patterns and severe weather events, sea levels, and populations living in coastal zones or other vulnerable regions. In June 1988, amidst then record heat waves, Dr. James Hansen of the NASA Goddard Institute testified to the U.S. Congress and the world that the signal of humanity’s impact on climate change had emerged unmistakably from the background of natural climate variation, and that scientists could state “with 99 percent confidence” that long-term warming was underway.10 Days later, more than 300 experts—including scientists, business leaders, and government ministers from 46 countries— meeting in Toronto, Canada called for an immediate Action Plan for the Protection of the Atmosphere to reduce global CO2 emissions by 50%. Significantly, and amidst many other action points, the Conference called on governments and industry to seek immediate ways to reduce fossil fuel combustion, deploy new and existing emissions reduction technologies, and to label products “to allow consumers to judge the extent and nature of the atmospheric contamination that arises from the manufacture and use of the product.”11 In the following weeks, 42 legislators called on the President of the United States to immediately begin negotiations on a climate treaty and proposed a National Energy Policy to Reduce Global Warming. At a Congressional hearing on the bill, a leading U.S. Senator observed: “Little debate remains in the scientific community about the increased levels of carbon dioxide in the atmosphere. Global atmospheric concentrations of CO2 have been steadily increasing since the advent of the industrial age. … We have been told that the earth is already committed to warming of as much as five degrees Fahrenheit. Is it too early to act to try to slow down global warming? I hope we will not hear further calls for delay. Instead, I hope that we will receive recommendations for how working alone and in concert with countries all around the globe, we can slow the rate of emissions of the greenhouse gases and work to stabilize our climate before it gets away from us.12 The events of 1988 are significant for their recognition, based on what was even then decades of mounting evidence and growing scientific consensus, that climate change was almost certainly occurring, that humans were very likely the cause, and that the problem demanded urgent and dramatic action. They are significant for another reason as well. Despite this strong scientific consensus, despite the urgency, and notwithstanding the clear warnings to government and to industry actors that they must take action to reduce climate risks while actively working to warn 10 Spencer Weart, The Discovery of Global Warming 150 (Rev. ed. 2008). Toronto Conference on the Changing Atmosphere: Implications for Global Security (27-30 June, 1988), reported in Dean Edwin Abrahamson (ed.), The Challenge of Global Warming 53 (Island Press, Wash. D.C., 1989). 12 U.S. Senate Committee on Environment and Natural Resources, Hearing to Establish and National Energy Policy to Reduce Global Warming, 100th Cong. 2d Sess. (Aug. 11, 1988), S. Hrg. 100-923 at 2-3 (Statement of Senator Timothy Wirth). 11 4