flux to space.

Figure 2: Vertical cross-section of the annual global energy budget. Determined from a combination of satellite-derived radiation measurements and reanalysis data over the period of 1984–2004.

This pure IR energy blocking by CO2 versus compensating temperature increase for radiation equilibrium is unrealistic for the long-term and slow CO2 increases that are occurring. Only half of the blockage of 3.7 W/m2 at the surface should be expected to go into an temperature increase. The other half (about 1.85 W/m2) of the blocked IR energy to space will be compensated by surface energy loss to support enhanced evaporation. This occurs in a similar way to how the Earth’s surface energy budget compensates for half its solar gain of 171 W/m2 by surface-to-air upward water vapor flux due to evaporation.

Assuming that the imposed extra CO2 doubling IR blockage of 3.7 W/m2 is taken up and balanced by the Earth’s surface in the same way as the solar absorption is taken up and balanced, we should expect a direct warming of only ~0.5◦C for a doubling of CO2. The 1◦C expected warming that is commonly accepted incorrectly assumes that all the absorbed IR goes to the balancing outward radiation with no energy going to evaporation.

Consensus Science Exaggerates Humidity and Temperature Effects

A major premise of the GCMs has been their application of the National Academy of Science (NAS) 1979 study3 – often referred to as the Charney Report – which hypothesized that a doubling of atmospheric CO2 would bring about a general warming of the globe’s mean temperature of 1.5–4.5◦C (or an average of ~3.0◦C). These large warming values were based on the report’s assumption that the relative humidity (RH) of the atmosphere remains quasiconstant as the globe’s temperature increases. This assumption was made without any type of cumulus convective cloud model and was based solely on the Clausius–Clapeyron (CC) equation and the assumption that the RH of the air will remain constant during any future CO2-induced temperature changes. If RH remains constant as atmospheric temperature increases, then the water vapor content in the atmosphere must rise exponentially.

With constant RH, the water vapor content of the atmosphere rises by about 50% if atmospheric temperature is increased by 5◦C. Upper tropospheric water vapor increases act to raise the atmosphere’s radiation emission level to a higher and thus colder level. This reduces the amount of outgoing IR energy which can escape to space by decreasing T^4.

These model predictions of large upper-level tropospheric moisture increases have persisted in the current generation of GCM forecasts.§ These models significantly overestimate globally-averaged tropospheric and lower stratospheric (0–50,000 feet) temperature trends since 1979 (Figure 7).

Figure 8: Decline in upper tropospheric RH. Annually-averaged 300 mb relative humidity for the tropics (30°S–30°N). From NASA-MERRA2 reanalysis for 1980–2016. Black dotted line is linear trend.

All of these early GCM simulations were destined to give unrealistically large upper-tropospheric water vapor increases for doubling of CO2 blockage of IR energy to space, and as a result large and unrealistic upper tropospheric temperature increases were predicted. In fact, if data from NASA-MERRA24 and NCEP/NCAR5 can be believed, upper tropospheric RH has actually been declining since 1980 as shown in Figure 8. The top part of Table 1 shows temperature and humidity differences between very wet and dry years in the tropics since 1948; in the wettest years, precipitation was 3.9% higher than in the driest ones. Clearly, when it rains more in the tropics, relative and specific humidity decrease. A similar decrease is seen when differencing 1995–2004 from 1985–1994, periods for which the equivalent precipitation difference is 2%. Such a decrease in RH would lead to a decrease in the height of the radiation emission level and an increase in IR to space.

The Earth’s natural thermostat – evaporation and precipitation

What has prevented this extra CO2-induced energy input of the last 50 years from being realized in more climate warming than has actually occurred? Why was there recently a pause in global warming, lasting for about 15 years?  The compensating influence that prevents the predicted CO2-induced warming is enhanced global surface evaporation and increased precipitation.

Annual average global evaporational cooling is about 80 W/m2 or about 2.8 mm per day.  A little more than 1% extra global average evaporation per year would amount to 1.3 cm per year or 65 cm of extra evaporation integrated over the last 50 years. This is the only way that such a CO2-induced , 1 W/m2 IR energy gain sustained over 50 years could occur without a significant alteration of globally-averaged surface temperature. This hypothesized increase in global surface evaporation as a response to CO2-forced energy gain should not be considered unusual. All geophysical systems attempt to adapt to imposed energy forcings by developing responses that counter the imposed action. In analysing the Earth’s radiation budget, it is incorrect to simply add or subtract energy sources or sinks to the global system and expect the resulting global temperatures to proportionally change. This is because the majority of CO2-induced energy gains will not go into warming the atmosphere. Various amounts of CO2-forced energy will go into ocean surface storage or into ocean energy gain for increased surface evaporation. Therefore a significant part of the CO2 buildup (~75%) will bring about the phase change of surface liquid water to atmospheric water vapour. The energy for this phase change must come from the surface water, with an expenditure of around 580 calories of energy for every gram of liquid that is converted into vapour. The surface water must thus undergo a cooling to accomplish this phase change.

Therefore, increases in anthropogenic CO2 have brought about a small (about 0.8%) speeding up of the globe’s hydrologic cycle, leading to more precipitation, and to relatively little global temperature increase. Therefore, greenhouse gases are indeed playing an important role in altering the globe’s climate, but they are doing so primarily by increasing the speed of the hydrologic cycle as opposed to increasing global temperature.

Figure 9: Two contrasting views of the effects of how the continuous intensification of deep
cumulus convection would act to alter radiation flux to space.
The top (bottom) diagram represents a net increase (decrease) in radiation to space

Tropical Clouds Energy Control Mechanism

It is my hypothesis that the increase in global precipitation primarily arises from an increase in deep tropical cumulonimbus (Cb) convection. The typical enhancement of rainfall and updraft motion in these areas together act to increase the return flow mass subsidence in the surrounding broader clear and partly cloudy regions. The upper diagram in Figure 9 illustrates the increasing extra mass flow return subsidence associated with increasing depth and intensity of cumulus convection. Rainfall increases typically cause an overall reduction of specific humidity (q) and relative humidity (RH) in the upper tropospheric levels of the broader scale surrounding convective subsidence regions. This leads to a net enhancement of radiation flux to space due to a lowering of the upper-level emission level. This viewpoint contrasts with the position in GCMs, which suggest that an increase in deep convection will increase upper-level water vapour.

Figure 10: Conceptual model of typical variations of IR, albedo and net (IR + albedo) associated with three different areas of rain and cloud for periods of increased precipitation.

The albedo enhancement over the cloud–rain areas tends to increase the net (IR + albedo) radiation energy to space more than the weak suppression of (IR + albedo) in the clear areas. Near-neutral conditions prevail in the partly cloudy areas. The bottom diagram of Figure 9 illustrates how, in GCMs, Cb convection erroneously increases upper tropospheric moisture. Based on reanalysis data (Table 1, Figure 8) this is not observed in the real atmosphere.

Ocean Overturning Circulation Drives Warming Last Century

A slowing down of the global ocean’s MOC is the likely cause of most of the global warming that has been observed since the latter part of the 19th century.15 I hypothesize that shorter multi-decadal changes in the MOC16 are responsible for the more recent global warming periods between 1910–1940 and 1975–1998 and the global warming hiatus periods between 1945–1975 and 2000–2013.

Figure 12: The effect of strong and weak Atlantic THC. Idealized portrayal of the primary Atlantic Ocean upper ocean currents during strong and weak phases of the thermohaline circulation (THC)

Figure 13 shows the circulation features that typically accompany periods when the MOC is stronger than normal and when it is weaker than normal. In general, a strong MOC is associated with a warmer-than-normal North Atlantic, increased Atlantic hurricane activity, increased blocking action in both the North Atlantic and North Pacific and weaker westerlies in the mid-latitude Southern Hemisphere. There is more upwelling of cold water in the South Pacific and Indian Oceans, and an increase in global rainfall of a few percent occurs. This causes the global surface temperatures to cool. The opposite occurs when the MOC is weaker than normal.

The average strength of the MOC over the last 150 years has likely been below the multimillennium average, and that is the primary reason we have seen this long-term global warming since the late 19th century. The globe appears to be rebounding from the conditions of the Little Ice Age to conditions that were typical of the earlier ‘Medieval’ and ‘Roman’ warm periods.

Summary and Conclusions

The Earth is covered with 71% liquid water. Over the ocean surface, sub-saturated winds blow, forcing continuous surface evaporation. Observations and energy budget analyses indicate that the surface of the globe is losing about 80 W/m2 of energy from the global surface evaporation process. This evaporation energy loss is needed as part of the process of balancing the surface’s absorption of large amounts of incoming solar energy. Variations in the strength of the globe’s hydrologic cycle are the way that the global climate is regulated. The stronger the hydrologic cycle, the more surface evaporation cooling occurs, and greater the globe’s IR flux to space. The globe’s surface cools when the hydrologic cycle is stronger than average and warms when the hydrologic cycle is weaker than normal. The strength of the hydrologic cycle is thus the primary regulator of the globe’s surface temperature. Variations in global precipitation are linked to long-term changes in the MOC (or THC).

I have proposed that any additional warming from an increase in CO2 added to the atmosphere is offset by an increase in surface evaporation and increased precipitation (an increase in the water cycle). My prediction seems to be supported by evidence of upper tropospheric drying since 1979 and the increase in global precipitation seen in reanalysis data. I have shown that the additional heating that may be caused by an increase in CO2 results in a drying, not a moistening, of the upper troposphere, resulting in an increase of outgoing radiation to space, not a decrease as proposed by the most recent application of the greenhouse theory.

Deficiencies in the ability of GCMs to adequately represent variations in global cloudiness, the water cycle, the carbon cycle, long-term changes in deep-ocean circulation, and other important mechanisms that control the climate reduce our confidence in the ability of these models to adequately forecast future global temperatures. It seems that the models do not correctly handle what happens to the added energy from CO2 IR blocking.

Figure 13: Effect of changes in MOC: top, strong MOC; bottom weak MOC. SLP: sea level pressure; SST, sea surface temperature.

Solar variations, sunspots, volcanic eruptions and cosmic ray changes are energy-wise too small to play a significant role in the large energy changes that occur during important multi-decadal and multi-century temperature changes. It is the Earth’s internal fluctuations that are the most important cause of climate and temperature change. These internal fluctuations are driven primarily by deep multi-decadal and multi-century ocean circulation changes, of which naturally varying upper-ocean salinity content is hypothesized to be the primary driving mechanism. Salinity controls ocean density at cold temperatures and at high latitudes where the potential deep-water formation sites of the THC and SAS are located. North Atlantic upper ocean salinity changes are brought about by both multi-decadal and multi-century induced North Atlantic salinity variability.

josh-knobs

 Footnote:

The main point from Bill Gray was nicely summarized in a previous post Earth Climate Layers

The most fundamental of the many fatal mathematical flaws in the IPCC related modelling of atmospheric energy dynamics is to start with the impact of CO2 and assume water vapour as a dependent ‘forcing’.  This has the tail trying to wag the dog. The impact of CO2 should be treated as a perturbation of the water cycle. When this is done, its effect is negligible. — Dr. Dai Davies

climate-onion2

Correcting Flaws in Global Warming Projections

William Mason Gray (1929-2016), pioneering hurricane scientist and forecaster and professor of atmospheric science at Colorado State University.

