Global warming is "unequivocal [and] evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level." Moreover, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." These and other compelling conclusions are offered by the Intergovernmental Panel on Climate Change (IPCC) in a much-heralded report released February 2—Climate Change 2007: The PhysicalrnScience Basis—Summary for Policymakers. "Very likely," in IPCC speak, means that the panel considers its conclusion to be 90% certain.
展开▼
