Climate Science | Science Matters

March 2025 Oceans Cooling Persists

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

The ocean covers 71% of the globe and drives average temperatures;
SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
A major El Nino was the dominant climate feature in recent years.

HadSST is generally regarded as the best of the global SST data sets, and so the temperature story here comes from that source. Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated. HadSST4 is the same as v.3, except that the older data from ship water intake was re-estimated to be generally lower temperatures than shown in v.3. The effect is that v.4 has lower average anomalies for the baseline period 1961-1990, thereby showing higher current anomalies than v.3. This analysis concerns more recent time periods and depends on very similar differentials as those from v.3 despite higher absolute anomaly values in v.4. More on what distinguishes HadSST3 and 4 from other SST products at the end. The user guide for the current version HadSST4.1.1.0 is here. The charts and analysis below is produced from the current data.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST4 starting in 2015 through February 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes. That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period. A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C last year, ~0.3° higher than the 2015 peak. Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. After 12 months of cooling in SH and the Tropics, the Global anomaly came back down, led by NH cooling the last 8 months from its 1.3C peak in August, down to 0.8C in March. With some recent warming in the Tropics and SH, all regions are now close together nearly at the global anomaly, about 0.1C higher than the average for this period.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures. It is the ocean that warms the air, not the other way around. Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years. Heat builds up in the equatorial Pacific to the west of Indonesia and so on. Then when enough of it builds up it surges across the Pacific and changes the currents and the winds. As it surges toward South America it was discovered and named in the 19th century It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world. We feel it when it gets rainier in Southern California for example. So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well. One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

The graph below is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations. Previous posts focused on the rise and fall of the last El Nino starting in 2015. This post adds a longer view, encompassing the significant 1998 El Nino and since. The color schemes are retained for Global, Tropics, NH and SH anomalies. Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July.

To enlarge image, open in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations. Previous posts focused on the rise and fall of the last El Nino starting in 2015. This post adds a longer view, encompassing the significant 1998 El Nino and since. The color schemes are retained for Global, Tropics, NH and SH anomalies. Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8, a lower peak warming in 2009-10, following by cooling in 2011-12. Again SSTs are average 2013-14.

Now a different pattern appears. The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off. But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average. In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16. NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.) Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021. In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year. Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping. After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, with a slight upward bump in February-March 2025.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH. The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before. After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future. So I find that ERSSTv5 AMO dataset has current data. It differs from Kaplan, which reported average absolute temps measured in N. Atlantic. “ERSST5 AMO follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.” So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed. As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin. Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak was holding at 1.4C before declining. An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years. 2010, 2021, 2022 all peaked strongly in August or September. 1998 and 2007 were mildly warm. 2016 and 2018 were matching or cooler than the global average. 2023 started out slightly warm, then rose steadily to an extraordinary peak in July. August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April. Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June. In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began. Now 2025 started much lower than the previous year and is headed sharply downward.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The purple line is the average anomaly 1980-1996 inclusive, value 0.17. The orange line the average 1980-2024, value 0.38, also for the period 1997-2012. The red line is 2013-2024, value 0.67. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity: Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher than expected 1-2 years in the future. As livescience put it: Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be? Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century. SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.” The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect. The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

Footnote: Why Rely on HadSST4

HadSST is distinguished from other SST products because HadCRU (Hadley Climatic Research Unit) does not engage in SST interpolation, i.e. infilling estimated anomalies into grid cells lacking sufficient sampling in a given month. From reading the documentation and from queries to Met Office, this is their procedure.

HadSST4 imports data from gridcells containing ocean, excluding land cells. From past records, they have calculated daily and monthly average readings for each grid cell for the period 1961 to 1990. Those temperatures form the baseline from which anomalies are calculated.

In a given month, each gridcell with sufficient sampling is averaged for the month and then the baseline value for that cell and that month is subtracted, resulting in the monthly anomaly for that cell. All cells with monthly anomalies are averaged to produce global, hemispheric and tropical anomalies for the month, based on the cells in those locations. For example, Tropics averages include ocean grid cells lying between latitudes 20N and 20S.

Gridcells lacking sufficient sampling that month are left out of the averaging, and the uncertainty from such missing data is estimated. IMO that is more reasonable than inventing data to infill. And it seems that the Global Drifter Array displayed in the top image is providing more uniform coverage of the oceans than in the past.

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

Politicized Science Case Study: National Climate Assessment

Posted on April 8 by Ron Clutz

This post incorporates two dimensions of climate science reporting: firstly what and who are involved in the production, and secondly what the Trump administration might do to achieve a more balanced result. A recent article exposes the process by which the US National Climate Assessment (NCA) has been produced while ensuring that true believers control the content. Brent Scher writes at Daily Wire Meet The Government Consultants Raking In Millions To Spread Climate Doom. Excerpts in italics with my bolds and added images.

The government is outsourcing the ‘crown jewel’ of
climate change research to liberal climate consultants.

More than three decades ago, Congress launched an initiative called the U.S. Global Change Research Program. Today, it spends billions of dollars a year empowering liberal climate scientists to spread climate change doom.

The government group says its role is to provide the “scientific foundation to support informed decision-making across the United States” on climate change. It’s done so by producing five National Climate Assessment reports, which are considered the “crown jewel” of climate research.

Despite taking funding from at least ten separate government agencies, producing the report seems to be the group’s sole function. The most recent iteration — published in 2023 and still prominently showcased on its government website — warns that “severe climate risks to the United States will continue to grow.” The next report is due out in the next couple of years, according to E&E News.

The National Climate Assessment is not simply an intellectual exercise, but rather one that carries real policy might. Congress and agencies use it to justify regulations and funding decisions, and states and cities across the country lean on it as the non-partisan scientific foundation for their own climate action plans. In summary, it is the scientific bedrock for directing policy at all levels of government towards liberal climate change goals.

While the U.S. Global Change Research Program states on its website that it has a budget of $4.95 billion in 2025, it only lists two full-time employees. So, who’s getting paid to put the massive and consequential report together?

Sources familiar with past iterations of the National Climate Assessment say the work is largely outsourced to a group called ICF, a massive government contractor that has an active contract to work on the report. The Daily Wire identified at least one active contract from NASA for ICF to “support” the U.S. Global Change Research Program. ICF is set to be paid millions of dollars during the Trump administration to “assist the nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change.”

The contract was first announced in June 2021, and described as a $34 million, five-year contract to help with the National Climate Assessments. Only $18 million has been paid out, according to the government spending database. But with another assessment on deck and ICF under contract for another year, the additional $16 million could be disbursed in the next year.

A climate scientist who has worked on the National Climate Assessment
in the past says ICF runs the show, virtually controlling
the entire U.S. Global Change Research Program.

“By providing all staff for the USGCRP, a federal agency, the ICF exerts undue influence over the global change narrative and priorities presented by the federal government,” said the official, who requested anonymity to discuss the work. “The ICF, through the USGCRP, exerts an undue influence on the production of the National Climate Assessment every four years. With the exception of its Executive Director and the Director of the National Climate Assessment, the ICF supplies all staff associated with the USGCRP.”

ICF takes in far more in government contracts than its active $34 million from NASA. An analysis of federal spending data found that the consulting firm rakes in hundreds of millions of dollars each year through federal contracts, and took in over $2 billion during the Biden administration.

The consulting firm is likely aware that the scope of its government work could be slashed during Trump’s term, and so are investors. Its stock price was at $171 a share days ahead of last November’s election, but has since cratered to just $77 a share, the lowest it had been since the last time Trump was president. (Yes, the stock price fell before the current market volatility caused by tariffs).

Houston Keene, a former journalist who now leads a government transparency organization, argues that unnamed government consultants shouldn’t be paid millions to chart the nation’s climate policy.

“The public deserves an honest assessment from the government on the state of climate science,” Keene said. “That requires an objective, nonpartisan author who does not have financial interests in the outcome. ICF appears to be none of these things.”

“There can be no proper assessment with scientific integrity when a clearly partisan and financially conflicted activist organization is holding the pen,” he said.

A top Trump administration official, Russell Vought, has signaled that he wanted to exert more oversight over the next climate assessment. Vought runs the powerful Office of Management and Budget, and has openly stated that he wants to make deep cuts to “woke and weaponized” spending.

Vought has specifically called out the U.S. Global Change Research Program’s report, arguing that the bureaucrats who write it end up with outsized power over government action. He’s called for an investigation of the political leanings of the contractors that assemble the report.

A March 2025 report at SciAm provides background on recent developments regarding the NCA: Trump Official Who Tried to Downplay Major Climate Report Now Will Oversee It. Excerpts in italics with my bolds and added images.

Stuart Levenbach alarmed scientists years ago when he attempted
to meddle with a congressionally mandated climate report

Stuart Levenbach was tapped last month by administration officials to serve as associate director for natural resources, energy, science, and water in the Office of Management and Budget.

The previous time President Donald Trump was in the White House, Levenbach attempted to tone down the summary conclusions of the National Climate Assessment, a wide-ranging report that relies on the contributions of hundreds of researchers to assess how global warming is transforming the United States.

