A Note to Journalists: Please take few minutes to read some of this so that maybe you can skip asking me for an interview.

Around 3 p.m. ET today, 29 July 2025, a Department of Energy report entitled “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate” will be made available here. This is the report providing the scientific basis for today’s announced decision by EPA Administrator Lee Zeldin to reconsider the 2009 CO2 Endangerment Finding.

The report has 5 authors: John Christy, Judith Curry, Steve Koonin, Ross McKitrick, and myself.

We were asked by DOE Secretary Wright a few months ago to produce this report. As the first few pages of the report will explain, we had no pressure to come to any conclusions; we asked for complete autonomy.

Also, we had no knowledge through the whole process of what the decision-makers at the EPA were going to do regarding energy policy. We suspected the Endangerment Finding would be the topic of greatest interest, but we also knew that the EPA’s strategy for rescinding that could take a mostly legal approach, with little need for science arguments… for now.

Even today, I have no idea how much recent court rulings vs. updated (and less biased) science figured into the EPA’s decision.

Why a DOE Report to Support an EPA Decision?

My understanding is that the Trump Administration and all of its Executive Branch agencies have been very busy on myriad issues. Only one of the executive-level appointees in the Administration had the background knowledge and interest to invest in making this science report happen: Energy Secretary Chris Wright. I suspect (this is my reading between the lines) that it was agreed between the White House, EPA, and DOE that Sec. Wright would take the lead on the science document.

Chris called me at home and asked me if I would participate, and he asked who I would recommend for other authors of the report. He had been following my research for many years. He also had on his list of potential contributors the others who now appear on the report with me.

During preparation of the report we decided to avoid any engagement with the press on what we were doing. It would have only been a distraction, and we had little time to accomplish what the Obama Administration spent years and millions of dollars to produce as the original Technical Support Document (TSD) for the 2009 Endangerment Finding.

Our report has 141 pages, 350 references (most if not all peer-reviewed), 6.6% of which were studies we authored or co-authored. The report could not address every claim made in the 2009 Endangerment Finding’s Technical Support Document. Instead, we focused on some of the central claims, the science underpinning them, and especially on the National Climate Assessments, especially NCA4 and NCA5 (the latest), which are relied upon by the U.S. Congress to assist in the making of laws and apportioning research funds.

One thing I learned through this process is how prolific and smart a researcher Ross McKitrick (U. of Guelph, Ontario) is. He was indispensable to our effort. But everyone brought their own experiences and opinions to the process, and we often had disagreements… but none that could not be quickly resolved.

Another thing I learned was just how poorly the science of climate change has been communicated to the public. For example, if you follow Roger Pielke, Jr’s research you will know that most of what the public has been told about climate change and severe weather has been a lie — and Roger still considers human climate change to be an issue worth addressing. It’s just not a “crisis”, and nothing we see in severe weather has been tied to human greenhouse gas emissions.

And that’s not a skeptical talking point, it’s according to the IPCC (!)

Energy Secretary Chris Wright and EPA Administrator Lee Zeldin will be in Indianapolis today (29 July 2025) to announce major climate regulation changes…so, stay tuned!

UPDATE: E&E News (by Politico) provides an unusually neutral assessment of what will be announced: https://www.eenews.net/articles/epa-seeks-to-limit-its-power-to-curb-climate-pollution/

Here’s video of the announcement. I’m one of the 5 scientists chosen to write the DOE report for Sec. Wright which provided the scientific basis for EPA Administrator Zeldin’s decision.

None of us asked to write this report had any insider knowledge of what Zeldin would decide… we were simply asked to write a report of what we believed the threat of increasing CO2 posed to the U.S. That report will be posted very soon (if it hasn’t already). I will do a separate post on that.

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for June, 2025 was +0.48 deg. C departure from the 1991-2020 mean, down slightly from the May, 2025 anomaly of +0.50 deg. C.

The Version 6.1 global area-averaged linear temperature trend (January 1979 through June 2025) now stands at +0.16 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).

The following table lists various regional Version 6.1 LT departures from the 30-year (1991-2020) average for the last 18 months (record highs are in red).

The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for June, 2025, and a more detailed analysis by John Christy, should be available within the next several days here.

