In 1990, University of Alabama at Huntsville scientists Roy Spencer and John Christy created a data set that estimates the temperature of the Earth’s atmosphere by using instruments on satellites (microwave sounding units) that measure microwave radiation in the atmosphere. According to their latest estimates, the Earth’s lower atmosphere has warmed significantly since satellite measurements began in 1979, but not quite as fast as thermometer measurements of temperatures at the Earth’s surface.

Spencer and Christy have also long disputed the degree to which humans are contributing to that warming, and have thus often been called to testify before Congress by policymakers seeking justification to oppose climate legislation. On the 25th anniversary of their satellite data set, Alabama.com interviewed the pair to discuss their science and climate contrarianism. The resulting discussion was quite revealing.



Consensus Denial



For example, when asked about the 97% expert consensus on human-caused global warming, Christy offered an inaccurate response,



The American Meteorological Society did their survey and they specifically asked the question, Is man the dominate controller of climate over the last 50 years? Only 52 percent said yes. That is not a consensus at all in science ... Roy and I have both made the statement that we are in the 97 percent because we believe in some (man-made) effect.

Ever since my colleagues and I published our global warming consensus paper two years ago in which we found a 97% consensus in the peer-reviewed literature on human-caused global warming, Roy Spencer has been claiming to be part of the 97%. As I showed two years ago, he’s not. Spencer and Christy each authored five papers captured in our climate science literature survey. Among those papers, we classified one of Spencer’s and two of Christy’s as minimizing or rejecting the human influence on global warming, and the others as not taking a position on the issue.



That makes both of them authors of the less than 3% of peer-reviewed climate science papers rejecting the consensus on human-caused global warming. This is an indisputable fact – the 97% consensus figure is based on our team’s categorization of the scientific literature, and we put their research outside the 97% consensus. Spencer and Christy reject this fact because they don’t understand our study – specifically that papers minimizing the human influence on global warming fall outside the 97% consensus. Their research is nevertheless among the 3% of outliers.



As for the American Meteorological Society (AMS) survey, only 13% of participants described climate science as their field of expertise. The Heartland Institute – the source of the story linked in the above quote by Christy – misrepresented the associated study so badly that the AMS executive director took the unusual step of issuing a public reprimand against their behavior. Studies of climate science experts have again and again found a 97% consensus on human-caused global warming.

Data and Research Quality

Spencer and Christy’s data set has undergone many major corrections to address various errors and biases. This is how science always progresses, but those who believe that adjustments to surface temperature measurements are part of a conspiracy (including Roy Spencer) always seem to neglect the major adjustments to the satellite data. In fact, in its early days, Spencer and Christy’s data set seemed to indicate the atmosphere was cooling, before a series of big adjustments were made.

Evolution of UAH lower tropospheric temperature trends from satellite observations. Source: Cosmopolis; Abraham et al. (2014).

As discussed in my book and as a paper that John Abraham and I published with several colleagues last year showed, much of Spencer and Christy’s contrarian research has not withstood subsequent scientific scrutiny.

we conclude then that the quality of work of contrarian-view scientists, as showcased here by representative case studies, is notably lower than that of scientists who hold the consensus view ... We find that the scientific literature includes a series of strong responses from the mainstream scientific community including criticisms, corrections, and in some cases, resignation of editors. The contrarian views were often found to be unsubstantiated by the data and are no longer seriously considered by many climate scientists.

In fact, the accuracy of Spencer and Christy’s atmospheric temperature estimates remains a question of rigorous scientific dispute today. While the Alabama.com interview says,

Still, they carry on - comfortable in their research and data that has remained true to their findings

That comfort may very well be misplaced.

Conspiracies and Biases

When asked about data from government agencies contradicting their contrarian beliefs about the dangers associated with climate change, Christy said,

NASA, NOAA, EPA, DOE, those are agencies. Agency leaders are appointed by the government, by the current administration. They do not represent objective independent scientific organizations. They can’t. They are appointed by the head. They try. People who come out with different views in their organizations are found to be squashed. There is an agenda in those agencies ... There are skeptics in NASA and NOAA, a good number. But they are quiet. They know in this administration, they don’t speak out.

This is an ironic answer given the recent revelations that scientists in Florida have been barred from using phrases like “climate change” and “global warming.” Similarly, the George W. Bush administration was accused of censoring government reports about climate change. It’s contrarians who have tried to squash inconvenient scientific research, not those who accept the scientific consensus on human-caused global warming.



Fossil Fuel Interests

The interview also included an extensive discussion about fossil fuels, with Roy Spencer saying,

When I talk to scientists who should be objective over a beer at the end of the day, I will argue with them and their final position will always be, ‘Yeah, but we need to get away from fossil fuels anyway.’ Where did that come from? Are you an expert in alternative energy sources and what they cost? How many poor people are you going to hurt? How many more people are you going to make poor through energy poverty because they are paying five to 10 times as much for their energy?

Roy Spencer is of course not an energy or economics expert either. Experts in these fields who have published research on the subject have found that fossil fuels are incredibly expensive, when we account for all of their costs. For example, one recent study conservatively estimated that including pollution costs, coal is about 4 times more expensive than wind and 3 times more expensive than solar energy in the USA today. Additionally, poorer countries are generally the most vulnerable to climate change impacts. John Christy made similarly backwards arguments,

Carbon dioxide makes things grow. The world used to have five times as much carbon dioxide as it does now. Plants love this stuff. It creates more food. CO2 is not the problem ... There is absolutely no question that carbon energy provides with longer and better lives. There is no question about that.



The ‘CO2 is plant food’ argument is a gross oversimplification. For example, rising carbon dioxide levels increase the greenhouse effect, causing global warming, which in turn intensifies droughts. As we’re seeing in California right now (the Golden State turning brown), that’s not good for plants.

Christy also made a key mistake in those comments. Energy gives people longer and better lives, but there’s absolutely no reason that energy must come from carbon-intensive fossil fuel sources. In fact, my colleague John Abraham is helping developing countries in Africa deploy clean energy sources instead.

Christy and Spencer have also been affiliated with various conservative fossil fuel-funded think tanks. And Spencer is on the Board of Advisors of the Cornwall Alliance – a religious group that essentially believes God wouldn’t let damaging climate change happen. Spencer has also made some controversial comments, calling those who disagree with him “global warming Nazis” as well as declaring “I love FoxNews” and saying,



I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government.

Spencer and Christy made a valuable scientific contribution by creating their atmospheric temperature data set. However, given how few climate scientists dispute the expert consensus on human-caused global warming, it’s useful to examine their research and comments with a critical eye. When we do, it becomes clear that they have less in common with Galileo than with the scientists who disputed the links between smoking and cancer.

