Science

Intergovernmental Panel on Climate Change (IPCC)
http://www.ipcc.ch/

National Oceanic and Atmospheric Administration (NOAA)
http://www.climate.gov/

U.S. Global Change Research Program
http://www.globalchange.gov/

National Climate Assessment 2014
http://nca2014.globalchange.gov/

National Academy of Sciences: “Climate Change: Evidence and Causes”
http://nas-sites.org/americasclimatechoices/more-resources-on-climate-change/climate-change-evidence-and-causes/