WASHINGTON, DC, June 22, 2006 (ENS) – The Earth is hotter today than it has been in four centuries and likely warmer than it has been in the past 1,000 years, according to a review of surface temperature research released Thursday by the U.S. National Academies of Science.
The 155 page report provides additional evidence that “human activities are responsible for much of the warming,” the authors said.
The study, written by a panel of 12 climate experts, assesses the state of scientific efforts to reconstruct surface temperature records for the Earth over approximately the last 2,000 years.
Widespread reliable instrument records of global temperatures are available only for the last 150 years, leaving scientists to estimate past climatic conditions by analyzing proxy evidence from sources such as tree rings, corals, ocean and lake sediments, cave deposits, ice cores, boreholes, and glaciers.
Committee chair Gerald North said the panel’s review of instrument and proxy data affords “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.”