Global warming record. Satellite map of land surface temperature anomalies for 3-10 December 2015, the warmest December on record in parts of the Northern Hemisphere. Part of the trend of global warming, 2015 was the warmest year since modern records began in 1880. This map shows where Earth's surface was warmer or cooler in the daytime than the average temperatures for the same week or month from 2001-2010. Red is warmer than average, white is normal, and blue is cooler than average. The observations were collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite.