Climate Change Warning: Hansen Testifies Before Senate
NASA climatologist James Hansen testified before the Senate Energy and Natural Resources Committee on June 23, 1988, declaring with "99 percent confidence" that global warming was caused by human activities. His testimony, delivered during a record heat wave in Washington, received extensive media coverage and is credited with putting climate change on the political agenda. That same year, the Intergovernmental Panel on Climate Change (IPCC) was established by the United Nations to assess the scientific consensus on climate change. The IPCC's subsequent reports progressively strengthened the certainty that human greenhouse gas emissions were causing unprecedented warming. By its fifth assessment report in 2014, the IPCC declared it "extremely likely" (95-100% probability) that human influence was the dominant cause of warming observed since the mid-20th century.
June 23, 1988
38 years ago
Key Figures & Places
What Else Happened on June 23
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The Treaty of Athis-sur-Orge forced the Flemish to pay crushing war indemnities and cede key territories to the French crown following their defeat at Mons-en-P…
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