Based on the first ten months of this year, 2011 is on track to become the tenth warmest year since record keeping began in 1850 — and the warmest ever during a cooling, La Niña event — according to yesterday’s Provisional Statement on the Status of the Global Climate from the UN’s World Meteorological Organization.
Global temperature anomolies during la Niña years compared to other years (click to enlarge).
During the same period, extent of Arctic sea ice reached the second lowest level on record (seasonal minimum 35% below the 1979-2000 average) and it’s volume recorded as the lowest ever, surpassing the previous low set 2010.
One of the strongest La Niña events of the past 60 years emerged in the tropical Pacific during the second half of 2010 and continued through May of this year. Such events typically produce reduce global temperatures by 0.10 to 0.15°C compared to the years immediately before, and after and 2011 has thus far been no exception. This year’s global temperatures have been lower than in 2010 but warmer than recent moderate-to-strong La Niña years: 0.36°C warmer than 2008, 0.27°C above 2000 temperatures, and 0.12°C higher than 1989.
Global average temperature anomolies, 1850 to 2011-to-date (click to enlarge).
Despite the strong la Niña, global combined sea surface and land surface air temperature for 2011 (January–October) is currently estimated at 0.41°C ± 0.11°C (0.74°F ± 0.20°F) above the 1961–1990 annual average of 14.00°C/57.2°F.
“Concentrations of greenhouse gases in the atmosphere have reached new highs,” said WMO Secretary-General Michel Jarraud of yesterday’s report. “They are very rapidly approaching levels consistent with a 2-2.4 degree Centigrade rise in average global temperatures which scientists believe could trigger far reaching and irreversible changes in our Earth, biosphere and oceans.”
Indeed, thirteen of the warmest years on record have occurred in the past 15 years.
Final updates and figures for 2011 will be published in March 2012 in the annual WMO Statement on the Status of the Global Climate.
