Animation showing the NASA GISS Five Year Average Global Temperature Anomalies from 1884 - 2008. GISS (Goddard Institute for Space Studies) analyzes the global temperature each year using a variety of tools, including meteorological stations, ships, and satellites. The historical record allows scientists to analyze how the temperature has changed through the recent past. This sequence shows the anomaly, or departure from normal, for temperature from 1884 through 2008. In this case, normal is the 1951 - 1980 mean temperature. Five year averages are used for the yearly temperatures to account for year to year variability. The warmest year in this record is 2005. 2007 tied 1998 for the second warmest year in a century. Over the past 30 years, there has been a rapid warming trend. In fact, eight of the warmest years have been recorded since 1998. The greatest warming has been observed in the arctic. Areas that are dark red indicate the greatest warming, while dark blue areas indicate the greatest cooling. The temperature varies from 2C (3.6F) below normal to 2C (3.6F) above normal.