The blue line shows estimates of Arctic temperatures over the last 2,000 years. The green line shows the long-term cooling trend. The red line shows the recent warming based on actual observations. (Courtesy Science, modified by UCAR.)
Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, 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 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.