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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Climate Hustle


Dana Nuccitelli is an environmental scientist at a private environmental consulting firm in the Sacramento, California area. He has a Bachelor's Degree in astrophysics from the University of California at Berkeley, and a Master's Degree in physics from the University of California at Davis.

Dana has been researching climate science, economics, and solutions since 2006, and has contributed to Skeptical Science since September, 2010.  He also blogs at The Guardian, and is the author of Climatology versus Pseudoscience.  He has published climate-related papers on various subjects, from the build-up of heat in the Earth's climate system to the expert consensus on human-caused global warming.

Follow him on Twitter.


Nuccitelli, D., Way, R., Painting, R., Church, J., & Cook, J. (2012). Comment on ocean heat content and Earth's radiation imbalance. II. Relation to climate shifts. Physics Letters A.

Cook, J., Nuccitelli, D., Green, S.A., Richardson, M., Winkler, B., Painting, R., Way, R., Jacobs, P., & Skuce, A. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters, 8(2), 024024+. 

Cook, J., Oreskes, N., Doran, P. T., Anderegg, W. R., Verheggen, B., Maibach, E. W., Carlton, J. S., Lewandowsky, S., Skuce, A. G., Green, S. A., & Nuccitelli, D. (2016). Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. Environmental Research Letters, 11(4), 048002.

Cook, J., Nuccitelli, D., Skuce, A., Way, R., Jacobs, P., Painting, R., Honeycutt, R., Green, S.A. (2014). Reply to Comment on ‘Quantifying the consensus on anthropogenic global warming in the scientific literature: a Reanalysis’. Energy Policy. DOI: 10.1016/j.enpol.2014.06.002

Nuccitelli, D. A., Abraham, J. P., Benestad, R. E., & Mandia, S. A. (2013). Comment on: Akasofu, S.-I. On the Present Halting of Global Warming. Climate 2013, 1, 4–11. Climate, 1(2), 76-83.

Abraham, J., Cook, J., Fasullo, J., Jacobs, P., Mandia, S., & Nuccitelli, D. (2014). Review of the consensus and asymmetric quality of research on human-induced climate changeCosmopolis2014(1), 3-18.

Benestad, R. E., Hygen, H. O., Dorland, R. V., Cook, J., & Nuccitelli, D. (2013). Agnotology: learning from mistakes. Earth System Dynamics Discussions, 4(1), 451-505.

Nuccitelli, D., Richter, M. J., & McCall, B. J. (2005). A search for interstellar carbon-60. In IAU Symposium (Vol. 235, p. 236P).

Encrenaz, T., Bézard, B., Greathouse, T., Holmes, S., Richter, M., Nuccitelli, D., & Forget, F. et al. (2006, February). Ground-based high-resolution IR spectroscopy of Mars: H2O and H2O2 mapping, search for CH4, and determination of CO2 isotopic ratios. In Second Workshop on Mars Atmosphere Modelling and Observations, held February.


Recent blog posts

Climate denial is like The Matrix; more Republicans are choosing the red pill

Posted on 19 July 2017 by dana1981 &

Trump’s EPA administrator Scott Pruitt wants to hold televised ‘Red Team/Blue Team’ climate science ‘debates.’ The idea is that a ‘Red Team’ of scientists will challenge the mainstream findings of ‘Blue Team’ scientists. That may sound familiar, because it’s exactly how the peer-review process works. But climate deniers have lost the debate in the peer-reviewed literature, with over 97% of peer-reviewed studies endorsing the consensus on human-caused global warming, and the few contrarian papers being flawed and failing to withstand scientific scrutiny

So Scott Pruitt is trying to put his thumb on the scale, giving the less than 3% of contrarian scientists equal footing on a ‘Red Team.’ John Oliver showed how to do a statistically representative televised climate debate (so brilliantly that it’s been viewed 7.4m times), but it’s probably not what Pruitt had in mind:

Climate ‘Red Teams’ are a concept that the fossil fuel-funded Heritage Foundation tried four years ago, calling its 2013 ‘NIPCC report’ part of the group’s “Red Team mission.” But much like climate contrarian research papers, the NIPCC report was riddled with errors and long-debunked myths.

The name also evokes images of the red and blue pills in The Matrix, in which characters could choose to remain in the Matrix (denial) by taking the blue pill, or accept reality with the red pill. In this case the colors are reversed, but the concept is the same – by choosing the red team, Pruitt and company are choosing the soothing comfort of denial over the harsh reality of human-caused climate change and the threats it poses.

