The U.S. National Climate Assessment: The Science of Climate Change [INVITED]

The U.S. National Climate Assessment (NCA) draws upon the latest scientific understanding of climate and climate change, synthesizing recent advances in the understanding of the science of climate change, and providing a succinct overview of the past and projected effects of climate change on the United States. This presentation will provide an overview of draft findings from the 2013 NCA report chapter on the science of climate change, including observed trends and projected future climate changes for the United States. The chapter and the associated appendix discusses both natural- and human-induced forcings on the climate system, the resulting effects on temperature and precipitation, including the effects of natural variability, and examines shifts in the growing season, frequency and intensity of extreme weather events, sea level rise, ice cover, and ocean acidification. The chapter includes regional analyses, including evaluations for Alaska and Hawaii, and well as for various regions of the continental United States. We also developed a special appendix for the assessment on commonly asked questions about the science of climate change. The chapter provides a foundation for the entire NCA report, which evaluates climate change trends and impacts in each region of the United States and on various socioeconomic and ecological sectors. It is also a key contribution to international climate assessments, including the Intergovernmental Panel on Climate Change.