The New US Climate Report

The media gets it wrong. From The New York Post:

Activists tend to exaggerate the impacts of climate change while underestimating the costs of tackling it. The reception to the new US climate assessmentwas instructive. The report largely attempts to remain soberly scientific, and follows the even more careful global report by the United Nations’ climate-science panel, known as the IPCC. Sadly, accurate science doesn’t make for good television; predicting the end of times does.
Among many others, widely quoted climate scientist Michael Mann talked up the report to NPR and CNN, saying its predictions are already borne out in today’s “unprecedented weather extremes.” Actually, the assessment, and science, tell a different story. “Drought statistics over the entire contiguous US have declined,” the report finds, reminding us that “the Dust Bowl era of the 1930s remains the benchmark drought and extreme heat event.” 

On flooding, the assessment accepts the IPCC’s finding, which “did not attribute changes in flooding to anthropogenic [human] influence nor report detectable changes in flooding magnitude, duration or frequency.” Even more dramatic was CNN’s headline, screaming that “climate change will shrink [US] economy” by 10 percent, a figure also repeated on The New York Times front page. 

Actually, the UN’s climate scenarios envision US GDP per capita will more than triple by the end of this century, so this 10 percent reduction would come from an economy 300 percent larger than it is today. A slightly smaller bonanza, in other words. But the 10 percent figure is itself dodgy. It assumes that temperatures will increase about 14 degrees Fahrenheit by the end of the century. This is unlikely. The US climate assessment itself estimates that, with no significant climate action, American temperatures will increase by between 5 and 8.7 degrees. Using the high estimate of 8.7 degrees, the damage would be only half as big, at 5 percent. But even the 8.7-degree warming estimate is unrealistically pessimistic. This stems from an extreme high-emission scenario that expects almost the entire world to revert to using massive amounts of coal: a five-fold increase from today. That, in turn, assumes a much higher amount of fossil fuels than are plausibly available for use, according to one study. Another study likewise found the scenario “exceptionally unlikely.” 

So, even a 5 percent reduction in the size of the American economy only follows from picking unlikely worst-case scenarios. Moreover, two-thirds of the purported 10 percent damage to the economy comes from just one category: heat deaths. While it is true that more people die when it is unusually hot, it is not true that lives are shorter in hotter places. That’s because people adapt. And studies of migrants show people do so very quickly, within weeks. (Read more.)

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