An insightful straight-forward interview with Dr. John Christy published today at yellowhammernews  Alabama’s state climatologist John Christy rebuts claims of recent fires, heat waves being caused by human activity (H/T Climate Depot) Excerpts in italics with my bolds.

There is one particular word that Dr. John Christy turns to frequently for describing climate science: murky.

It’s a point of view foundational to his own research, and a message underpinning each of his twenty appearances before various congressional committees.

“It’s encouraging because they wouldn’t invite you back unless your message was compelling and not only compelling, but accurate,” Christy, Alabama’s state climatologist, told Yellowhammer News in an interview.

Christy, whose day job involves doing research and teaching as the Distinguished Professor of Atmospheric Science at the University of Alabama in Huntsville (UAH), has gained notoriety over the years for dissenting from mainstream climate scientists and policymakers who argue that climate change is anthropogenic, or man-made, and that something must be done to stop it.

A “working-stiff” scientist

Dissent has gained for Christy the characterization as a “climate change skeptic” or “denier,” as critics refer to him, but he himself rejects those terms.

“I’m a working-stiff atmospheric scientist,” he said, “as opposed to those who support modeling efforts, those who use data sets that other people create and analyze them, but they don’t build them themselves.”

According to Christy, the result of fewer “working-stiff” scientists contributing to the prevailing climate debate is more frequent misuses of data.

“They’re not aware of what goes into it,” Christy said, referring to the data.

“Here we have a science that’s so dominated by personalities that claim the science is settled, yet when you walk up to them and say prove it, they can’t,” he said.

Christy spoke at length about what can be proven and what cannot in his self-described “murky” field, referring often to principles of the scientific method.

“You cannot prove extra greenhouse gases have done anything to the weather,” he said, responding to claims made by many scientists that more greenhouse gases have caused extreme weather patterns to intensify.

“We do not have an experiment that we can repeat and do,” he said.

Christy outlined another problem with attempts to implicate greenhouse gases: a failure to account for things countering trapping effects.

“We know that the extra greenhouse gases should warm the planet,” he said. “The weak part of that theory though is that when you add more greenhouse gases that trap heat, things happen that let it escape as well, and so not as much is trapped as climate models show.”

Economics of climate policy

Though his scientific arguments are primary, Christy also frequently discusses in interviews and testimonies the economic consequences of proposed climate change mitigation policy via carbon reduction.

“Every single person uses energy, carbon energy, and relies on carbon-based energy,” Christy said. “None of our medical advances, none of our technological advances, none of our progress would have happened in the last hundred years without energy derived from carbon.”

Christy contrasts that reality within the modern, developed world with the world he saw working as a missionary teacher in impoverished Africa during the 1970s.

“The energy source was wood chopped from the forest, the energy transmission system was the backs of women and girls hauling wood an average of three miles each day, the energy use system was burning the wood in an open fire indoors for heat and light,” Christy told members of the House Committee on Energy in 2006.

Broad availability to affordable energy enriches countries, Christy said, praising carbon.

“It is not evil. It is the stuff of life. It is plant food,” he said.

What about the fires and heat waves?

According to the National Interagency Fire Center, fires were burning in fifteen states as of Tuesday, August 14.

Alaska reported seventeen fires, Arizona reported eleven, both Oregon and Colorado reported ten, and California reported nine.

Much of the news media’s discussion about these fires over the past few weeks has established a correlation between the many fires and anthropogenic climate change, a correlation that Dr. Christy rejects.

Christy argues that exacerbating fires out west, particularly in California, results from human mismanagement. Such states have enacted strict management practices that disallow low-level fires from burning, he said.

“If you don’t let the low-intensity fires burn, that fuel builds up year after year,” Christy said. “Now once a fire gets going and it gets going enough, it has so much fuel that we can’t put it out.”

“In that sense, you could say that fires today are more intense, but it’s because of human management practices, not because mother nature has done something,” Christy said.

Data from the Fire Center indicates that the number of wildfires have been decreasing since the 1970s overall, though acreage burned has increased significantly.

As for the heat, Christy said there’s nothing abnormal going on in the United States.

“Heat waves have always happened,” he said. “Our most serious heatwaves were in the 1930’s. We have not matched those at all.”

Christy continued, “It is only a perception that is being built by the media that these are dramatic worst-ever heat wave kind of things but when we look at the numbers, and all science is numbers, we find that there were periods that were hotter, hotter for longer periods in the past, so it’s very hard to say that this was influenced by human effects when you go back before there could have been human effects and there’s the same or worse kind of events.”

Though Christy didn’t deny that the last three years have been the hottest ever recorded globally, he doesn’t concede that the changes are attributable to anything other than climate’s usual and historical erraticism.

