^ Knutson, Thomas R. (2008). "Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions". Nature Geoscience1: 359. doi:10.1038/ngeo202.
^State of the Union Address, retrieved 2008-01-28. "The United States is committed to strengthening our energy security and confronting global climate change. And the best way to meet these goals is for America to continue leading the way toward the development of cleaner and more energy-efficient technology."
^ Guptal, Sujata; et al. (2007-05-04). "Policies, Instruments and Co-operative Arrangements" (PDF). Policies, Instruments and Co-operative Arrangements. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change 21. Intergovernmental Panel on Climate Change. Retrieved on 2008-04-26. "..developed countries as a group would need to reduce their emissions to below 1990 levels in 2020 (on the order of –10% to 40% below 1990 levels for most of the considered regimes) and to still lower levels by 2050 (40% to 95% below 1990 levels), even if developing countries make substantial reductions."
