Good Reef!

A United States government report compiled by scientists with impeccable pedigrees provides a refreshing insight into the realities of climate change, writes IPA Senior Fellow and Chief Economist Adam Creighton.

At the 2025 Bush Summit in Ballarat Anthony Albanese defended his government’s ever-more-radical plans to ‘decarbonise’ the Australian economy by invoking ‘the science’.

“The science told us that climate change was real,” he told a sceptical crowd in September. “And we are seeing more extreme weather events, and more intense weather events,” he added, prompting boos from a mainly regional audience increasingly fed up with the rollout of wind turbines and solar panels in their communities.

Advocates of ever-more-ambitious renewable energy targets typically proffer the spectre of catastrophic climate change to make their case, especially as it has become obvious the so-called transition is pushing up power prices, and China, India and the US—the world’s biggest emitters—are not taking emissions targets seriously.

Yet fearmongering about climate change has become more difficult in the wake of a recent report by the US Department of Energy (DOE), titled A Critical Review of Impacts of Greenhouse Gas Emissions on the US Climate, aimed at the educated layperson.

The report dares to question the alarmist narrative: the costs of climate change are far less catastrophic than assumed, extreme weather events have not become more frequent or severe, climate change models have proved a poor guide to changes in the weather, and even US unilateral sacrifices will have little discernible impact on global outcomes.

The 131-page document, published in late July, could become one of the most consequential government documents on energy ever if it survives the inevitable onslaught from supporters of the conventional wisdom, and punctures the widespread misconception that “97 per cent of climate scientists” support catastrophism.

The report’s credibility lies not only in having the institutional imprimatur of the world’s most powerful government but in the intellectual pedigree of its authors: John Christy, Judith Curry, Steven Koonin, Ross McKitrick, and Roy Spencer. Each is a veteran of climate debates, with decades of work in atmospheric science, climate modelling, or economic analysis.

The authors are not ‘deniers’. They concede carbon dioxide emissions have increased to about 420 parts per million from 280 ppm in the early 1800s. And they concur with the mainstream that greenhouse gases “exert a warming influence on the climate and weather”, a long-established theory first postulated in the late 19th century. But they dispute the attribution of most or more than half of the 1.07 degree Celsius of global warming since 1850 to human activity, contrary to most other government agencies.

The report dares to question the alarmist narrative.

Such a claim does not allow sufficiently for natural climate change, which has varied throughout history and long before humans could have been a factor, influenced by changes in solar activity.

The authors find it implausible that such “natural external drivers” have had essentially no net impact on the warming since 1850, which is a core assumption of analysis commissioned by the United Nations’ Intergovernmental Panel on Climate Change (IPCC).

For instance, the sharp increase in global temperatures in the last decade could be explained by “a significant reduction in planetary albedo since 2015, which has coincided with at least two years of record global warmth”. This refers to a decline in the fraction of incoming solar radiation that is reflected back into space rather than being absorbed by the planet.

Research suggests the primary explanation for the decline in the Earth’s albedo since 2015 was changes in cloud levels, much of which seems to be due to natural climate variability. Another contributor to declining planetary albedo is the fact that in many ways the air has become cleaner, and “cleaner air means less solar radiation is reflected [back into space], which contributes to surface warming”.

The Medieval Warm period and the Little Ice Age of the 17th and 18th centuries are two better-known examples of climate change that cannot be attributed to humans. Others include a period of global cooling between 1945 and 1976, known as the Grand Hiatus, which included a 0.3 degrees Celsius drop in ocean temperatures between about 1968 and 1972.

“The time series of global surface temperature anomalies since 1850 shows irregular variations of significant amplitude against the background of an overall warming trend,” the report says. The infamous ‘hockey stick’ chart, showing a rapid increase in global temperatures, hinges in part on the Great Pacific Climate Shift of 1976-1977—a natural climatic event closely associated with long-term cooling and warming phases. The shift in 1976 was the start of a period of accelerated global warming. “When the Great Pacific Climate Shift is accounted for in climate attribution analyses since 1950, 40 per cent or more of the warming in the second half of the 20th century is attributed to natural internal variability,” the report states.

Despite all this, droughts, floods, hurricanes and heat waves around the world are typically attributed to climate change by the media, and political and institutional elites, creating a steady drumbeat of news reports that serve to convince an uninformed and credulous public that we’re facing an existential threat.

