POSTED 16 MAR 1999
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Global satellite map.
NASA Goddard Space Center.
A new report suggests that the 1990s were the warmest decade of the millennium, with 1998 the warmest year so far. The report also found that the warming in the 20th century counters a 1,000-year-long cooling trend. The study, by Michael Mann and Raymond Bradley of the University of Massachusetts and Malcolm Hughes of the University of Arizona, appears in the March 15 Geophysical Research Letters. "Temperatures in the latter half of the 20th century were unprecedented," said Bradley. The study involved a close examination of natural archives, such as tree rings and ice cores, which record climate variations each year. These natural archives allow researchers to consider the short instrumental record of climate against a longer-term perspective.
©1999, University of Wisconsin, Board of Regents.