The year 2008 tied with 2001 as the eighth warmest year on record for the Earth, based on the combined average of worldwide land and ocean surface temperatures through December, according to a preliminary analysis by NOAA’s National Climatic Data Center in Asheville, N.C. For December alone, the month also ranked as the eighth warmest globally, for the combined land and ocean surface temperature. The assessment is based on records dating back to 1880.
The analyses in NCDC’s global reports are based on preliminary data, which are subject to revision. Additional quality control is applied to the data when late reports are received several weeks after the end of the month and as increased scientific methods improve NCDC’s processing algorithms.
NCDC’s ranking of 2008 as the eighth warmest year compares to a ranking of ninth warmest based on an analysis by NASA’s Goddard Institute for Space Studies. The NOAA and NASA analyses differ slightly in methodology, but both use data from NOAA's National Climatic Data Center – the federal government's official source for climate data.
Global Temperature Highlights – 2008
- The combined global land and ocean surface temperature from January-December was 0.88 degree F (0.49 degree C) above the 20th Century average of 57.0 degrees F (13.9 degrees C). Since 1880, the annual combined global land and ocean surface temperature has increased at a rate of 0.09 degree F (0.05 degree C) per decade. This rate has increased to 0.29 degree F (0.16 degree C) per decade over the past 30 years.
- Separately, the global land surface temperature for 2008, through December, was sixth warmest, with an average temperature 1.46 degrees F (0.81 degree C) above the 20th Century average of 47.3 degrees F (8.5 degrees C).
- Also separately, the global ocean surface temperature for 2008, through December, was 0.67 degree F (0.37 degree C) above the 20th Century average of 60.9 degrees F (16.1 degrees C) and ranked tenth warmest.
Global Temperature Highlights – December 2008
- The December combined global land and ocean surface temperature was 0.86 degree F (0.48 degree C) above the 20th Century average of 54.0 degrees F (12.2 degrees C).
- Separately, the December 2008 global land surface temperature was 1.22 degrees F (0.68 degree C) above the 20th Century average of 38.7 degrees F (3.7 degrees C) and ranked 14th warmest.
- For December, the global ocean surface temperature was 0.74 degree F (0.41 degree C) above the 20th Century average of 60.4 degrees F (15.7 degrees C) and tied with December 2001 and December 2005 as sixth warmest.
Other Global Highlights for 2008
- The United States recorded a preliminary total of 1,690 tornadoes during 2008, which is well above the 10-year average of 1,270 and ranks as the second highest annual total since reliable records began in 1953. The high number of tornado-related fatalities during the first half of the year made 2008 the 10th deadliest with a 2008 total of 125 deaths.
- Northern Hemisphere snow cover extent in December was 16.95 million square miles (43.91 million square kilometers). This was 0.17 million square miles (0.43 million square kilometers) above the 1966-2008 December average. Northern Hemisphere snow cover extent was below average for most of 2008.
- Arctic sea ice extent in 2008 reached its second lowest melt season extent on record in September. The minimum of 1.80 million square miles (4.67 million square kilometers) was 0.80 million square miles (2.09 million square kilometers) below the 1979-2000 average minimum extent.