Thanks to GWPF for publishing posthumously Bill Gray’s understanding of global warming/climate change.  The paper was compiled at his request, completed and now available as Flaws in applying greenhouse warming to Climate Variability This post provides some excerpts in italics with my bolds and some headers.  Readers will learn much from the entire document (title above is link to pdf).

The Fundamental Correction

The critical argument that is made by many in the global climate modeling (GCM) community is that an increase in CO2 warming leads to an increase in atmospheric water vapor, resulting in more warming from the absorption of outgoing infrared radiation (IR) by the water vapor. Water vapor is the most potent greenhouse gas present in the atmosphere in large quantities. Its variability (i.e. global cloudiness) is not handled adequately in GCMs in my view. In contrast to the positive feedback between CO2 and water vapor predicted by the GCMs, it is my hypothesis that there is a negative feedback between CO2 warming and and water vapor. CO2 warming ultimately results in less water vapor (not more) in the upper troposphere. The GCMs therefore predict unrealistic warming of global temperature. I hypothesize that the Earth’s energy balance is regulated by precipitation (primarily via deep cumulonimbus (Cb) convection) and that this precipitation counteracts warming due to CO2.

Figure 14: Global surface temperature change since 1880. The dotted blue and dotted red lines illustrate how much error one would have made by extrapolating a multi-decadal cooling or warming trend beyond a typical 25-35 year period. Note the recent 1975-2000 warming trend has not continued, and the global temperature remained relatively constant until 2014.

Projected Climate Changes from Rising CO2 Not Observed

Continuous measurements of atmospheric CO2, which were first made at Mauna Loa, Hawaii in 1958, show that atmospheric concentrations of CO2 have risen since that time. The warming influence of CO2 increases with the natural logarithm (ln) of the atmosphere’s CO2 concentration. With CO2 concentrations now exceeding 400 parts per million by volume (ppm), the Earth’s atmosphere is slightly more than halfway to containing double the 280 ppm CO2 amounts in 1860 (at the beginning of the Industrial Revolution).∗

We have not observed the global climate change we would have expected to take place, given this increase in CO2. Assuming that there has been at least an average of 1 W/m2 CO2 blockage of IR energy to space over the last 50 years and that this energy imbalance has been allowed to independently accumulate and cause climate change over this period with no compensating response, it would have had the potential to bring about changes in any one of the following global conditions:

  • Warm the atmosphere by 180◦C if all CO2 energy gain was utilized for this purpose – actual warming over this period has been about 0.5◦C, or many hundreds of times less.
  • Warm the top 100 meters of the globe’s oceans by over 5◦C – actual warming over this period has been about 0.5◦C, or 10 or more times less.
  • Melt sufficient land-based snow and ice as to raise the global sea level by about 6.4 m. The actual rise has been about 8–9 cm, or 60–70 times less. The gradual rise of sea level has been only slightly greater over the last ~50 years (1965–2015) than it has been over the previous two ~50-year periods of 1915–1965 and 1865–1915, when atmospheric CO2 gain was much less.
  • Increase global rainfall over the past ~50-year period by 60 cm.

Earth Climate System Compensates for CO2

If CO2 gain is the only influence on climate variability, large and important counterbalancing influences must have occurred over the last 50 years in order to negate most of the climate change expected from CO2’s energy addition. Similarly, this hypothesized CO2-induced energy gain of 1 W/m2 over 50 years must have stimulated a compensating response that acted to largely negate energy gains from the increase in CO2.

The continuous balancing of global average in-and-out net radiation flux is therefore much larger than the radiation flux from anthropogenic CO2. For example, 342 W/m2, the total energy budget, is almost 100 times larger than the amount of radiation blockage expected from a CO2 doubling over 150 years. If all other factors are held constant, a doubling of CO2 requires a warming of the globe of about 1◦C to enhance outward IR flux by 3.7 W/m2 and thus balance the blockage of IR flux to space.

Figure 2: Vertical cross-section of the annual global energy budget. Determined from a combination of satellite-derived radiation measurements and reanalysis data over the period of 1984–2004.

This pure IR energy blocking by CO2 versus compensating temperature increase for radiation equilibrium is unrealistic for the long-term and slow CO2 increases that are occurring. Only half of the blockage of 3.7 W/m2 at the surface should be expected to go into an temperature increase. The other half (about 1.85 W/m2) of the blocked IR energy to space will be compensated by surface energy loss to support enhanced evaporation. This occurs in a similar way to how the Earth’s surface energy budget compensates for half its solar gain of 171 W/m2 by surface-to-air upward water vapor flux due to evaporation.

Assuming that the imposed extra CO2 doubling IR blockage of 3.7 W/m2 is taken up and balanced by the Earth’s surface in the same way as the solar absorption is taken up and balanced, we should expect a direct warming of only ~0.5◦C for a doubling of CO2. The 1◦C expected warming that is commonly accepted incorrectly assumes that all the absorbed IR goes to the balancing outward radiation with no energy going to evaporation.

Consensus Science Exaggerates Humidity and Temperature Effects

A major premise of the GCMs has been their application of the National Academy of Science (NAS) 1979 study3 – often referred to as the Charney Report – which hypothesized that a doubling of atmospheric CO2 would bring about a general warming of the globe’s mean temperature of 1.5–4.5◦C (or an average of ~3.0◦C). These large warming values were based on the report’s assumption that the relative humidity (RH) of the atmosphere remains quasiconstant as the globe’s temperature increases. This assumption was made without any type of cumulus convective cloud model and was based solely on the Clausius–Clapeyron (CC) equation and the assumption that the RH of the air will remain constant during any future CO2-induced temperature changes. If RH remains constant as atmospheric temperature increases, then the water vapor content in the atmosphere must rise exponentially.

With constant RH, the water vapor content of the atmosphere rises by about 50% if atmospheric temperature is increased by 5◦C. Upper tropospheric water vapor increases act to raise the atmosphere’s radiation emission level to a higher and thus colder level. This reduces the amount of outgoing IR energy which can escape to space by decreasing T^4.

These model predictions of large upper-level tropospheric moisture increases have persisted in the current generation of GCM forecasts.§ These models significantly overestimate globally-averaged tropospheric and lower stratospheric (0–50,000 feet) temperature trends since 1979 (Figure 7).

Figure 8: Decline in upper tropospheric RH. Annually-averaged 300 mb relative humidity for the tropics (30°S–30°N). From NASA-MERRA2 reanalysis for 1980–2016. Black dotted line is linear trend.

All of these early GCM simulations were destined to give unrealistically large upper-tropospheric water vapor increases for doubling of CO2 blockage of IR energy to space, and as a result large and unrealistic upper tropospheric temperature increases were predicted. In fact, if data from NASA-MERRA24 and NCEP/NCAR5 can be believed, upper tropospheric RH has actually been declining since 1980 as shown in Figure 8. The top part of Table 1 shows temperature and humidity differences between very wet and dry years in the tropics since 1948; in the wettest years, precipitation was 3.9% higher than in the driest ones. Clearly, when it rains more in the tropics, relative and specific humidity decrease. A similar decrease is seen when differencing 1995–2004 from 1985–1994, periods for which the equivalent precipitation difference is 2%. Such a decrease in RH would lead to a decrease in the height of the radiation emission level and an increase in IR to space.

The Earth’s natural thermostat – evaporation and precipitation

What has prevented this extra CO2-induced energy input of the last 50 years from being realized in more climate warming than has actually occurred? Why was there recently a pause in global warming, lasting for about 15 years?  The compensating influence that prevents the predicted CO2-induced warming is enhanced global surface evaporation and increased precipitation.

Annual average global evaporational cooling is about 80 W/m2 or about 2.8 mm per day.  A little more than 1% extra global average evaporation per year would amount to 1.3 cm per year or 65 cm of extra evaporation integrated over the last 50 years. This is the only way that such a CO2-induced , 1 W/m2 IR energy gain sustained over 50 years could occur without a significant alteration of globally-averaged surface temperature. This hypothesized increase in global surface evaporation as a response to CO2-forced energy gain should not be considered unusual. All geophysical systems attempt to adapt to imposed energy forcings by developing responses that counter the imposed action. In analysing the Earth’s radiation budget, it is incorrect to simply add or subtract energy sources or sinks to the global system and expect the resulting global temperatures to proportionally change. This is because the majority of CO2-induced energy gains will not go into warming the atmosphere. Various amounts of CO2-forced energy will go into ocean surface storage or into ocean energy gain for increased surface evaporation. Therefore a significant part of the CO2 buildup (~75%) will bring about the phase change of surface liquid water to atmospheric water vapour. The energy for this phase change must come from the surface water, with an expenditure of around 580 calories of energy for every gram of liquid that is converted into vapour. The surface water must thus undergo a cooling to accomplish this phase change.

Therefore, increases in anthropogenic CO2 have brought about a small (about 0.8%) speeding up of the globe’s hydrologic cycle, leading to more precipitation, and to relatively little global temperature increase. Therefore, greenhouse gases are indeed playing an important role in altering the globe’s climate, but they are doing so primarily by increasing the speed of the hydrologic cycle as opposed to increasing global temperature.

Figure 9: Two contrasting views of the effects of how the continuous intensification of deep
cumulus convection would act to alter radiation flux to space.
The top (bottom) diagram represents a net increase (decrease) in radiation to space

Tropical Clouds Energy Control Mechanism

It is my hypothesis that the increase in global precipitation primarily arises from an increase in deep tropical cumulonimbus (Cb) convection. The typical enhancement of rainfall and updraft motion in these areas together act to increase the return flow mass subsidence in the surrounding broader clear and partly cloudy regions. The upper diagram in Figure 9 illustrates the increasing extra mass flow return subsidence associated with increasing depth and intensity of cumulus convection. Rainfall increases typically cause an overall reduction of specific humidity (q) and relative humidity (RH) in the upper tropospheric levels of the broader scale surrounding convective subsidence regions. This leads to a net enhancement of radiation flux to space due to a lowering of the upper-level emission level. This viewpoint contrasts with the position in GCMs, which suggest that an increase in deep convection will increase upper-level water vapour.

