John Christy is a climate scientist, with a particular focus in atmospheric temperature trends. Many conservatives present Christy as being an intellectually serious "skeptic" of carbon-dioxide-induced (CO2-induced), man-made climate change . Yet Christy has repeatedly misled Congress and the public. Christy's most egregiously misleading statements include:
- Christy insinuates that the NOAA's ocean temperature data was manipulated, even though other data sources confirmed the NOAA's results. Christy provides no evidence for his charge of data manipulation. Instead Christy makes the charge simply because the NOAA data conflicts with Christy's claim that ocean warming is due to natural, non-anthropogenic factors (for more on this, see section 3.8 of part 2 of my series on "John Christy and the Tropical Tropospheric Hot Spot").
- Christy presents temperatures from one layer of the atmosphere (the lower tropopause and/or the upper troposphere) as if they were temperatures from a different layer of the atmosphere (the stratosphere). This allowed Christy to avoid addressing stratospheric cooling. Stratospheric cooling is one of the hallmarks of CO2-induced global warming; solar-induced global warming would not cause this cooling, as stated in a source that Christy himself co-authored. Stratospheric cooling is therefore inconvenient for Christy's position, since Christy hopes to attribute much of the recent global warming to the Sun. This may explain why Christy obscured the presence of stratospheric cooling, even though Christy knew that the stratosphere cooled (for more on this, see "Myth: The Sun Caused Recent Global warming and the Tropical Stratosphere Warmed").
- When Christy claims that the tropical stratosphere warmed, Christy contradicts his co-authored research. And when Christy conflates the tropical stratosphere with the tropical lower tropopause (and/or the tropical upper troposphere), Christy blatantly contradicts his previous statements he cited to Congress (for more on this, see "Myth: The Sun Caused Recent Global Warming and the Tropical Stratosphere Warmed").
- For years Christy erroneously claimed that the troposphere has not warmed. Even after admitting the troposphere warmed, Christy continued to use a number of tactics to under-estimate tropospheric warming, including falsely assuming that the lower troposphere cooled at noon when the Sun was shining and warmed at midnight (for more on this, see "Myth: The Sun Caused Recent Global Warming and the Tropical Stratosphere Warmed" and section 3.1 of "John Christy Fails to Show that Climate Models Exaggerate CO2-induced Warming").
- In a non-peer-reviewed blog article Christy cited to Congress, Christy claims that a solar-induced ocean cycle (ENSO) caused most of the recent tropospheric warming. He also states that CO2 caused no significant, observable tropospheric warming. Yet in a subsequent peer-reviewed paper, Christy admitts that ENSO did not cause most of the recent tropospheric warming and that CO2 caused statistically significant, observable tropospheric warming (for more on this, see "Myth: The Sun Caused Recent Global Warming and the Tropical Stratosphere Warmed" and section 3.5 of "John Christy Fails to Show that Climate Models Exaggerate CO2-induced Warming").
- Christy uses a solar index to argue that solar-induced changes in ENSO caused most of the recent global warming. He later admitted that this arbitrary index compromised the relationship between the solar index and the temperature trends the solar index was meant to predict (for more on this, see "Myth: The Sun Caused Recent Global Warming and the Tropical Stratosphere Warmed" and section 3.6 of "John Christy Fails to Show that Climate Models Exaggerate CO2-induced Warming").
- In 2007, Christy admitted that human burning of fossil fuels caused most of the increase in atmospheric CO2 levels. He also admitted that increased greenhouse gases caused most of the global warming over the past 50 years. Ten years later in 2017, Christy no longer accepted that increased greenhouse gas levels caused most of the recent global warming, despite the fact that even more evidence of CO2-induced warming accumulated from in the ten years from 2007 to 2017 (for more on this, see "Myth: The Sun Caused Recent Global Warming and the Tropical Stratosphere Warmed").
- Christy insinuates that amplified warming in the lower atmosphere (the troposphere) is specifically a signature of CO2-induced global warming, even though Christy likely knows that this amplification should occur with any cause of global warming at the Earth's surface. This means that even if non-anthropogenic factors caused most of the recent global warming (as Christy claims), then tropospheric amplification should still occur (for more on this, see section 3.2 of part 1 of my series on "John Christy and the Tropical Tropospheric Hot Spot").
- In his congressional testimony, Christy presents a graph that shows evidence of amplified warming in the troposphere. Christy then brazenly contradicts this graph by citing a report/blogpost in which he claims that there is no evidence of tropospheric amplification. Then Christy provides a graph of this amplification to someone else for their Congressional testimony (for more on this, see "Myth: John Christy Thinks There is No Evidence of the Hot Spot").
- Christy fails to address numerous studies that show amplified warming in the troposphere, even though this evidence contradicts Christy's claims. Christy then blatantly moves the goalposts when it appears that warming trends may pass some of his criteria for tropospheric amplification (for more on this, see section 3.1 of part 1 and see section 3.7 of part 2 of my series on "John Christy and the Tropical Tropospheric Hot Spot").
The climate scientist Ben Santer allegedly said that Christy was "not even a third-rate scientist ," and that Christy had "made a scientific career out of being wrong ." I respectfully disagree. Christy seems to be very skilled when it comes to scientific research. But Christy made his public name by being misleading and by telling political conservatives what they wanted to hear. Christy makes claims in public that likely would never make it past competent peer review. Understanding this point helped me better grasp the public debate and scientific discussion on climatology.
When I first became interested in climate science and man-made (anthropogenic) climate change, I thought that much of the discussion was made up of "skeptics" and "consensus scientists." I believed that Christy was a member of the former group, as were Roy Spencer, Richard Lindzen, Judith Curry, and other prominent critics of mainstream climate science. These skeptics, I thought, did not accept the some of the mainstream science on anthropogenic climate change, but sufficient evidence would probably convince these folks. These skeptics were likely wrong, but they were rational, as intellectually honest as at least your average person, and not denialists. They might present evidence that would change my mind.
I was wrong. As I read more scientific research, examined the claims made by these "skeptics" on their blogs and other non-peer-reviewed outlets, etc., I realized that I had mis-characterized the discussion. The discussion that I and other non-experts were viewing was largely not a debate between "skeptics" and "consensus scientists." It was more like the debates on AIDS denialism and the anti-vaccination movement, fields closer to my area of expertise.
Since at least the early 2000s, the real scientific skeptics accepted that no sound evidence had been provided showing that vaccines caused autism. What's left now are anti-vaxxers who still think that vaccines cause autism, despite overwhelming evidence to the contrary. And since at least the early 1990s, the real scientific skeptics accepted that HIV causes AIDS. What's left now are AIDS denialists who do not accept that HIV causes AIDS, in spite of the overwhelming evidence on this topic. Similarly, the real skeptics (such as Richard Muller [1; 20] and Ronald Bailey ) already changed their mind in response to the overwhelming evidence that humans caused most of the post-1950s global warming. What's left now are people like Christy, who keep their position in spite of, not because of, the evidence. So the climate science debate I was observing was a debate between ideologically-motivated denialists vs. a well-supported, evidence-based scientific consensus [2 - 6; 8 - 10; 12 - 19]:
"Denialism can be recognised by the presence of six key features [...]. [...] It is, however, important not to confuse denialism with genuine scepticism, which is essential for scientific progress. Sceptics are willing to change their minds when confronted with new evidence; deniers are not ."
You may disagree with my assessment. I just ask that you scrutinize Christy's claims (and the claims of other prominent "skeptics", such as Spencer, Lindzen, Curry, Watts, Happer, Loehle, Moore, and Corbyn) in light of scientific evidence and sound reasoning. I think you will find their positions are not just wrong, but obviously misleading. My blogposts cite evidence in support of this point, at least with respect to Christy's claims. So if you do not believe me, then feel free to examine the sources I cite in my posts and come to your own conclusion.
- "Richard Muller: I Was wrong on Climate Change"
- "Science denialism: Evolution and climate change"
- "How the growth of denialism undermines public health"
- "Denialism: what is it and how should scientists respond?"
- "The ethics of belief, cognition, and climate change pseudoskepticism: Implications for public discourse"
- "Manufactured scientific controversy: Science, rhetoric, and public debate"
- "Though scorned by colleagues, a climate-change skeptic is unbowed"
- "Climate Denial 101: A User’s Guide to the arguments of global warming skeptics"
- "Sceptics and deniers of climate change not to be confused"
- "What evidence would persuade you that man-made climate change is real?"
- "Promoting pro-environmental action in climate change deniers"
- "Debating global warming in media discussion forums: Strategies enacted by “persistent deniers” and implications for schooling"
- "Countering evidence denial and the promotion of pseudoscience in autism spectrum disorder"
- "Science denial as a form of pseudoscience"
- "Science denial: a guide for scientists"
- "Science denial and the science classroom"
- "AIDS denialism and public health practice"
- "The conversion of a climate-change skeptic"