Arctic temperatures have been dropping for the last 2,000 years. Since 1900, temperature anomaly has turned positive, indicating temperatures started becoming warmer than the long term average, new research indicates. The study, which incorporates geologic records and computer simulations, provides new evidence that the Arctic would be cooling if not for greenhouse gas emissions that are overpowering natural climate patterns. The Summer temperature anomaly changed from about — 1 to + 1 which is a very large change.

The international study, led by Northern Arizona University and the National Center for Atmospheric Research (NCAR), will be published in the September 4 edition of Science. It was primarily funded by the National Science Foundation, NCAR’s sponsor.

The scientists reconstructed summer temperatures across the Arctic over the last 2,000 years by decade, extending a view of climate far beyond the 400 years of Arctic-wide records previously available at that level of detail. They found that thousands of years of gradual Arctic cooling, related to natural changes in Earth’s orbit, would continue today if not for emissions of carbon dioxide and other greenhouse gases.

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