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How did those early climate predictions turn out?

Have you ever been told that climate projections of the future are bad and they are not worth looking at? I’ve heard that many times. You might wonder how they know. My husband John Knox of the UGA Geography Department recently looked at a couple of the older climate predictions of climate to see how well they stacked up. Here is what he found.

1967: Manabe and Wetherald, in the Journal of the Atmospheric Sciences, publish the first relatively realistic estimates of global climate change due to rising greenhouse gases. Their estimate, based on a climate model: a doubling of CO2 would lead to a warming of 2.36 degrees Celsius.

This prediction was made during a cold period, with slightly decreasing planetary surface temperatures.

How good a prediction was it? The red line is the Manabe-Wetherald prediction. The blue line is observed temperatures.

The first image shows you how unlikely the warming would have seemed to be back in 1967, unless you understood–as atmospheric scientists had for a decade and more–the effect of greenhouse gases on climate.

The second image shows you how the prediction played out through 2016, based on the additional amount of CO2 put into the atmosphere after 1967.

That’s a remarkably accurate 50-year prediction, isn’t it?

You might wonder why all you seem to hear is that the climate models are wrong and that the climate modelers are just a bunch of liars who lie to make money. Consider the possibility that these claims are a giant example of projection.

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No photo description available.

And another one below:

1980: Manabe and Stouffer, Journal of Geophysical Research-Oceans, demonstrate “polar amplification,” i.e. higher latitudes warm more than lower latitudes with increased greenhouse gases. (They did a modeling sensitivity study using a 4x CO2 scenario.) Their study revealed that the warming would be more pronounced in the NH high latitudes in winter than in summer.

2019: Svalbard, Norway is 4C warmer than it was in 1971, having warmed 5x faster than the rest of the planet over that time. 7x faster in winter. Check out the graphic, from a Guardian article I posted recently.

The predictions I heard about global warming in graduate school in the late 1980s are being verified all around us in the late 2010s. Perhaps the least-told story is how accurate the predictions have been. There’s been so much money and energy devoted to making the world think that the climate models are wrong, terrible, awful, run by Al Gore, satanic, etc. Nope. They’ve told a consistent story for decades, and that story is being played out in a thousand places now.

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