World temperatures in 2010 may be the warmest on record, the U.K. Met Office said, as it plans to calibrate a decade of data to account for newer sensors.
The average temperature for the year through October shows 2010 will be one of the two warmest years in a series that goes back to 1850, said Vicky Pope, head of climate science at the Met Office. Scientists at the agency are preparing to revise data since 2000 to adjust for a new method that masked some of the rising temperature trend, she said.
Nine climate indicators, from temperatures in the lower atmosphere and humidity to rising sea levels, declining sea ice and shrinking glaciers all point toward a warming climate, according to a report today from the agency, which compiles one of the three main time series of global temperatures.
“There’s a very clear warming trend but it’s not as rapid as it was before,” Pope told reporters yesterday in London. Where the average temperature rose at about 0.16 degrees per decade since the 1970s, the rate through the 2000s has been from 0.05 to 0.13 degrees, she said.
The decadal rate for the 2000s may be 0.03 degrees higher once adjustments have been made to compensate for an increase in the use of buoys to take sea temperature measurements, Pope said. The buoys measure sea temperatures as being slightly lower than ships, which were used more in the past, according to Matthew Palmer, an ocean scientist at the Met Office.
“We’ve effectively underestimated the rate of warming over the past decade,” Palmer said. A new series will be published at an as yet unspecified date, according to the Met Office.
The global average temperature for the year through the end of October was 0.52 degrees Celsius (0.94 degrees Fahrenheit) warmer than the 1961 through 1990 average of 14 degrees, the same as 1998, the hottest year in the Met Office series.
“It’s currently the second-warmest year on record,” Pope said, noting that 1998 had a “strong” El Nino phenomenon, a cyclical warming of the Pacific Ocean that typically raises the global average temperature. This year began with an El Nino and has switched to the reverse phase, called La Nina, she said.
While the Met Office didn’t provide a figure, the 0.03-degree revision in the decadal rate would add a tenth of that, 0.003 degrees, to this year’s data relative to 1998, which predates the period being revised.
The Met Office compiles the data along with the University of East Anglia in eastern England, which last year had thousands of e-mails stolen from its servers and posted on the Internet, causing skeptics to charge that the data were manipulated. Three investigations have since cleared the school.
WMO, NOAA, NASA
The World Meteorological Organization is due to announce a first estimate of 2010 temperatures on Dec. 2 during two weeks of United Nations climate changes talks in Cancun, Mexico.
The U.S. National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration publish two other widely used global average temperature series. They have 2005 as the warmest year due to differences in the way they account for temperatures in parts of the world where there are no monitoring stations.
This year may eclipse 2005 as the warmest in the 131-year NASA series, the agency’s Goddard Institute for Space Studies said on Sept. 30. The 12-month rolling average global temperature posted a record in the year through April, James Hansen, NASA’s top climate scientist, said in June.