The monthly anomalies for various regions for the four deep layers we monitor from satellites will be available in the next several days at the following locations:

Lower Troposphere

Mid-Troposphere

Tropopause

Lower Stratosphere

Most of you are probably not aware that my wife of 48 years, Doreen (“Reenie”) J. Spencer passed away two weeks ago today, on June 7. Reenie had suffered for many years from autoimmune and fatty liver disease, and her condition worsened in the last several months. By the time she agreed to go to the hospital, it was too late to do anything except keep her comfortable.

We married the year I changed my major from computer science to atmospheric science and moved from Michigan State University to the University of Michigan. Reenie was always my most loyal supporter and fiercest defender, exhibiting the ‘sisu’ of her Finnish heritage.

Her spirit is now relieved of her earthly sufferings.

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for May, 2025 was +0.50 deg. C departure from the 1991-2020 mean, down from the April, 2025 anomaly of +0.61 deg. C.

The Version 6.1 global area-averaged linear temperature trend (January 1979 through May 2025) remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).

The following table lists various regional Version 6.1 LT departures from the 30-year (1991-2020) average for the last 17 months (record highs are in red).

The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for May, 2025, and a more detailed analysis by John Christy, should be available within the next several days here.

The monthly anomalies for various regions for the four deep layers we monitor from satellites will be available in the next several days at the following locations:

Lower Troposphere

Mid-Troposphere

Tropopause

Lower Stratosphere

It took the better part of two years to satisfy the reviewers, but finally our paper Urban Heat Island Effects in U.S. Summer Surface Temperature Data, 1895–2023 has been published in the AMS Journal of Applied Meteorology and Climatology.

To quickly summarize, we used the average temperature differences between nearby GHCN stations and related those to population density (PD) differences between stations. Why population density? Well, PD datasets are global, and one of the PD datasets goes back to the early 1800s, so we can compute how the UHI effect has changed over time. The effect of PD on UHI temperature is strongly nonlinear, so we had to account for that, too. (The strongest rate of warming occurs when population just starts to increase beyond wilderness conditions, and it mostly stabilizes at very high population densities; This has been known since Oke’s original 1973 study).

We then created a dataset of UHI warming versus time at the gridpoint level by calibrating population density increases in terms of temperature increase.

The bottom line was that 65% of the U.S. linear warming trend between 1895 and 2023 was due to increasing population density at the suburban and urban stations; 8% of the warming was due to urbanization at rural stations. Most of that UHI effect warming occurred before 1970.

But this does not necessarily translate into NOAA’s official temperature record being corrupted at these levels. Read on…

What Does This Mean for Urbanization Effects in the Official U.S. Temperature Record?

That’s a good question, and I don’t have a good answer.

One of the reviewers, who seemed to know a lot about the homogenization technique used by NOAA, said the homogenized data could not be used for our study because the UHI-trends are mostly removed from those data. (Homogenization looks at year-to-year [time domain] temperature changes at neighboring stations, not the spatial temperature differences [space domain] like we do). So, we were forced to use the raw (not homogenized) U.S. summertime GHCN daily average ([Tmax+Tmin]/2) data for the study. One of the surprising things that reviewer claimed was that homogenization warms the past at currently urbanized stations to make their less-urbanized early history just as warm as today.

So, I emphasize: In our study, it was the raw (unadjusted) data which had a substantial UHI warming influence. This isn’t surprising.

But that reviewer of the paper said most of the spurious UHI warming effect has been removed by the homogenization process, which constitutes the official temperature record as reported by NOAA. I am not convinced of this, and at least one recent paper claims that homogenization does not actually correct the urban trends to look like rural trends, but instead it does “urban blending” of the data. As a result, which trends are “preferred” by that statistical procedure are based upon a sort of “statistical voting” process (my terminology here, which might not be accurate).

So, it remains to be seen just how much spurious UHI effect there is in the official, homogenized land-based temperature trends. The jury is still out on that.

Of course, if sufficient rural stations can be found to do land-based temperature monitoring, I still like Anthony Watts’ approach of simply not using suburban and urban sites for long-term trends. Nevertheless, most people live in urbanized areas, so it’s still important to quantify just how much of those “record hot” temperatures we hear about in cities are simply due to urbanization effects. I think our approach gets us a step closer to answering that question.