Scientists say Levenbach tried to downplay climate risks in the fourth installment of the report, which comes out every four years or so. In that edition, Levenbach was concerned especially with the higher greenhouse gas emissions assumptions the report partially relied on and sought to soften the language of the report’s summary, the scientists say.

“He was the one that tried to slow it down to the point of it not coming out,” said Don Wuebbles, a climate scientist at the University of Illinois who has worked on all five previous National Climate Assessments.

Levenbach’s delay tactics were ultimately unsuccessful, and the fourth installment of the report was released in 2018 on the day after Thanksgiving.

In response to questions from Politico’s E&E News, a Trump administration official with the Office of Management and Budget described the scientists’ concerns as “fake news.”

The National Climate Assessment is based on a range of emissions scenarios, including those that are not worst-case scenarios. The fourth version of the report concluded the country was not on track to cut carbon dioxide emissions at a pace to avoid some of the worst consequences of climate change.

At the time, Levenbach’s role at NOAA carried more weight than usual because the agency was operating without a permanent administrator, and did so for the entire first Trump presidency. Reached for comment, OMB spokeswoman Rachel Cauley did not deny that Levenbach tried to alter the report, but she criticized how it was put together.

“The assessment was riddled with the worst case scenario and
the authors weren’t transparent about it,” she said in a statement.”

Levenbach is joining OMB at a time when its director, Russ Vought, wants to suppress climate science throughout the federal government and increase Trump White House oversight over the next installment of the National Climate Assessment, which is due out in 2026 or 2027.

Levenbach’s appointment to a powerful White House role with oversight of the nation’s scientific endeavors comes at a time when the administration is preparing a possible challenge to the endangerment finding, a bedrock ruling which considers greenhouse gases a danger to public health and is a foundation of climate regulations.

March 2025 UAH Yo-yo Temps

Posted on April 5 by Ron Clutz

The post below updates the UAH record of air temperatures over land and ocean. Each month and year exposes again the growing disconnect between the real world and the Zero Carbon zealots. It is as though the anti-hydrocarbon band wagon hopes to drown out the data contradicting their justification for the Great Energy Transition. Yes, there was warming from an El Nino buildup coincidental with North Atlantic warming, but no basis to blame it on CO2.

As an overview consider how recent rapid cooling completely overcame the warming from the last 3 El Ninos (1998, 2010 and 2016). The UAH record shows that the effects of the last one were gone as of April 2021, again in November 2021, and in February and June 2022 At year end 2022 and continuing into 2023 global temp anomaly matched or went lower than average since 1995, an ENSO neutral year. (UAH baseline is now 1991-2020). Then there was an usual El Nino warming spike of uncertain cause, unrelated to steadily rising CO2 and now dropping steadily.

For reference I added an overlay of CO2 annual concentrations as measured at Mauna Loa. While temperatures fluctuated up and down ending flat, CO2 went up steadily by ~60 ppm, a 15% increase.

Furthermore, going back to previous warmings prior to the satellite record shows that the entire rise of 0.8C since 1947 is due to oceanic, not human activity.

gmt-warming-events

The animation is an update of a previous analysis from Dr. Murry Salby. These graphs use Hadcrut4 and include the 2016 El Nino warming event. The exhibit shows since 1947 GMT warmed by 0.8 C, from 13.9 to 14.7, as estimated by Hadcrut4. This resulted from three natural warming events involving ocean cycles. The most recent rise 2013-16 lifted temperatures by 0.2C. Previously the 1997-98 El Nino produced a plateau increase of 0.4C. Before that, a rise from 1977-81 added 0.2C to start the warming since 1947.

Importantly, the theory of human-caused global warming asserts that increasing CO2 in the atmosphere changes the baseline and causes systemic warming in our climate. On the contrary, all of the warming since 1947 was episodic, coming from three brief events associated with oceanic cycles. And in 2024 we saw an amazing episode with a temperature spike driven by ocean air warming in all regions, along with rising NH land temperatures, now dropping below its peak.

Chris Schoeneveld has produced a similar graph to the animation above, with a temperature series combining HadCRUT4 and UAH6. H/T WUWT

March 2025 UAH Temps Yo-yo, Ocean First, Then Land

With apologies to Paul Revere, this post is on the lookout for cooler weather with an eye on both the Land and the Sea. While you heard a lot about 2020-21 temperatures matching 2016 as the highest ever, that spin ignores how fast the cooling set in. The UAH data analyzed below shows that warming from the last El Nino had fully dissipated with chilly temperatures in all regions. After a warming blip in 2022, land and ocean temps dropped again with 2023 starting below the mean since 1995. Spring and Summer 2023 saw a series of warmings, continuing into 2024 peaking in April, then cooling off to the present.

UAH has updated their TLT (temperatures in lower troposphere) dataset for March 2025. Due to one satellite drifting more than can be corrected, the dataset has been recalibrated and retitled as version 6.1 Graphs here contain this updated 6.1 data. Posts on their reading of ocean air temps this month are ahead of the update from HadSST4. I posted recently on SSTs February 2025 Oceans Keep Cool. These posts have a separate graph of land air temps because the comparisons and contrasts are interesting as we contemplate possible cooling in coming months and years.

Sometimes air temps over land diverge from ocean air changes. In July 2024 all oceans were unchanged except for Tropical warming, while all land regions rose slightly. In August we saw a warming leap in SH land, slight Land cooling elsewhere, a dip in Tropical Ocean temp and slightly elsewhere. September showed a dramatic drop in SH land, overcome by a greater NH land increase. 2025 has shown a sharp contrast between land and sea, first with ocean air temps falling in January recovering in February. Then land air temps, especially NH, dropped in February and recovered in March.

Note: UAH has shifted their baseline from 1981-2010 to 1991-2020 beginning with January 2021. v6.1 data was recalibrated also starting with 2021. In the charts below, the trends and fluctuations remain the same but the anomaly values changed with the baseline reference shift.

Presently sea surface temperatures (SST) are the best available indicator of heat content gained or lost from earth’s climate system. Enthalpy is the thermodynamic term for total heat content in a system, and humidity differences in air parcels affect enthalpy. Measuring water temperature directly avoids distorted impressions from air measurements. In addition, ocean covers 71% of the planet surface and thus dominates surface temperature estimates. Eventually we will likely have reliable means of recording water temperatures at depth.

Recently, Dr. Ole Humlum reported from his research that air temperatures lag 2-3 months behind changes in SST. Thus cooling oceans portend cooling land air temperatures to follow. He also observed that changes in CO2 atmospheric concentrations lag behind SST by 11-12 months. This latter point is addressed in a previous post Who to Blame for Rising CO2?

After a change in priorities, updates are now exclusive to HadSST4. For comparison we can also look at lower troposphere temperatures (TLT) from UAHv6.1 which are now posted for March 2025. The temperature record is derived from microwave sounding units (MSU) on board satellites like the one pictured above. Recently there was a change in UAH processing of satellite drift corrections, including dropping one platform which can no longer be corrected. The graphs below are taken from the revised and current dataset.

The UAH dataset includes temperature results for air above the oceans, and thus should be most comparable to the SSTs. There is the additional feature that ocean air temps avoid Urban Heat Islands (UHI). The graph below shows monthly anomalies for ocean air temps since January 2015.

In 2021-22, SH and NH showed spikes up and down while the Tropics cooled dramatically, with some ups and downs, but hitting a new low in January 2023. At that point all regions were more or less in negative territory.

After sharp cooling everywhere in January 2023, there was a remarkable spiking of Tropical ocean temps from -0.5C up to + 1.2C in January 2024. The rise was matched by other regions in 2024, such that the Global anomaly peaked at 0.86C in April. Since then all regions have cooled down sharply to a low of 0.27C in January. In February 2025, SH rose from 0.1C to 0.4C pulling the Global ocean air anomaly up to 0.47C, where it stayed in March.

Land Air Temperatures Tracking in Seesaw Pattern

We sometimes overlook that in climate temperature records, while the oceans are measured directly with SSTs, land temps are measured only indirectly. The land temperature records at surface stations sample air temps at 2 meters above ground. UAH gives tlt anomalies for air over land separately from ocean air temps. The graph updated for March is below.

Here we have fresh evidence of the greater volatility of the Land temperatures, along with extraordinary departures by SH land. The seesaw pattern in Land temps is similar to ocean temps 2021-22, except that SH is the outlier, hitting bottom in January 2023. Then exceptionally SH goes from -0.6C up to 1.4C in September 2023 and 1.8C in August 2024, with a large drop in between. In November, SH and the Tropics pulled the Global Land anomaly further down despite a bump in NH land temps. February showed a sharp drop in NH land air temps from 1.07C down to 0.56C, pulling the Global land anomaly downward from 0.9C to 0.6C. Now that drop is reversed in March with both NH and Global land back to January values, despite another drop in SH land air temps.