@jeremywbeaman is a contributing writer for Yellowhammer News

Iowa trivia: Refrain from Iowa Corn Song: “We’re from I-o-way, I-o-way, That’s where the tall corn grows.” Athletic teams that represent Iowa State University are called the “Cyclones,” after the devastating 1895 storms, the most extreme weather in state history. My mother was born and raised near Cedar Rapids, IA.

Today a website in Iowa reblogged my post Who to Blame for Rising CO2?  Returning the favor I draw your attention to a concise, comprehensive and reasonable statement of their climate perspective.  The website is Iowa Climate Science Education (Red title is link).  Excerpts below from their position statement in italics with my bolds.

Scientists disagree about the causes and consequences of climate for several reasons. Climate is an interdisciplinary subject requiring insights from many fields. Very few scholars have mastery of more than one or two of these disciplines. Fundamental uncertainties arise from insufficient observational evidence and disagreements over how to interpret data and how to set the parameters of models. The Intergovernmental Panel on Climate Change (IPCC), created to find and disseminate research finding a human impact on global climate, is not a credible source. It is agenda-driven, a political rather than scientific body, and some allege it is corrupt. Finally, climate scientists, like all humans, can be biased. Origins of bias include careerism, grant-seeking, political views, and confirmation bias.

Probably the only “consensus” among climate scientists is that human activities can have an effect on local climate and that the sum of such local effects could hypothetically rise to the level of an observable global signal. The key questions to be answered, however, are whether the human global signal is large enough to be measured and if it is, does it represent, or is it likely to become, a dangerous change outside the range of natural variability? On these questions, an energetic scientific debate is taking place on the pages of peer-reviewed science journals.

In contradiction of the scientific method, IPCC assumes its implicit hypothesis – that dangerous global warming is resulting, or will result, from human-related greenhouse gas emissions – is correct and that its only duty is to collect evidence and make plausible arguments in the hypothesis’s favor. It simply ignores the alternative and null hypothesis, amply supported by empirical research, that currently observed changes in global climate indices and the physical environment are the result of natural variability.

The results of the global climate models (GCMs) relied on by IPCC are only as reliable as the data and theories “fed” into them. Most climate scientists agree those data are seriously deficient and IPCC’s estimate for climate sensitivity to CO2 is too high. We estimate a doubling of CO2 from pre-industrial levels (from 280 to 560 ppm) would likely produce a temperature forcing of 3.7 Wm-2 in the lower atmosphere, for about ~1°C of prima facie warming. The recently quiet Sun and extrapolation of solar cycle patterns into the future suggest a planetary cooling may occur over the next few decades.

In a similar fashion, all five of IPCC’s postulates, or assumptions, are readily refuted by real-world observations, and all five of IPCC’s claims relying on circumstantial evidence are refutable. For example, in contrast to IPCC’s alarmism, we find neither the rate nor the magnitude of the reported late twentieth century surface warming (1979–2000) lay outside normal natural variability, nor was it in any way unusual compared to earlier episodes in Earth’s climatic history. In any case, such evidence cannot be invoked to “prove” a hypothesis, but only to disprove one. IPCC has failed to refute the null hypothesis that currently observed changes in global climate indices and the physical environment are the result of natural variability.

Rather than rely exclusively on IPCC for scientific advice, policymakers should seek out advice from independent, nongovernment organizations and scientists who are free of financial and political conflicts of interest. Our conclusion, drawn from its extensive review of the scientific evidence, is that any human global climate impact is within the background variability of the natural climate system and is not dangerous. In the face of such facts, the most prudent climate policy is to prepare for and adapt to extreme climate events and changes regardless of their origin. Adaptive planning for future hazardous climate events and change should be tailored to provide responses to the known rates, magnitudes, and risks of natural change. Once in place, these same plans will provide an adequate response to any human-caused change that may or may not
emerge.

Policymakers should resist pressure from lobby groups to silence scientists who question the authority of IPCC to claim to speak for “climate science.” The distinguished British biologist Conrad Waddington wrote in 1941,

“It is important that scientists must be ready for their pet theories to turn out to be wrong. Science as a whole certainly cannot allow its judgment about facts to be distorted by ideas of what ought to be true, or what one may hope to be true.” (Waddington, 1941).

This prescient statement merits careful examination by those who continue to assert the fashionable belief, in the face of strong empirical evidence to the contrary, that human CO2 emissions are going to cause dangerous global warming.

Reference
Waddington, C.H. 1941. The Scientific Attitude. London, UK: Penguin Books.

A high ridge in Antarctica on the East Antarctic Plateau where temperatures in several hollows can dip down to minus 144 F.

National Geographic Coldest Place on Earth Found—Here’s How
“It’s a place where Earth is so close to its limit, it’s almost like another planet.”