The data suggest such attribution is ridiculous: hurricanes in the US show “no statistically significant trend since 1920”, and only one of the 10 strongest on record to make landfall has occurred in the 21st century, the authors point out. Severe tornadoes have exhibited a “noticeable downward trend in the number since 1950”.

While the IPCC reports focus on temperature extremes since 1950, a longer record shows heat waves and droughts were most pronounced in the ‘Dust Bowl era of the 1930s’: “The overall reduction in numbers of both cold and hot extremes over the past century indicates a climate less prone to extremes,” the authors conclude, noting that many of the worst extreme weather and climate events in US history occurred in or before the first half of the 20th century.

The alarmist narrative around rising sea levels is not supported by observed data either, and relies on highly speculative modelling. Globally, sea levels have risen on average by little more than 20cm since 1900, or by “about two stacked pennies a year”. Global sea levels have been rising (and falling) since time immemorial. The most recent cycle of rising sea levels began “during the period 1820-1860, well before most anthropogenic greenhouse gas emissions”.

The PM’s reference to extreme weather isn’t even sustained by the IPCC.

The US National Oceanic and Atmospheric Administration in 2022 predicted a further increase of as much as a foot (about 30.5cm) in Manhattan by 2050. That “would require a dramatic acceleration beyond anything observed since the early 20th century”, or more than twice the current rate and three times the rate of the past century.  At least this prediction, unlike long-term climate change forecasts, could be debunked within a relatively short time.

As for all the popular angst about the supposedly vanishing ice caps, the decline in the extent of Arctic sea ice (around the North Pole) which had been observed since 1980, stopped in 2007. And around the South Pole, the IPCC concedes “there has been no significant trend in Antarctic Sea ice areas from 1979 to 2020”. Rutgers University’s Snow Lab finds that winter snow cover in the Northern Hemisphere has not been decreasing; if anything, it has shown an increasing trend.

The prime minister’s reference to extreme weather is not even sustained by the IPCC. Of the 33 categories of ‘climatic impact-drivers’, the technical term for the manifestations of changing weather—such as the frequency and severity of landslides, snow, hail, wind speed, and sea levels—human behaviour, for example through emissions, has had a statistically reliable impact (with a high degree of confidence) on only five, and these did not include droughts and floods, which is what Mr Albanese probably had in mind. Even if the extreme weather events had become more common or severe in a statistically meaningful way, attribution would be next to impossible given the massive variability of such events. “There are only about 130 years of reliable observational records that can be analysed statistically,” the authors write. The relevant historical period for an accurate analysis would need to extend hundreds of thousands of years at least.

It is a little disconcerting to learn of the so-called ARkStorm of December 1861, which “dumped nearly 10 feet of rain in parts of California and submerged the entire Central Valley for weeks under as much as 15 feet of water”. Human activity could not have influenced such a storm; but imagine how the media would react were such an event to recur today!

The authors conclude “Many of the worst extreme weather and climate events in US history occurred in or before the first half of the 20th century, including the early 19th century.”

The Western North American heat wave of June 2021 triggered dystopian headlines, prompting World Weather Attribution, an international research body, to declare it would have been at least 150 times rarer without human-induced climate change.

Yet, according to the DOE report, “subsequent peer reviewed analyses showed that the event was caused by rare meteorological conditions that were not made more probable by global warming”.Untangling the contribution of humans to climate change among numerous known and unknown confounding factors is a herculean task, and not one that should inspire the sorts of definitive conclusions that dominate the public debate. Al Gore in his well-known movie An Inconvenient Truth (2006) made much of a supposed causal relationship between rising CO2 emissions and temperature changes over a period of 440,000 years.

But it turns out, awkwardly for Gore, that the temperature changes were affecting atmospheric CO2 levels and not the other way around—at least according to one well-known statistical technique that teases out (Granger-causes) causality.

Climate models have attracted a level of reverence in the public mind they do not deserve. The several dozen that underpin the doomsday forecasts out to 2100 and beyond, which keep the public fearful and supportive of radical decarbonisation agendas, have “shown substantially more warming than the [actual] observations since 1979”. Nor have these models been able to accurately predict climate outcomes in the past using earlier climate data. As for the future, “the range of future warming they produce in response to a hypothetical doubling of atmospheric CO2 extends over a factor of three”.

Even if a model were a miraculously accurate reflection of the world, its future forecasts would only be as good as the assumptions about greenhouse gas concentrations in the atmosphere well into the future.

