The global temperature this year reached its warmest on record based on a 12-month-rolling average, James Hansen, the top climate change scientist at the U.S. National Aeronautics and Space Administration, said today.
The mean surface temperature in the year through April was about 0.65 of a degree Celsius (1.17 degree Fahrenheit) warmer than the 1951 to 1980 mean, according to a graph in a 37-page draft paper on the website of NASA’s Goddard Institute for Space Studies. That makes it a fraction warmer than the previous peak in 2005. Absolute temperatures weren’t published in the paper.
“Record high global temperature during the period with instrumental data was reached in 2010,” Hansen and three co-authors wrote in the paper. “As for the calendar year, it is likely that the 2010 global surface temperature in the GISS analysis also will be a record.”
The figures strengthen the case that temperatures show a warming in the climate. Critics of efforts to regulate greenhouse gas emissions from fossil fuels had pointed to another data, compiled by the U.K. Met Office, which puts 1998 as the warmest year, as evidence that the Earth is cooling.
The document will be submitted to Reviews of Geophysics, a scientific journal, Hansen said today in an e-mail. The NASA data series uses information from 6,300 monitoring stations around the world and is one of the three main gauges of global temperature used by the United Nations Intergovernmental Panel on Climate Change to compile its assessments.
Hansen’s paper “looks like a modest addition to the continuing build-up of evidence” for global warming, Michael Grubb, a member of the U.K. Climate Change Committee, which advises the government, said today in a telephone interview.
Efforts to stem global warming have taken a knock in the past six months after a cold winter in parts of the U.S., China and Europe at the same time as errors were revealed in the United Nation’s biggest climate change report and scientists at the U.K.’s University of East Anglia were accused of suppressing dissent on the issue.
“Public perception has been radically impacted by a short campaign” by climate skeptics, said Grubb, who’s also chairman of the advisory group Climate Strategies at the University of Cambridge. “That is deeply troubling if you want a sensible long-term solution to climate change.”
The latest findings may reinvigorate international talks on fighting global warming in Bonn this week. Those discussions stalled in Copenhagen in December. Skepticism about man-made global warming by senators including James Inhofe, an Oklahoma Republican, has helped undermine efforts to pass U.S. laws to limit greenhouse gases.
Grubb and Abyd Karmali, global head of carbon markets at Bank of America Merrill Lynch, both said that long-term trends in the climate series are more important than data for any single year.
“One year is not going to make or break anything, the most important thing is the long term trend,” Karmali said today in a telephone interview in London. “I don’t see any reason why public opinion would change one way or another” because of the latest data.
NASA’s temperature series and another compiled by the U.S. National Climatic Data Center currently have 2005 as the warmest calendar year on record. Those two, along with the Met Office’s data set, are the three main gauges of global temperature. All three series show a warming trend in the last half-century.