Just how cold can it get on Earth’s surface? About minus 144°F, according to recent satellite measurements of the coldest known place on the planet.

Scientists recorded this extreme temperature on the ice sheet deep in the middle of Antarctica during the long, dark polar winter. As they report this week in Geophysical Research Letters, the team thinks this is about as cold as it can possibly get in our corner of the solar system.

“It’s a place where Earth is so close to its limit, it’s almost like another planet,” says study leader Ted Scambos, a researcher at the National Snow and Ice Data Center at the University of Colorado, Boulder.

The measurement smashes the previous record for the coldest known air temperature in the natural world: a frigid minus 128.6°F felt in 1983 at the Russian Vostok Station, not far from the South Pole. Humans can’t inhale air that cold for more than a few breaths—it would cause our lungs to hemorrhage. Russian scientists ducking out to check on the weather station would wear masks that warmed the air before they breathed it in.

DEATHLY HOLLOWS
While the East Antarctic ice sheet looks flat at the surface, it actually domes ever so slightly from center to edge like a vast, icy turtle shell. Vostok is perched near the top of the dome, on about 2.2 miles of ice, but it’s not quite at the apex. Scambos’s team suspected that it could get even colder at the very highest parts of the ice sheet.

There aren’t any weather stations perched at the peak of the ice sheet, and there isn’t anyone there to check on them in the dead of Antarctic winter. But satellites can sense the temperature at the surface of the ice as they pass overhead. So Scambos and his colleagues sifted through several years of satellite data, mapping out when and where temperatures dipped low.

Sure enough, they found about a hundred little pockets of exceptional cold scattered across the highest parts of the ice sheet. The coldest spots were in shallow depressions in the ice, little hollows where the surface isn’t perfectly smooth. That’s probably because cold air sinks into these depressions like it sinks into a river valley or a canyon, says John Turner, a polar scientist with the British Antarctic Survey who was not involved in the study.

“They’re such shallow dips, you probably couldn’t even see them with your eyes,” he says.

The air warms up by a few degrees right above the surface, which is where the scientists at Vostok had recorded the previous coldest temperature. By comparing the satellite measurements to data from the nearest weather stations, Scambos and his team figured out that the air temperatures in this region would be a little warmer near human-head height, about minus 137°F. But right at the surface, where your feet would touch the snow, they saw temperatures of minus 144°F.

“But you hope your feet wouldn’t ever touch the snow,” Scambos says. “That would not be fun at all.”

OBSCURING THE VIEW
Only very special conditions lead to such extreme cold. First, it has to be the dead of winter, long after the midnight sun sets for the season. Then, the air needs to be still for a few days, and the sky needs to be perfectly clear, without a wisp of a cloud or a shimmer of diamond dust above the ice sheet.

As cold as it may be, ice radiates a tiny amount of heat. Normally, most of that heat is captured by water vapor in the atmosphere and gets beamed back down to Earth’s surface, trapping warmth in the lower atmosphere.

But during dry spells in Antarctica, when most of the water vapor has been wrung out of the atmosphere, “it starts to open a window that isn’t usually open anywhere else on Earth,” Scambos says. Then, faint heat emitted by the ice sheet can escape all the way to space, leaving the ice surface even colder.

The ultra-clear conditions that enable these chilly events are also ideal for looking out into space, which is why scientists placed a telescope just a few miles from the extreme cold spots Scambos’ team pinpointed.

“Water vapor is our nemesis,” says Craig Kulesa, an astronomer from the University of Arizona who runs the High Elevation Antarctic Terahertz Telescope, or, somewhat satirically, HEAT. “We put our telescope at this superbly dry site, but if we put it 10 miles away, would it be any better?”

It may be a question worth considering as the climate changes around the globe, though there’s nowhere else on this planet they could go where conditions would be better. Water vapor concentrations in the atmosphere are increasing, which in turn means more of the ice-emitted heat gets trapped near the surface—keeping it warmer. So, the perfectly clear conditions that are ideal for looking into space will become less frequent—and any scientists hoping to break the record for sensing extreme cold on Earth may be running out of time.

“As we see increases in greenhouse gas and water vapor concentrations, we’re expecting warming across the Antarctic of about 3 to 4°C,” says Turner. “Seeing any new temperature lows will be more and more unlikely. The odds are just getting smaller.”

The subtropical jet streams are weaker and higher in the atmosphere at 10-16 kilometers above sea level. Jet streams wander laterally in quite dramatic waves and can exhibit huge changes in altitude. Breaks in the tropopause at the Polar, Hadley and Ferrel circulation cells cause the streams to form. The combination of circulation and Coriolis forces acting on the cell masses drive the phenomenon. The Polar jet, being at a lower altitude, strongly affects weather and aviation. It is most often found between the latitudes of 30 degrees and 60 degrees, while you can find the subtropical jets at 30 degrees. A jet stream is generally a few hundred kilometers wide and only about 5 kilometers high.

