The global average surface temperature warmed about 0.9 °F over the second half of the 20th Century,{{fact-science}} and to some the warming appears to be related to increases in [[carbon dioxide]] and other greenhouse gases. The possibility of adverse consequences has become a major concern for environmentalists.
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The global average surface temperature warmed about 0.9 °F over the second half of the 20th Century,{{fact-science}}.
Assessments of climate science by the [[United Nations]] (see [[IPCC]] - ''Intergovernmental Panel on Climate Change'')
Assessments of climate science by the [[United Nations]] (see [[IPCC]] - ''Intergovernmental Panel on Climate Change'')