The Bigger Picture UAH Global Since 1980

The chart shows monthly Global Land and Ocean anomalies starting 01/1980 to present. The average monthly anomaly is -0.03, for this period of more than four decades. The graph shows the 1998 El Nino after which the mean resumed, and again after the smaller 2010 event. The 2016 El Nino matched 1998 peak and in addition NH after effects lasted longer, followed by the NH warming 2019-20. An upward bump in 2021 was reversed with temps having returned close to the mean as of 2/2022. March and April brought warmer Global temps, later reversed

With the sharp drops in Nov., Dec. and January 2023 temps, there was no increase over 1980. Then in 2023 the buildup to the October/November peak exceeded the sharp April peak of the El Nino 1998 event. It also surpassed the February peak in 2016. In 2024 March and April took the Global anomaly to a new peak of 0.94C. The cool down started with May dropping to 0.9C, and in June a further decline to 0.8C. October went down to 0.7C, November and December dropped to 0.6C. February went down to 0.5C, now back up to 0.6C driven by the bounce in NH land air temps.

The graph reminds of another chart showing the abrupt ejection of humid air from Hunga Tonga eruption.

TLTs include mixing above the oceans and probably some influence from nearby more volatile land temps. Clearly NH and Global land temps have been dropping in a seesaw pattern, nearly 1C lower than the 2016 peak. Since the ocean has 1000 times the heat capacity as the atmosphere, that cooling is a significant driving force. TLT measures started the recent cooling later than SSTs from HadSST4, but are now showing the same pattern. Despite the three El Ninos, their warming had not persisted prior to 2023, and without them it would probably have cooled since 1995. Of course, the future has not yet been written.

The Right Climate Stuff

Posted on April 3 by Ron Clutz

Not everyone is aware that the scientists and engineers who made the NASA space program successful disputed the global warming/climate change narrative promoted at the agency by people like James Hansen.

After all the slogan in the NASA workplace was that of Edward Deming, and they were only convinced by the facts rather than feelings or opinions about the future. Many of them formed the Right Climate Stuff Foundation.

https://www.therightclimatestuff.com/

In particular Walter Cunningham explained his reasoning in an article In Science, Ignorance is not Bliss. Excerpts in italics with my bolds and added images.

NASA has played a key role in one of the greatest periods of scientific progress in history. It is uniquely positioned to collect the most comprehensive data on our biosphere. For example, recently generated NASA data enabled scientists to finally understand the Gulf Stream warming mechanism and its effect on European weather. Such data will allow us to improve our models, resulting in better seasonal forecasts.

NASA’s Aqua satellite is showing that water vapor, the dominant greenhouse gas, works to offset the effect of carbon dioxide (CO2). This information, contrary to the assumption used in all the warming models, is ignored by global warming alarmists.

Climate understanding and critical decision making require
comprehensive data about our planet’s land, sea, and atmosphere.

Without an adequate satellite system to provide such data, policy efforts and monitoring international environmental agreements are doomed to failure. Our satellite monitoring capability is being crippled by interagency wrangling and federal budget issues. As much as a third of our satellites need replacing in the next couple of years.

NASA should be at the forefront in the collection of scientific evidence and debunking the current hysteria over human-caused, or Anthropogenic Global Warming (AGW). Unfortunately, it is becoming just another agency caught up in the politics of global warming, or worse, politicized science.

Advocacy is replacing objective evaluation of data, while
scientific data is being ignored in favor of emotions and politics.

There are excellent correlations between the regular fluctuations of the Sun and the Earth’s temperature, while scientists can not find a relationship between industrial activity, energy consumption, and global temperatures. But global warming is an issue no longer being decided in the scientific arena.

Saying the Earth is warming is to state the obvious. Since the end of the ice age, the Earth’s temperature has increased approximately 16 degrees Fahrenheit and sea levels have risen a total of 300 feet. That is certain and measurable evidence of warming, but it is not evidence of AGW—human-caused warming.

We can track the temperature of the Earth back for millennia. Knowing the temperature of the Earth, past or present, is a matter of collecting data, analyzing it, and coming up with the best answer to account for the data. Collecting such data on a global basis is a NASA forte. I believe in global climate change, but there is no way that humans can influence the temperature of our planet to any measurable degree with the tools currently at their disposal. Any human contribution to global temperature change is lost in the noise of terrestrial and cosmic factors.

Our beautiful home planet has been warming and cooling for the last 4.8 billion years. Most recently, it has been warming—be it ever so slightly—but there is nothing unusual about it! The changes and rates of change in the Earth’s temperature, just since the Industrial Revolution, have occurred many times in our climatic history. While climate scientists generally agree that the Earth’s temperature is always changing, not many of them would say that humans are responsible for those changes.

None of this is to say there are not legitimate reasons to restrict emissions of any number of chemicals into the atmosphere. We should just not fool ourselves into thinking we will change the temperature of the Earth by doing so.

In a December 2007 Senate report, 400 prominent scientists signed a letter pointing out that climate change was a well-known natural phenomenon, and that adapting to it is far more sensible than attempting to prevent it. Their ranks included experts in climatology, geology, oceanography, biology, glaciology, biogeography, meteorology, economics, chemistry, mathematics, environmental sciences, engineering, physics, and paleo-climatology.

Their message: When changes are gradual, man has
an almost infinite ability to adapt and evolve.

The fearmongers of global warming base their case on the correlation between CO2 and global temperature, even though we cannot be sure which is cause and which is effect. Historically, temperature increases have preceded high CO2 levels, and there have been periods when atmospheric CO2 levels were as much as 16 times what they are now, periods characterized not by warming but by glaciation. You might have to go back half a million years to match our current level of atmospheric CO2, but you only have to go back to the Medieval Warming Period, from the 10th to the 14th Century, to find an intense global warming episode, followed immediately by the drastic cooling of the Little Ice Age. Neither of these events were caused by variations in CO2 levels.

Even though CO2 is a relatively minor constituent of “greenhouse gases,” alarmists have made it the whipping boy for global warming (probably because they know how fruitless it would be to propose controlling other principal constituents, H2O, CH4, and N2O). Since human activity does contribute a tiny portion of atmospheric CO2, they blame us for global warming.

Other inconvenient facts ignored by the activists: Carbon dioxide is a nonpolluting gas, essential for plant photosynthesis. Higher concentrations of CO2 in the atmosphere produce bigger harvests.

In spite of warnings of severe consequences from rising seas, droughts, severe weather, species extinction, and other disasters, the U.S. has not been stampeded into going along with the recommendations of the UN Panel on Climate Change (IPCC)—so far. Even though evidence supports the American position, we have begun to show signs of caving in to the alarmists.

With scientific evidence going out of style,
emotional arguments and anecdotal data are ruling the day.

The media subjects us to one frightening image of environmental nightmare after another, linking each to global warming. Journalists and activist scientists use hurricanes, wildfires, and starving polar bears to appeal to our emotions, not to our reason. They are far more concerned with anecdotal observations, such as the frozen sea ice inside the Arctic Circle, than they are with understanding why it is happening and how frequently it has occurred in the past.

After warnings that 2007 would be the hottest year on record and a record year for hurricanes, what we experienced was the coolest year since 2001 and, by some measures, the most benign hurricane season in the Northern Hemisphere in three decades.

Even though recent changes in our atmosphere are all within the bounds of the Earth’s natural variability, a growing number of people are willing to throw away trillions of dollars on fruitless solutions. Why do we allow emotional appeals and anecdotal data to shape our conclusions and influence our expenditures with the science and technology we have available at our fingertips?

The situation is complex, but the sad state of scientific literacy in America today is partially to blame for belief in AGW. When a 2006 National Science Foundation survey found 25 percent of Americans not knowing the Earth revolves around the Sun, you know that science education is at a new low and society is vulnerable to the emotional appeal of AGW.

And don’t underestimate the role of politics and political correctness.

The public debate should focus on the real cause of global temperature change and whether we can do anything about it. Is global warming a natural inevitability, or is it AGW—human caused?

The conflict over AGW has deteriorated into a religious war; a war between true believers in human-caused global warming and nonbelievers; between those who accept AGW on faith and those who consider themselves more sensible and better informed. “True believers” are beyond being interested in evidence; it is impossible to reason a person out of positions they have not been reasoned into.

It doesn’t help that NASA scientist James Hansen was one of the early alarmists claiming humans caused global warming. Hansen is a political activist who spreads fear even when NASA’s own data contradict him.

Warming in the upper atmosphere should occur before any surface warming effect, but NASA’s own data show that has not been happening. Global temperature readings—accurate to 0.1 degree Celsius—are gathered by orbiting satellites. Interestingly, in the 18 years those satellites have been recording global temperatures, they have actually shown a slight decrease in average temperatures.

Hansen is currently calling for a reduction of atmospheric CO2 by 10 percent and a moratorium on coal-fired power plants, while claiming the Bush administration is censoring him. Other so-called scientists are saying the world must bring carbon emissions to near zero to keep temperatures from rising.

In today’s politically correct environment, many are reluctant to dispute the popular wisdom; when they do, they are frequently ignored. When NASA Administrator Michael Griffin, Hansen’s boss and a distinguished scientist in his own right, attempted to draw a distinction between Hansen’s personal and political views and the science conducted by his agency, he was soon forced to back off.

It is the true believers who, when they have no facts on their side, try to silence their critics. When former NASA mathematician Ferenc Miskolczi pointed out that “greenhouse warming” may be mathematically impossible, NASA would not allow him to publish his work. Miskolczi dared to question the simplifying assumption in the warming model that the atmosphere is infinitely thick. He pointed out that when you use the correct thickness—about 65 miles—the greenhouse effect disappears! Ergo: no AGW. Miskolczi resigned in disgust and published his proof in the peer reviewed Hungarian journal Weather. [See: The Curious Case of Dr. Miskolczi]

For nearly a decade now, there has been no global warming. Even though atmospheric CO2 has continued to accumulate—up about 4 percent in the last 10 years—the global mean temperature has remained flat. That should raise obvious questions about CO2 being the cause of climate change.