In the early 2010s, the IPCC produced a range of potential trajectories for CO2 emissions into the future, from which temperature increases could be inferred given various estimated sensitivities. The most extreme, known as RCP8.5, implies nearly five degrees Celsius of warming from 1900 to 2100. This speculative, low probability, high emissions scenario represents a ‘worst case’ future trajectory. Yet “some 16,800 scientific papers published between 2010 and 2020 used the RCP8.5 scenario, with about 4,500 of the articles linking RCP8.5 to the concept of business-as-usual”.

Perhaps the most provocative part of the DOE report focuses on the possibility that global warming and increased carbon dioxide in the air could be beneficial, a point barely addressed by the IPCC. Between a quarter and half of the Earth experienced a beneficial ‘greening’ between 1982 and 2011, owing to the increased levels of carbon dioxide in the air.

A 2021 National Bureau of Economic Research study found “CO2 emissions had boosted US crop production since 1940 by 50 to 80 per cent”. Another study, from 2023, found “A warming climate would yield positive benefits for French agriculture that were between two and 20 times larger than had previously been estimated”.

After all, plants and animals evolved under much higher levels of CO2 in the past. Drawing on the work of IPA Adjunct Fellow Peter Ridd, the DOE report demonstrates that concerns regarding the impact of higher water temperature and decreasing pH on the Great Barrier Reef are unwarranted. Recent data shows coral coverage on the reef has surged over the past decade, rather than declined, as many people mistakenly believe.

Humans could even benefit from higher overall temperatures, given extreme cold is significantly more lethal than extreme heat, a fact on which the IPCC has been silent. According to data compiled by the Centers for Disease Control and Prevention, from 1999 to 2015 in the US there were 2.2 deaths per 1,000,000 people for which cold was the main underlying cause, compared to 1.3 for heat. Our ability to manage temperature extremes and natural disasters has improved dramatically, too. The Galveston hurricane of 1900 killed over 8,000 people while Katrina in 2005 left 1,800 dead. Public policy expert Professor Roger Pielke Jr noted, as the DOE report highlighted, that “losses per weather disaster as a proportion of GDP have decreased by about 80 per cent since 1980”.

The final sections of the report underscore the pointlessness, not to mention the extraordinary cost, of even the US taking drastic action to curb greenhouse emissions, which would at best elicit “undetectably small direct impacts on the global climate”. For instance, eliminating the entire stock of US combustion engine cars and trucks, an unrealistic eventuality in any case, would “retard the accumulation of CO2 in the atmosphere by a year or two over a century”.

Supporting a mainstream narrative confers benefits rather than costs.

For context, the US is responsible for roughly 13 per cent of the world’s annual CO2 emissions. Australia’s share of annual CO2 emissions is roughly one per cent. This means any trace impact from Australia’s emissions reduction initiatives will be even less noticeable. The DOE report also reviews economic arguments, pioneered by William Nordhaus, that the costs of seeking to aggressively reduce emissions are far greater than the costs of climate change, even assuming that global emissions control can be coordinated at no cost.

Proponents of climate change alarmism have swiftly condemned the report, most notably a group of 85 climate scientists, led by Andrew Dessler and Robert Kopp, who called it “biased, full of errors, and not fit to inform policymaking”. They accuse the authors of cherry-picking, misquoting peer-reviewed research, “and a general dismissal of the vast majority of decades of peer-reviewed research”.

Rarely do mainstream reports elicit such visceral denunciations. Yet the stakes are high. Lee Zeldin, the administrator of the Environmental Protection Agency, has made clear the Trump administration would like to reverse the 2009 ‘endangerment finding’, which listed six greenhouse gases including CO2 as “risks to public health and welfare”. US regulations that seek to limit emissions depend on this finding.

Judith Curry, one of the authors, on her personal blog praised the 439-page Dessler et al criticism, for “actually behaving like scientists with their rebuttal”, unlike other criticism which she dismissed as politically motivated, proffered by non-experts, or examples of committing the logical fallacies of appeals to authority or (alleged) consensus.

Where does this leave the interested citizen, who does not have the time to read the academic literature? It is very difficult for a good faith lay observer to arbitrate between these competing claims. One, seemingly larger, group of scientists gravitates towards the catastrophist narrative, while another suggests the threats are exaggerated.

Science is not a democracy, and the Covid pandemic for one illustrated starkly how wrong the so-called ‘consensus’ experts and their models can be. Unfortunately, unlike Covid cases and deaths, predictions of climate disaster decades into the future are conveniently immune to real-time verification.

