Tuesday, September 8, 2009

Arctic offers more evidence of human influences on climate change

A new study indicates that Arctic temperatures suddenly increased during the last 50 years of the period from A.D. 1 to the year 2000. Because this warming occurred abruptly during the 20th century while atmospheric greenhouse gases were accumulating, these findings provide additional evidence that humans are influencing climate.

Incorporating geologic records, biologic records and computer simulations, the study reconstructed Arctic summer temperatures at a resolution down to decades, and thereby extends the climate record a full 1,600 years beyond the 400 year-long record that was previously available at that resolution. This newly lengthened record shows that recent warming was preceded by a cooling trend that lasted at least 1,900 years and should have continued throughout the 20th century. These results indicate that recent warming is more anomalous than previously documented, says Darrell Kaufman of Northern Arizona University—the lead author of the study.

Click here for the complete article in U.S. News & World Report.

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