Instead, AGW enthusiasts are embracing more regulation, greater government spending, and higher taxes in a futile attempt to control what is beyond our control—the Earth’s temperature. One of their political objectives, unstated of course, is the transfer of wealth from rich nations to poor nations or, as the social engineers put it, from the North to the South, which may be their real agenda.

Climate Lemmings

In the face of overwhelming evidence for natural temperature variation, proponents of AGW are resorting to a precautionary argument: “We must do something just in case we are responsible, because the consequences are too terrible if we are to blame and do nothing.” They hope to stampede government entities into committing huge amounts of money before their fraud is completely exposed—before science and truth save the day.

Politicians think they can reverse global warming by stabilizing CO2 emissions with a cockamamie scheme of “cap and trade.” A government entity would sell CO2 allocations to those industries producing it. The trillions of dollars in new taxes and devastation to the economy would be justified by claiming it will lower the temperature of the Earth. This rationalization is dependent on two assumptions: (1) that CO2 is responsible for the cause of changes in the Earth’s temperature, and (2) a warmer Earth would be bad for humanity.

The reality is that atmospheric CO2 has a minimal impact on greenhouse gases and world temperature. Water vapor is responsible for 95 percent of the greenhouse effect. CO2 contributes just 3.6 percent, with human activity responsible for only 3.2 percent of that. That is why some studies claim CO2 levels are largely irrelevant to global warming.

Without the greenhouse effect to keep our world warm, the planet would have an average temperature of minus 18 degrees Celsius. Because we do have it, the temperature is a comfortable plus 15 degrees Celsius. Based on the seasonal and geographic distribution of any projected warming, a good case can be made that a warmer average temperature would be even more beneficial for humans.

For a tiny fraction of the trillions of dollars a cap-and-trade system would eventually cost the United States, we could pay for development of clean coal, oil-shale recovery systems, and nuclear power, and have enough left over to pay for exploration of our solar system.

By law, NASA cannot involve itself in politics, but it can surely champion the role of science to inform politicians. With so many uninformed and misguided politicians ignoring the available science, NASA should fill the void. NASA is synonymous with science. Allowing our priorities to drift away from hard science is tantamount to embracing decadence. NASA will surely suffer; and politicizing science is killing it.

I do see hopeful signs that some true believers are beginning to harbor doubts about AGW. Let’s hope that NASA can focus the global warming discussion back on scientific evidence before we perpetrate an economic disaster on ourselves.

Walter Cunningham, (1932–2023) geophysicist, fighter pilot and Apollo 7 astronaut, who flew the first test flight of the Apollo Program, Apollo 7. In 2010, Cunningham published a short book titled “Global Warming: Facts versus Faith” His editorial was published in the Houston Chronicle on August 15, 2010, Climate change alarmists ignore scientific methods. (When You Don’t Have the Facts, Appeal to Public Opinion). In 2012, he and other former astronauts and NASA employees sent a letter to the agency criticizing its role advocating a high degree of certainty that man-made CO2 is a major cause of climate change while neglecting empirical evidence that calls the theory into question.

Can You Trust an AI/ML Model to Forecast?

Posted on March 23 by Ron Clutz

The latest fashion in model building is adding AI/ML (Artificial Intelligence/Machine Learning) technology to numerical models for weather forecasting. No doubt soon there will be climate models also claiming improved capability by doing this. A meteorological example is called Aardvark Weather and a summary is provided at Tallbloke’s Talkshop Scientists say fully AI-driven weather prediction system delivers accurate forecasts faster with less computing power.

Like all inventions there are weaknesses along with the claimed benefits. Here’s a short list of the things that can go wrong with these new gadgets. The concerns below are listed along with some others in a paper Understanding the Weaknesses of Machine Learning: Challenges and Limitations by Oyo Jude. Excerpts in italics with my bolds.

Introduction

Machine learning (ML) has become a cornerstone of modern technological advancements, driving innovations in areas such as healthcare, finance, and autonomous systems. Despite its transformative potential, ML is not without its flaws. Understanding these weaknesses is crucial for developing more robust and reliable systems. This article delves into the various challenges and limitations faced by ML technologies, providing insights into areas where improvements are needed

Data Quality and Bias

Data Dependency

Machine learning models are highly dependent on the quality and quantity of data used for training. The performance of an ML model is only as good as the data it is trained on. Common issues related to data quality include:

Incomplete Data: Missing or incomplete data can lead to inaccurate models and predictions. Incomplete datasets may not represent the full spectrum of possible inputs, leading to biased or skewed outcomes.
Noisy Data: Noise in data refers to irrelevant or random information that can obscure the underlying patterns the model is supposed to learn. Noisy data can reduce the accuracy of ML models and complicate the learning process.

Data Bias

Bias in data can significantly impact the fairness and accuracy of ML systems. Key forms of data bias include:

Selection Bias: Occurs when the data collected is not representative of the target population. For example, if a model is trained on data from a specific demographic group, it may not perform well for individuals outside that group.
Label Bias: Arises when the labels or categories used in supervised learning are subjective or inconsistent. Label bias can skew the model’s understanding and lead to erroneous predictions.

Model Interpretability and Transparency

Complexity of Models

Many advanced ML models, such as deep neural networks, are often described as “black boxes” due to their complexity. The lack of transparency in these models presents several challenges:

Understanding Model Decisions: It can be difficult to understand how a model arrived at a specific decision or prediction, making it challenging to diagnose errors or biases in the system.
Trust and Accountability: The inability to interpret model decisions can undermine trust in ML systems, particularly in high-stakes applications such as healthcare or criminal justice. Ensuring accountability and fairness becomes challenging when the decision-making process is opaque.
Explainability: Efforts to improve model interpretability focus on developing techniques and tools to make complex models more understandable. Techniques such as feature importance analysis, surrogate models, and visualization tools aim to provide insights into model behavior and decisions. However, achieving a balance between model performance and interpretability remains an ongoing challenge.

Generalization and Overfitting

Overfitting

Overfitting occurs when a model learns not only the underlying patterns in the training data but also the noise, resulting in poor performance on new, unseen data. This issue can be particularly problematic with complex models and limited data. Strategies to mitigate overfitting include:

Cross-Validation: Using techniques like k-fold cross-validation helps assess model performance on different subsets of the data, reducing the risk of overfitting.
Regularization: Regularization methods, such as L1 and L2 regularization, add penalties to the model’s complexity to prevent it from fitting noise in the training data.

Generalization

Generalization refers to a model’s ability to perform well on unseen data that was not part of the training set. Achieving good generalization is crucial for the practical application of ML models. Challenges related to generalization include:

Domain Shift: When the distribution of the data changes over time or across different domains, a model trained on one dataset may not generalize well to new data. Addressing domain shift requires continuous monitoring and updating of models.
Data Scarcity: In scenarios where limited data is available, models may struggle to generalize effectively. Techniques such as data augmentation and transfer learning can help address data scarcity issues.

Comment:

Many similar issues have been raised against climate models, undermining claims their outputs are valid projections of future climate states. For example, the issue of detailed and reliable data persists. It appears that even the AI/ML weather forecasting inventions are dependent on ERA5, which has a record of only ~40 years to use for training purposes. I’m suspending belief in these things for now–new improved black boxes sound too much like the Sorcerer’s Apprentice.

Disney’s portrayal of the Sorcerer’s Apprentice in over his head.

February 2025 Oceans Keep Cool

Posted on March 20 by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

The ocean covers 71% of the globe and drives average temperatures;
SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
A major El Nino was the dominant climate feature in recent years.

Note: When doing monthly updates of HadSST4, it’s typical that values for the previous month or two will appear with slight adjustments. However this time there were scores of changed values scattered throughout the set and all values since 1979. Strangely, the new values were in text format, so I needed to convert them to values in the spreadsheets. Comparing the new and old datasets showed that the changes were mostly in the third decimal, and mostly negative (i.e. the adjusted value lower than the previous one.) Overall, the global average anomaly since 1980 was lower by 0.01C. The charts and analysis below is produced from the current data.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST3 starting in 2015 through February 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C last year, ~0.3° higher than the 2015 peak. Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. After 10 months of cooling in SH and the Tropics, the Global anomaly came back down, led by NH cooling the last 4 months from its peak in August. It’s now about 0.1C higher than the average for this period. Note that the Tropical anomaly has cooled from 1.28C in 2024/01 to 0.72C as of 2025/2.

Comment:

A longer view of SSTs

To enlarge image, open in new tab.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future. So I find that ERSSTv5 AMO dataset has current data. It differs from Kaplan, which reported average absolute temps measured in N. Atlantic. “ERSST5 AMO follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.” So the values represent sst anomaly differences between the N. Atlantic and the Global ocean.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

Curiosity: Solar Coincidence?