Fortunately, it seems like a growing number of Republican leaders are choosing the red pill.



Study: On climate change and elsewhere, politicians more conservative than citizens

Posted on 14 July 2017 by dana1981 &

Academics have identified a skew in American politics, in which policies that are implemented are much more conservative than average Americans prefer. A new paper  by David Broockman at Stanford University and Christopher Skovron from the University of Michigan suggests a cause for this disparity: American politicians perceive their constituents’ positions as more conservative than they are in actuality on a wide range of issues; for example, Republican politicians tend to overestimate support for their conservative health care views by a whopping 20 percentage points. As Broockman and his colleague Christopher Warshaw of MIT put it in an article for the New York Times: “Research shows that politicians are surprisingly poor at estimating public opinion in their districts and state, Republicans in particular.” This in turn appears to be caused by greater political engagement among conservative constituents, who contact their members of Congress more frequently than liberal voters.

The study's authors looked at data surveying thousands of American politicians’ perceptions of their constituents’ opinions, and compared those results to actual public opinion. They found that both Democratic and Republican politicians perceive that public opinion is more conservative than it is in actuality, but it’s especially true among Republican legislators. That matches patterns in grassroots mobilization—Republican voters are about 40 percent more likely to contact their member of Congress’ office than Democratic voters, especially when their member of Congress is a fellow Republican.

The conservative bias in Republican politicians’ perceptions of constituent opinion extended to every question in the survey, on issues such as firearms background checks, where GOP politicians perceive 36 percent more support for their conservative positions than there actually is among the general public—something that statisticians call “skew.” Similar overestimates occur regarding the depth of support for conservative positions on the banning of assault rifles (overestimated by about 18 percent), granting amnesty to illegal immigrants (9 percent), banning abortion (9 percent), and gay marriage (7 percent). This again matches statistics on grassroots mobilization—conservative constituents are especially well-organized and vocal on the issue of gun control.

The survey didn’t include any questions about climate change, but that’s another issue on which Republican politicians’ perceptions of constituent opinion appear extremely skewed.



Conservatives are again denying the very existence of global warming

Posted on 10 July 2017 by dana1981 &

As we well know, climate myths are like zombies that never seem to die. It’s only a matter of time before they rise from the dead and threaten to eat our brains. And so here we go again – American conservatives are denying the very existence of global warming.

Working backwards from a politically-motivated conclusion

The claim is based on what can charitably be described as a white paper, written by fossil fuel-funded contrarians Joseph D’Aleo and Craig Idso along with James Wallace III. Two months ago, D’Aleo and Wallace published another error-riddled white paper on the same website with fellow contrarian John Christy; both papers aimed to undermine the EPA’s Endangerment Finding.

The Endangerment Finding concluded that the scientific research clearly shows that carbon pollution endangers public health and welfare via climate change impacts, and therefore according to the US Supreme Court, the EPA must regulate carbon pollution under the Clean Air Act. Conservatives who benefit from the fossil fuel status quo and oppose all climate policies have urged the Trump administration to go after the Endangerment Finding.

Both papers are rife with flaws because they start from a desired conclusion – that the science underpinning Endangerment Finding is somehow wrong – and work backwards trying to support it. In this paper, the contrarians try to undermine the accuracy of the global surface temperature record, which has been validated time and time again. They don’t bother trying to hide their bias – the paper refers to “Climate Alarmists” and speaks of invalidating the Endangerment Finding.

The errors in the white paper

The paper itself has little scientific content. Using charts taken from climate denier blogs, the authors claim that every temperature record adjustment since the 1980s has been in the warming direction, which is simply false. As Zeke Hausfather pointed out, referencing work by Nick Stokes, roughly half of the adjustments have resulted in cooling and half in warming. Moreover, the net adjustment to the raw data actually reduces the long-term global warming trend:

View image on Twitter



Why the Republican Party's climate policy obstruction is indefensible

Posted on 5 July 2017 by dana1981 &

Two weeks ago, Senator Al Franken (D-MN) had an exchange with Trump’s Department of Energy Secretary Rick Perry about climate change. 

Perry’s responses perfectly summarized the Republican Party’s current position on the subject. The problem is that it’s an indefensible position.

