The GISS Land-Ocean Temperature Index put 2013 into the top ten warmest years in the global record, even though temperatures in the United States were not much warmer than usual.
An analysis of global temperatures by NASA scientists shows that 2013 was the seventh warmest year since 1880 (tied with 2006 and 2009). Nine of the 10 warmest years on record all have occurred since 2000, with 2010 and 2005 ranking as the warmest. Scientists at NASA’s Goddard Institute for Space Studies (GISS) reported that 2013 continued the long-term trend of rising air temperatures over the land and sea surface.
The top map above depicts global temperature anomalies in 2013. It does not show absolute temperatures, but instead shows how much warmer or cooler the Earth was compared to an averaged base period from 1951 to 1980. The GISS team assembles its analysis with publicly available data from roughly 6,300 meteorological stations around the world; ship-based and satellite observations of sea surface temperature; and Antarctic research station measurements. For more explanation of how the analysis works, read World of Change: Global Temperatures.
The global average temperature for 2013 was 14.6° Celsius (58.3° Fahrenheit), which is 0.6°C (1.1°F) warmer than the mid-20th century baseline. The average global temperature has risen about 0.8°C (1.4°F) since 1880. Exact rankings for individual years are sensitive to data inputs and analysis methods.
“Long-term trends in surface temperatures are unusual, and 2013 adds to the evidence for ongoing climate change,” said GISS climatologist Gavin Schmidt. “While one year or one season can be affected by random weather events, this analysis shows the necessity for continued, long-term monitoring.”