Scientists at NASA’s Goddard Institute for Space Studies (GISS) released figures yesterday showing that 2010 tied with 2005 as the hottest year on record since 1880. This is despite the unusually cold temperatures across Europe and strong La Nina phenomenon. The place of next hottest year is a tie between 1998, 2002, 2003, 2006 and 2007. The global average temperature has been rising at an average rate of 0.20°C per decade.
GISS collect weather data from more than 1000 meteorological stations around the globe, from satellite measurements of sea temperatures and from Antarctic research stations. The data are then processed to find anomalies in temperature variations. Every month, the temperature at each location is compared to the temperature on the same date one year previously. That variation is then compared to the average temperature for the thirty years between 1950 and 1980 (which serves as the baseline for all analysis). The results closely match those produced independently by the Met Office Hadley Centre in the UK, and the National Oceanic and Atmospheric Administration’s National Climatic Data Center.
What’s interesting about the 2010 temperature record is that, even though the second half of the year was marked by strong La Nina conditions (which bring cool sea temperatures to the eastern pacific ocean), the global average still managed to match the previous hottest year on record! According to the data, the year was 0.74°C hotter than the baseline period.
Paradoxically, the unusually cold winter in Europe may be cause by rising global temperatures – as arctic ice melts, it insulates the northern oceans less effectively, allowing them to warm significantly. Some regions in northeast Canada were as much as 18°C hotter than usual this December! This hot air and the corresponding loss of ice may be driving the cold air further south, to chill the mid-northern latitudes. But even taking this into account, seven of the last ten european winters were still warmer than average, compared to the 1950-1980 baseline.
For the full report, click here: http://www.giss.nasa.gov/research/news/20110112/