Summary

Footnote: Why Rely on HadSST4

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

02/2025 Update–Temperature Changes, CO2 Follows

Posted on March 17 by Ron Clutz

Previously I have demonstrated that changes in atmospheric CO2 levels follow changes in Global Mean Temperatures (GMT) as shown by satellite measurements from University of Alabama at Huntsville (UAH). That background post is reprinted later below.

My curiosity was piqued by the remarkable GMT spike starting in January 2023 and rising to a peak in April 2024, and then declining afterward. I also became aware that UAH has recalibrated their dataset due to a satellite drift that can no longer be corrected. The values since 2020 have shifted slightly in version 6.1, as shown in my recent report Oceans Rapidly Cooling UAH January 2025.

In this post, I test the premise that temperature changes are predictive of changes in atmospheric CO2 concentrations. The chart above shows the two monthly datasets: CO2 levels in blue reported at Mauna Loa, and Global temperature anomalies in purple reported by UAHv6.1, both through February 2025. Would such a sharp increase in temperature be reflected in rising CO2 levels, according to the successful mathematical forecasting model? Would CO2 levels decline as temperatures dropped following the peak?

The answer is yes: that temperature spike resulted
in a corresponding CO2 spike as expected.
And lower CO2 levels followed the temperature decline.

Above are UAH temperature anomalies compared to CO2 monthly changes year over year.

Changes in monthly CO2 synchronize with temperature fluctuations, which for UAH are anomalies now referenced to the 1991-2020 period. CO2 differentials are calculated for the present month by subtracting the value for the same month in the previous year (for example February 2025 minus February 2024). Temp anomalies are calculated by comparing the present month with the baseline month. Note the recent CO2 upward spike and drop following the temperature spike and drop.

The final proof that CO2 follows temperature due to stimulation of natural CO2 reservoirs is demonstrated by the ability to calculate CO2 levels since 1979 with a simple mathematical formula:

For each subsequent year, the CO2 level for each month was generated

CO2 _{this month this year} = a + b × Temp _{this month this year} + CO2 _{this month last year}

The values for a and b are constants applied to all monthly temps, and are chosen to scale the forecasted CO2 level for comparison with the observed value. Here is the result of those calculations.

In the chart calculated CO2 levels correlate with observed CO2 levels at 0.9987 out of 1.0000. This mathematical generation of CO2 atmospheric levels is only possible if they are driven by temperature-dependent natural sources, and not by human emissions which are small in comparison, rise steadily and monotonically. For a more detailed look at the recent fluxes, here are the results since 2015, an ENSO neutral year.

For this recent period, the calculated CO2 values match the annual lows, while some annual generated values of CO2 are slightly higher or lower than observed at other months of the year. Still the correlation for this period is 0.9932.

Key Point

Changes in CO2 follow changes in global temperatures on all time scales, from last month’s observations to ice core datasets spanning millennia. Since CO2 is the lagging variable, it cannot logically be the cause of temperature, the leading variable. It is folly to imagine that by reducing human emissions of CO2, we can change global temperatures, which are obviously driven by other factors.

Background Post Temperature Changes Cause CO2 Changes, Not the Reverse

This post is about proving that CO2 changes in response to temperature changes, not the other way around, as is often claimed. In order to do that we need two datasets: one for measurements of changes in atmospheric CO2 concentrations over time and one for estimates of Global Mean Temperature changes over time.

Climate science is unsettling because past data are not fixed, but change later on. I ran into this previously and now again in 2021 and 2022 when I set out to update an analysis done in 2014 by Jeremy Shiers (discussed in a previous post reprinted at the end). Jeremy provided a spreadsheet in his essay Murray Salby Showed CO2 Follows Temperature Now You Can Too posted in January 2014. I downloaded his spreadsheet intending to bring the analysis up to the present to see if the results hold up. The two sources of data were:

Temperature anomalies from RSS here: http://www.remss.com/missions/amsu

CO2 monthly levels from NOAA (Mauna Loa): https://www.esrl.noaa.gov/gmd/ccgg/trends/data.html

Changes in CO2 (ΔCO2)

Uploading the CO2 dataset showed that many numbers had changed (why?).

The blue line shows annual observed differences in monthly values year over year, e.g. June 2020 minus June 2019 etc. The first 12 months (1979) provide the observed starting values from which differentials are calculated. The orange line shows those CO2 values changed slightly in the 2020 dataset vs. the 2014 dataset, on average +0.035 ppm. But there is no pattern or trend added, and deviations vary randomly between + and -. So last year I took the 2020 dataset to replace the older one for updating the analysis.

Now I find the NOAA dataset starting in 2021 has almost completely new values due to a method shift in February 2021, requiring a recalibration of all previous measurements. The new picture of ΔCO2 is graphed below.

The method shift is reported at a NOAA Global Monitoring Laboratory webpage, Carbon Dioxide (CO2) WMO Scale, with a justification for the difference between X2007 results and the new results from X2019 now in force. The orange line shows that the shift has resulted in higher values, especially early on and a general slightly increasing trend over time. However, these are small variations at the decimal level on values 340 and above. Further, the graph shows that yearly differentials month by month are virtually the same as before. Thus I redid the analysis with the new values.

Global Temperature Anomalies (ΔTemp)

The other time series was the record of global temperature anomalies according to RSS. The current RSS dataset is not at all the same as the past.

Here we see some seriously unsettling science at work. The purple line is RSS in 2014, and the blue is RSS as of 2020. Some further increases appear in the gold 2022 rss dataset. The red line shows alterations from the old to the new. There is a slight cooling of the data in the beginning years, then the three versions mostly match until 1997, when systematic warming enters the record. From 1997/5 to 2003/12 the average anomaly increases by 0.04C. After 2004/1 to 2012/8 the average increase is 0.15C. At the end from 2012/9 to 2013/12, the average anomaly was higher by 0.21. The 2022 version added slight warming over 2020 values.

RSS continues that accelerated warming to the present, but it cannot be trusted. And who knows what the numbers will be a few years down the line? As Dr. Ole Humlum said some years ago (regarding Gistemp): “It should however be noted, that a temperature record which keeps on changing the past hardly can qualify as being correct.”

Given the above manipulations, I went instead to the other satellite dataset UAH version 6. UAH has also made a shift by changing its baseline from 1981-2010 to 1991-2020. This resulted in systematically reducing the anomaly values, but did not alter the pattern of variation over time. For comparison, here are the two records with measurements through December 2023.

Comparing UAH temperature anomalies to NOAA CO2 changes.

Here are UAH temperature anomalies compared to CO2 monthly changes year over year.

Changes in monthly CO2 synchronize with temperature fluctuations, which for UAH are anomalies now referenced to the 1991-2020 period. As stated above, CO2 differentials are calculated for the present month by subtracting the value for the same month in the previous year (for example June 2022 minus June 2021). Temp anomalies are calculated by comparing the present month with the baseline month.

The final proof that CO2 follows temperature due to stimulation of natural CO2 reservoirs is demonstrated by the ability to calculate CO2 levels since 1979 with a simple mathematical formula:

For each subsequent year, the co2 level for each month was generated

CO2 _{this month this year} = a + b × Temp _{this month this year} + CO2 _{this month last year}

Jeremy used Python to estimate a and b, but I used his spreadsheet to guess values that place for comparison the observed and calculated CO2 levels on top of each other.

In the chart calculated CO2 levels correlate with observed CO2 levels at 0.9986 out of 1.0000. This mathematical generation of CO2 atmospheric levels is only possible if they are driven by temperature-dependent natural sources, and not by human emissions which are small in comparison, rise steadily and monotonically.

Comment: UAH dataset reported a sharp warming spike starting mid year, with causes speculated but not proven. In any case, that surprising peak has not yet driven CO2 higher, though it might, but only if it persists despite the likely cooling already under way.

Previous Post: What Causes Rising Atmospheric CO2?

nasa_carbon_cycle_2008-1

This post is prompted by a recent exchange with those reasserting the “consensus” view attributing all additional atmospheric CO2 to humans burning fossil fuels.

The IPCC doctrine which has long been promoted goes as follows. We have a number over here for monthly fossil fuel CO2 emissions, and a number over there for monthly atmospheric CO2. We don’t have good numbers for the rest of it-oceans, soils, biosphere–though rough estimates are orders of magnitude higher, dwarfing human CO2. So we ignore nature and assume it is always a sink, explaining the difference between the two numbers we do have. Easy peasy, science settled.

What about the fact that nature continues to absorb about half of human emissions, even while FF CO2 increased by 60% over the last 2 decades? What about the fact that in 2020 FF CO2 declined significantly with no discernable impact on rising atmospheric CO2?

These and other issues are raised by Murray Salby and others who conclude that it is not that simple, and the science is not settled. And so these dissenters must be cancelled lest the narrative be weakened.

The non-IPCC paradigm is that atmospheric CO2 levels are a function of two very different fluxes. FF CO2 changes rapidly and increases steadily, while Natural CO2 changes slowly over time, and fluctuates up and down from temperature changes. The implications are that human CO2 is a simple addition, while natural CO2 comes from the integral of previous fluctuations. Jeremy Shiers has a series of posts at his blog clarifying this paradigm. See Increasing CO2 Raises Global Temperature Or Does Increasing Temperature Raise CO2 Excerpts in italics with my bolds.

