Global temperatures have warmed significantly since 1880, the beginning of what scientists call the "modern record." At this time, the coverage provided by weather stations allowed for essentially global temperature data. As greenhouse gas emissions from energy production, industry and vehicles have increased, temperatures have climbed, most notably since the late 1970s. In this animation of temperature data from 1880-2011, reds indicate temperatures higher than the average during a baseline period of 1951-1980, while blues indicate lower temperatures than the baseline average.
Data source: NASA Goddard Institute for Space Studies. Visualization credit: NASA Goddard Space Flight Center Scientific Visualization Studio
Note: For more information, see NASA Finds 2011 Ninth-Warmest Year on Record.