New global warming info?

[CCTAU 3,350]

Make sure you hit the link.

Study of Greenland Ice Finds Rapid Change in Past Climate

By WALTER SULLIVAN

To the astonishment of climate specialists, an analysis of ice extracted from the full depth of the Greenland ice sheet has shown that except for the 8,000 to 10,000 years since the last glacial epoch, the climate over the past 250,000 years has changed frequently and abruptly.

The findings suggest that the period of stable climate in which human civilization has flourished might be unusual, and that the current climate may get either warmer or colder much more quickly than had been believed -- in spans of decades or even less.

The data are likely to bolster concern that future changes in climate might not be spread over many centuries, allowing farmers to adjust to altered growing conditions and coastal cities to deal with rising sea levels, for example.

Scientists have speculated for years about the effects of climate warming. Even a rise of a few feet in sea level would flood many food-producing regions and populous areas.

Commenting on the new research, Dr. Andrew J. Weaver of the University of Victoria in British Columbia said that if the climate became colder Europe would be covered with snow much longer. As glaciers advanced, he said, they would reflect more of the Sun's energy back into space, chilling the climate even more. Warmer and Colder Periods

The scientists said their data showed that significantly warmer periods and significantly colder periods had occurred during the last interval between glacial epochs, about 115,000 to 135,000 years ago. They said they could not tell whether that meant similar changes were in store. Their findings were reported today in two papers in the journal Nature.

Previous studies had shown that there were abrupt changes in climate during glacial epochs, but the new results show that the same was true in the periods when glaciers had retreated. In one "catastrophic event" during the last interglacial period, the average temperature plunged 25 degrees Fahrenheit to ice-age levels for about 70 years, the scientists reported.

The authors said they did not have an explanation for the rapid shifts. They also said it was a mystery why the climate of the last 8,000 to 10,000 years had been "strangely stable."

In a commentary in the journal, Dr. J. W. C. White of the Institute of Arctic and Alpine Research of the University of Colorado said it was "difficult to express the importance" of the reports on the ice findings. Need for 'Global Cooperation'

"Adaptation -- the peaceful shifting of food-growing areas, coastal populations and so on -- seemed possible, if difficult, when abrupt change meant a few degrees in a century," he wrote. "It now seems a much more formidable task, requiring global cooperation with swift recognition and response."

The new studies found that the average global temperature can change as much as 18 degrees Fahrenheit in a couple of decades during interglacial periods, Dr. White said. The current average global temperature is 59 degrees Fahrenheit.

The Greenland studies are based on ice samples extracted by a consortium of scientists from eight European nations. They reached a depth of 9,938 feet, using a drill mounted on the crest of the Greenland ice cap, 10,624 feet above sea level. Silt in the lower 20 feet of ice indicated that bedrock was near.

The scientists meticulously examined various properties of the ice layers laid down each year by snowfall. The record of past climate was inferred from the analysis of oxygen in each layer of ice. The amount of a lighter form of oxygen relative to a heavier form is assumed to indicate the climate temperature when the snow fell.

The time scale for the last 14,500 years came from counting annual layers. Beyond that, age estimates were based on assumed accumulation rates.

In a separate project, scientists from more than 20 American universities and agencies have drilled at a site in Greenland 20 miles west of the Europeans. They have reached bottom, said Michael Morrison of the University of New Hampshire, associate director of the project.

They expect not only to confirm the European findings, but also to provide more detailed data on temperatures, atmospheric composition and ancient volcanic eruptions, particularly in the Northern Hemisphere.

The research on the last period between glaciers is considered important because it may provide hints about the effects of rising levels of atmospheric gases, like carbon dioxide, that have a warming effect similar to that caused by the glass in a greenhouse.

"As the last interglacial seems to have been slightly warmer than the present one," the new report said, "its unstable climate raises questions about the effects of future global warming." Hippos in the Thames

At one point between the last two glacial epochs, the climate melted enough polar ice to raise sea levels some 30 feet. As noted by a member of the drilling team, Dr. David A. Peel of the British Antarctic Survey, it was so warm in England that hippopotamuses wallowed in the Thames and lions roamed its banks.

One reason for special concern is the link between temperature and the atmospheric content of the so-called greenhouse gases. Early this year French researchers noted that microscopic air bubbles extracted from ancient ice in both Greenland and Antarctica have shown "a remarkable correlation" between a rise in atmospheric carbon dioxide and an increase in temperature.

Results from both the European and American ice cores, said a companion report in the current issue of Nature, "have revealed large, abrupt climate changes of at least regional extent during the late stages of the last glaciation." It said these suggest that "the climate in the North Atlantic region is apt to reorganize itself rapidly, perhaps even within a few decades."

The new findings show that such changes also occurred in the previous ice age and in the warm period in between. It had been assumed that climate during that interglacial period had been as stable as during the current post-glacial period.

Since the end of the last ice age, only moderate climate changes have occurred. These include the medieval warm period, when the Vikings settled Greenland, and the "Little Ice Age" from 1550 to 1850, when Pieter Bruegel, the 16th-century Flemish artist, painted scenes of ice skating.

The article was signed by eight scientists from the Niels Bohr Institute in Copenhagen, most of them co-authors of the primary report. They were led by Dr. Willi Dansgaard, a veteran of Greenland drilling. Other authors were from France, Iceland and the Lamont-Doherty Earth Observatory of Columbia University.

In his commentary, Dr. White wrote: "We humans have built a remarkable socioeconomic system during perhaps the only time when it could be built, when climate was sufficiently stable to allow us to develop the agricultural infrastructure required to maintain an advanced society. We don't know why we have been so blessed, but even without human intervention, the climate system is capable of stunning variability.

"If the Earth came with an operating manual, the chapter on climate might begin with a caveat that the system has been adjusted at the factory for optimum comfort, so don't touch the dials."

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[autigeremt 6,717]

Has anyone ever thought of the effects of the Earths position in relation to the sun and the oliptical orbit? I may need to look at that and see. It could be a determining factor, but who knows?

[AUloggerhead 2,253]

Has anyone ever thought of the effects of the Earths position in relation to the sun and the oliptical orbit? I may need to look at that and see. It could be a determining factor, but who knows?

Yep -- a Russian scientist did only about 80 years ago: meet Milutin Milankovitch

[autigeremt 6,717]

Outstanding. Thank you for the information. I have been wondering about that for a few years, but never got around to looking into the research aspect of it.

[CCTAU 3,350]

Since no one really made the link with the link, I will let you in on a secret. THIS ARTICLE WAS WRITTEN IN 1993. We knew 15 years ago the the earth has always had sudden changes in climate that occur every decade or so. But we keep trying to blame it on other things. Al Gore's new religion is just that, A RELIGION.