The following graph which shows the change in CO2 levels (rather than the levels directly) makes this much clearer.

Note the vertical scale refers to the first differential of the CO2 level not the level itself. The graph depicts that change rate in ppm per year.

There are big swings in the amount of CO2 emitted. Taking the mean as 1.6 ppmv/year (at a guess) there are +/- swings of around 1.2 nearly +/- 100%.

And, surprise surprise, the change in net emissions of CO2 is very strongly correlated with changes in global temperature.

This clearly indicates the net amount of CO2 emitted in any one year is directly linked to global mean temperature in that year.

For any given year the amount of CO2 in the atmosphere will be the sum of

all the net annual emissions of CO2
in all previous years.

For each year the net annual emission of CO2 is proportional to the annual global mean temperature.

This means the amount of CO2 in the atmosphere will be related to the sum of temperatures in previous years.

So CO2 levels are not directly related to the current temperature but the integral of temperature over previous years.

The following graph again shows observed levels of CO2 and global temperatures but also has calculated levels of CO2 based on sum of previous years temperatures (dotted blue line).

Summary:

The massive fluxes from natural sources dominate the flow of CO2 through the atmosphere. Human CO2 from burning fossil fuels is around 4% of the annual addition from all sources. Even if rising CO2 could cause rising temperatures (no evidence, only claims), reducing our emissions would have little impact.

Atmospheric CO2 Math

Ins: 4% human, 96% natural
Outs: 0% human, 98% natural.
Atmospheric storage difference: +2%
(so that: Ins = Outs + Atmospheric storage difference)

Balance = Atmospheric storage difference: 2%, of which,
Humans: 2% X 4% = 0.08%
Nature: 2% X 96 % = 1.92%

Ratio Natural : Human =1.92% : 0.08% = 24 : 1

Resources

For a possible explanation of natural warming and CO2 emissions see Little Ice Age Warming Recovery May be Over

Resources:

CO2 Fluxes, Sources and Sinks

Who to Blame for Rising CO2?

Fearless Physics from Dr. Salby

Minefield to Defuse EPA GHG Endangerment Finding

Posted on March 14 by Ron Clutz

When first using this image, I was noting how naive were politicians (the Brits, for example) to legislate future CO2 emissions reductions, opening themselves up to lawsuits and legal constraints on policy decisions. Now the same advice applies to the Trump administration targeting the root of the poisonous tree of climate alarmism. First the lay of the land from EPA Director Zeldin, in italics with my bolds:

Trump EPA Kicks Off Formal Reconsideration of Endangerment Finding with Agency Partners

March 12, 2025

EPA Press Office (press@epa.gov)

WASHINGTON – U.S. Environmental Protection Agency (EPA) Administrator Lee Zeldin announced the agency will be kicking off a formal reconsideration of the 2009 Endangerment Finding in collaboration with the Office of Management and Budget (OMB) and other relevant agencies. EPA also intends to reconsider all of its prior regulations and actions that rely on the Endangerment Finding.

Administrator Zeldin: “After 16 years, EPA will formally reconsider the Endangerment Finding.” “The Trump Administration will not sacrifice national prosperity, energy security, and the freedom of our people for an agenda that throttles our industries, our mobility, and our consumer choice while benefiting adversaries overseas. We will follow the science, the law, and common sense wherever it leads, and we will do so while advancing our commitment towards helping to deliver cleaner, healthier, and safer air, land, and water.”

White House OMB Director Russ Vought: “EPA’s regulation of the climate affects the entire national economy—jobs, wages, and family budgets. It’s long overdue to look at the impacts on our people of the underlying Obama endangerment finding.”

Secretary of the Interior Doug Burgum: “The United States produces energy smarter, cleaner, and safer than anywhere else in the world. To achieve President Trump’s vision for energy dominance, we are prioritizing innovation over regulation to attain an affordable, reliable, clean, and secure energy future for all Americans.”

Energy Secretary Chris Wright: “The 2009 Endangerment finding has had an enormously negative impact on the lives of the American people. For more than 15 years, the U.S. government used the finding to pursue an onslaught of costly regulations – raising prices and reducing reliability and choice on everything from vehicles to electricity and more. It’s past time the United States ensures the basis for issuing environmental regulations follows the science and betters human lives.”

Transportation Secretary Duffy: “Thanks to President Trump’s leadership and the hard work of Administrator Zeldin, we are taking another important step toward ushering in a golden age of transportation. The American people voted for a government that prioritizes affordable, safe travel and lets them choose the vehicles they drive. Today we are delivering on that promise, and this will allow the DOT to accelerate its work on new vehicle fuel economy standards that will lower car prices and no longer force Americans to purchase electric vehicles they don’t want.”

Office of Information and Regulatory Affairs Administrator Jeff Clark: “Since 2009, I’ve consistently argued that the endangerment finding required a consideration of downstream costs imposed on both mobile sources like cars and stationary sources like factories. Under the enlightened leadership of President Trump and Administrator Zeldin, the time for fresh thought has finally arrived.”

In President Trump’s Day One Executive Order, “Unleashing American Energy,” he gave the EPA Administrator a 30-day deadline to submit recommendations on the legality and continuing applicability of the 2009 Endangerment Finding. After submitting these recommendations, EPA can now announce its intent to reconsider the 2009 Endangerment Finding.

When EPA made the Endangerment Finding in 2009, the agency did not consider any aspect of the regulations that would flow from it. EPA’s view then was that the Finding itself did not impose any costs, and that EPA could not consider future costs when making the Finding. EPA has subsequently relied on the Endangerment Finding as part of its justification for seven vehicle regulations with an aggregate cost of more than one trillion dollars, according to figures in EPA’s own regulatory impact analyses. The Endangerment Finding has also played a significant role in EPA’s justification of regulations of other sources beyond cars and trucks.

Congress tasked EPA under Section 202 of the Clean Air Act with regulating new motor vehicles when the Administrator determines that emissions of an air pollutant endanger public health and welfare. But the Endangerment Finding went about this task in what appears to be a flawed and unorthodox way. Contrary to popular belief, the Endangerment Finding did not directly find that carbon dioxide emissions from U.S. cars endanger public welfare. Instead, the Finding looks at a combination of emissions of six different gases—and cars don’t even emit all six. It then creatively added multiple leaps, arguing that the combined six gases contribute some mysterious amount above zero to climate change and that climate change creates some mysterious amount of endangerment above zero to public health. These mental leaps were the only way the Obama-Biden Administration could come to its preferred conclusion, even if it did not stick to the letter of the Clean Air Act.

The Endangerment Finding acknowledges and identifies significant uncertainties in the science and assumptions used to justify the decision. In the 16 years since EPA issued the Endangerment Finding, the world has seen major developments in innovative technologies, science, economics, and mitigation. EPA has never before asked for public comment on the implications these developments have had on the Endangerment Finding, but now it will as part of the reconsideration process it intends to undertake. Additionally, major Supreme Court decisions in the intervening years, including Loper Bright Enterprises v. Raimondo, West Virginia v. EPA, Michigan v. EPA, and Utility Air Regulatory Group v. EPA, have provided new guidance on how the agency should interpret statutes to discern Congressional intent and ensure that its regulations follow the law.

As part of this reconsideration process, EPA will leverage the expertise of the White House Budget Office, including the Office of Information and Regulatory Affairs, White House Office of Science and Technology Policy, National Oceanic and Atmospheric Administration, and other relevant agencies.

It is in the best interest of the American people for EPA to ensure that any finding and regulations are based on the strongest scientific and legal foundation. The reconsideration of the Endangerment Finding and EPA’s regulations that have relied on it furthers this interest. The agency cannot prejudge the outcome of this reconsideration or of any future rulemaking. EPA will follow the Administrative Procedure Act and Clean Air Act, as applicable, in a transparent way for the betterment of the American people and the fulfillment of the rule of law.

This was announced in conjunction with a number of historic actions to advance President Trump’s Day One executive orders and Power the Great American Comeback. Combined, these announcements represent the greatest and most consequential day of deregulation in the history of the United States. The overhaul of the Endangerment Finding along with other massive rules represents the death of the Green New Scam and drives a dagger straight into the heart of the climate change religion. While accomplishing EPA’s core mission of protecting the environment, the agency is committed to fulfilling President Trump’s promise to unleash American energy, lower costs for Americans, revitalize the American auto industry, restore the rule of law, and give power back to states to make their own decisions.

Objections from the usual suspects

“This decision ignores science and the law,” David Doniger, senior strategist and attorney for climate and energy at the Natural Resources Defense Council, said in a statement. “Abdicating EPA’s clear legal duty to curb climate-changing pollution only makes sense if you consider who would benefit: the oil, coal, and gas magnates who handed the president millions of dollars in campaign contributions.”

Vickie Patton, the Environmental Defense Fund’s general counsel, said any move to undo the finding “would be reckless, unlawful, and ignore EPA’s fundamental responsibility to protect Americans from destructive climate pollution. We will vigorously oppose it.”

“They don’t have a winning hand. Having the power to do this doesn’t tell you anything about whether or not what they’re doing makes sense on the merits,” said Joseph Goffman, who ran EPA’s air office during the Biden administration. “They’ve got nothing on the merits.”