Wrong on the science

The Republican position is based upon a rejection of established climate science. When confronted with the conclusion that global warming is 100% due to human activities, Perry responded, “I don’t believe that ... don’t buy it.” But of course it’s not a matter of belief – that’s what the scientific evidence indicates. There have been dozens of studies quantifying the various contributions to recent global warming. I summarized ten of them in the chart below (details here), and the answer is clear:

all of it

Human contribution to global surface warming over the past 50 to 65 years based on ten peer-reviewed studies (see for details). Illustration: Dana Nuccitelli and John Cook



Trump fact check: Climate policy benefits vastly exceed costs

Posted on 30 June 2017 by dana1981 &

When people who benefit from maintaining the status quo argue against climate policies, they invariably use two misleading tactics: exaggerating the costs of climate policies, and ignoring their benefits—economic and otherwise. In justifying his historically irresponsible decision to withdraw America from the Paris Agreement on climate change, President Trump followed this same playbook, falsely claiming: “The cost to the economy at this time would be close to $3 trillion in lost GDP [gross domestic product].”

That statistic originated from a report by National Economic Research Associates, Inc., which explicitly notes that it “does not take into account potential benefits from avoided emissions. The study results are not a benefit-cost analysis of climate change.” As Yale economistKenneth Gillingham noted, the report’s cost estimates are also based on one specific set of policy actions that the United States could implement to meet its Paris pledges. But there’s an infinite combination of possible climate policy responses, with some costing more than others.

For example, a revenue-neutral carbon tax is the proposed policy that currently has the most widespread support. One such proposal by the Climate Leadership Council has been endorsed by a broad coalition that includes Stephen Hawking, ExxonMobil, the Nature Conservancy, and George Shultz. And the Citizens’ Climate Lobby—a nonpartisan grassroots organization advocating for a similar policy—recently sent over 1,000 volunteers to lobby members of Congress in Washington, DC.

Regional Economic Modeling, Inc. (REMI) evaluated how the Citizens’ Climate Lobby’s proposed policy would impact the US economy. The REMI report concluded that implementing a rising price on carbon pollution and returning 100 percent of the revenue equally to American taxpayers would grow the economy and modestly increase personal disposable income, employment, and gross domestic product—the total of all goods and services produced within a nation’s borders. And the REMI report didn’t even include the financial benefits of slowing climate change and curbing its harmful economic impacts.

Those benefits are potentially massive. In terms of climate change, many of the benefits are realized in avoided costs.



Climate scientists just debunked deniers' favorite argument

Posted on 28 June 2017 by dana1981 &

Whenever they hold one of their frequent hearings to reject and deny established climate science, congressional Republicans invariably trot out contrarian scientist John Christy, who disputes the accuracy of climate models. In doing so, Christy uses a cherry-picked, error riddled chart, but there’s a nugget of truth in his argument. Although the discrepancy isn’t nearly as large as Christy’s misleading chart suggests, atmospheric temperatures seem not to have warmed quite as fast since the turn of the century as climate model simulations anticipated they would.

santer figure

Remote Sensing Systems estimate of the temperature of the middle troposphere compared to the CMIP5 multi-model average (top frame), and the difference between the two over time (bottom frame). Illustration: Santer et al. (2017), Nature Geoscience

How you react to this information is a good test of whether you’re a skeptic or a denier. A denier will declare “aha, the models are wrong, therefore we don’t need any climate policies!” A skeptic will ask what’s causing the difference between the observational estimates and model simulations.

There are many possible explanations. Maybe the tricky and often-adjusted estimates of the atmospheric temperature made by instruments on orbiting satellites are biased. Maybe there’s something wrong with the models, or our understanding of Earth’s atmosphere. Maybe the inputs used in the model simulations are flawed. The answer is likely a combination of these possibilities, but in congressional testimony earlier this year, Christy tried to place the blame entirely on the models, with a denier-style framing:

the average of the models is considered to be untruthful in representing the recent decades of climate variation and change, and thus would be inappropriate for use in predicting future changes in the climate or for related policy decisions.

And in testimony to Congress in December 2015, Christy offered his unsupported speculation that the discrepancy was a result of climate models being too sensitive to rising greenhouse gases:



Exxon, Stephen Hawking, greens, and Reagan’s advisors agree on a carbon tax

Posted on 23 June 2017 by dana1981 &

What do ExxonMobil, Stephen Hawking, the Nature Conservancy, and Ronald Reagan’s Secretary of Treasury and Chief of Staff have in common? All have signed on as founding members to the Climate Leadership Council, which has met with the White House to propose a revenue-neutral carbon tax policy.