Is Population Density the Best Way to Do This?

We used PD data because there are now global datasets, and at least one of them extends centuries into the past. But, since we use population density in our study, we cannot account for additional UHI effects due to increased prosperity even when population has stabilized.

For example, even if population density no longer increases over time in some urban areas, there have likely been increases in air conditioning use, with more stores and more parking lots, as wealth has increased since, say, the 1970s. We have started using a Landsat-based dataset of “impervious surfaces” to try to get at part of this issue, but those data only go back to the mid-1970s. But it will be a start.

I suppose I shouldn’t be surprised. For the uninitiated, while Politico is allegedly a news organization, it has a history of supporting Progressive and Leftist causes.

To be fair, the summary lead at the top of the article is pretty good: “A common refrain: Climate policy hurts the poor, and the continued use of fossil fuels is a boon for humanity.“ But, at best, today’s Politico article entitled, “Meet the 4 influencers shaping Chris Wright’s worldview” is a mix of truths, half-truths, and misleading innuendoes. The article is by Scott Waldman. The four alleged influencers of Energy Secretary Chris Wright’s views on climate science and energy policy are, in order, Bjorn Lomborg, me, Alex Epstein, and John Constable.

I will let the others speak for themselves. What follows is, verbatim, the article addressing my influence on Sec. Wright. I don’t need to comment on everything because some of it is true. I will only offer clarifications where appropriate. Why? Because there are a lot of untruths circulating about me and unless I address them from time to time, those things become part of a narrative that is difficult to dislodge.

Quotes from the article are in italics; my response & clarifications are in bold:

Spencer, whose work was cited as a resource in Wright’s report, is a research scientist at the University of Alabama in Huntsville and is listed as an adviser to the Heartland Institute, which promotes climate misinformation. I used to give talks at Heartland conferences, but haven’t in recent years. I don’t have a formal relationship with them. I don’t speak for Heartland Institute, but I thoroughly disagree with the claim that they promote “climate misinformation”. That shoe fits Politico much better.

While some of Spencer’s work on atmospheric temperatures and other areas of study has been funded by NASA and the Energy Department, he has attacked federal climate researchers as being biased because they receive taxpayer money, and he has claimed that people alive today won’t experience global warming. On the first point… true. On the second point, I believe what I have said is that most people today will never notice global warming in their lifetimes because it is too weak (about 0.02 deg. C per year) compared to natural climate, seasonal, and day-to-day weather variability. In my book, people who believe they have witnessed human-caused global warming are about as delusional as flat-Earthers.

Spencer also served as a visiting fellow for the Heritage Foundation, which produced the Project 2025 policy proposal that has guided the first months of President Donald Trump’s second term.

The groups Spencer has been affiliated with have received millions of dollars in donations from foundations that oppose regulations, but he claims the American public has “been misled by the vested interests who financially benefit from convincing the citizens we are in a climate crisis.” That includes environmental groups and journalists, in his telling. And I stand by that claim. Look at the artwork at the top of this article, and see if you can figure out what it implies.

“Climate change is big business for a lot of players,” he wrote in a Heritage Foundation publication. “That includes a marching army of climate scientists whose careers now depend on a steady stream of funding from governments.” True. And I have said my career also depends upon that funding.

For years, Spencer has worked with organizations that have received funding from an interlinked network of fossil fuel companies — a multitrillion-dollar global industry — as well as wealthy foundations with billions of dollars in holdings that support groups opposing climate and energy regulations. What are you implying, Scott? That I’ve been paid off by this multitrillion dollar global industry? I know that’s what you are doing. But they have never funded me. At most, I have giving an occasional invited talk, which I receive honoraria for when offered (standard practice, and the same has applied to environmental organizations I have spoken to).

He states on his website that he has not been paid by oil companies, but a court filing in 2016 revealed that he received funding from Peabody Energy, the coal giant that for years spent millions of dollars on funding climate denial groups. That was one of my invited talks: As I recall, it was a Peabody board of directors meeting, and they wanted someone to provide a counterpoint to a Natural Resources Defense Council (NRDC) talk given at the same meeting. Peabody never funded me to do work.