As a journalist I always paid greater attention to scientists who spoke up against a consensus because of the significant professional and social costs they incurred. They must truly believe their arguments. In contrast, supporting a mainstream narrative confers benefits rather than costs, suggesting at least some proportion of scientists would choose not to speak out against, or indeed actively support, a catastrophist narrative.

Moreover, the political dimension of climate science cannot be ignored. It is obvious the catastrophist narrative requires massive government regulation of households and business. Those inclined to more powerful and intrusive government for philosophical reasons, who tend to congregate in government agencies, might promote the mainstream narrative because of this, rather than for ‘scientific’ reasons.

The eagerness with which some agencies have sought to fearmonger is telling. For instance, the National Oceanic and Atmospheric Administration in May 2025 had to publicly withdraw its so called Billion Dollar Disaster publication, which attempted to show severe weather events were becoming more costly. It failed to normalise the series properly for changes in population exposure and wealth, which would in fact have demonstrated the opposite trend. It stretches credulity that someone in an agency of highly educated people hadn’t understood this.

US Energy Secretary Chris Wright, who commissioned the report, said it had “exceeded his expectations” when he dissolved the ad hoc working group in early September. “The discourse around this issue will benefit from your work and the public comment process; both create long overdue space for a variety of scientific viewpoints,” he wrote.

We won’t know which group was ‘right’ about climate change for decades. In the meantime, it is likely to be the public’s growing awareness of the extreme costs of seeking to reduce emissions that undermines confidence in the catastrophist ‘consensus’.

IN GOOD COMPANY

These are the five authors of the US Department of Energy report, A Critical Review of Impacts of Greenhouse Gas Emissions on the US Climate.

John Christy is the Distinguished Professor of Atmospheric Science and Director of the Earth System Science Center at The University of Alabama in Huntsville where he began studying global climate issues in 1987. Since November 2000 he has been Alabama’s State Climatologist. In 1989 Dr. Roy Spencer (see below) and Christy developed a global temperature data set from microwave data observed from satellites beginning in 1979. For this work, they were awarded NASA’s Medal for Exceptional Scientific Achievement in 1991. In 1996, they received a Special Award from the American Meteorological Society “for developing a global, precise record of earth’s temperature from operational polar-orbiting satellites, fundamentally advancing our ability to monitor climate”.

Judith Curry is a climatologist and former School of Earth and Atmospheric Sciences chair at Georgia Institute of Technology. Her research interests include hurricanes, remote sensing, atmospheric modelling, polar climates, air-sea interaction, climate models, and unmanned aerial vehicles for atmospheric research. She was a member of the National Research Council’s Climate Research Committee. The author of over 180 scientific papers on weather and climate, she was a recipient of the Henry G. Houghton Research Award from the American Meteorological Society in 1992.

Steven Koonin is a theoretical physicist and the Edward Teller Fellow at Stanford University’s Hoover Institution. Before joining Stanford in 2024, he was a professor at New York University, with appointments in the Stern School of Business, the Tandon School of Engineering, and the Department of Physics. He served as undersecretary for science in the US Department of Energy under President Obama from 2009 to 2011, where his portfolio included the climate research program and energy technology strategy. He was the lead author of the US Department of Energy’s Strategic Plan (2011) and the inaugural Department of Energy Quadrennial Technology Review (2011). Before joining the government, Koonin spent five years as chief scientist for BP, researching renewable energy options. For almost 30 years, he was a professor of theoretical physics at Caltech, and served for nine years as Caltech’s vice president and provost.

Ross McKitrick is a Canadian economist specialising in environmental economics and policy analysis. He is a Professor of Economics at the University of Guelph. He is now engaged in projects relating to state-contingent environmental policy, econometric methods for measuring global warming, and evaluating climate models. He built and published one of the first national-scale Computable General Equilibrium models for analysing the effect of carbon taxes on the Canadian economy in the 1990s. He has testified before the US Congress and committees of the Canadian House of Commons and Senate.

Roy Spencer is a meteorologist and climate scientist. He is a principal research scientist at the University of Alabama in Huntsville, and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer on NASA’s Aqua satellite. After receiving his PhD in 1982, Spencer worked for two years as a research scientist in the Space Science and Engineering Center at the University of Wisconsin–Madison. He then joined NASA’s Marshall Space Flight Center as a visiting scientist in 1984, where he later became senior scientist for climate studies.

This article from the Spring 2025 edition of the IPA Review is written by IPA Senior Fellow and Chief Economist Adam Creighton.