Temperature Rise Confirmed

From the National Academy of Sciences, Press Release WASHINGTON -- There is sufficient evidence from tree rings, boreholes, retreating glaciers, and other "proxies" of past surface temperatures to say with a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years, according to a new report from the National Research Council. Less confidence can be placed in proxy-based reconstructions of surface temperatures for A.D. 900 to 1600, said the committee that wrote the report, although the available proxy evidence does indicate that many locations were warmer during the past 25 years than during any other 25-year period since 900. Very little confidence can be placed in statements about average global surface temperatures prior to A.D. 900 because the proxy data for that time frame are sparse, the committee added. From The Houston Chronicle June 23, 2006, 6:39AM Congress told climate on hot streak Scientific panel confirms rising temperatures over the past 400 years By ERIC BERGER Copyright 2006 Houston Chronicle The Earth is warmer today than at any point the last 400 years, and likely the last millennium, a committee convened by the National Academy of Sciences concluded in a report released Thursday. Congress sought the 155-page analysis of Earth's past temperatures after a dispute erupted a year ago, when Texas Congressman Joe Barton sharply questioned the methods of Michael Mann and two other researchers, who had published scientific papers stating the Northern Hemisphere was warmer during the late 20th century than at any time in the past 1,000 years. Upon presenting its report to Congress, the scientific panel said its findings generally support the research by Mann and his colleagues. "It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries," said Gerald North, the committee's chairman and an atmospheric scientist at Texas A&M University.