Spencer has appeared before Congress a number of times, typically as a Republican witness attacking climate policy and downplaying climate risks. He served as the climatologist for the late conservative commentator Rush Limbaugh, who regularly promoted climate denialism on his show. Again with the “climate denialism” mantra? You really don’t have a second gear, do you, Scott? I don’t deny “climate”. I don’t even deny recent warming. I don’t even deny that recent warming is probably mostly due to humans.

Like Lomborg, Spencer claims climate policy will hurt the poor even as science has overwhelmingly shown the effects of global warming would disproportionately affect the world’s most vulnerable populations. “Science” has shown no such thing. Opportunistic researchers have indeed made such claims, though. But Lomborg, Epstein, and Roger Pielke Jr. are better at refuting those claims than I am.

He authored a book entitled: “Climate Confusion: How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguided Policies That Hurt the Poor.”

Spencer did not respond to a request for comment. True. I long ago learned which media outlets cannot be trusted to represent what I say fairly.

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for April, 2025 was +0.61 deg. C departure from the 1991-2020 mean, up a little from the March, 2025 anomaly of +0.57 deg. C.

The Version 6.1 global area-averaged linear temperature trend (January 1979 through April 2025) remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).

The following table lists various regional Version 6.1 LT departures from the 30-year (1991-2020) average for the last 16 months (record highs are in red).

The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for April, 2025, and a more detailed analysis by John Christy, should be available within the next several days here.

The monthly anomalies for various regions for the four deep layers we monitor from satellites will be available in the next several days at the following locations:

Lower Troposphere

Mid-Troposphere

Tropopause

Lower Stratosphere

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for March, 2025 was +0.58 deg. C departure from the 1991-2020 mean, up from the February, 2025 anomaly of +0.50 deg. C.

The Version 6.1 global area-averaged linear temperature trend (January 1979 through March 2025) remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).

The following table lists various regional Version 6.1 LT departures from the 30-year (1991-2020) average for the last 15 months (record highs are in red).

The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for March, 2025, and a more detailed analysis by John Christy, should be available within the next several days here.

The monthly anomalies for various regions for the four deep layers we monitor from satellites will be available in the next several days at the following locations:

Lower Troposphere

Mid-Troposphere

Tropopause

Lower Stratosphere

While some among us continue to be distracted by supposed “chemtrails” high in the atmosphere, lurking right under our noses has been the ultimate conspiracy: Cartrails.

Modern cars are programmed to emit cartrails, containing nefarious and noxious chemicals. As many people can attest, breathing problems become worse in cities where these vehicles-emitting-deadly-vapour-trails are most concentrated.

This never happened many years ago; I know because my grandfather (who was born in the late 1800s) once told me they NEVER had cartrails back when he was a kid.

So, what kinds of chemicals are they poisoning us with? Well, many years ago it was lead in gasoline. But we found out about that conspiracy, which was meant to destroy the nervous systems of our children. So, what was lead replaced with?

That’s an interesting story. My confidential whistleblower (who must remain nameless for fear of retribution) tells me that the government people got together with the car manufacturing people and the petroleum refining people, and they found a NEW way to poison us: platinum, palladium and rhodium microparticles inside super-heated boxes innocuously called “catalytic converters”.

Do you know what palladium microparticles do to the human nervous system??

Well, neither do I. But I’m sure it isn’t good.

The opportunity to poison us with our own cars is SO much more efficient than “chemtrails”. First, the poisoning occurs right here at ground-level, where we breathe the air into our fragile lungs.

Secondly, the amount of fuel used by cars and trucks is many times that used by jet aircraft, thus increasing the human exposure.

Finally, the emissions are nearly invisible on most days. How sinister is that?? Invisible pollution!

And this is why they make jet aircraft emit so much water vapor (which produces cirrus clouds). It’s to keep people distracted with chemtrail theories so that we don’t realize the real threat is right under our noses: Cartrails. You heard it here first. Spread the word. Start a cartrail blog. Vent your fears and frustrations on social media. Go for it.