Figure 10: Conceptual model of typical variations of IR, albedo and net (IR + albedo) associated with three different areas of rain and cloud for periods of increased precipitation.

The albedo enhancement over the cloud–rain areas tends to increase the net (IR + albedo) radiation energy to space more than the weak suppression of (IR + albedo) in the clear areas. Near-neutral conditions prevail in the partly cloudy areas. The bottom diagram of Figure 9 illustrates how, in GCMs, Cb convection erroneously increases upper tropospheric moisture. Based on reanalysis data (Table 1, Figure 8) this is not observed in the real atmosphere.

Ocean Overturning Circulation Drives Warming Last Century

A slowing down of the global ocean’s MOC is the likely cause of most of the global warming that has been observed since the latter part of the 19th century.15 I hypothesize that shorter multi-decadal changes in the MOC16 are responsible for the more recent global warming periods between 1910–1940 and 1975–1998 and the global warming hiatus periods between 1945–1975 and 2000–2013.

Figure 12: The effect of strong and weak Atlantic THC. Idealized portrayal of the primary Atlantic Ocean upper ocean currents during strong and weak phases of the thermohaline circulation (THC)

Figure 13 shows the circulation features that typically accompany periods when the MOC is stronger than normal and when it is weaker than normal. In general, a strong MOC is associated with a warmer-than-normal North Atlantic, increased Atlantic hurricane activity, increased blocking action in both the North Atlantic and North Pacific and weaker westerlies in the mid-latitude Southern Hemisphere. There is more upwelling of cold water in the South Pacific and Indian Oceans, and an increase in global rainfall of a few percent occurs. This causes the global surface temperatures to cool. The opposite occurs when the MOC is weaker than normal.

The average strength of the MOC over the last 150 years has likely been below the multimillennium average, and that is the primary reason we have seen this long-term global warming since the late 19th century. The globe appears to be rebounding from the conditions of the Little Ice Age to conditions that were typical of the earlier ‘Medieval’ and ‘Roman’ warm periods.

Summary and Conclusions

The Earth is covered with 71% liquid water. Over the ocean surface, sub-saturated winds blow, forcing continuous surface evaporation. Observations and energy budget analyses indicate that the surface of the globe is losing about 80 W/m2 of energy from the global surface evaporation process. This evaporation energy loss is needed as part of the process of balancing the surface’s absorption of large amounts of incoming solar energy. Variations in the strength of the globe’s hydrologic cycle are the way that the global climate is regulated. The stronger the hydrologic cycle, the more surface evaporation cooling occurs, and greater the globe’s IR flux to space. The globe’s surface cools when the hydrologic cycle is stronger than average and warms when the hydrologic cycle is weaker than normal. The strength of the hydrologic cycle is thus the primary regulator of the globe’s surface temperature. Variations in global precipitation are linked to long-term changes in the MOC (or THC).

I have proposed that any additional warming from an increase in CO2 added to the atmosphere is offset by an increase in surface evaporation and increased precipitation (an increase in the water cycle). My prediction seems to be supported by evidence of upper tropospheric drying since 1979 and the increase in global precipitation seen in reanalysis data. I have shown that the additional heating that may be caused by an increase in CO2 results in a drying, not a moistening, of the upper troposphere, resulting in an increase of outgoing radiation to space, not a decrease as proposed by the most recent application of the greenhouse theory.

Deficiencies in the ability of GCMs to adequately represent variations in global cloudiness, the water cycle, the carbon cycle, long-term changes in deep-ocean circulation, and other important mechanisms that control the climate reduce our confidence in the ability of these models to adequately forecast future global temperatures. It seems that the models do not correctly handle what happens to the added energy from CO2 IR blocking.

Figure 13: Effect of changes in MOC: top, strong MOC; bottom weak MOC. SLP: sea level pressure; SST, sea surface temperature.

Solar variations, sunspots, volcanic eruptions and cosmic ray changes are energy-wise too small to play a significant role in the large energy changes that occur during important multi-decadal and multi-century temperature changes. It is the Earth’s internal fluctuations that are the most important cause of climate and temperature change. These internal fluctuations are driven primarily by deep multi-decadal and multi-century ocean circulation changes, of which naturally varying upper-ocean salinity content is hypothesized to be the primary driving mechanism. Salinity controls ocean density at cold temperatures and at high latitudes where the potential deep-water formation sites of the THC and SAS are located. North Atlantic upper ocean salinity changes are brought about by both multi-decadal and multi-century induced North Atlantic salinity variability.

 Footnote:

The main point from Bill Gray was nicely summarized in a previous post Earth Climate Layers

The most fundamental of the many fatal mathematical flaws in the IPCC related modelling of atmospheric energy dynamics is to start with the impact of CO2 and assume water vapour as a dependent ‘forcing’.  This has the tail trying to wag the dog. The impact of CO2 should be treated as a perturbation of the water cycle. When this is done, its effect is negligible. — Dr. Dai Davies

climate-onion2

Courtroom Climate Science

atmprofile

This is an update to a previous post on the climate science brief submitted to Judge Alsup’s tutorial.  In a recent article, Dr. Fred Singer draws some implications from one of the many points in the brief written by Happer, Koonin and Lindzen.  The Singer essay is Does the Greenhouse Gas CO2 cool the climate? in the American Thinker.

First the pertinent paragraph from the legal brief.  In responding to Judge Alsup’s eighth question the scientists said this (my bolds):

On average, the absorption rate of solar radiation by the Earth’s surface and atmosphere is equal to emission rate of thermal infrared radiation to space. Much of the radiation to space does not come from the surface but from greenhouse gases and clouds in the lower atmosphere, where the temperature is usually colder than the surface temperature, as shown in the figure on the previous page. The thermal radiation originates from an “escape altitude” where there is so little absorption from the overlying atmosphere that most (say half) of the radiation can escape to space with no further absorption or scattering. Adding greenhouse gases can warm the Earth’s surface by increasing the escape altitude. To maintain the same cooling rate to space, the temperature of the entire troposphere, and the surface, would have to increase to make the effective temperature at the new escape altitude the same as at the original escape altitude. For greenhouse warming to occur, a temperature profile that cools with increasing altitude is required.

Over most of the CO2 absorption band (between about 580 cm-1 and 750 cm-1 ) the escape altitude is the nearly isothermal lower stratosphere shown in the first figure. The narrow spike of radiation at about 667 cm-1 in the center of the CO2 band escapes from an altitude of around 40 km (upper stratosphere), where it is considerably warmer than the lower stratosphere due heating by solar ultraviolet light which is absorbed by ozone, O3. Only at the edges of the CO2 band (near 580 cm-1 and 750 cm-1 ) is the escape altitude in the troposphere where it could have some effect on the surface temperature. Water vapor, H2O, has emission altitudes in the troposphere over most of its absorption bands. This is mainly because water vapor, unlike CO2, is not well mixed but mostly confined to the troposphere.

Dr. Singer picks up on this and comments (my bolds):

“Greenhouse gas” only means that CO2 absorbs some infrared (IR) radiation; it does not guarantee climate warming.

In fact, the outcome depends mostly on atmospheric structure, measured by balloon-borne radiosondes. It is expressed by the so-called atmospheric lapse rate (ALR), defined as change in atmospheric temperature with altitude.[ii] [Note that “lapse rate” has nothing to do with back-sliding alcoholics and smokers.]

Physicists who have examined our counter-intuitive hypothesis, all agree with the science — albeit somewhat reluctantly. Such is the power of group-think that even experts, with some exception, find the idea that CO2 might cool the climate difficult to accept.

STRATOSPHERE ALR is positive Temperature increases
with altitude
TROPOPAUSE ALR is zero Temperature is constant
TROPOSPHERE ALR is negative Temperature decreases
with altitude

The ALR is generally negative in the troposphere[iii] as much as [minus] -6.5 degree C per km of altitude. [The troposphere is the lowest atmospheric layer, from zero up to about 50,000 foot altitude.]

ALR goes through zero in the tropopause region, the layer that separates the troposphere from the overlying stratosphere. The ALR turns positive in the stratosphere, just above [see schematic nearby.[iv] [The warming of the stratosphere is produced by absorption of energy by stratospheric ozone.]

The key result

Adding a tiny increment of CO2 raises slightly the “effective” altitude for emitting Outgoing Long-wave (OLR), the Radiation (IR), going out to space from a CO2 molecule.

Because of the reversal in the atmospheric temperature structure, OLR is:

1. of lower energy than normal if the effective altitude remains in the troposphere; and

2. a bit higher than normal if this effective altitude is in the stratosphere.

In case 2., the stratospheric CO2 emission “borrows” some energy from the surface emission — hence “cooling” the surface.

The previous post Cal Climate Tutorial: The Meat appears below as background.

An overview of a submission by Professors Happer, Koonin and Lindzen was in Climate Tutorial for Judge Alsup

This post goes into the meat and potatoes of that submission with excerpts from Section II: Answers to specific questions (my bolds)

Question 1: What caused the various ice ages (including the “little ice age” and prolonged cool periods) and what caused the ice to melt? When they melted, by how much did sea level rise?

The discussion of the major ice ages of the past 700 thousand years is distinct from the discussion of the “little ice age.” The former refers to the growth of massive ice sheets (a mile or two thick) where periods of immense ice growth occurred, lasting approximately eighty thousand years, followed by warm interglacials lasting on the order of twenty thousand years. By contrast, the “little ice age” was a relatively brief period (about four hundred years) of relatively cool temperatures accompanied by the growth of alpine glaciers over much of the earth.

Tutorial 1

The last glacial episode ended somewhat irregularly. Ice coverage reached its maximum extent about eighteen thousand years ago. Melting occurred between about twenty thousand years ago and thirteen thousand years ago, and then there was a strong cooling (Younger Dryas) which ended about 11,700 years ago. Between twenty thousand years ago and six thousand years ago, there was a dramatic increase in sea level of about 120 meters followed by more gradual increase over the following several thousand years. Since the end of the “little ice age,” there has been steady increase in sea-level of about 6 inches per century.

slide12

As to the cause of the “little ice age,” this is still a matter of uncertainty. There was a long hiatus in solar activity that may have played a role, but on these relatively short time scales one can’t exclude natural internal variability. It must be emphasized that the surface of the earth is never in equilibrium with net incident solar radiation because the oceans are always carrying heat to and from the surface, and the motion systems responsible have time scales ranging from years (for example ENSO) to millennia.

The claim that orbital variability requires a boost from CO2 to drive ice ages comes from the implausible notion that what matters is the orbital variations in the global average insolation (which are, in fact, quite small) rather than the large forcing represented by the Milankovitch parameter. This situation is very different than in the recent and more modest shorter-term warming, where natural variability makes the role of CO2 much more difficult to determine.

Question 2: What is the molecular difference by which CO2 absorbs infrared radiation but oxygen and nitrogen do not?

