El crepúsculo del movimiento climático alarmista

The flood of new data has forced the United Nations to revise downward its prognostications of ocean-level increases. The worst-case sea level rise by 2100 was revised downward from 3.7 meters in the first IPCC report to 1.2 to in the second, to 0.8 in the third, and to 0.6 in the fourth. The most recent IPCC assessment report, AR5, expressed “medium confidence” that there is a least a 66 percent probability of sea levels rising from 0.45 meters to 0.82 meters in a high-carbon-emissions scenario.

The prognostications of extreme weather, which alarmists matter-of-factly blame on anthropogenic climate change, have been increasingly discredited. Neither tornados nor hurricanes have been more frequent or intense since 1950 than they were in the half-century before—though we can’t know for sure because precise data on tornados and cyclones is too recent. Likewise, predictions of infectious diseases such as malaria spreading more widely have also been largely discounted in more recent IPCC reports, because vulnerability to infectious diseases correlates less with warm climates than with poverty and the poor public health conditions it entails, both of which risk being greatly exacerbated by strong decarbonization policies.

This recurring failure to explain the past and predict the present hasn’t stopped alarmists from claiming, as the President did recently on Twitter, “Ninety-seven percent of scientists agree: climate change is real, man-made and dangerous.” The President perhaps was relying on the most famous of the surveys claiming a near-universal consensus on man-made climate change—a 2013 survey by the Australian John Cook and several colleagues in the journal Environmental Research Letters. Cook and his colleagues surveyed the abstracts of 11,944 peer-reviewed journal articles drawn from a simple database search of key terms. They classified the papers on the basis of whether the papers expressed an opinion on whether “humans are causing global warming” and, if so, whether the opinion embraced or rejected the consensus. They found that about two-thirds expressed no opinion, and of the third that did, nearly all embraced the consensus.

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