Michael Mann, a climate scientist at the University of Pennsylvania dismissed the EPA’s action as “just the latest form of Republican climate denial. They can no longer deny climate change is happening, so instead they’re pretending it’s not a threat, despite the overwhelming scientific evidence that it is, perhaps, the greatest threat that we face today.”

The Pathways and the Risks

Shuting Pomerleau gives insight into activists worries and the possibilities: Is EPA’s Endangerment Finding at Risk?

If EPA’s endangerment finding is rescinded, it may not have any material impact on the agency’s legal basis for issuing future climate regulations on GHG emissions, since the IRA amended the CAA to grant explicit authority to the agency. Nevertheless, repealing the endangerment finding would likely create chaos and uncertainty for U.S. climate policy.

First, rescinding the endangerment finding would make it much easier for the Trump Administration to repeal the existing EPA GHG emissions regulations because the original legal basis for this authority would no longer exist. Under the Obama and Biden Administrations, EPA has issued several sector-based GHG emissions regulations using the endangerment finding as a legal basis.

Second, repealing the endangerment finding would immediately subject EPA to legal challenges that could last years. Before the dispute could be adjudicated by the courts, there would be considerable confusion and uncertainty over compliance with the existing regulations. This would negatively impact the regulatory environment for businesses, as they need durable and consistent policies to make long-term investment decisions.

From the perspective of policymaking, rescinding EPA’s endangerment finding puts a big question mark on the outlook of U.S. climate policies. Currently, at the federal level, the United States uses a patchwork of policies to mitigate GHG emissions, such as handing out massive clean energy tax subsidies under the IRA and relying on command-and-control EPA regulations. The IRA energy tax provisions will likely be subject to at least partial repeal in an upcoming 2025 reconciliation bill. Even if a future administration seeks to regulate GHG emissions via EPA rulemaking, it would take a long time, and generally such regulations are costly, inflexible, and vulnerable to legal challenges.

What to Expect Next

EPA to Accept Nominations for Science Boards

March 12, 2025

EPA Press Office (press@epa.gov)

WASHINGTON – Today, U.S. Environmental Protection Agency (EPA) Administrator Lee Zeldin announced that a notice will be published in the Federal Register seeking nominations for the Science Advisory Board (SAB) and Clean Air Scientific Advisory Committee (CASAC). Nominations will be accepted for 30 days following publication of the Federal Register notice.

“Reconstituting the Science Advisory Board and Clean Air Scientific Advisory Committee are critical to ensuring that the agency receives scientific advice consistent with its legal obligations to advance our core mission of protecting human health and the environment,” said EPA Administrator Zeldin. “I look forward to receiving nominations to build an independent group of advisors to aid the agency’s rulemaking.”

In January, EPA announced its decision to reset these federal advisory committees
to reverse the politicization of SAB and CASAC under the Biden-Harris Administration.

Ocean Warms, Land Cools UAH February 2025

Posted on March 13 by Ron Clutz

As an overview consider how recent rapid cooling completely overcame the warming from the last 3 El Ninos (1998, 2010 and 2016). The UAH record shows that the effects of the last one were gone as of April 2021, again in November 2021, and in February and June 2022 At year end 2022 and continuing into 2023 global temp anomaly matched or went lower than average since 1995, an ENSO neutral year. (UAH baseline is now 1991-2020). Now we have had an usual El Nino warming spike of uncertain cause, unrelated to steadily rising CO2 and now dropping steadily.

For reference I added an overlay of CO2 annual concentrations as measured at Mauna Loa. While temperatures fluctuated up and down ending flat, CO2 went up steadily by ~60 ppm, a 15% increase.

Furthermore, going back to previous warmings prior to the satellite record shows that the entire rise of 0.8C since 1947 is due to oceanic, not human activity.

gmt-warming-events

Importantly, the theory of human-caused global warming asserts that increasing CO2 in the atmosphere changes the baseline and causes systemic warming in our climate. On the contrary, all of the warming since 1947 was episodic, coming from three brief events associated with oceanic cycles. And now in 2024 we have seen an amazing episode with a temperature spike driven by ocean air warming in all regions, along with rising NH land temperatures, now dropping below its peak.

Chris Schoeneveld has produced a similar graph to the animation above, with a temperature series combining HadCRUT4 and UAH6. H/T WUWT

mc_wh_gas_web20210423124932

February 2025 Ocean Warms, Land Cools

UAH has updated their TLT (temperatures in lower troposphere) dataset for February 2025. Due to one satellite drifting more than can be corrected, the dataset has been recalibrated and retitled as version 6.1 Graphs here contain this updated 6.1 data. Posts on their reading of ocean air temps this month are ahead of the update from HadSST4. I posted recently on SSTs January 2025 Oceans Still Cool. These posts have a separate graph of land air temps because the comparisons and contrasts are interesting as we contemplate possible cooling in coming months and years.

Sometimes air temps over land diverge from ocean air changes. In July 2024 all oceans were unchanged except for Tropical warming, while all land regions rose slightly. In August we saw a warming leap in SH land, slight Land cooling elsewhere, a dip in Tropical Ocean temp and slightly elsewhere. September showed a dramatic drop in SH land, overcome by a greater NH land increase. This month has contrasting warming in ocean air anomalies, especially in SH, somewhat offset by land air cooling especially in NH.

After a change in priorities, updates are now exclusive to HadSST4. For comparison we can also look at lower troposphere temperatures (TLT) from UAHv6.1 which are now posted for February 2025. The temperature record is derived from microwave sounding units (MSU) on board satellites like the one pictured above. Recently there was a change in UAH processing of satellite drift corrections, including dropping one platform which can no longer be corrected. The graphs below are taken from the revised and current dataset.

After sharp cooling everywhere in January 2023, there was a remarkable spiking of Tropical ocean temps from -0.5C up to + 1.2C in January 2024. The rise was matched by other regions in 2024, such that the Global anomaly peaked at 0.86C in April. Since then all regions have cooled down sharply. In February 2025, SH rose from 0.1C to 0.4C pulling the Global ocean air anomaly up from 0.3C to 0.5C.

Land Air Temperatures Tracking in Seesaw Pattern

The Bigger Picture UAH Global Since 1980

The graph reminds of another chart showing the abrupt ejection of humid air from Hunga Tonga eruption.

R.I.P. Climate Back Radiation

Posted on March 8 by Ron Clutz

Beware false and misleading Cartoons.

A brief recent video by Markus Ott explains why the notion of “back radiation” in Earth’s climate should be laid to rest. I provide a transcript text in italics with my bolds and key exhibits.

Ott/Shula: The second law of thermodynamics and the greenhouse effect

This is the first of a short series of physics videos. This series is intended to be a follow up to Tom Shula’s presentation in which we can take more time to go into the fundamentals and derivations of our results. Since Tom and I are attacking the foundations of modern climate science, it makes sense to start with the thermodynamic aspects of the greenhouse effect.

In this video I will not talk about greenhouse gas molecules. I will look at the Green House Effect from the perspective of classical thermodynamics. Classical thermodynamics describes matter as a continuum and does not care about the atomic or molecular structure of matter. The laws of thermodynamics have proven to be universally valid hypotheses, and theories that contradict the laws of thermodynamics have always proved to be wrong

In connection with the greenhouse effect, the second law of Thermodynamics is particularly interesting. There are various equivalent formulations for the the second law of thermodynamics which states that thermal energy cannot be completely converted into other forms of energy. Rudolf Clausius was the first to formulate the second law in the form that heat does not flow spontaneously from cold to hot bodies. Later in 1865 he developed on that basis the concept of entropy.

Those who believe in thermodynamics categorize this statement as an eternal truth and therefore find it very difficult to understand how the greenhouse effect is supposed to work. How can the atmosphere which is mostly colder than the Earth’s surface heat the Surface by means of back radiation, and by as much as 33°C? Greenhouse effect believers like to refer to Carl Schwarzschild’s 1906 paper About the equilibrium of the solar atmosphere to answer this question.

In order to clarify this question of faith we will take a closer look at this much cited and probably rarely read article which was written in a German adequate to a highly educated man. I posted a manual translation of the text on my substack page. Without going into the details of his calculations we will look at how Schwarzschild comes to the conclusion that the sun’s atmosphere not only radiates outwards into space but that a significant proportion of radiation is also directed inwards towards the base of the sun’s atmosphere.

Such an inward or downward back radiation can also be measured at the bottom of the Earth’s atmosphere. This observation is taken as a reason to postulate a similar radiation equilibrium in the Earth’s atmosphere. The greenhouse effect is said to be the result of that back radiation.

The starting point for Schwarzschild’s article is the observation that the brightness of the visible solar disc is not evenly distributed. The brightness decreases towards the edge. The diagram shows the observed brightness distribution as a blue line. Schwarzschild compares two conceivable mechanisms of heat transport through the solar atmosphere in order to determine the cause of this brightness distribution. Heat transport through radiative transfer which requires a radiative equilibrium in the Solar atmosphere, and heat transport by convection with an adiabatic equilibrium in the Solar atmosphere.