Molecules like CO2, H2O, CO or NO are called a greenhouse-gas molecules, because they can efficiently absorb or emit infrared radiation, but they are nearly transparent to sunlight. Molecules like O2 and N2 are also nearly transparent to sunlight, but since they do not absorb or emit thermal infrared radiation very well, they are not greenhouse gases. The most important greenhouse gas, by far, is water vapor. Water molecules, H2O, are permanently bent and have large electric dipole moments.

Question 3: What is mechanism by which infrared radiation trapped by CO2 in the atmosphere is turned into heat and finds its way back to sea level?

Unscattered infrared radiation is very good at transmitting energy because it moves at the speed of light. But the energy per unit volume stored by the thermal radiation in the Earth’s atmosphere is completely negligible compared to the internal energy of the air molecules.

Although CO2 molecules radiate very slowly, there are so many CO2 molecules that they produce lots of radiation, and some of this radiation reaches sea level. The figure following shows downwelling radiation measured at the island of Nauru in the Tropical Western Pacific Ocean, and at colder Point Barrow, Alaska, on the shore of the Arctic Ocean.

So the answer to the last part of the question, “What is the mechanism by which … heat … finds its way back to sea level?” is that the heat is radiated to the ground by molecules at various altitudes, where there is usually a range of different temperatures. The emission altitude is the height from which radiation could reach the surface without much absorption, say 50% absorption. For strongly absorbed frequencies, the radiation reaching the ground comes from low-altitude molecules, only a few meters above ground level for the 667 cm-1 frequency at the center of the CO2 band. More weakly absorbed frequencies are radiated from higher altitudes where the temperature is usually colder than that of the surface. But occasionally, as the data from Point Barrow show, higher-altitude air can be warmer than the surface.

Closely related to Question 3 is how heat from the absorption of sunlight by the surface gets back to space to avoid a steadily increasing surface temperature. As one might surmise from the figure, at Narau there is so much absorption from CO2 and by water vapor, H2O, that most daytime heat transfer near the surface is by convection, not by radiation. Especially important is moist convection, where the water vapor in rising moist air releases its latent heat to form clouds. The clouds have a major effect on radiative heat transfer. Cooled, drier, subsiding air completes the convection circuit. Minor changes of convection and cloudiness can have a bigger effect on the surface temperature than large changes in CO2 concentrations.

Question 4: Does CO2 in the atmosphere reflect any sunlight back into space, such that the reflected sunlight never penetrates the atmosphere in the first place?

The short answer to this question is “No”, but it raises some interesting issues that we discuss below.

Molecules can either scatter or absorb radiation. CO2 molecules are good absorbers of thermal infrared radiation, but they scatter almost none. Infrared radiant energy absorbed by a CO2 molecule is converted to internal vibrational and rotational energy. This internal energy is quickly lost in collisions with the N2 and O2 molecules that make up most of the atmosphere. The collision rates, billions per second, are much too fast to allow the CO2 molecules to reradiate the absorbed energy, which takes about a second. CO2 molecules in the atmosphere do emit thermal infrared radiation continuously, but the energy is almost always provided by collisions with N2 and O2 molecules, not by previously absorbed radiation. The molecules “glow in the dark” with thermal infrared radiation.

H2O CO2 absorption spectrums

The figure shows that water vapor is by far the most important absorber. It can absorb both thermal infrared radiation from the Earth and shorter-wave radiation from the Sun. Water vapor and its condensates, clouds of liquid or solid water (ice), dominate radiative heat transfer in the Earth’s atmosphere; CO2 is of secondary importance.

If Question 4 were “Do clouds in the atmosphere reflect any sunlight back into space, such that the reflected sunlight never penetrates the atmosphere in the first place?” the answer would be “Yes”. It is common knowledge that low clouds on a sunny day shade and cool the surface of the Earth by scattering the sunlight back to space before it can be absorbed and converted to heat at the surface.

The figure shows that very little thermal radiation from the surface can reach the top of the atmosphere without absorption, even if there are no clouds. But some of the surface radiation is replaced by molecular radiation emitted by greenhouse molecules or cloud tops at sufficiently high altitudes that the there are no longer enough higher-altitude greenhouse molecules or clouds to appreciably attenuate the radiation before it escapes to space. Since the replacement radiation comes from colder, higher altitudes, it is less intense and does not reject as much heat to space as the warmer surface could have without greenhousegas absorption.

As implied by the figure, sunlight contains some thermal infrared energy that can be absorbed by CO2. But only about 5% of sunlight has wavelengths longer than 3 micrometers where the strongest absorption bands of CO2 are located. The Sun is so hot, that most of its radiation is at visible and near-visible wavelengths, where CO2 has no absorption bands.

Question 5: Apart from CO2, what happens to the collective heat from tail pipe exhausts, engine radiators, and all other heat from combustion of fossil fuels? How, if at all, does this collective heat contribute to warming of the atmosphere?

After that energy is used for heat, mobility, and electricity, the Second Law of Thermodynamics guarantees that virtually all of it ends up as heat in the climate system, ultimately to be radiated into space along with the earth’s natural IR emissions. [A very small fraction winds up as visible light that escapes directly to space through the transparent atmosphere, but even that ultimately winds up as heat somewhere “out there.”]

How much does this anthropogenic heat affect the climate? There are local effects where energy use is concentrated, for example in cities and near power plants. But globally, the effects are very small. To see that, convert the global annual energy consumption of 13.3 Gtoe (Gigatons of oil equivalent) to 5.6 × 1020 joules. Dividing that by the 3.2 × 107 seconds in a year gives a global power consumption of 1.75 × 1013 Watts. Spreading that over the earth’s surface area of 5.1 × 1014 m2 results in an anthropogenic heat flux of 0.03 W/m2 . This is some four orders of magnitude smaller than the natural heat fluxes of the climate system, and some two orders of magnitude smaller than the anthropogenic radiative forcing.

Question 6: In grade school many of us were taught that humans exhale CO2 but plants absorb CO2 and return oxygen to the air (keeping the carbon fiber). Is this still valid? If so why hasn’t plant life turned the higher levels of CO2 back into oxygen? Given the increase in population on earth (four billion), is human respiration a contributing factor to the buildup of CO2?

If all of the CO2 produced by current combustion of fossil fuels remained in the atmosphere, the level would increase by about 4 ppm per year, substantially more than the observed rate of around 2.5 ppm per year, as seen in the figure above. Some of the anthropogenic CO2 emissions are being sequestered on land or in the oceans.

high_resolution1

There is evidence that primary photosynthetic productivity has increased somewhat over the past half century, perhaps due to more CO2 in the atmosphere. For example, the summerwinter swings like those in the figure above are increasing in amplitude. Other evidence for modestly increasing primary productivity includes the pronounced “greening” of the Earth that has been observe by satellites. An example is the map above, which shows a general increase in vegetation cover over the past three decades.

The primary productivity estimate mentioned above would also correspond to an increase of the oxygen fraction of the air by 50 ppm, but since the oxygen fraction of the air is very high (209,500 ppm), the relative increase would be small and hard to detect. Also much of the oxygen is used up by respiration.

The average human exhales about 1 kg of CO2 per day, so the 7 billion humans that populate the Earth today exhale about 2.5 x 109 tons of CO2 per year, a little less than 1% of that is needed to support the primary productivity of photosynthesis and only about 6% of the CO2 “pollution” resulting from the burning of fossil fuels. However, unlike fossil fuel emissions, these human (or more generally, biological) emissions do not accumulate in the atmosphere, since the carbon in food ultimately comes from the atmosphere in the first place.

Question 7: What are the main sources of CO2 that account for the incremental buildup of CO2 in the atmosphere?

The CO2 in the atmosphere is but one reservoir within the global carbon cycle, whose stocks and flows are illustrated by Figure 6.1 from IPCC AR5 WG1:

There is a nearly-balanced annual exchange of some 200 PgC between the atmosphere and the earth’s surface (~80 Pg land and ~120 Pg ocean); the atmospheric stock of 829 Pg therefore “turns over” in about four years.

Human activities currently add 8.9 PgC each year to these closely coupled reservoirs (7.8 from fossil fuels and cement production, 1.1 from land use changes such as deforestation). About half of that is absorbed into the surface, while the balance (airborne fraction) accumulates in the atmosphere because of its multicentury lifetime there. Other reservoirs such as the intermediate and deep ocean are less closely coupled to the surface-atmosphere system.

Much of the natural emission of CO2 stems from the decay of organic matter on land, a process that depends strongly on temperature and moisture. And much CO2 is absorbed and released from the oceans, which are estimated to contain about 50 times as much CO2 as the atmosphere. In the oceans CO2 is stored mostly as bicarbonate (HCO3 – ) and carbonate (CO3 – – ) ions. Without the dissolved CO2, the mildly alkaline ocean with a pH of about 8 would be very alkaline with a pH of about 11.3 (like deadly household ammonia) because of the strong natural alkalinity.

Only once in the geological past, the Permian period about 300 million years ago, have atmospheric CO2 levels been as low as now. Life flourished abundantly during the geological past when CO2 levels were five or ten times higher than those today.

Question 8: What are the main sources of heat that account for the incremental rise in temperature on earth?

The only important primary heat source for the Earth’s surface is the Sun. But the heat can be stored in the oceans for long periods of time, even centuries. Variable ocean currents can release more or less of this stored heat episodically, leading to episodic rises (and falls) of the Earth’s surface temperature.

Incremental changes of the surface temperature anomaly can be traced back to two causes: (1) changes in the surface heating rate; (2) changes in the resistance of heat flow to space. Quasi periodic El Nino episodes are examples of the former. During an El Nino year, easterly trade winds weaken and very warm deep water, normally blown toward the coasts of Indonesia and Australia, floats to the surface and spreads eastward to replace previously cool surface waters off of South America. The average temperature anomaly can increase by 1 C or more because of the increased release of heat from the ocean. The heat source for the El Nino is solar energy that has accumulated beneath the ocean surface for several years before being released.

On average, the absorption rate of solar radiation by the Earth’s surface and atmosphere is equal to emission rate of thermal infrared radiation to space. Much of the radiation to space does not come from the surface but from greenhouse gases and clouds in the lower atmosphere, where the temperature is usually colder than the surface temperature, as shown in the figure on the previous page. The thermal radiation originates from an “escape altitude” where there is so little absorption from the overlying atmosphere that most (say half) of the radiation can escape to space with no further absorption or scattering. Adding greenhouse gases can warm the Earth’s surface by increasing the escape altitude. To maintain the same cooling rate to space, the temperature of the entire troposphere, and the surface, would have to increase to make the effective temperature at the new escape altitude the same as at the original escape altitude. For greenhouse warming to occur, a temperature profile that cools with increasing altitude is required.

