17. Department of Defense, Quadrennial Defense Review Report (Washington, D.C.: U.S. Department of Defense, 2010, available at http://www.defense.gov/qdr/, accessed March 1, 2011); D. C. Blair, Annual Threat Assessment of the U.S. Intelligence Community. Statement for the Record to the Senate Select Committee on Intelligence (2010, available at http://www.dni.gov/testimonies/20100202_testimony.pdf, accessed February 28, 2011); NRC, Advancing the Science of Climate Change (Washington, D.C.: National Academies Press, 2010), Chapter 15.
18. Center for Climate Strategies, Impacts of Comprehensive Climate and Energy Policy Options on the U.S. Economy(Washington, D.C.: Johns Hopkins University, 2010, available at http://advanced.jhu.edu/academic/government/energy-policy-report/, accessed March 1, 2011); N. M. Bianco and F. T. Litz, Reducing Greenhouse Gas Emissions in the United States: Using Existing Federal Authorities and State Action (Washington, D.C.: World Resources Institute, 2010, available at http://www.wri.org/publication/reducing-ghg-emissions-using-existing-federal-authorities-andstate-action, accessed March 8, 2011).
19. M. Betsill and H. Bulkeley, “Cities and the multilevel governance of global climate change” (Global Governance 12 :141-159, 2006).
20. See, for example, E. Ostrom, “A multi-scale approach to coping with climate change and other collective action problems” (Solutions 1:27-36, 2010).
1. For a historical overview of the science of climate change, see S. R. Weart, The Discovery of Global Warming (Cambridge, MA: Harvard University Press, 2008).
2. According to IPCC (Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assess ment Report of the Intergovernmental Panel on Climate Change, eds. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H. L. Miller [Cambridge, UK: Cambridge University Press, 2007]): “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.”
3. The temperature of the lower atmosphere is measured directly by instruments mounted on weather balloons (see, e.g., M. P. McCarthy, H. A. Titchner, P. W. Thorne, S. F. B. Tett, L. Haimberger, and D. E. Parker, “Assessing bias and uncertainty in the HadAT-adjusted radiosonde climate record” [Journal of Climate 21(4):817-832, 2008]) and indirectly by satellites that measure the energy radiated upward from the Earth at specific wavelengths (J. R. Christy, R. W. Spencer, W. D. Braswell, “MSU tropospheric temperatures: Dataset construction and radiosonde comparisons” [Journal of Atmospheric and Oceanic Technology 17:1153-1170, 2000]; J. R. Christy, R. W. Spencer, W. B. Norris, and W. D. Braswell, “Error estimates of version 5.0 of MSUAMSU bulk atmospheric temperatures” [Journal of Atmospheric and Oceanic Technology 20:613-629, 2003]; C. A. Mears and F. J. Wentz, “Construction of the remote sensing systems V3.2 atmospheric temperature records from the MSU and AMSU microwave sounders” [Journal of Atmospheric and Oceanic Technology 26:1040-1056, 2009, doi: 10.1175/2008JTECHA1176.1]). Trends in these data have been assessed in detail by the U. S. Climate Change Science Program (CCSP (Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences, Synthesis and Assessment Product 1.1, eds. T. R. Karl, S. J. Hassol, C. D. Miller, and W. L. Murray [Washington, D.C.: National Oceanic and Atmospheric Administration, 2006]) and the IPCC (Climate Change 2007 WG1, Summary for Policymakers).
4. The warming of the uppermost 700 meters of the world oceans is documented in S. J. Levitus, I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, and A. V. Mishonov, “Global ocean heat content 1955-2008 in light of recently revealed instrumentation problems” (Geophysical Research Letters 36:L07608, 2009).
5. According to the IPCC (Climate Change 2007, Ch9): “anthropogenic forcing has likely contributed to recent decreases in Arctic sea ice extent and to glacier retreat.”
6. IPCC (Climate Change 2007 WG1, Ch9) concludes “It is likely that anthropogenic forcing has contributed to the general warming observed in the upper several hundred meters of the ocean during the latter half of the 20th century.”