He calculates how the brightness distribution on the solar disc should be for these two cases. Because his results for the radiative equilibrium Orange Line in the diagram matched the observed brightness distribution Blue Line better than his results for the adiabatic equilibrium Gray Line, he assumes that a radiative equilibrium prevails in the Solar atmosphere. We will disregard his description of the adiabatic equilibrium here, and restrict ourselves to his description of the radiative equilibrium.

Kirchhoff’s law of radiation plays a central role in Schwarzschild’s model. Kirchhoff’s law of radiation describes the relationship between absorption and emission of a real body in thermal equilibrium. It states that radiation absorption and emission correspond to each other for a given wavelength. A body that absorbs well also radiates well. This can be visualized as follows: We consider a body 2 that is located in a cavity of another body 1. Vacuum prevails in the intermediate space. If both bodies have the same temperature the radiant power absorbed by Body 2 must be the same as the radiant power emitted by it because otherwise the temperature of body 2 would change. This means that in thermal equilibrium Kirchhoff’s law of radiation represents a kind of radiation energy conservation law for body 2.

The layout of Schwarzschild’s radiative transfer model of the solar atmosphere is quite simple. An unknown heat source in the core of the Sun generates heat; a possible liquid outer core transports this heat by convection to the bottom of the solar atmosphere; the heat is then transported outwards into space solely by radiative transfer. He does not go any further into the properties of the sun’s core. He only assumes that the core heats the solar atmosphere evenly at its boundary surface. It is very important that this heating occurs so evenly that convection currents do not form in the Solar atmosphere.

In Schwarzschild’s model the solar atmosphere is assumed to have the following properties:

♦ the solar atmosphere is stably stratified without convection;
♦ temperature and density increase continuously from the top of the atmosphere to the ground
♦ the vertical profile of temperature is smaller than the adiabatic vertical profile;
♦ each layer of the sun’s atmosphere absorbs and emits radiation without loss;
♦ the energy flow which flows from an unknown source inside the Sun through the solar atmosphere into the outer space is in a steady state.

Since a downwelling radiation is also measurable on the ground of Earth’s atmosphere, modern climate science assumes that Schwarzschild’s radiation transfer model is also applicable to our atmosphere. Now let’s take a look at the applicability of Schwarzschild’s model to the Earth’s atmosphere.

It is striking that Schwarzschild has practically constructed his model around Kirchhoff’s law of radiation. He has to make a number of not particularly plausible assumptions in order to create a local thermal equilibrium between the layers of his solar atmosphere. As mentioned before most of these assumptions serve to prevent convection in his model. This is critically important because as soon as convection comes into play, the condition of local thermal equilibrium is no longer fulfilled. The vertical convection currents and the associated turbulence destroy Schwarzschild’s homogeneous stratification of the atmosphere. Large local temperature jumps occur Kirchhoff’s law of radiation is therefore no longer applicable.

To summarize and formulate this somewhat more abstractly: In order to create the conditions for Pure radiation transport through the solar atmosphere Schwarzschild must construct an atmosphere with a very high degree of order. In liquid or gaseous systems even minor disturbances will cause such a state to change into a disordered convective State. Under convective conditions Kirchhoff’s law of radiation and thus the radiative transfer equation are not valid.

This transition to the convective state takes place with a large entropy gain. It is therefore spontaneous and irreversible. Accordingly, there should be no radiative transfer and no greenhouse effect in our troposphere since it is dominated by convection currents.

Look at a volume element under convective conditions such as those that prevail in our troposphere. The volume element absorbs radiation and converts the radiation energy into heat. Before it can convert the heat back into radiation it is caught by a convection current and lifted. This causes it to move into areas with lower ambient pressure. It expands and performs volume work in the process. It draws the energy for this volume work from its heat content and therefore cools down. The amount of heat that the volume element has converted into volume work can no longer be converted back into radiation. The conservation of radiation energy is therefore no longer given.

Kirchhoff’s law of radiation can no longer be applied to the volume element. The entropy of the volume element increases, the process is irreversible lifting and acceleration. Work performed by the volume element derives their energy from the heat content of the volume element and also contribute to the irreversibility of radiation absorption under convective conditions. Global circulations also affect these processes but that will be discussed in another video.

I would like to point out that radiation absorption and emission are irreversible processes. In themselves the reemission of radiation from an excited molecule occurs randomly in any direction. This means that the information about the direction of the previously absorbed radiation is lost during emission The emitted Photon transfers part of its momentum to the emitting molecule. Its energy and therefore also its frequency are therefore different from that of the previously absorbed Photon. Schwarzschild also excludes these effects through his choice of boundary conditions: steady state radiation flux and frequency independence of absorptivity and emission.

In one of my previous videos I made fun about the fact that the 33° greenhouse effect is calculated by assuming that the solar Radiance is homogeneously distributed over the Earth’s surface with 240 W per square meter. Now with a deeper understanding of Schwarzschild’s model we get an idea about the origin of this rather strange assumption. In his radiation transfer model the base of the solar atmosphere is heated internally and homogenously by the solar core. This homogeneous heating is very important since an inhomogeneous heating would cause convection which is incompatible with Kirchhoff’s law of radiation and would spoil his model. In a rather hapless attempt to apply Schwarzschild’s radiation transfer model, the same is done to the externally and unevenly heated surface of the Earth.

To summarize briefly the irreversibility of radiation absorption in air under convective conditions makes back radiation and thus the greenhouse effect impossible. This statement seems to be in direct contradiction to the observation that a downwelling atmospheric radiation can be measured at the bottom of the Earth’s atmosphere. The diagram here shows the measured values from a measuring station near Munich. In the next video I will show that back radiation is not what most people think of it to be, and how it is compatible with the laws of thermodynamics.

The most important takeaway from this video is that Kirchhoff’s law of radiation presents a kind of radiation energy conservation law, and that this radiation energy conservation is not given under convective conditions. As far as I know all radiation transfer models assume a universal validity of Kirchhoff’s law of radiation. The only exception is at very high altitudes where the air molecules only very rarely collide with each other. Since the results of the radiation transfer models are based on this false basic assumptions, they are wrong.

That is not to say that Carl Schwarzschild’s work is nonsense. His original idea is very applicable to transparent systems without convection; for example in the production of large telescope mirrors. The cooling behavior after the glass mass has solidified can be described very well using radiation transfer methods.

Footnote Regarding Observation of Downwelling IR near Earth Surface

Figure 1. This is a plot of the outgoing radiation spectrum from Earth. Within the normal IR thermometer and scanner range of 7.5 to 14 micrometers, only ozone (O3), which is mostly above cloud level absorbs and emits significant radiation. Within the 15 μm CO2 “divot” nearly all surface emissions are absorbed within 1.5 meters of the surface, at the edges of the divot, emissions are absorbed within 690 meters. There is very little absorption and emission by GHGs in the IR thermometer range in the troposphere, aka the atmospheric window.

From Andy May Beyond CO₂: Unraveling the Roles of Energy, Water Vapor, and Convection in Earth’s Atmosphere

Because the humid lower atmosphere is nearly opaque to most surface emitted radiation that is outside the atmospheric windows, surface emissions are absorbed by GHGs very close to the surface. According to Heinz Hug, at sea level, with a CO₂ concentration of 357 PPM and 2.6% water vapor, 99.94% of all surface radiation in the main CO₂ frequency band at about 15 μm is normally absorbed in the lower 10 meters of the atmosphere (Hug, 2012). Even at the edges of the deep CO₂ frequency band (see figure 1, as well as figures 4 & 5 here) where any increase in the CO₂ effect would be observed, 99.9% of the surface radiation is absorbed in the first 690 meters (Hug, 2000).

Heinz Hug goes on to say that is why climate change caused by CO2 cannot be measured directly in the laboratory and can only be modeled. In our opinion, the effect of CO2 is so small it will likely never be measured. In a similar fashion, any “back radiation” that makes it to the surface, outside atmospheric windows, is from the lower 10 meters of the atmosphere, the remaining emissions from the lower 10 meters of the atmosphere are captured by other greenhouse gases, almost always water vapor molecules.

Surface emissions in the frequencies that cannot be absorbed or emitted by GHGs, those in the so-called “atmospheric windows” are not captured, these are the frequencies utilized by IR thermometers and scanners, typically 7.5 to 14 micrometers as shown in figure 1. Water vapor is often a very weak absorber and emitter in portions of these windows. Carbon dioxide strongly absorbs and re-emits IR at two key frequencies: around 4.26 μm (microns) and 14.99 μm. The common vanadium oxide (VOx) based microbolometer long-wave infrared detectors cover wavelengths from 8-14 µm range. So, both CO2 absorption bands are outside the range of the common hand-held infrared thermometer/bolometer.

The radiation seen when IR thermometers and scanners are pointed at the sky is surface radiation scattered by atmospheric particles and clouds. The radiation seen by IR thermometers and scanners cannot be emitted by greenhouse gases or clouds because neither GHGs nor clouds emit in frequencies that can be detected by the devices. As noted in van Wijngaarden and Happer (2025) scattered longwave IR originates only in water droplets or ice or other particulates, there is negligible scattering of IR by molecules, especially in the atmospheric windows.

Background Paper with complete discussion

Missing Link in the GHE, Greenhouse Effect, by Thomas Shula – Markus Ott, USA – Germany
2024.

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