Sediment shows record warming since 1950

The Asian Age , Wednesday, October 21, 2009
Correspondent : —AFP
Washington, Oct. 20: Sediment cores from a small Arctic lake in Canada stretching back 200,000 years show unprecedented gains in global warming since 1950, indicating human activity is the likely cause, a study said.

"The past few decades have been unique in the past 200,000 years in terms of the changes we see in the biology and chemistry recorded in the cores," University of Colorado glaciologist Yarrow Axford said in the study by Canadian and US researchers.

"We see clear evidence for warming in one of the most remote places on earth at a time when the Arctic should be cooling because of natural processes," added the chief author of the study published on Monday in the Proceedings of the National Academy of Sciences.

For thousands of years, environmental changes in a remote lake on Canada’s Baffin Island closely matched natural, cyclical climate changes such as those caused by the Earth’s periodic wobble as it swings around the sun, the researchers said.

However, lake sediment cores dating from 1950 show that expected climate cooling was overridden by human activity like greenhouse gas emissions, the study said. Researchers were able to reconstruct the local climate over the past 200,000 years by analysing algae, insect fossils and geochemical traces in sediment cores extracted from the 100-acre lake.

 
SOURCE : http://www.asianage.com/presentation/leftnavigation/news/international/sediment-shows-record-warming-since-1950.aspx
 


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