Dr. Roger Pielke Jr. believes “human-caused climate change is real and poses significant risks” and thinks “mitigation and adaptation should be policy priorities.” From 1993–2001 he was a Scientist at the National Center for Atmospheric Research, a premier site for American computer climate modeling. He’s the author, co-author or co-editor of seven books, including The Honest Broker: Making Sense of Science in Policy and Politics (2007, Cambridge University Press), The Climate Fix: What Scientists and Politicians Won’t Tell you About Global Warming (2010, Basic Books) and The Rightful Place of Science: Disasters and Climate Change (2014, Consortium for Science, Policy & Outcomes). He’s not a “climate skeptic,” “climate denier,” or “science denier.”

But Pielke’s certainly skeptical of the Fourth National Climate Assessment (NCA), vol. 2 of which, “Impacts, Risks, and Adaptation in the United States,” was published last Friday by the United States Global Change Research Program and predicts that human-induced global warming could reduce U.S. GDP by 10% by the end of this century—a message blared by headlines around the nation.

Pielke’s complaints aren’t broad generalizations. They’re precise. Yet they expose systemic problems with the NCA: a strong tendency to ignore contrary evidence (what logicians call “confirmation fallacy” and scientists call “confirmation bias”) and present conclusions based on extremely unlikely scenarios as if they were likely.

Over the years, Pielke has specialized in studying long-term, observational data on the frequency and intensity of hurricanes and the human deaths and the value of property destruction they cause. He’s pointed out that the increase in property losses is entirely because the amount of property in their paths has increased. Meanwhile, death tolls have fallen because all that property protects people. And—and this is crucial—while there’s been an increase in property damages, there’s been no increase but rather a slight decrease in the frequency and intensity of hurricanes over the period of allegedly manmade global warming, despite the fact that global warming alarmists claim that hurricanes become more frequent and stronger with warming.

So it’s not surprising that Pielke’s first interest on looking at the new NCA was in how it handles hurricanes. What he found didn’t impress him.

“I’m a nerd interested in science advice,” he Tweeted, “so I was curious how it is that the 2018 US National Climate Assessment failed to include or overlooked trends in US landfalling hurricanes which would, ahem, seem pretty important in a US climate report. So I looked at public comments.” That is, he looked at reviewers’ comments submitted before the NCA was finalized—comments that could, had they been taken seriously, have resulted in corrections before publication. What did he find?

One expert had commented, “National Hurricane Center going back to the 1800s data clearly indicate a drop in the decadal rate of US landfalling hurricanes since the 1960s … instead you spin the topic to make it sound like the trends are all towards more cyclones.”

Did the NCA’s authors and editors correct the “spin”? No. They responded that landfalling hurricanes weren’t particularly relevant: “We disagree with the reviewer’s assertion that information on a sub-set of data, consisting of landfalling storms, is more relevant ….”

Well, okay, that sounds reasonable, doesn’t it? Aren’t the NCA’s editors simply pointing out that the reviewer is committing the fallacy of hasty generalization, confusing the part with the whole?

Not so, Pielke replies. “Let’s observe here hurricanes are discussed at length in the report, and every hurricane that is discussed is … a landfalling storm. The failure to include trend data on US landfalling hurricanes in USNCA is a remarkable choice. What were they thinking, no one would notice?”

The reviewer’s comment wasn’t a case of hasty generalization. It appealed to precisely the data that were relevant to the assessment’s discussion of hurricanes. Frankly, the NCA wasn’t—and shouldn’t have been—particularly interested in hurricanes that never made landfall. Why? Because it’s an assessment of risks to Americans. Hurricanes that never make landfall pose very little risk: minor adjustments to flight and shipping routes, yes, but at very low cost. The only hurricanes that cause significant damage are those that make landfall. Hence, the trend data on landfalling hurricanes are precisely the data the NCA should have focused on. Instead, it ignored them—because they didn’t support the predetermined conclusion, namely, that global warming was causing, and would continue causing, an increase in the frequency and strength of hurricanes that strike the United States and destroy property and threaten lives.

Pielke’s overall assessment of the National Climate Assessment?

USNCA Vol. 1 very good.

USNCA Vol. 2 not so good:

• heavy reliance on RCP 8.5*
• (mis)use of Steyer/Bloomberg study on GDP $$ (2x RCP 8.5!!)*
• Ignoring climate data on hurricanes while promoting hurricane impacts.

We are seeing the Trumpification of climate science.

*A little explanation: An RCP is a “Representative Concentration Pathway,” that is, the projected future concentration of greenhouse gases in earth’s atmosphere hypothesized by the United Nations Intergovernmental Panel on Climate Change (IPCC), together with its consequences for global temperature, the health of the biosphere, and human wellbeing. RCP 8.5 is, as David Furphy explained on Medium.com,

the nightmare scenario in which emissions continue to increase rapidly through the early and mid parts of the century. By 2100 annual emissions have stabilised at just under 30 gigatonnes of carbon compared to around 8 gigatonnes in 2000.

Concentrations of CO2 in the atmosphere accelerate and reach 950 ppm by 2100 and continue increasing for another 100 years.

Population growth is high, reaching 12 billion by centuries end. This is at the high end of the UN projections. Economic growth is similar to RCP6 but assumes much lower incomes and per capita growth in developing countries.

This scenario is highly energy intensive with total consumption continuing to grow throughout the century reaching well over 3 times current levels. Oil use grows rapidly until 2070 after which it drops even more quickly. Coal provides the bulk of the large increase in energy consumption

Land use continues current trends with crop and grass areas increasing and forest area decreasing.

I.e., RCP 8.5 is an extreme, not at all the likely path of greenhouse gas concentrations. Yet the NCA relies heavily on it in projecting climate change’s consequences for the United States. That’s what I had in mind when I said, above, that the NCA tends to present conclusions based on extremely unlikely scenarios as if they were likely.

**And a little more explanation: Pielke’s reference to the NCA’s “(mis)use of Steyer/Bloomberg study on GDP $$ (2x RCP 8.5!!)” is a little cryptic. Here’s my translation:

• The Steyer/Bloomberg study shouldn’t have been used at all because it was paid for by two major proponents of global warming alarmism both of whom have vested interest in policies that depend on that message.
• Yet the NCA not only uses it, it misuses it, because it presents its conclusions as if they were realistic. They’re not. The Steyer/Bloomberg study assumes warming of 15 degrees F, which is two times more than the warming hypothesized in RCP 8.5—and RCP 8.5 itself is already an extreme outlier.
• There’s an obvious conflict of interest behind all this: “the sole review editor for this chapter is an alum of the Center for American Progress … which is funded by Tom Steyer.”

Well, of course, all the climate alarmists who swooned over the wonderful new NCA, issued, after all, by President Donald Trump’s administration, can take comfort, because Pielke’s just a Trumpster and wants to shield his hero, right? Except, that Pielke also wrote in the same series of Tweets, “Trump is a buffoon (on climate and more).” Oh. Well.

The implication: Pielke considers the new NCA the buffoonification of climate science.

Here are screenshots of Pielke’s Tweets: