Climate changing,US Senate panel told

摘要

Several climate researchers told a largely receptive Senate Energy Committee July 21 human activity is a substantial cause of global warming outside the range of natural variability,and the climate is changing as a consequence.The scientific understanding of climate change"is now sufficiently clear to show that climate change from global warming is already upon us,"said James Hurrell,with the National Center for Atmospheric Research."Uncertainties remain,especially regarding how climate will change on regional and local scales.But the climate is changing and uncertainties make the need for action all the more imperative."