One of the biggest scandals so far in climate science publishing has suckered in a number of government policy advisers around the world including the UK Office for Budget Responsibility (OBR). Last July, the British Budget-leaking bunglers estimated that the country’s Gross National Product (GNP) would be 7.8% less in 50 years’ time due to the effect of human-caused climate change. Newly-revised ‘climate impact’ figures suggest that annual borrowing to fund the national debt would be over £50 billion higher at 2025 prices. The claims update and increase previous September 2024 guesses due to “several significant developments… in the evidence base”. An in-depth investigation by the Daily Sceptic can reveal that these updated figures are junk since they are linked directly to the disgraced paper called Kotz et al (KLW24) that was retracted this month by Nature.
The OBR is not alone in having statistical egg all over its face since the work that arose from the Potsdam Institute for Climate Impact Research, a known nest of hard line climate activists, was widely used by other government organisations including the US Congressional Budget Office, the OECD and the World Bank. All seem to have relied on a so-called damage impacts model found in KLW24 that produced the headline claim that the world would be poorer over the next century by $78 trillion due to humans fiddling with the climate thermostat. Catsnip of course, to mainstream climate catastrophising clots with suggestions from the Green Blob-funded Climate Brief that the paper was the second most featured climate work in the media last year.
Now it has all ended in tears and disgrace. The Nature retraction has been long (too long!) in coming since it has been obvious for some time that the paper was riddled with fatal flaws. The authors had admitted that the errors were too substantial for a correction.
The OBR’s latest estimates of climate damage are based on a rise of 3°C from pre-industrial times and are “informed by NGFS Phase V”. This is a key admission. For its economic damages projections, the OBR relied on Network for Greening the Financial System scenarios which explicitly incorporated the Kotz et al paper. This information updates a NGFS damage function model that estimates GDP losses from climate impacts. Comments in the OBR report along with footnotes reference both NGFS Phase V and Kotz et al. “The most recent data and updated modelling suggest that the damage to GDP from climate change is likely to be more severe than previously thought”, observes the OBR.
The NGFS was set up at the height of the recent Green Mania by a consortium of central banks and supervisory authorities. It produces research and scenario development along with what is called best practice sharing on climate and environmental risks in finance. It has a distinctly turn of the decade feel about it with the financial and business world now moving on from its pie-in-the-sky platitudes. The connection with the Kotz paper is unlikely to improve its image, particularly with the government organisations that fell hook, line and sinker for its Phase V inventions. It still claims support in around 90 countries but not, alas, in the most important financial country in the world. It didn’t take long for Trump in America to withdraw the Federal Reserve, the Federal Deposit Insurance Corporation and the Department of the Treasury.
In April 2024, a hysterical Guardian went into climate catastrophising overdrive by reporting the Kotz guess that world income would fall by a nearly a fifth within 26 years. The political clickbait kicker was clearly displayed in the Guardian’s first paragraph with a note that “the costs of damage will be six times higher than the price of limiting global heating to 2°C”. Lead author Maximillian Kotz was noted to claim that the strong income reductions were caused by climate impacts on, amongst others, agricultural yields, labour productivity and infrastructure. To date, the Guardian does not seem to have thought it necessary to inform its readers about the retraction, nor has it made any corrections to its original fantasy report.
What is wrong with the Kotz paper? Where to begin? It appears that it suffered from a combination of data inaccuracies and methodology shortcomings that fundamentally undermined the core predictions of climate-driven economic damage. The problems appear to have cascaded through the report and were acknowledged as too substantial for a mere correction. Almost unbelievably, it appears that problems over a Uzbekistan economic dataset from 1995–1999 led to model estimates of temperature impacts on growth inflating global projections by a factor of around three. For their part, the authors have issued a revised paper for ‘peer review’ with slightly lower catastrophising claims. But the world is moving on from Net Zero and the market for scary nonsense is diminishing by the day.
The OBR needs to amend its figures in the light of the Kotz retraction. The NGFS has acknowledged the central role played by Kotz in underpinning the physical risk estimates in Phase V. It has advised users to consider this limitation when making up, pardon, calculating its own figures using the scenarios.
