Four Degrees Warming by 2100?

Until now, global warming predictions have varied significantly. A new study in Nature closes the gap in those predictions, favoring the more extreme models. Until now, climatologists did not understand how climate change would affect cloud formation. They now know that atmospheric mixing will “dry out” clouds, making cloud formation increasingly difficult as the planet warms. Fewer clouds globally means warming accelerates. By 2100, expect four degrees of warming.

For a plain language explanation of the new study and its implications, see The Guardian.

Professor Steven Sherwood, at the University of New South Wales, in Australia, who led the new work, said: “This study breaks new ground twice: first by identifying what is controlling the cloud changes and second by strongly discounting the lowest estimates of future global warming in favour of the higher and more damaging estimates.”

“4C would likely be catastrophic rather than simply dangerous,” Sherwood told the Guardian. “For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet”, with sea levels rising by many metres as a result.


I enjoy reading commentators. Those on the Guardian piece were especially instructive. I draw your attention to two types of silliness. The first illustrates the real hayseed approach, the rube who hoists his suspenders, laughs, making it all a joke:

Irblgr: And no doubt these are the same scientists that are frozen in a ship in Antarctica, stuck in ice.

This kind of idiotic approach assumes a very small view of what is the planet. While many of you are experiencing absolutely frigid weather–I am–, did you know that this November was globally the warmest November on record? Sorry, local weather is no indication of what is happening globally.

Then there is the cynical dude who has no conception of the path we must experience to see the prediction. He understands little, yet thinks he is quite smart.

Maentwrog: If it wasn’t going to arrive for 87 years, I would [not] care much one way or the other.

He thinks someone will throw a switch in 2100 and Presto! Four Degrees of Warming suddenly appears.

I have very intelligent friends who think this way. They do not understand that these predictions are ones at the end of a long process.

Think. If it will be four degrees by 2100, when will it be two degrees of warming? When will it be one degree of warming? What does two degrees of warming entail? What does one degree of warming entail?

I do not know the answers to these questions…and I have not seen anyone talk much about them. We always want to look at end points, not what happens on our way to them.

What I do know is that many of us are in for one hell of a ride.

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