Over most of the CO2 absorption band (between about 580 cm-1 and 750 cm-1 ) the escape altitude is the nearly isothermal lower stratosphere shown in the first figure. The narrow spike of radiation at about 667 cm-1 in the center of the CO2 band escapes from an altitude of around 40 km (upper stratosphere), where it is considerably warmer than the lower stratosphere due heating by solar ultraviolet light which is absorbed by ozone, O3. Only at the edges of the CO2 band (near 580 cm-1 and 750 cm-1 ) is the escape altitude in the troposphere where it could have some effect on the surface temperature. Water vapor, H2O, has emission altitudes in the troposphere over most of its absorption bands. This is mainly because water vapor, unlike CO2, is not well mixed but mostly confined to the troposphere.

Summary

To summarize this overview, the historical and geological record suggests recent changes in the climate over the past century are within the bounds of natural variability. Human influences on the climate (largely the accumulation of CO2 from fossil fuel combustion) are a physically small (1%) effect on a complex, chaotic, multicomponent and multiscale system. Unfortunately, the data and our understanding are insufficient to usefully quantify the climate’s response to human influences. However, even as human influences have quadrupled since 1950, severe weather phenomena and sea level rise show no significant trends attributable to them. Projections of future climate and weather events rely on models demonstrably unfit for the purpose. As a result, rising levels of CO2 do not obviously pose an immediate, let alone imminent, threat to the earth’s climate.

Full text of submission is here

Our Goldilocks Climate

haze_archean_2_cropped_2In the fairy tale, Goldilocks entered the three bears’ house to find one bowl of soup too hot, another too cold, and one just right for her to eat. A new study of our planetary history suggests that since its beginning our climate has been self-regulating to avoid extremes, with much less variability in temperature and oceanic pH than previously thought.

An overview of the finding comes from an article in Phys.org and is followed by excerpts from the paper itself published in PNAS.

Introductory Comments from Phys.org article Earth’s stable temperature past suggests other planets could also sustain life  April 2, 2018, University of Washington. Excerpts with my bolds.

Theories about the early days of our planet’s history vary wildly. Some studies have painted the picture of a snowball Earth, when much of its surface was frozen. Other theories have included periods that would be inhospitably hot for most current lifeforms to survive.

New research from the University of Washington suggests a milder youth for our planet. An analysis of temperature through early Earth’s history, published the week of April 2 in the Proceedings of the National Academy of Sciences, supports more moderate average temperatures throughout the billions of years when life slowly emerged on Earth.

“Our results show that Earth has had a moderate temperature through virtually all of its history, and that is attributable to weathering feedbacks—they do a good job at maintaining a habitable climate,” said first author Joshua Krissansen-Totton, a UW doctoral student in Earth and space sciences.

To create their estimate, the researchers took the most recent understanding for how rocks, oceans, and air temperature interact, and put that into a computer simulation of Earth’s temperature over the past 4 billion years. Their calculations included the most recent information for how seafloor weathering occurs on geologic timescales, and under different conditions.

Seafloor weathering was more important for regulating temperature of the early Earth because there was less continental landmass at that time, the Earth’s interior was even hotter, and the seafloor crust was spreading faster, so that was providing more crust to be weathered,” Krissansen-Totton said.

The paper is by Joshua Krissansen-Totton el al., Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model PNAS (2018). Excerpts with my bolds.

The existence of a negative feedback to balance the carbon cycle on million-year timescales is undisputed. Without it, atmospheric CO2 would be depleted, leading to a runaway icehouse, or would accumulate to excessive levels (34). However, the relative importance of continental and seafloor weathering in providing this negative feedback, and the overall effectiveness of these climate-stabilizing and pH-buffering feedbacks on the early Earth are unknown.

In this study, we apply a geological carbon cycle model with ocean chemistry to the entirety of Earth history. The inclusion of ocean carbon chemistry enables us to model the evolution of ocean pH and realistically capture the pH-dependent and temperature-dependent kinetics of seafloor weathering. This is a significant improvement on previous geological carbon cycle models (e.g., refs. 12 and 35) that omit ocean chemistry and instead adopt an arbitrary power-law dependence on pCO2 for seafloor weathering which, as we show, overestimates CO2 drawdown on the early Earth. By coupling seafloor weathering to Earth’s climate and the geological carbon cycle, we calculate self-consistent histories of Earth’s climate and pH evolution, and evaluate the relative importance of continental and seafloor weathering through time. The pH evolution we calculate is therefore more robust than that of Halevy and Bachan (29) because, unlike their model, we do not prescribe pCO2 and temperature histories.

The climate and ocean pH of the early Earth are important for understanding the origin and early evolution of life. However, estimates of early climate range from below freezing to over 70 °C, and ocean pH estimates span from strongly acidic to alkaline. To better constrain environmental conditions, we applied a self-consistent geological carbon cycle model to the last 4 billion years. The model predicts a temperate (0–50 °C) climate and circumneutral ocean pH throughout the Precambrian due to stabilizing feedbacks from continental and seafloor weathering. These environmental conditions under which life emerged and diversified were akin to the modern Earth. Similar stabilizing feedbacks on climate and ocean pH may operate on earthlike exoplanets, implying life elsewhere could emerge in comparable environments.

Schematic of carbon cycle model used in this study. Carbon fluxes (Tmol C y−1) are denoted by solid green arrows, and alkalinity fluxes (Tmol eq y−1) are denoted by red dashed arrows. The fluxes into/out of the atmosphere–ocean system are outgassing, Fout, silicate weathering, Fsil, carbonate weathering, Fcarb, and marine carbonate precipitation, Pocean. The fluxes into/out of the pore space are basalt dissolution, Fdiss, and pore-space carbonate precipitation, Ppore. Alkalinity fluxes are multiplied by 2 because the uptake or release of one mole of carbon as carbonate is balanced by a cation with a 2+ charge (typically Ca2+). A constant mixing flux, J (kg y−1), exchanges carbon and alkalinity between the atmosphere–ocean system and pore space.

The dissolution of basalt in the seafloor is dependent on the spreading rate, pore-space pH, and pore-space temperature (SI Appendix A). This formulation is based on the validated parameterization in ref. 36. Pore-space temperatures are a function of climate and geothermal heat flow. Empirical data and fully coupled global climate models reveal a linear relationship between deep ocean temperature and surface climate (36). Equations relating pore-space temperature, deep ocean temperature, and sediment thickness are provided in SI Appendix A.

Carbon leaves the atmosphere–ocean system through carbonate precipitation in the ocean and pore space of the oceanic crust. At each time step, the carbon abundances and alkalinities are used to calculate the carbon speciation, atmospheric pCO2, and saturation state assuming chemical equilibrium. Saturation states are then used to calculate carbonate precipitation fluxes (SI Appendix A). We allow calcium (Ca) abundance to evolve with alkalinity, effectively assuming no processes are affecting Ca abundances other than carbonate and silicate weathering, seafloor dissolution, and carbonate precipitation. The consequences of this simplification are explored in the sensitivity analysis in SI Appendix C. We do not track organic carbon burial because organic burial only constitutes 10–30% of total carbon burial for the vast majority of Earth history (40), and so the inorganic carbon cycle is the primary control.

We conclude that current best knowledge of Earth’s geologic carbon cycle precludes a hot Archean. Our results are insensitive to assumptions about ocean chemistry, internal evolution, and weathering parameterizations, so a hot early Earth would require some fundamental error in current understanding of the carbon cycle. Increasing the biotic enhancement of weathering by several orders of magnitude as proposed by Schwartzman (60) does not produce a hot Archean because this is mathematically equivalent to zeroing out the continental weathering flux (Fig. 4). In this case the temperature-dependent seafloor weathering feedback buffers the climate of the Earth to moderate temperatures (SI Appendix, Fig. S14). Dramatic temperature increases (or decreases) due to albedo changes also do not change our conclusions due to the buffering effect of the carbon cycle (see above). If both continental and seafloor weathering become supply limited (e.g., refs. 49 and 61), then temperatures could easily exceed 50 °C. However, in this case the carbon cycle would be out of balance, leading to excessive pCO2 accumulation within a few hundred million years unless buffered by some other, unknown feedback.

The only way to produce Archean climates below 0 °C in our model is to assume the Archean outgassing flux was 1–5× lower than the modern flux (SI Appendix, Fig. S12). However, dramatically lowered Archean outgassing fluxes contradict known outgassing proxies and probably require both a stagnant lid tectonic regime and a mantle more reduced than zircon data suggest, which lowers the portion of outgassed CO2 (SI Appendix C). Moreover, even when outgassing is low, frozen climates are not guaranteed (SI Appendix, Fig. S12).

We observe that modeled temperatures are relatively constant throughout Earth history, with Archean temperatures ranging from 271 to 314 K. The combination of continental and seafloor weathering efficiently buffers climate against changes in luminosity, outgassing, and biological evolution. This temperature history is broadly consistent with glacial constraints and recent isotope proxies (Fig. 3D). The continental weathering buffer dominates over the seafloor weathering buffer for most of Earth history, but in the Archean the two carbon sinks are comparable (SI Appendix, Fig. S1). Indeed, if seafloor weathering were artificially held constant, then continental weathering alone may be unable to efficiently buffer the climate of the early Earth—the temperature distribution at 4.0 Ga extends to 370 K, and the atmospheric pCO2 distribution extends to 7 bar (SI Appendix, Fig. S3).

In our nominal model, the median Archean surface temperature is slightly higher than modern surface temperatures. If solar evolution were the only driver of the carbon cycle, then Archean temperatures would necessarily be cooler than modern temperatures; weathering feedbacks can mitigate this cooling but not produce warming. Warmer Archean climates are possible because elevated internal heat flow, lower continental land fraction, and lessened biological enhancement of weathering all act to warm to Precambrian climate. These three factors produce a comparable warming effect (SI Appendix, Fig. S17A and Appendix C), although the magnitude of each is highly uncertain and so temperate Archean temperatures cannot be uniquely attributed to any one variable.

Conclusions

The early Earth was probably temperate. Continental and seafloor weathering buffer Archean surface temperatures to 0–50 °C. This result holds for a broad range of assumptions about the evolution of internal heat flow, crustal production, spreading rates, and the biotic enhancement of continental weathering. Even in extreme scenarios with negligible subaerial Archean land and high methane abundances, a hot Archean (>50 °C) is unlikely. Sub-0 °C climates are also unlikely unless the Archean outgassing flux was unrealistically lower than the modern flux.

The seafloor weathering feedback is important, but less dominant than previously assumed. Consequently, the early Earth would not have been in a snowball state due to pCO2 drawdown from seafloor weathering. In principle, little to no methane is required to maintain a habitable surface climate, although methane should be expected in the anoxic Archean atmosphere once methanogenesis evolved (ref. 62, chap. 11).