The group started with impeccable conservative credentials, bringing on cabinet members from the last three Republican presidential administrations (Ronald Reagan, George HW Bush, and George W Bush): two former Secretaries of State, two former Secretaries of Treasury, and two former chairmen of the President’s Council of Economic Advisors. It was founded by Ted Halstead, who explained the group’s proposed policy in a TED talk:

Some of the world’s brightest scientific and economic minds have since become founding members, including Stephen HawkingSteven ChuMartin Feldstein, and Lawrence Summers. So have ExxonMobil, BP, and Shell. But it’s not just the oil industry joining the call for a carbon tax; GM, Proctor & Gamble, Pepsico, and Johnson & Johnson are among the major companies signing on. As have environmental groups like the Nature Conservancy.

Citizens’ Climate LobbyrepublicEn, the Niskanen Center, and the Weather Channel are among the Climate Leadership Council’s strategic partners.



New research may resolve a climate ‘conundrum’ across the history of human civilization

Posted on 14 June 2017 by dana1981 &

Earth’s last ice age ended about 12,000 years ago. The warmer and more stable climate the followed allowed for the development of agriculture and the rise of human civilization. This important period encompassing the past 12,000 years is referred to as the Holocene geological epoch. It also created a “conundrum” for climate scientists, because global temperatures simulated by climate models didn’t match reconstructions from proxy data.

To be specific, the overall temperature change during the Holocene matched pretty well in reconstructions and models, but the pattern didn’t. The best proxy reconstruction from a 2013 paper led by Shaun Marcott estimated more warming than models from 12,000 to 7,000 years ago. Then over the past 7,000 years, Marcott’s reconstruction estimated about 0.5°C cooling while model simulations showed the planet warming by about the same amount.

A new paper led by Jonathan Baker may help to resolve that discrepancy. The scientists examined stalagmites from a cave in the southern Ural Mountains of Russia. The ratio of oxygen isotopes in the stalagmites can be used to estimate past winter temperatures. The Marcott study had one known shortcoming – the proxy temperature data they used mostly represented the summer season. And as Baker explained, changes in the Earth’s orbital cycles have caused summer cooling and winter warming during the Holocene:



Pittsburgh and Paris join over 200 cities and states rejecting Trump on climate

Posted on 8 June 2017 by dana1981 &

I was elected to represent the citizens of Pittsburgh, not Paris

So said Donald Trump in a speech justifying his irrational, historically irresponsible decision to withdraw the United States from the Paris international climate treaty. Of course, 75% of Pittsburgh residents voted for Hillary Clinton, and many city residents have since written about the outdatedness and absurdityof Trump’s invocation of Pittsburgh, which aims to be 100% powered by renewable energy by 2035. In fact, Pittsburgh joined 210 other “climate cities”representing 54 million Americans (17% of the national population), pledging:

we will adopt, honor, and uphold the commitments to the goals enshrined in the Paris Agreement. We will intensify efforts to meet each of our cities’ current climate goals, push for new action to meet the 1.5 degrees Celsius target, and work together to create a 21st century clean energy economy.

Yesterday, the mayors of Pittsburgh and Paris co-authored a New York Times editorial rejecting Trump’s efforts to pin the two cities against each other on climate change.

Additionally, 12 states (California, New York, Washington, Connecticut, Delaware, Hawaii, Massachusetts, Minnesota, Oregon, Rhode Island, Vermont, and Virginia) plus Puerto Rico created the US Climate Alliance, committed to upholding the Paris accord. These states represent 97 million Americans – 30% of the national population.

climate states

States joining the US Climate Alliance shown in green. Illustration: Dana Nuccitelli



Donald Trump just cemented his legacy as America’s worst-ever president

Posted on 1 June 2017 by dana1981 &

In an inexplicable abdication of any semblance of responsibility or leadership, Donald Trump has announced that he will begin the process to withdraw the United States from the Paris climate treaty, joining Nicaragua and Syria as the only world countries rejecting the agreement. It now seems inevitable that the history books will view Trump as America’s worst-ever president.

Trump’s withdrawal from the Paris treaty is a mostly symbolic act. America’s pledges to cut its carbon pollution were non-binding, and his administration’s policies to date had already made it impossible for America to meet its initial Paris climate commitment for 2025. The next American president in 2020 can re-enter the Paris treaty and push for policies to make up some of the ground we lost during Trump’s reign.

However, withdrawing from the Paris treaty is an important symbolic move – a middle finger to the rest of the world, and to future generations. America is by far the largest historical contributor to climate change. Ironically, on the heels of Trump’s claim that most NATO members aren’t paying their fair share to the organization, America has announced that we won’t do our fair share to curb the climate change threats that we are the most responsible for.



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