Earth's Climate Warming Abruptly, Scientist Says

Tropical-Zone Glaciers May Be at Risk of Melting
Earth's climate is undergoing an abrupt change, ending a cooler period that began with a swift "cold snap" in the tropics 5,200 years ago that coincided with the start of cities, the beginning of calendars and the biblical great flood, a leading expert on glaciers has concluded.

The warming around Earth's tropical belt is a signal suggesting that the "climate system has exceeded a critical threshold," which has sent tropical-zone glaciers in full retreat and will melt them completely "in the near future," said Lonnie G. Thompson, a scientist who for 23 years has been taking core samples from the ancient ice of glaciers.

Thompson, writing with eight other researchers in an article published Monday in the Proceedings of the National Academy of Sciences, said the ice samples show that the climate can and did cool quickly, and that a similarly abrupt warming change started about 50 years ago. Humans may not have the luxury of adapting to slow changes, he suggests.

"There are thresholds in the system," Thompson said in an interview in his lab at Ohio State University. When they are crossed, "there is the risk of changing the world as we know it to some form in which a lot of people on the planet will be put at risk."

http://www.washingtonpost.com/wp-dyn/content/article/2006/06/26/AR2006062601237.html

"But the finding likely to cause the most debate is Thompson's conclusion that a swift and sudden cooling of the climate five millennia ago occurred simultaneously with key changes in civilizations.

"It represents a time where, for many parts of the world, people ceased to be hunters and gatherers and formed cities," he said. "Many of the modern calendars began around this time. It would also fall in the general time frame of the biblical flood."


Cities were formed after agriculture became popular, it's the only way you can support a city. It would be tough for agriculture (that relies on stable seasons) to become popular at a time when the climate was changing. I think his dates are screwed up somewhere. After the climate change, yes, but during?

>> It would be tough for agriculture (that relies on stable seasons) to become popular at a time when the climate was changing. <<

Just recently I read an article explaining how disrupted terrain -- such as deforestation from floods -- provided a window of opportunity for grains to flourish. They could exploit the torn landscape because their normal competitors had been destroyed.

So the article's theory was that during a time of ecological upheaveal grains appeared in great enough numbers to draw the attention of humans. It didn't take long to figure out how to purposely "disrupt" the soil -- through flooding and plowing -- and help the grains grow.

The article may have been posted here on DU within the last few months. This is where I do most of my science reading. :)

Never heard of it before.

And at the end of the article:

Gavin Schmidt, a scientist at NASA's Goddard Institute for Space Studies in New York, applauded Thompson's work but said his conclusions about events 5,200 years ago have many skeptics.

"You would have to put that argument as more intriguing rather than definitive," Schmidt said. "There are a number of issues in the tropical ice cores that are problematic for dating things 4,000 to 5,000 years ago."

The claim sounds like more fodder for the deniers, which makes me suspicious.

this AM

:cry: