2008 Global Surface Temperature in GISS Analysis

• Main Authors: James Hansen, Makiko Sato, Reto Ruedy, Ken Lo
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Antarctic; The Antarctic; Antarctic Peninsula; Pacific; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.177.6751; http://www.columbia.edu/%7Ejeh1/mailings/2009/20090113_Temperature.pdf

analysis 2008 is the ninth warmest year in the period of instrumental measurements, which extends back to 1880. The ten warmest years all occur within the 12-year period 1997-2008. The two standard deviation (95 percent confidence) uncertainty in comparing recent years is estimated as 0.05°C [Reference 2], so we can only conclude with confidence that 2008 was somewhere within the range from 7 th to 10 th warmest year in the record. The map of global temperature anomalies in 2008, Figure 1 (right), shows that most of the world was either near normal or warmer than in the base period (1951-1980). Eurasia, the Arctic and the Antarctic Peninsula were exceptionally warm, while much of the Pacific Ocean was cooler than the long-term average. The relatively low temperature in the tropical Pacific was due to a strong La Nina that existed in the first half of the year. La Nina and El Nino are opposite phases of a natural oscillation of tropical temperatures, La Nina being the cool phase. Figure 2 (top) provides seasonal resolution of global and low latitude surface temperature, and an index that measures the state of the natural tropical temperature oscillation. The figure indicates that the La Nina cool cycle peaked in early 2008. The global effect of the tropical oscillation is made clear by the average temperature anomaly over the global ocean (Figure 2, bottom). The