Fundamental questions and unknowns concerning natural climate change are presented in this 2007 essay Challenges to Our Understanding of the General Circulation: Abrupt Climate Change by Richard Seager and David S. Battisti. Excerpts in italics with my bolds.

The abrupt climate changes that occurred during the last glaciation and deglaciation are mind boggling both in terms of rapidity and magnitude. That winters in the British Isles could switch between mild, wet ones very similar to today and ones in which winter temperatures dropped to as much as 20◦C below freezing, and do so in years to decades, is simply astounding. No state-of-the-art climate model, of the kind used to project future climate change within the Intergovernmental Panel on Climate Change process, has ever produced a climate change like this.

The problem for dynamicists working in this area is that the period of instrumental observations, and model simulations of that period, do not provide even a hint that drastic climate reorganizations can occur.  Our understanding of the general circulation is based fundamentally on this period or, more correctly, on the last 50 years of it, a time of gradual climate change or, at best, more rapid changes of modest amplitude. So it is not surprising that our encyclopedia of knowledge of the general circulations contains many ideas of negative feedbacks between circulation features that may help explain climate variability but also stabilize the climate (Bjerknes 1964; Hazeleger et al. 2005; Shaffrey and Sutton 2004). The modern period has not been propitious for studying how the climate can run away to a new state. Because of this, our understanding has to be limited

The normal explanation of how such changes occurred is that deepwater formation in the Nordic Seas abruptly ceased or resumed forcing a change in ocean heat flux convergence and changes in sea ice. However, coupled GCMs only produce such rapid cessations in response to unrealistically large freshwater forcing and have not so far produced a rapid resumption.

The discussions of the spatial extent of abrupt climate changes in glacial times and during the last deglaciation should make it clear that the causes must be found in changes in the general circulations of the global, as opposed to regional, atmosphere and ocean circulation. The idea that the THC changes and directly impacts a small area of the globe, and that somehow most of the rest of the world piggy-backs along in a rather systematic and reliable way seems dubious.

Thus the problems posed by abrupt change in the North Atlantic region are:
1. How could sea ice extend so far south in winter during the stadials?
2. How, during the spring and summer of stadials, can there be such an enormous influx of heat as to melt the ice and warm the water below by close to 10◦C? If 50 m of water needs to be warmed up by this much in four months, it would take an average net surface heat flux of 150 Wm−2, more than twice the current average between early spring and midsummer and more than can be accounted for by any increase in summer solar irradiance (as during the Younger Dryas).
3. How can this stadial state of drastic seasonality abruptly shift into one similar to that of today with a highly maritime climate in western Europe? Remember that both states can exist in the presence of large ice sheets over North America and Scandinavia.

In thinking of ways to reduce the winter convergence of heat into the mid and high-latitude North Atlantic, we might begin with the storm tracks and mean atmosphere circulation. The Atlantic storm track and jet stream have a clear southwest-to-northeast trajectory, whereas the Pacific ones are more zonal over most of their longitudinal reach (Hoskins and Valdes 1990). If the Atlantic storm track and jet could be induced to take a more zonal track, akin to its Pacific cousin, the North Atlantic would cool.

Here we have argued that the abrupt changes must involve more than changes in the North Atlantic Ocean circulation. In particular it is argued that the degree of winter cooling around the North Atlantic must be caused by a substantial change in the atmospheric circulation involving a great reduction of atmospheric heat transport into the region. Such a change could, possibly, be due to a switch to a regime of nearly zonal wind flow across the Atlantic, denying western Europe the warm advection within stationary waves that is the fundamental reason for why Europe’s winters are currently so mild. Such a change in wind regime would, presumably, also cause a change in the North Atlantic Ocean circulation as the poleward flow of warm, salty waters from the tropics into the Nordic Seas is diverted south by the change in wind stress curl. This would impact the location and strength of deep water formation and allow sea ice to expand south.

The North Atlantic Oscillation (NAO) is is a largely atmospheric mode from fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic low and the Azores high. Through fluctuations in the strength of the Icelandic low and the Azores high, it controls the strength and direction of westerly winds and location of storm tracks across the North Atlantic. It is part of the Arctic oscillation, and varies over time with no particular periodicity. Wikipedia

Recent Wind Research

A decade later we have further insight into the role of winds in climate change by means  of a paper discussed in this Futurity article Wind shifts may explain Europe’s ‘weird’ winters  Excerpts in italics with my bolds.

