Thursday, March 31, 2016

Meanwhile Back on Planet Earth...

The news is not good.

And no, this is not an April Fool's joke.

Little more than a week ago, a new study suggested that the planet is already heating to the point that an abrupt climate shift could be triggered, leading to enough sea level rise in fifty years--not centuries as most climate science says-- to force evacuations from coastal cities.  The New York Times summary included:

Their idea is that the initial melting of the great ice sheets will put a cap of relatively fresh water on the ocean surfaces near Antarctica and Greenland. That, they think, will slow or even shut down the system of ocean currents that redistributes heat around the planet and allows some of it to escape into space. Warmth will then accumulate in the deeper parts of the ocean, the scientists think, speeding the melting of parts of the ice sheets that sit below sea level.

The study, based in part on historical data, was immediately controversial not only for conclusions that contradict consensus climate science but for one of its chief authors: James Hansen.  When he was at NASA he was the gold standard for climate, but since he has left his job to become an advocate and critic of efforts to address the climate crisis, he's sometimes seen as the new James Lovelock--the pioneer who becomes an alarmist and maybe a bit of a crank.  However, as the Times story concludes, this study will be examined seriously and may well inspire more thorough examination of past and present climate data.

But just today (March 31) a completely different study came to a startlingly similar conclusion.  As the Washington Post led:

  Sea levels could rise nearly twice as much as previously predicted by the end of this century if carbon dioxide emissions continue unabated, an outcome that could devastate coastal communities around the globe, according to new research published Wednesday. The main reason? Antarctica.

Antarctic melting has largely not figured in previous calculations, but with new climate models that take current understanding of the Antarctic into consideration, sea level rise doubles--and faster as well.

The difference between the two studies is maybe a few decades and that it's less inevitable in this study than in Hansen's.  To coin a phrase, it's not dark yet--but it's getting there.

If emissions continue at a high rate, however, the outcome is basically the same.  Sea level rise will become serious in the next fifty years, and thereafter become catastrophic:

“Under the high emissions scenario, the 22nd century would be the century of hell,” Strauss said. “There would really be an unthinkable level of sea rise. It would erase many major cities and some nations from the map … That century would become the century of exodus from the coast.”

In terms of the political impact of these new studies, Jonathan Chiat's column title put the baseline succinctly: New Antarctic Melting Study Confirms Voting Republican Would Trigger Worldwide Catastrophe.  The column itself is a decent summary of the current situation, both in terms of positive steps to address the climate crisis, and how the challenge just got bigger with the finding of these studies, should they hold up.

Elizabeth Kolbert at the New Yorker provides context for this second study, but comes to the same political conclusion as Chiat.

Chiat may well be too optimistic in his suggestion that current policies set in motion will be sufficient to avoid global catastrophe.  But it's pretty certain that denying the climate crisis or refusing to address it will guarantee global catastrophe.  And some of the people who will experience it are alive right now.

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