After this scientific car crash, it might be preferable for the OBR to get out of the climate catastrophising business altogether. Any serious number-crunching economist should be appalled at having to report fantasy figures produced by useless computer climate models. In addition, it is patently obvious that the OBR knows little about the science of climate change. In the first paragraph, it promotes its fictional impact report by quoting a recent five-year temperature record. That short period is practically weather, not a meaningful climate trend. It then goes on to suggest that the UK economy is facing “increasingly volatile and extreme weather”, a common scare that is not backed up by the data. Then it reports that temperatures will continue to rise until the emission of all ‘greenhouse’ gases reach zero, a claim that has no validity based on observations and measurements in both the historical and paleo climate records.
It seems not to have occurred to the OBR that an extreme Net Zero solution will lead to world starvation, death on a truly shocking scale, economic collapse and global societal breakdown. Even the Guardian would baulk at reporting on the almost unimaginable cost of all that.
Chris Morrison is the Daily Sceptic’s Environment Editor. Follow him on X.
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Now go on, tell me that anybody who believed this retracted rubbish wasn’t ignorant and gullible, just like the reviewers and editors involved in its publication.
While you’re doing it, tell me why people who believe that adding CO2 to air makes thermometers hotter shouldn’t be called ignorant and gullible!
What – cat got your tongue?
w00f!
No one would be accused of being ignorant or gullible for accepting the results of a peer reviewed paper published in a highly regarded scientific journal. That issues were immediately identified and called out speaks to the success of transparency in scientific research.
I’ll note that the authors have prepared an updated version of the paper with the issues corrected, and the results change very little:
https://zenodo.org/records/16835838
Oh come off it! The original paper was garbage. The new revised paper is garbage. I accuse you of being ignorant and gullible. Or worse. What’s your trip anyway, Alan J? Why here? Be honest about your intentions, if that’s possible.
The original paper had methodological issues that slightly impacted its conclusions, and the revised paper removes those issues. Unless you have some new insights about the revised paper, your criticism is meritless. I don’t care what you accuse me of.
YAY! Way to go defending garbage. Rats always do that too and they keep coming back for more.
As is the case with the ignorant and gullible, in an attempt to save face, you now start talking about a “revised” paper. I haven’t read that paper yet (if it exists), but I assume it will be merely a rehashing of the original nonsense, hoping that editors and reviewers will maintain their high levels of ignorance and gullibility. They may even toss a dash of stupidity into the mix, and be forced to retract even more rubbish.
Read the paper yourself, and guarantee it contains no errors! Can’t even assert that, can you?
I linked the revised paper for you above. It is the original manuscript, revise to remove the methodological issues that led to the retraction. If there are remaining issues in the new manuscript, it is publicly available, so critics can feel free to point them out. The authors and journal are maintaining good standards of transparency and accountability.
The original paper had methodological issues that slightly impacted its conclusions, and the revised paper removes those issues.
No it doesn’t. It’s a house of cards. It estimates economic impacts fabricated out of thin air and founded on unproven claims from climate models that can’t replicate global climate because they are inaccurate because they’re missing significant influences like the contribution of water vapor and clouds to heating and cooling. The appendices of IPCC reports note, “because the climate system is inherently nonlinear and chaotic, predictability of the climate system is inherently limited,” in other words virtually impossible.
So what you have is flawed economic models biased by selectively ignoring the well-known and measured benefits of atmospheric CO2, the use of fossil fuels, and continuing human technological progress derived from flawed climate models biased by selectively ignoring the well-known and measured benefits of increased atmospheric CO2 and influences on global temperature far more significant than CO2 and methane like water vapor and clouds. It’s junk science. Or as Donald Trump accurately and succinctly put it, the greatest hoax ever.
Yes, they would (I assume you meant “should”, but were a tad sloppy). Obviously, the paper was rubbish – hence its retraction. Anybody who was knowledgeable and skeptical realised the worthlessness of the paper after reading it.
