Scientists have beaten down the best climate denial argument | Dana Nuccitelli

Clouds don’t act as a climate thermostat, and they’re not going to save us from global warming

Climate deniers have come up with a lot of arguments about why we shouldn’t worry about global warming – about 200 of them – but most are quite poor, contradictory, and easily debunked by consulting the peer-reviewed scientific literature. The cleverest climate contrarians settle on the least implausible argument – that equilibrium climate sensitivity (ECS – how much a doubling of the amount of carbon dioxide in the atmosphere will increase Earth’s surface temperature) is low, meaning that the planet will warm relatively slowly in response to human carbon pollution.

But they have to explain how that can be the case, because there are a lot of factors that amplify global warming. For example, a warmer atmosphere holds more water vapor, which is itself a greenhouse gas, adding further warming. Warming also melts ice, leaving Earth’s surface less reflective, absorbing more sunlight. There are a number of these amplifying ‘feedbacks,’ but few that would act to significantly slow global warming.

Out now in @Nature: @KenCaldeira and I show that Earth’s recent energy budget suggests greater future global warming than raw climate model projections indicate.https://t.co/yLHlwAZt5C pic.twitter.com/CsdRMKHLWH

This leads to one of the biggest “skeptical” talking points: “Observational estimates of ECS are much lower than models” or “Models are too sensitive to CO2”. In the session today, it’s clear that the scientific community has beaten the shit out of this problem. 2/

In a year or so, “Observational estimates of ECS are much lower than models” will be sitting next to “global warming stopped in 1998” or “the surface temperature record can’t be trusted” in the junk yard of discredited skeptical ideas. 5/