Ignoring transient excursions, the pH of Earth’s ocean has evolved monotonically from 6.6+0.6−0.4 at 4.0 Ga (2σ) to 7.0+0.7−0.5 at 2.5 Ga (2σ), and 8.2 in the modern ocean. This evolution is robust to assumptions about ocean chemistry, internal heat flow, and other carbon cycle parameterizations. Consequently, similar feedbacks may control ocean pH and climate on other Earthlike planets with basaltic seafloors and silicate continents, suggesting that life elsewhere could emerge in comparable environments to those on our early planet.

A Third Brief to Climate Tutorial

I just found out, thanks to Francis Menton, that a third skeptical brief was submitted to Judge Alsup in reference to his tutorial.  The thrust apparently is to show that the temperature record does not support the claim that recent variability is anything out of the ordinary.

The article by Francis Menton is Klimate Kraziness: A California Judge Holds A “Tutorial” On Climate Science  posted at Manhatton Contrarian.

The third friend of the court brief  was by  The Concerned Household Electricity Consumers Council, which presented work of many scientists, most notably James Wallace III, Joseph D’Aleo, John Christie, and Craig Idso.  Menton’s explanation below from his article.

Not to downplay the work of my co-amici, but we are the one of the three groups that emphatically made the essential scientific point that the most credible data as to world temperatures, properly analyzed, preclude rejection of the null hypothesis that natural factors are the predominant if not only cause of the observed warming. As stated in our submission:

The conclusion of the work is that each of EPA’s “lines of evidence” has been invalidated by the best empirical evidence, and therefore the attribution of any observed climate change, including global warming, to rising atmospheric CO2 concentrations has not been established.

And, further on in our presentation:

[T]hese natural factor impacts fully explain the trends in all relevant temperature data sets over the last 50 or more years. This research, like Wallace (2016), found that rising atmospheric concentrations did not have a statistically significant impact on any of the (14) temperature data sets that were analyzed. Wallace 2017 concludes that, “at this point, there is no statistically valid proof that past increases in atmospheric CO2 concentrations have caused what have been officially reported as rising, or even record setting, temperatures.”

As they say, read the whole thing (here)

Footnote:

The post The Climate Story (Illustrated) provides a set of graphics making the same argument:  The temperature record does not support climate alarm.

Independently the prestigious Société de Calcul Mathématique (Society for Mathematical Calculation) has written a detailed 195-page White Paper that presents a blistering point-by-point critique of the key dogmas of global warming, starting with the temperature record.  See Bonn COP23 Briefing for Realists

Inside the Climate Tutorial

Thanks to an article at Wired, we get a first glimpse into what transpired at the March 21 courtroom tutorial called by Federal District court  Judge Alsup.  From a science perspective, it looks at the moment like a missed opportunity.  The oil company lawyers sat in silence, allowing Chevron’s lead attorney to speak for them, and he mainly quoted from IPCC documents.  The calculation seems to be taking a position that we didn’t know more and not any sooner than the IPCC came to conclusions in their series of assessment reports.  The plaintiffs let alarmist scientists present on their behalf, and can now claim their opinions were not refuted.

The Wired article is In the Courtroom, Climate Science Needs Substance–and Style Excerpts below with my bolds.

Outside the usual procedural kabuki of the courtroom, the truth is no one really knew what to expect from this court-ordered “tutorial.” For a culture based in large measure on precedent, putting counsel and experts in a room to hash out climate change for a trial—putting everyone on the record, in federal court, on what is and is not true about climate science—was literally unprecedented.

What Alsup got might not have been a full on PowerPoint-powered preview of the trial. But it did reveal a lot about the styles and conflicts inherent in the people who produce the carbon and the people who study it.

The other petrochemists put forth Theodore Boutrous, an AC-130 gunship of a lawyer who among other things got the US Supreme Court to overturn the California law against same-sex marriage. Here, retained specifically by Chevron, Boutrous argued what seemed to be climate change’s chapter-and-verse. He extolled the virtues of the several IPCC reports, 2013 most recently, and quoted them liberally. Boutrous talked about how the reports’ conclusions have gotten more and more surefooted about “anthropogenic” causes of climate change—it’s people!—and outcomes like sea level rise. “From Chevron’s perspective, there’s no debate about climate science,” Boutrous said. “Chevron accepts what this scientific body—scientists and others—what the IPCC has reached consensus on.”

Still, over the course of the morning, Boutrous nevertheless tried to neg the IPCC in two specific ways. One was a classic: He challenged the models that climate scientists use to attempt to predict the future. These computer models, Boutrous said, are “increasingly complex. That can make the modeling more powerful.” But with great power comes great potential wrongness. “Because it’s an attempt to represent things in the real world, the complexity can bring more risk.” He assured the court that Chevron agreed with the IPCC approach—posting up a slide pulled from an IPCC report that showed the multicolored paths of literally hundreds of models, using different emissions scenarios and essentially describing the best case and worst case (and a bunch of in-between cases). It looked like a blast of fireworks emerging from observed average temperature, headed chaotically up and to the right.

So here comes the crux of the thing—a question not of whether climate change is real, but whether you can ascribe blame for it. Leaning heavily on more IPCC quotes, Boutrous showed slides and statistics saying that climate change is a global problem that doesn’t differentially affect the West Coast of North America and isn’t caused by any one emitter. Or even any one source of emissions. Anthropogenic emissions are driven by things like population size, economic activities, lifestyle, energy use, land use patterns, and technology and climate policy, according to the IPCC. “The IPCC does not say it’s the extraction and production of oil,” Boutrous said. “It’s economic activity that creates the demand for energy and that leads to emissions.”

If that seems a little bit like the “guns don’t kill people; people kill people” of petrochemical capitalism, well, Judge Alsup did start the morning by saying today was a day for science, not politics.

So what knives did the representatives of the state of California bring to this oil-fight? Here’s where style is interesting. California didn’t front lawyers. For the science tutorial, the municipalities fronted scientists—people who’d been first authors on chapters in the IPCC reports from which Boutrous quoted, and one who’d written a more recent US report and a study of sea level rise in California. They knew their stuff and could answer all of Judge Alsup’s questions … but their presentations were more like science conference fodder than well-designed rhetoric.

For example, Myles Allen, leader of the Climate Research Program at the University of Oxford, gave a detailed, densely-illustrated talk on the history and science of climate change…but he also ended up in an extended back and forth with Alsup about whether Svante Arrhenius’ 1896 paper hypothesizing that carbon dioxide in Earth’s atmosphere warmed the planet explicitly used the world “logarithmic.” Donald Wuebbles, an atmospheric scientist at the University of Illinois and co-author of the Nobel Prize-winning 2007 IPCC report, mounted a grim litany of all the effects scientists can see, today, of climate, but Alsup caught him up asking for specific things he disagreed with Boutrous on—a tough game since Boutrous was just quoting the IPCC.

Then Alsup and Wuebbles took a detour into naming other renewable power sources besides solar and wind. “Nuclear would not put out any CO2, right? We might get some radiation as we drive by, but maybe in retrospect we should have taken a hard look at nuclear?” Alsup interrupted. “No doubt solar is good where you can use it, but do you really think it could be a substitute for supplying the amount of power America used in the last 30 years?”

“I think solar could be a significant factor of our energy future,” Wuebbles said. “I don’t think there’s any one silver bullet.”

In part, one might be tempted to put some blame on Alsup here. You might remember him from such trials as Uber v. Waymo, where he asked for a similar tutorial on self-driving car technology. Or from Oracle v. Google, a trial for which Alsup taught himself a little of the programming language Java so he’d understand the case better. Or from his intercession against the Trump administration’s attempt to cancel the Deferred Action for Childhood Arrivals program, protecting the immigration status of so-called Dreamers. “He’s kind of quirky and not reluctant to do things kind of outside the box,” said Deborah Sivas, Director of the Environmental and Natural Resource Law & Policy Program at Stanford Law School. “And I think he sees this as a precedent-setting case, as do the lawyers.”

It’s possible, then, to infer that Alsup was doing more than just getting up to speed on climate change on Wednesday. The physics and chemistry are quite literally textbook, and throughout the presentations he often seemed to know more than he was letting on. He challenged chart after chart incisively, and often cut in on history. When Allen brought up Roger Revelle’s work showing that oceans couldn’t absorb carbon—at least, not fast enough to stave off climate change, Alsup interrupted.

“Is it true that Revelle initially thought the ocean would absorb all the excess, and that he came to this buffer theory a little later?” Alsup asked.

“You may know more of this history than I do,” Allen said.

But on the other hand, some of what the litigators seemed to not know sent the scientists in the back in literal spasms. When Boutrous couldn’t answer Alsup’s questions about the specific causes of early 20th-century warming (presumably before the big industrial buildup of the 1950s), Allen and Wuebbles, sitting just outside the gallery, clenched fists and looked like they were having to keep from shouting out the answer. Later, Alsup acknowledged that he’d watched An Inconvenient Truth to prepare, and Boutrous said he had, too.

All of which makes it hard to tell whether bringing scientists to this table was the right move. And maybe that has been the problem all along. The interface where utterly flexible law and policy moves against the more rigid statistical uncertainties of scientific observation has always been contested space. The practitioners of both arts seem foreign to each other; the cultural mores differ.

Maybe that’s what this “tutorial” was meant for. As Sivas says, the facts aren’t really in doubt here. Or rather, most of them aren’t, and maybe Alsup will use today as a kind of discovery process, a way to crystalize the difference between uncertainty in science and uncertainty under the law. “That’s what judges do. They decide the credibility of one expert over another,” Sivas says. “That doesn’t mean it’s scientific truth. It means it’s true as a legal claim.”

The skeptical scientific brief was filed by esteemed scientists Happer, Koonin and Lindzen, but its effect is not yet evident.  More details are at Cal Climate Tutorial: The Meat

Cal Climate Tutorial: The Meat

Prevous posts provided the context regarding the Climate Tutorial requested by Judge Alsup in the lawsuit case filed by California cities against big oil companies: Cal Court to Hear Climate Tutorial

An overview of a submission by Professors Happer, Koonin and Lindzen was in Climate Tutorial for Judge Alsup

This post goes into the meat and potatoes of that submission with excerpts from Section II: Answers to specific questions (my bolds)

Question 1: What caused the various ice ages (including the “little ice age” and prolonged cool periods) and what caused the ice to melt? When they melted, by how much did sea level rise?

The discussion of the major ice ages of the past 700 thousand years is distinct from the discussion of the “little ice age.” The former refers to the growth of massive ice sheets (a mile or two thick) where periods of immense ice growth occurred, lasting approximately eighty thousand years, followed by warm interglacials lasting on the order of twenty thousand years. By contrast, the “little ice age” was a relatively brief period (about four hundred years) of relatively cool temperatures accompanied by the growth of alpine glaciers over much of the earth.