In the mid-1990s, scientists assembled the first century-long record of North Atlantic sea surface temperatures and quickly discovered a cycle of heating and cooling at the surface of the ocean. Each of these phases lasted for decades, even as temperatures warmed overall during the course of the century. Since this discovery, these fluctuations in ocean temperature have been linked to all manner of Northern Hemisphere climate disturbances, from Sahel drought to North Atlantic hurricanes.

Research also linked European climate variability to the temperature swings of its neighboring ocean in the spring, summer, and fall. Surprisingly, however, no imprint of the ocean’s variability could be found in Western Europe’s wintertime temperature record. This absence was especially puzzling in light of the fact that Europe’s mild winters are a direct consequence of its enviable location downwind of the North Atlantic.

Now, a study by researchers at McGill University and the University of Rhode Island suggests the answer to this puzzle lies in the winds themselves. The fluctuations in ocean temperature are accompanied by shifts in the winds. These wind shifts mean that air arrives in Western Europe via very different pathways in decades when the surface of the North Atlantic is warm, compared to decades when it is cool.

(a) Time series of the linearly detrended North Atlantic SST (black lines, referred to as the AMO index) and SAT averaged over western Europe ([36N 60N] × [10W 3E]; shown in coloured lines) in July (top panel) and January (bottom panel). Bold lines show 10-year running means. The correlation coefficient between the 10-year running mean of the detrended SAT and AMO index is 0.61 in July (statistically significant at 10% confidence level even after accounting for the reduced effective degrees of freedom due to autocorrelation of the time series) and −0.02 in January; these correlations are insensitive to the averaging region chosen for western Europe. The red circles on January plot indicate the AMO-positive years chosen for the composite analysis, whereas the blue circles indicate the AMO-negative years chosen. (b) Study region encompassing western Europe ([36N 60N] × [10W 3E]) and locations for the backtracked Lagrangian particle release (black squares).

The new research reveals that in decades in which North Atlantic sea surface temperatures are elevated, winds deliver air to Europe disproportionately from the north.

In contrast, in decades of coolest sea surface temperature, swifter winds extract more heat from the western and central Atlantic before arriving in Europe. The researchers suggest the distinct atmospheric pathways hide the ocean oscillation from Europe in winter.

“It is often presumed that the cooler North Atlantic will quickly lead to cooling in Europe, or at least a slowdown in its rate of warming,” says Ayako Yamamoto, a PhD student at McGill University and lead author of the study. “But our research suggests that the dynamics of the atmosphere might stop this relative cooling from showing up in Europe in winter in the decades following an Atlantic cooling.”

The complete paper is The absence of an Atlantic imprint on the multidecadal variability of wintertime European temperature by Ayako Yamamoto & Jaime B. Palter Nature Communications (2016). Excerpts in italics with my bolds.

Figure 2: The spatial pattern of the AMO index and its relationship with the atmospheric flow in January. Composite maps of (a) sea surface temperature (SST) field and (b) 500 hPa geopotential height field (Z500) for AMO anomalously positive years (left panel) and negative years (right panel). The January mean field is shown in contours, and its departure from the 72-year climatology is represented by colour shading. The thick grey contour line in a denotes 0 °C, whereas thin (dashed) lines denote positive (negative) SST every 5 °C. The black dashed lines in b are drawn through the local maxima of the geopotential height field at each latitude, which is the point where the wind changes direction from south–westerly to north–westerly.

The large-scale atmospheric flow varies with the AMO index (Fig. 2b). The difference in the 500-hPa geopotential height (Z500) field, which is analogous to streamlines, shows that the direction of winds arriving in western Europe changes between the two AMO phases: winds are more northerly during the anomalous AMO-positive years, whereas they are more zonal during the AMO-negative years (Fig. 2b). The more tightly spaced isohypses during the AMO-negative years indicate a swifter flow relative to the AMO-positive years. Accordingly, the AMO-negative years see an elongated and more zonal January storm track (Supplementary Fig. 1), which is consistent with results from a free-running climate model7. Composite Z500 maps constructed with more complete sampling of the longer decadal periods associated with the AMO show similar, albeit weaker, anomaly patterns (Supplementary Fig. 2a).

In winter in the North Atlantic, SST is almost always warmer than the surface air temperature (SAT), so the ocean loses heat rapidly to the atmosphere over the entirety of the basin (that is, positive fluxes in our convention; Fig. 3b and Supplementary Fig. 3b). The fluxes over the warm Gulf Stream and its North Atlantic Current extension are generally a factor of five higher than found elsewhere. However, a view of the fluxes weighted by the fraction of time the particles spend in each location on their journey to western Europe (Fig. 3c and Supplementary Fig. 3c) suggests a reduced role of these strong flux regions in establishing western European wintertime temperature.

