Tuesday, February 20, 2007

Coldening and Warmening

EUReferendum enjoys Claudia Rosett's commentators and their pdf downloads of global scaremongering from the 1970s:

Scientists Ask Why World Climate is Changing; Major Cooling May Be Ahead
The New York Times, 5/21/75
"Sooner or later a major cooling of the climate is widely considered inevitable…The drop in mean temperatures since 1950 in the Northern Hemisphere has been sufficient, for example, to shorten Britain’s growing season for crops by two weeks."
Brace Yourself for Another Ice Age
Science Digest, February 1973
"Baffin Island, located in the Canadian Arctic, now is covered with snowbanks all year after having been snow free for 30 or 40 years prior to the temperature drop. Pack ice around Iceland has now become a serious hindrance to navigation. Warmth loving animals once found in abundance in the northern part of the American Midwest in the early 1900s are settling further south."
While Tim Blair points out a Gore supporter with an inconvenient truth:
For decades, Giegengack was content to be a relatively obscure geologist who taught more than he published. Recently, though, he’s stepped into the swirling tempest surrounding global warming, in part because he says it’s not even one of the top 10 environmental problems we face.
He has described Al Gore’s documentary as “a political statement timed to present him as a presidential candidate in 2008.” And he added, “The glossy production is replete with inaccuracies and misrepresentations, and appeals to public fear as shamelessly as any other political statement that hopes to unite the public behind a particular ideology.” This from a guy who voted for Gore in 2000 and says he’d probably vote for him again.
Giegengack may have a personal 50-year perspective on global warming [that's how long he's been working in the field - since long before it became fashionable], but the time range he prefers to consult is more on the geologists’ scale. The Earth has been warming, he says, for about 20,000 years. We’ve only been collecting data on that trend for about 200 years. “For most of Earth history,” he says, “the globe has been warmer than it has been for the last 200 years. It has only rarely been cooler.” Those cooler periods have meant things like two miles of ice piled over much of what is now North America. Nothing to be nostalgic for.
To determine temperatures and carbon dioxide levels in the distant past, scientists rely on what they call the “proxy record.” There weren’t thermometers. So researchers drill deep down into the Antarctic ice sheet and the ocean floor and pull up core samples, whose varying chemical elements let them gauge both the CO2 levels and the temperatures of the distant past.

Gieg clicks a button, and three charts come together. The peaks and valleys of the Milankovi´c cycles for planetary temperature align well with the ocean-floor estimates, and those match closely the records of carbon dioxide concentrations and temperature indications from ice cores. So, the professor maintains, these core samples from the polar ice and ocean floor help show that the Earth’s temperature and the levels of carbon dioxide in the atmosphere have been in lockstep for tens of thousands of years.

Of course, that was long before anybody was burning fossil fuels. So Giegengack tells his students they might want to consider that “natural” climatic temperature cycles control carbon dioxide levels, not the other way around. That’s the crux of his argument with Gore’s view of global warming — he says carbon dioxide doesn’t control global temperature, and certainly not in a direct, linear way.

Gieg has lots more slides to show. He points out that within his lifetime, there was a three-decade period of unusually low temperatures that culminated in the popular consciousness with the awful winter of 1976-77. Back then, scientists started sounding the alarm about a new ice age.

Of course, it’s long been thought that the world would end either in fire or in ice. These days, the scientists are shouting fire. And in all his years around environmental issues, Giegengack has never heard so much shouting.
I know how he feels. Read the whole thing - it's long and detailed.

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