Even the motto of the Royal Society “Nullius in verba” says take no one’s word for it.
Gosh!
https://wattsupwiththat.com/2025/12/08/weekly-climate-and-energy-news-roundup-669/#comment-4139107
With this government it’s the daily crisis, and it really is daily now. And yet some quite lunatic things are happening in education and going entirely without mention. A particularly egregious example being:
“Children as young as five are being taught “abortion is a superpower” in a new book.” – MSN
Put down the teddy bears, kids and worry about the dying planet.
Food and fossil fuel production causing $5bn of environmental damage an hour’ – Grauniad
The OBR is yet another civil service offloading. Since Blair made the CS independent, getting anything the civil servants don’t approve of done is minimal. It’s riddled with activist groups and factions. A real swamp. Luckily, for mad Ed, they fully approve of net zero.
The OBR is still smarting after the absolute budget farce [the illusory black hole], losing its top man in the process. The OBR has, nonetheless, done its level best to get Reeves off the hook, even though they know she lied to the nation at the despatch box.
Nullius in verba. It’s more than just a maxim…
Chagos surrender update
BUY NOW: ‘Save Chagos’ Campaign Sticker and T-Shirt Series – Guido Fawkes
Addendum
Stickers saying “No Labour MPs” have now sprung up across venues.
Labour MPs are being banned from pubs and restaurants across the country following the Winter Budget. GF
This could catch on…
“Children as young as five are being taught “abortion is a superpower” in a new book.”
That should be prosecuted as criminal child abuse.
Trillions squandered on wind and solar and fossil fuel use continues to INCREASE.
And these idiots think the PURELY IMAGINARY costs of an IMPROVING climate will somehow be less than the continuation of clearly economically ruinous “climate/net zero” policies?!
People this delusional need to be in an asylum, not in government.
Is this state of affairs not the very definition of the triumph of belief over reason?
They even think government has their best interests at heart.
“We’re from the government and we are here to help.”
Time to run.
So this methodology was that sensitive to one +15-year-old, 4-year dataset from a 3rd world country? The authors got the answers they wanted so they did not question the results.
The authors got the answers they wanted and could readily sell to AGW/CAGW alarmists so they did not question the results.
The old adage that “A lie can travel halfway around the world before the truth puts on its shoes” isn’t adequate to describe the Climate Cult. They simply bury the truth, so it never even finds any shoes.
The Russian disruptor agents in the UK can go on holiday now.
Catastrowauling
Greta Thunberg claimed to “follow the science” which translates to she read a few headlines.
Seems this is another “Greta effect.”
Face, meet egg!
“ The Nature retraction has been long (too long!) in coming since it has been obvious for some time that the paper was riddled with fatal flaws.”
Nature published the warning that the reliability of the data was in question in November 2024:
“06 November 2024 Editor’s Note: Readers are alerted that the reliability of data and methodology presented in this manuscript is currently in question. Appropriate editorial action will be taken once this matter is resolved.”
They also published the detailed questions regarding the data in August 2025:
https://www.nature.com/articles/s41586-025-09206-5
It seems to me that that was a reasonably quick response, given the usual times it takes for publishing papers.
Very nice Chris. It is not enough that we find and critique worthless studies like this. We have our own scientists, academics, economists and what have you, we need to get going on our own study. The first thing we look at is to accept everything the CAGW fools are claiming and give them the fossil free society they so desperately want. List all the things we have now that we will lose and how much it will cost. Our GDP is sure to plummet from what it is now, in other words we will be far worse off in the future than we are now. The second part of the study would be for us to ignore the CAGW fools and develope our resources responsibly. We would have even more clean, reliable and affordable fossil fuel and nuclear energy. We would have plenty of energy for manufacturing, industry and yes AI. We would have the money and resources to maintain our infrastructure and build even better infrastructure. Our infrastructure would be the best up to date possible and able to withstand whatever weather/climate we face not to mention earthquakes and such. It isn’t even close they are asking us to go backwards we are saying no let’s move forward to a bright, clean and affordable future. They are losers we are not.