The difference in the number density of the particle positions between the composite AMO periods (Fig. 3d) shows a significant distinction in the preferred pathways, with the statistical significance increasing when results are separated by particles launched from northern and southern sub-regions of western Europe (Supplementary Fig. 3d). In the AMO-positive years, particles spend more of their 10-day trajectory recirculating locally to the southwest of Iceland. During the AMO-negative years, the pathways are anomalously long, and a greater number of trajectories originate from North America and the Arctic, before transiting over the Labrador Sea and mid-latitude North Atlantic.

The strengthening and lengthening of the storm track in sync with anomalously cooler North Atlantic SSTs has important implications for future climate. Given that decadal variability in North Atlantic SSTs may be driven partly by fluctuations in the strength of the AMOC10,11,12, our result suggests the possibility of a stabilizing feedback for ocean circulation: Cooler SSTs associated with a sluggish AMOC is linked with an atmospheric adjustment that enhances turbulent heat fluxes over oceanic convective regions in winter. These larger fluxes could possibly reinvigorate convection, deep water formation and the AMOC. Moreover, the observed link of the atmospheric circulation with the cool SST anomalies of the late 1970s to early 1990s is much like the predicted change of the storm track in response to a decline of the AMOC under global warming36. A weakened AMOC has long been thought to cause anomalous cooling in western Europe via a decline in oceanic heat transport and associated atmospheric feedbacks21. However, the changes we describe here in atmospheric Lagrangian trajectories and the heat fluxes along them could provide a mechanism that reduces the magnitude of European wintertime cooling on decadal time scales, even as they might stabilize the oceanic circulation.

The answer is blowin’ in the wind.  Bob Dylan

This informative post comes from Hannah Christensen Six clouds you should know about – and what they can reveal about the weather March 23, 2018 at phys.org. Text and images from the article.

You don’t need a supercomputer to predict how the weather above your head is likely to change over the next few hours – this has been known across cultures for millennia. By keeping an eye on the skies above you, and knowing a little about how clouds form, you can predict whether rain is on the way.

And moreover, a little understanding of the physics behind cloud formation highlights the complexity of the atmosphere, and sheds some light on why predicting the weather beyond a few days is such a challenging problem.

So here are six clouds to keep an eye out for, and how they can help you understand the weather.

1. Cumulus

Clouds form when air cools to the dew point, the temperature at which the air can no longer hold all its water vapour. At this temperature, water vapour condenses to form droplets of liquid water, which we observe as a cloud. For this process to happen, we require air to be forced to rise in the atmosphere, or for moist air to come into contact with a cold surface.

On a sunny day, the sun’s radiation heats the land, which in turn heats the air just above it. This warmed air rises by convection and forms Cumulus. These “fair weather” clouds look like cotton wool. If you look at a sky filled with cumulus, you may notice they have flat bases, which all lie at the same level. At this height, air from ground level has cooled to the dew point. Cumulus clouds do not generally rain – you’re in for fine weather.

2. Cumulonimbus

While small Cumulus do not rain, if you notice Cumulus getting larger and extending higher into the atmosphere, it’s a sign that intense rain is on the way. This is common in the summer, with morning Cumulus developing into deep Cumulonimbus (thunderstorm) clouds in the afternoon.

Near the ground, Cumulonimbus are well defined, but higher up they start to look wispy at the edges. This transition indicates that the cloud is no longer made of water droplets, but ice crystals. When gusts of wind blow water droplets outside the cloud, they rapidly evaporate in the drier environment, giving water clouds a very sharp edge. On the other hand, ice crystals carried outside the cloud do not quickly evaporate, giving a wispy appearance.

Cumulonimbus are often flat-topped. Within the Cumulonimbus, warm air rises by convection. In doing so, it gradually cools until it is the same temperature as the surrounding atmosphere. At this level, the air is no longer buoyant so cannot rise further. Instead it spreads out, forming a characteristic anvil shape.

3. Cirrus

Cirrus form very high in the atmosphere. They are wispy, being composed entirely of ice crystals falling through the atmosphere. If Cirrus are carried horizontally by winds moving at different speeds, they take a characteristic hooked shape. Only at very high altitudes or latitudes do Cirrus produce rain at ground level.

But if you notice that Cirrus begins to cover more of the sky, and gets lower and thicker, this is a good indication that a warm front is approaching. In a warm front, a warm and a cold air mass meet. The lighter warm air is forced to rise over the cold air mass, leading to cloud formation. The lowering clouds indicate that the front is drawing near, giving a period of rain in the next 12 hours.

4. Stratus

Stratus is a low continuous cloud sheet covering the sky. Stratus forms by gently rising air, or by a mild wind bringing moist air over a cold land or sea surface. Stratus cloud is thin, so while conditions may feel gloomy, rain is unlikely, and at most will be a light drizzle. Stratus is identical to fog, so if you’ve ever been walking in the mountains on a foggy day, you’ve been walking in the clouds.