Tutorial 1

The last glacial episode ended somewhat irregularly. Ice coverage reached its maximum extent about eighteen thousand years ago. Melting occurred between about twenty thousand years ago and thirteen thousand years ago, and then there was a strong cooling (Younger Dryas) which ended about 11,700 years ago. Between twenty thousand years ago and six thousand years ago, there was a dramatic increase in sea level of about 120 meters followed by more gradual increase over the following several thousand years. Since the end of the “little ice age,” there has been steady increase in sea-level of about 6 inches per century.

slide12

As to the cause of the “little ice age,” this is still a matter of uncertainty. There was a long hiatus in solar activity that may have played a role, but on these relatively short time scales one can’t exclude natural internal variability. It must be emphasized that the surface of the earth is never in equilibrium with net incident solar radiation because the oceans are always carrying heat to and from the surface, and the motion systems responsible have time scales ranging from years (for example ENSO) to millennia.

The claim that orbital variability requires a boost from CO2 to drive ice ages comes from the implausible notion that what matters is the orbital variations in the global average insolation (which are, in fact, quite small) rather than the large forcing represented by the Milankovitch parameter. This situation is very different than in the recent and more modest shorter-term warming, where natural variability makes the role of CO2 much more difficult to determine.

Question 2: What is the molecular difference by which CO2 absorbs infrared radiation but oxygen and nitrogen do not?

Molecules like CO2, H2O, CO or NO are called a greenhouse-gas molecules, because they can efficiently absorb or emit infrared radiation, but they are nearly transparent to sunlight. Molecules like O2 and N2 are also nearly transparent to sunlight, but since they do not absorb or emit thermal infrared radiation very well, they are not greenhouse gases. The most important greenhouse gas, by far, is water vapor. Water molecules, H2O, are permanently bent and have large electric dipole moments.

GHG blocks

Question 3: What is mechanism by which infrared radiation trapped by CO2 in the atmosphere is turned into heat and finds its way back to sea level?

Unscattered infrared radiation is very good at transmitting energy because it moves at the speed of light. But the energy per unit volume stored by the thermal radiation in the Earth’s atmosphere is completely negligible compared to the internal energy of the air molecules.

Although CO2 molecules radiate very slowly, there are so many CO2 molecules that they produce lots of radiation, and some of this radiation reaches sea level. The figure following shows downwelling radiation measured at the island of Nauru in the Tropical Western Pacific Ocean, and at colder Point Barrow, Alaska, on the shore of the Arctic Ocean.

So the answer to the last part of the question, “What is the mechanism by which … heat … finds its way back to sea level?” is that the heat is radiated to the ground by molecules at various altitudes, where there is usually a range of different temperatures. The emission altitude is the height from which radiation could reach the surface without much absorption, say 50% absorption. For strongly absorbed frequencies, the radiation reaching the ground comes from low-altitude molecules, only a few meters above ground level for the 667 cm-1 frequency at the center of the CO2 band. More weakly absorbed frequencies are radiated from higher altitudes where the temperature is usually colder than that of the surface. But occasionally, as the data from Point Barrow show, higher-altitude air can be warmer than the surface.

Barrow Nauru Radiance

Closely related to Question 3 is how heat from the absorption of sunlight by the surface gets back to space to avoid a steadily increasing surface temperature. As one might surmise from the figure, at Narau there is so much absorption from CO2 and by water vapor, H2O, that most daytime heat transfer near the surface is by convection, not by radiation. Especially important is moist convection, where the water vapor in rising moist air releases its latent heat to form clouds. The clouds have a major effect on radiative heat transfer. Cooled, drier, subsiding air completes the convection circuit. Minor changes of convection and cloudiness can have a bigger effect on the surface temperature than large changes in CO2 concentrations.

Question 4: Does CO2 in the atmosphere reflect any sunlight back into space, such that the reflected sunlight never penetrates the atmosphere in the first place?

The short answer to this question is “No”, but it raises some interesting issues that we discuss below.

Molecules can either scatter or absorb radiation. CO2 molecules are good absorbers of thermal infrared radiation, but they scatter almost none. Infrared radiant energy absorbed by a CO2 molecule is converted to internal vibrational and rotational energy. This internal energy is quickly lost in collisions with the N2 and O2 molecules that make up most of the atmosphere. The collision rates, billions per second, are much too fast to allow the CO2 molecules to reradiate the absorbed energy, which takes about a second. CO2 molecules in the atmosphere do emit thermal infrared radiation continuously, but the energy is almost always provided by collisions with N2 and O2 molecules, not by previously absorbed radiation. The molecules “glow in the dark” with thermal infrared radiation.

H2O CO2 absorption spectrums

The figure shows that water vapor is by far the most important absorber. It can absorb both thermal infrared radiation from the Earth and shorter-wave radiation from the Sun. Water vapor and its condensates, clouds of liquid or solid water (ice), dominate radiative heat transfer in the Earth’s atmosphere; CO2 is of secondary importance.

If Question 4 were “Do clouds in the atmosphere reflect any sunlight back into space, such that the reflected sunlight never penetrates the atmosphere in the first place?” the answer would be “Yes”. It is common knowledge that low clouds on a sunny day shade and cool the surface of the Earth by scattering the sunlight back to space before it can be absorbed and converted to heat at the surface.

The figure shows that very little thermal radiation from the surface can reach the top of the atmosphere without absorption, even if there are no clouds. But some of the surface radiation is replaced by molecular radiation emitted by greenhouse molecules or cloud tops at sufficiently high altitudes that the there are no longer enough higher-altitude greenhouse molecules or clouds to appreciably attenuate the radiation before it escapes to space. Since the replacement radiation comes from colder, higher altitudes, it is less intense and does not reject as much heat to space as the warmer surface could have without greenhousegas absorption.

As implied by the figure, sunlight contains some thermal infrared energy that can be absorbed by CO2. But only about 5% of sunlight has wavelengths longer than 3 micrometers where the strongest absorption bands of CO2 are located. The Sun is so hot, that most of its radiation is at visible and near-visible wavelengths, where CO2 has no absorption bands.

Question 5: Apart from CO2, what happens to the collective heat from tail pipe exhausts, engine radiators, and all other heat from combustion of fossil fuels? How, if at all, does this collective heat contribute to warming of the atmosphere?

After that energy is used for heat, mobility, and electricity, the Second Law of Thermodynamics guarantees that virtually all of it ends up as heat in the climate system, ultimately to be radiated into space along with the earth’s natural IR emissions. [A very small fraction winds up as visible light that escapes directly to space through the transparent atmosphere, but even that ultimately winds up as heat somewhere “out there.”]

How much does this anthropogenic heat affect the climate? There are local effects where energy use is concentrated, for example in cities and near power plants. But globally, the effects are very small. To see that, convert the global annual energy consumption of 13.3 Gtoe (Gigatons of oil equivalent) to 5.6 × 10^20 joules. Dividing that by the 3.2 × 10^7 seconds in a year gives a global power consumption of 1.75 × 10^13 Watts. Spreading that over the earth’s surface area of 5.1 × 10^14 m2 results in an anthropogenic heat flux of 0.03 W/m2 . This is some four orders of magnitude smaller than the natural heat fluxes of the climate system, and some two orders of magnitude smaller than the anthropogenic radiative forcing.

Question 6: In grade school many of us were taught that humans exhale CO2 but plants absorb CO2 and return oxygen to the air (keeping the carbon fiber). Is this still valid? If so why hasn’t plant life turned the higher levels of CO2 back into oxygen? Given the increase in population on earth (four billion), is human respiration a contributing factor to the buildup of CO2?

If all of the CO2 produced by current combustion of fossil fuels remained in the atmosphere, the level would increase by about 4 ppm per year, substantially more than the observed rate of around 2.5 ppm per year, as seen in the figure above. Some of the anthropogenic CO2 emissions are being sequestered on land or in the oceans.

high_resolution1

There is evidence that primary photosynthetic productivity has increased somewhat over the past half century, perhaps due to more CO2 in the atmosphere. For example, the summerwinter swings like those in the figure above are increasing in amplitude. Other evidence for modestly increasing primary productivity includes the pronounced “greening” of the Earth that has been observe by satellites. An example is the map above, which shows a general increase in vegetation cover over the past three decades.

The primary productivity estimate mentioned above would also correspond to an increase of the oxygen fraction of the air by 50 ppm, but since the oxygen fraction of the air is very high (209,500 ppm), the relative increase would be small and hard to detect. Also much of the oxygen is used up by respiration.

The average human exhales about 1 kg of CO2 per day, so the 7 billion humans that populate the Earth today exhale about 2.5 x 10^9 tons of CO2 per year, a little less than 1% of that is needed to support the primary productivity of photosynthesis and only about 6% of the CO2 “pollution” resulting from the burning of fossil fuels. However, unlike fossil fuel emissions, these human (or more generally, biological) emissions do not accumulate in the atmosphere, since the carbon in food ultimately comes from the atmosphere in the first place.

Question 7: What are the main sources of CO2 that account for the incremental buildup of CO2 in the atmosphere?

The CO2 in the atmosphere is but one reservoir within the global carbon cycle, whose stocks and flows are illustrated by Figure 6.1 from IPCC AR5 WG1:

There is a nearly-balanced annual exchange of some 200 PgC between the atmosphere and the earth’s surface (~80 Pg land and ~120 Pg ocean); the atmospheric stock of 829 Pg therefore “turns over” in about four years.

Human activities currently add 8.9 PgC each year to these closely coupled reservoirs (7.8 from fossil fuels and cement production, 1.1 from land use changes such as deforestation). About half of that is absorbed into the surface, while the balance (airborne fraction) accumulates in the atmosphere because of its multicentury lifetime there. Other reservoirs such as the intermediate and deep ocean are less closely coupled to the surface-atmosphere system.

Much of the natural emission of CO2 stems from the decay of organic matter on land, a process that depends strongly on temperature and moisture. And much CO2 is absorbed and released from the oceans, which are estimated to contain about 50 times as much CO2 as the atmosphere. In the oceans CO2 is stored mostly as bicarbonate (HCO3 – ) and carbonate (CO3 – – ) ions. Without the dissolved CO2, the mildly alkaline ocean with a pH of about 8 would be very alkaline with a pH of about 11.3 (like deadly household ammonia) because of the strong natural alkalinity.

Only once in the geological past, the Permian period about 300 million years ago, have atmospheric CO2 levels been as low as now. Life flourished abundantly during the geological past when CO2 levels were five or ten times higher than those today.

Question 8: What are the main sources of heat that account for the incremental rise in temperature on earth?

