Climate Change Paradox

The Great Climate Flip-flop

by WILLIAM H. CALVIN

When 'climate change' is referred to in the press, it normally means greenhouse warming, which, it is predicted, will cause flooding, severe windstorms, and killer heat waves. But warming could also lead, paradoxically, to abrupt and drastic cooling — a catastrophe that could threaten the end of civilization.

ONE of the most shocking scientific realizations of all time has slowly been dawning on us: the earth's climate does great flip-flops every few thousand years, and with breathtaking speed. We could go back to ice-age temperatures within a decade — and judging from recent discoveries, an abrupt cooling could be triggered by our current global-warming trend. Europe's climate could become more like Siberia's. Because such a cooling would occur too quickly for us to make readjustments in agricultural productivity and associated supply lines, it would be a potentially civilization-shattering affair, likely to cause a population crash far worse than those seen in the wars and plagues of history. What paleoclimate and oceanography researchers know of the mechanisms underlying such a climate "flip" suggests that global warming could start one in several different ways.

For a quarter century global-warming theorists have predicted that climate creep was going to occur and that we needed to prevent greenhouse gases from warming things up, thereby raising the sea level, destroying habitats, intensifying storms, and forcing agricultural rearrangements. Now we know — and from an entirely different group of scientists exploring separate lines of reasoning and data — that the most catastrophic result of global warming could be an abrupt cooling.

We are in a warm period now. Scientists have known for some time that the previous warm period started 130,000 years ago and ended, 117,000 years ago, with the return of cold temperatures that led to an ice age. But the ice ages aren't what they used to be. They were formerly thought to be very gradual, with both air temperature and ice sheets changing in a slow, 100,000-year cycle tied to changes in the earth's orbit around the sun. But our current warm-up, which started about 15,000 years ago, began abruptly, with the temperature rising sharply while most of the ice was still present. We now know that there's nothing 'glacially slow' about temperature change: superimposed on the gradual, long-term cycle have been dozens of abrupt warmings and coolings that lasted only centuries.

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also:

Abrupt Climate Change See also Sea Level Rise and Gulf Stream Shutdown Websites A Modest Proposal to Save the Planet Contraction and Convergence—Decreasing global emissions of carbon dioxide with justice and fairness Abrupt Climate Change From the Ocean and Climate Change Institute of Woods Hole Oceanographic Institution. This is by far the best and most comprehensive site on the Gulf Stream Shutdown and abrupt climate change Apocalypse Now: How Mankind is Sleepwalking to the End of the Earth Are We on the Brink of a New "Little Ice Age"?

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