5. Lenticular

Our final two cloud types will not help you predict the coming weather, but they do give a glimpse of the extraordinarily complicated motions of the atmosphere. Smooth, lens-shaped Lenticular clouds form as air is blown up and over a mountain range.

Once past the mountain, the air sinks back to its previous level. As it sinks, it warms and the cloud evaporates. But it can overshoot, in which case the air mass bobs back up allowing another Lenticular cloud to form. This can lead to a string of clouds, extending some way beyond the mountain range. The interaction of wind with mountains and other surface features is one of the many details that have to be represented in computer simulators to get accurate predictions of the weather.

6. Kelvin-Helmholtz

And lastly, my personal favourite. The Kelvin-Helmholtzcloud resembles a breaking ocean wave. When air masses at different heights move horizontally with different speeds, the situation becomes unstable. The boundary between the air masses begins to ripple, eventually forming larger waves.

Kelvin-Helmholtz clouds are rare – the only time I spotted one was over Jutland, western Denmark – because we can only see this process taking place in the atmosphere if the lower air mass contains a cloud. The cloud can then trace out the breaking waves, revealing the intricacy of the otherwise invisible motions above our heads.

The Earth’s North magnetic pole has been wandering at 10-year intervals from 1970 to 2020, as seen in this animation from the National Centers for Environmental Information.

This post discusses solar and geologic magnetic pole swapping (not with each other of course) and the implications for humans. First the earth and later on the sun.

What On Earth?

Newsweek chose to report yesterday on earth’s meandering north pole as shown in the cool graphic above. That article (here) aims at sensational possible calamities, including high energy radiation, space particles, ozone depletion and electrical blackouts. A more sober assessment is provided by the conversation Why the Earth’s magnetic poles could be about to swap places – and how it would affect us By Phil Livermore and Jon Mound of U. Leeds.Excerpts below with my bolds.

The Earth’s magnetic field surrounds our planet like an invisible force field – protecting life from harmful solar radiation by deflecting charged particles away. Far from being constant, this field is continuously changing. Indeed, our planet’s history includes at least several hundred global magnetic reversals, where north and south magnetic poles swap places. So when’s the next one happening and how will it affect life on Earth?

During a reversal the magnetic field won’t be zero, but will assume a weaker and more complex form. It may fall to 10% of the present-day strength and have magnetic poles at the equator or even the simultaneous existence of multiple “north” and “south” magnetic poles.

Geomagnetic reversals occur a few times every million years on average. However, the interval between reversals is very irregular and can range up to tens of millions of years.

There can also be temporary and incomplete reversals, known as events and excursions, in which the magnetic poles move away from the geographic poles – perhaps even crossing the equator – before returning back to their original locations. The last full reversal, the Brunhes-Matuyama, occurred around 780,000 years ago. A temporary reversal, the Laschamp event, occurred around 41,000 years ago. It lasted less than 1,000 years with the actual change of polarity lasting around 250 years.

In 2003, the so-called Halloween storm caused local electricity-grid blackouts in Sweden, required the rerouting of flights to avoid communication blackout and radiation risk, and disrupted satellites and communication systems. But this storm was minor in comparison with other storms of the recent past, such as the 1859 Carrington event, which caused aurorae as far south as the Caribbean.

The simple fact that we are “overdue” for a full reversal and the fact that the Earth’s field is currently decreasing at a rate of 5% per century, has led to suggestions that the field may reverse within the next 2,000 years. But pinning down an exact date – at least for now – will be difficult.

Since 2014, Swarm—a trio of satellites from the European Space Agency—has allowed researchers to study changes building at the Earth’s core, where the magnetic field is generated.

Historically, Earth’s North and South magnetic poles have flipped every 200,000 or 300,000 years—except right now, they haven’t flipped successfully for about 780,000 years. But the planet’s magnetic field is at long last showing signs of shifting.

The Earth’s magnetic field is generated within the liquid core of our planet, by the slow churning of molten iron. Like the atmosphere and oceans, the way in which it moves is governed by the laws of physics. We should therefore be able to predict the “weather of the core” by tracking this movement, just like we can predict real weather by looking at the atmosphere and ocean. A reversal can then be likened to a particular type of storm in the core, where the dynamics – and magnetic field – go haywire (at least for a short while), before settling down again.

The difficulties of predicting the weather beyond a few days are widely known, despite us living within and directly observing the atmosphere. Yet predicting the Earth’s core is a far more difficult prospect, principally because it is buried beneath 3,000km of rock such that our observations are scant and indirect. However, we are not completely blind: we know the major composition of the material inside the core and that it is liquid. A global network of ground-based observatories and orbiting satellites also measure how the magnetic field is changing, which gives us insight into how the liquid core is moving.