The only important primary heat source for the Earth’s surface is the Sun. But the heat can be stored in the oceans for long periods of time, even centuries. Variable ocean currents can release more or less of this stored heat episodically, leading to episodic rises (and falls) of the Earth’s surface temperature.

Incremental changes of the surface temperature anomaly can be traced back to two causes: (1) changes in the surface heating rate; (2) changes in the resistance of heat flow to space. Quasi periodic El Nino episodes are examples of the former. During an El Nino year, easterly trade winds weaken and very warm deep water, normally blown toward the coasts of Indonesia and Australia, floats to the surface and spreads eastward to replace previously cool surface waters off of South America. The average temperature anomaly can increase by 1 C or more because of the increased release of heat from the ocean. The heat source for the El Nino is solar energy that has accumulated beneath the ocean surface for several years before being released.

On average, the absorption rate of solar radiation by the Earth’s surface and atmosphere is equal to emission rate of thermal infrared radiation to space. Much of the radiation to space does not come from the surface but from greenhouse gases and clouds in the lower atmosphere, where the temperature is usually colder than the surface temperature, as shown in the figure on the previous page. The thermal radiation originates from an “escape altitude” where there is so little absorption from the overlying atmosphere that most (say half) of the radiation can escape to space with no further absorption or scattering. Adding greenhouse gases can warm the Earth’s surface by increasing the escape altitude. To maintain the same cooling rate to space, the temperature of the entire troposphere, and the surface, would have to increase to make the effective temperature at the new escape altitude the same as at the original escape altitude. For greenhouse warming to occur, a temperature profile that cools with increasing altitude is required.

Over most of the CO2 absorption band (between about 580 cm-1 and 750 cm-1 ) the escape altitude is the nearly isothermal lower stratosphere shown in the first figure. The narrow spike of radiation at about 667 cm-1 in the center of the CO2 band escapes from an altitude of around 40 km (upper stratosphere), where it is considerably warmer than the lower stratosphere due heating by solar ultraviolet light which is absorbed by ozone, O3. Only at the edges of the CO2 band (near 580 cm-1 and 750 cm-1 ) is the escape altitude in the troposphere where it could have some effect on the surface temperature. Water vapor, H2O, has emission altitudes in the troposphere over most of its absorption bands. This is mainly because water vapor, unlike CO2, is not well mixed but mostly confined to the troposphere.

Summary

To summarize this overview, the historical and geological record suggests recent changes in the climate over the past century are within the bounds of natural variability. Human influences on the climate (largely the accumulation of CO2 from fossil fuel combustion) are a physically small (1%) effect on a complex, chaotic, multicomponent and multiscale system. Unfortunately, the data and our understanding are insufficient to usefully quantify the climate’s response to human influences. However, even as human influences have quadrupled since 1950, severe weather phenomena and sea level rise show no significant trends attributable to them. Projections of future climate and weather events rely on models demonstrably unfit for the purpose. As a result, rising levels of CO2 do not obviously pose an immediate, let alone imminent, threat to the earth’s climate.

Full text of submission is here

Earth Climate Layers

Thanks to No Tricks Zone for posting work (here) by Dr. Dai Davies of Canberra. In his writing I found a fine summary paradigm leading to the image above.  This post presents a scientifically rigorous view of our planetary climate system, starting with an airless rocky surface and then conceptually adding the dynamic elements in layers.  The text below with my bolds and images comes from Energy and Atmosphere by Dr. Dai Davies of University of Canberra,  Website: http://brindabella.id.au/climarc/.

The Earth’s atmosphere in stages

This is an hypothetical scenario that allows us to build up a picture, step by step, of how having an atmosphere can influence a planet.

Baseline: Airless, Rocky Planet
As a starting point we consider how the Earth’s temperature might vary through the daily cycle if it was an airless, rocky planet much like the moon. During the day, the sun heats up a surface layer of the rock which cools through infrared radiation. The temperature follows the sun’s irradiation almost directly, rising and plunging over a range of hundreds of degrees.

Add: Radiatively Inert Atmosphere
If we add a radiatively inert atmosphere, its only means of gaining and losing heat would be thermal conduction through direct contact with the Earth’s surface. The heat capacity of a square meter column of the Earth’s atmosphere is equivalent to that of about 12 tonnes of granite, so far greater than a thin layer of rock heated by the sun. While the surface would still go through a temperature cycle, the atmosphere would achieve an equilibrium where the mean lower atmosphere matched the mean surface temperature – give-or-take geography and atmospheric circulation. It would act as a buffer that would stabilise surface temperatures – cooling the surface during the day and warming it at night. This is discussed further in note (a) with some simple calculations.

All molecules are radiatively active if the energy is high enough. A realistic atmosphere, such as a nitrogen and oxygen mix, absorbs some energy from the light and UV components of incoming solar radiation, but still can’t lose heat through infrared radiation.

Various wavelengths of solar EM radiation penetrate Earth’s atmosphere to various depths. Fortunately for us, all of the high energy X-rays and most UV is filtered out long before it reaches the ground. Much of the infrared radiation is also absorbed by our atmosphere far above our heads. Most radio waves do make it to the ground, along with a narrow “window” of IR, UV, and visible light frequencies. Credit: Image courtesy STCI/JHU/NASA.

Add: Water Vapour, Ignoring Condensation
We now add water vapour to the atmosphere at typical Earth levels of up to 4%, but ignore the effects of condensation. Water molecules are kicked into excited states by collisions with nitrogen or oxygen molecules which lose some kinetic energy in the collision. Most of this energy will return to kinetic in subsequent collisions. Otherwise, the energy is radiated in a random direction as an infrared photon, which creates a radiation flux that travels much faster and further than molecular movement. Their mean free path (mfp) is typically 50 metres in the surface atmosphere, increasing with altitude as the density of the air decreases and collisions are less frequent. A small part of this energy escapes to space, a smaller part is absorbed by the Earth’s surface, leading to a net transfer to space.

This radiative flux greatly increases the thermal coupling between the surface and near-surface atmosphere, adding to the transfer via direct thermal conduction and reducing the daily temperature cycle of the surface, tying it closer to the temperature of the lower atmosphere. Due to the highly nonlinear nature of radiant emission, this will have a net heating effect on the surface as described in note (a).

The increase in mfp with altitude means there is a small upward bias in photon transmission through the atmosphere’s photon sea created by molecular collisions. This net upward transfer of energy largely substitutes the direct infrared radiation from surface to space, adding a slight delay in the order of milliseconds. Heat is not ‘trapped’, as is commonly claimed, just slowed a little. It’s a rapid conduit, not a reservoir.

Add: Liquid Water Covering 70% of Surface
For the next stage in the transition towards our current atmosphere we add our present distribution of liquid water over 70% of the rocky surface. This changes things dramatically. First, rather than just heating a thin surface layer of rock that can radiate heat rapidly, the sun’s rays penetrate deep into the oceans, heating water that retains its heat until physical mixing brings it to the surface. In the upper ‘mixing layer’ this happens in days to months. Some is mixed deeper and can travel for centuries in deep ocean currents before surfacing.

At the surface of the oceans and wet land we now have evaporative cooling which extracts heat of vaporisation and cools the surface just as sweat cools our skin. Water vapour is lighter than air and reduces the air density. The lighter air rises, creating convection. As it rises it eventually cools to the point where liquid water condenses out to form clouds and dumps the heat of vaporisation into the upper atmosphere. The main impact of clouds is to reduce incoming solar radiation by reflecting it back out to space.

Most of the heating is in equatorial regions. The rising air creates the major Hadley circulation cells that carry heat polewards in the upper troposphere. The radiating upper air cools and becomes more dense as it travels, eventually sinking back to surface level and returning to equatorial regions.

Water isn’t the only radiative gas in our atmosphere, but it dominates. The next in significance is carbon dioxide. It’s main impact is in the upper atmosphere where most of the water vapour has condensed out. This impact is cooling. Its influence in the lower atmosphere is discussed later.

Finally, we add Life.

Early on, it added the oxygen to our atmosphere. Now, its plants have changed the surface albedo – the amount of the sun’s energy reflected back to space. Through transpiration they also add to evaporation in increasing the input of water vapour to the atmosphere. Some plants and algae produce aerosols that seed clouds – terrestrial plants increasing their chances of rain – marine biota reducing the incidence of destructive UV.

Summary

There is much more to be learned from this thorough, well written article, but I will conclude with Davies’ summation:

The most fundamental of the many fatal mathematical flaws in the IPCC related modelling of atmospheric energy dynamics is to start with the impact of CO2 and assume water vapour as a dependent ‘forcing’ (note e). This has the tail trying to wag the dog. The impact of CO2 should be treated as a perturbation of the water cycle. When this is done, its effect is negligible.

Extensive analysis of radiosonde data over time, and an associated theoretical analysis, by Miskolczi (6) has shown that the water cycle adapts to maintain saturation – maximum impact – in the combined effects of water vapour and any other radiative gasses.

The sudden increase in evaporative cooling of warm water creating an upper bound for wet surface temperatures, along with the freezing point of water limiting ocean temperatures at the poles, anchor the overall surface temperature of the Earth. The Earth’s orbit, variations in solar activity, and long term transport of heat in ocean currents, provide cyclic variations. The lapse rate just determines the height of the tropopause. The net effect of CO2 is to help cool the upper troposphere where water vapour levels are low.

The current small peak in temperatures is partly the result of heat returning from past millennial cycles – the historians’ climate optima of the Medieval, Roman and earlier warm periods. As then, solar activity is now at low levels.

Davies provides a concise synopsis of several posts touching on key elements of earth’s climate.

My own discussion of climate layers is in Climate Reductionism

The effect of an inert atmosphere is shown empirically in Planetary Warming: Back to Basics

The reference above to Dr. Miskolczi is elaborated in The Curious Case of Dr. Miskolczi

The role of oceans in storing and distributing heat is described in Climate Water Wheel

The passage of energy through the atmosphere is explained at On Climate Theories

“The Earth, a rocky sphere at a distance from the Sun of ~149.6 million kilometers, where the Solar irradiance comes in at 1361.7 W/m2, with a mean global albedo, mostly from clouds, of 0.3 and with an atmosphere surrounding it containing a gaseous mass held in place by the planet’s gravity, producing a surface pressure of ~1013 mb, with an ocean of H2O covering 71% of its surface and with a rotation time around its own axis of ~24h, boasts an average global surface temperature of +15°C (288K).

Why this specific temperature? Because, with an atmosphere weighing down upon us with the particular pressure that ours exerts, this is the temperature level the surface has to reach and stay at for the global convectional engine to be able to pull enough heat away fast enough from it to be able to balance the particular averaged out energy input from the Sun that we experience.

It’s that simple.”  E. M. Smith