August 25, 2004: US Government Report: Global Warming Caused by Humans

The US government’s Climate Change Science Program concludes in an annual report to Congress that emissions of carbon dioxide and other greenhouse gases are the only likely explanation for the rapid increase in global surface temperatures over the last three decades. It notes further that carbon dioxide and methane levels “have been increasing for about two centuries as a result of human activities and are now higher than they have been for over 400,000 years. Since 1750, CO2 concentrations in the atmosphere have increased by 30 percent and CH4 [Methane] concentrations in the atmosphere have increased by 150 percent.” The report, accompanied by a letter signed by the secretaries of energy and commerce and Bush’s science adviser, represents a dramatic shift in the administration’s view on climate change. Two years prior, when the Environmental Protection Agency similarly concluded in a report (see May 2002) that global warming is the result of human activity, Bush had dismissed it as something “put out by the bureaucracy” (see June 4, 2002). Myron Ebell, of the ExxonMobil-funded Competitive Enterprise Institute, an organization that is part of a campaign to discredit the consensus view that global warming is the result of human activity, says the report is “another indication that the administration continues to be incoherent in its global warming policies.” The report also acknowledges studies indicating that higher CO2 levels stimulate invasive weed growth more than it does crop growth. [Climate Change Science Program, 8/25/2004, pp. 79 ; New York Times, 8/26/2004]