Solar Pole Swapping Puts Earth to Shame

White lines show the magnetic field emanating from the sun’s surface. NASA

Background:

The sun as a whole also has a “global” magnetic field, oriented more or less north-south. So we can think of the sun as a large N-S magnet, like our Earth, but with smaller variously (but not randomly) oriented and continually evolving mini-magnets distributed over its photosphere (visible surface) and throughout its corona (extended atmosphere).

However, unlike our Earth, the sun’s large scale magnetic field flips over on a regular basis, roughly every 11 years. (Actually, Earth’s flips too, very irregularly. The last time was 780,000 years ago. But that’s another story.) Solar magnetic reversals occur close to solar maximum, when the number of sunspots is near its peak, though it is often a gradual process, taking up to 18 months.

A solar flare (the white patch on the sun), and an erupting prominence reaching into space, are features of our active sun, and place the size of Earth in context. NASA

Paul Cally solar physicist Monash U (here)

About the Current Quiet Sun

Euan Mearns considers the implications at Energy Matters The Death of Sunspot Cycle 24, Huge Snow and Record Cold  Excerpts below with my bolds.

8 meter snow depth in Chamonix in the shadow of Mont Blanc in the French Alps January 2018

It looks like the snow in this drift is ~ 8m deep. And this is in the valley, not in the high basins where the snow fields that feed the glaciers lie. Now it’s obviously far too early to begin to draw any conclusions. But IF we get a run of 3 or 4 winters that dump this much snow, it is not inconceivable for me to imagine Alpine glaciers once again beginning to advance. I’m totally unsure how long it takes for pressure in the glacier source to feed through to advance of the snout.

So what is going on? We’ve been told by climate scientists that snow would become a thing of the past. We’ve also been told that global warming might lead to more snow and less snow. And we’ve been told that warming might even lead to cooling. The competing theory to the CO2 greenhouse is that the Sun has a prominent role in modulating Earth’s climate that was so eloquently described by Phil Chapman in his post earlier this week. This theory simply observes a strong connection between a weak solar wind (that is expressed by low sunspot numbers) and cold, snowy winters in the N hemisphere. Uniquely, most of those who argue for a strong solar influence also acknowledge the overprint of anthropogenic CO2. The IPCC effectively sets the Sun to zero. The Sun is entering a grand solar minimum already christened the Eddy Minimum by the solar physics community.

Figure 2 It is crucial to look at the baseline closely that in 2009 actually touched zero for months on end. This is not normal for the low point of the cycle. Figure 3 shows how cycle 24 was feeble compared with recent cycles. And it looks like it will have a duration of ~10 years (2009-2019) which as the low end of the normal range which is 9 to 14 years with mean of 11 years. Chart adapted from SIDC is dated 1 January 2018.

Mearns provides this summary of his article Cosmic Rays, Magnetic Fields and Climate Change

Cosmic rays are deflected by BOTH the Sun’s and Earth’s magnetic fields and there may also be variations in the incident cosmic ray background. Cosmogenic isotope variations, therefore, do not only record variations in solar activity.

This has two significant implications for me: 1) when I have looked into cosmogenic isotopes in the past I have been perplexed by the fact that in parts you see a wonderful coherence with “climate” (T≠climate) while else where, the relationship breaks down, and 2) my recent focus has been on variations in spectrum from the Sun (which may still be important) but to the extent that the Laschamp event (Earth’s magnetic field) may also be implicated in climate change then the emphasis needs to shift to cosmic rays themselves i.e. what Svensmark has been saying for years.

For readers not familiar with Earth’s magnetic field. It periodically flips but on a time-scale of millions of years. The N pole moves to the S pole and in the process of doing so the magnetic field strength collapses as evidenced by “Figure 7” in Phil’s post. The last time this happened was during the Laschamp event ~ 41,000 years ago. There was a full but short lived reversal, but the Earth’s magnetic field did collapse.

Now here’s the main point. We know that the glacial cycles beat to a 41,000 year rhythm that is the obliquity (tilt) of Earth’s axis. The magnetic field originates in Earth’s liquid mainly iron core. This raises the question, can changes in obliquity affect the geo-dynamo. You have to read what Phil has written closely:

Since we absolutely know (don’t we?) that the interglacial to glacial transitions of the current ice age are caused by Milankovitch forcing, the usual interpretation is that there must be some unknown mechanism by which changes in the orbit of the Earth and/or the tilt of the polar axis affect the geodynamo, triggering the excursions.

For decades to centuries, Earth’s N magnetic pole was pretty well fixed to a point in northern Canada. Not much in the news, but it has recently begun to migrate, quite rapidly.

For a more complete description of solar effects effects on earth’s climate see
The cosmoclimatology theory

Earth’s magnetic field, in blue, shields the planet from the solar wind. NASA