(Reuters) - Global temperature data released in Britain on Wednesday points to a long-term warming trend.
Data from Britain’s Met Office Hadley Center and the Climatic Research Unit of the University of East Anglia (UEA) showed that 2010 was the second warmest behind 1998 in records dating back to 1850.
Last week, the U.S. National Climatic Data Center, an office of the National Oceanic and Atmospheric Administration (NOAA), and NASA’s Goddard Institute for Space Studies said 2010 had tied as the warmest year with 2005.
The three main agencies for tracking global temperatures say that year-by-year data differs partly because of the different treatment of Arctic data, where there are few measurements.
NASA said 2010 and 2005 were separated by less than 0.01 degree Celsius (0.018 F), a statistical tie given the uncertainties in the calculations.
The U.N.’s World Meteorological Organization compiles a ranking from all three main sources. It says human emissions of greenhouse gases are nudging temperatures higher and causing climate change with more floods, droughts and rising sea levels.
All 10 of the warmest years have been since 1998, when temperatures were boosted by a strong El Nino weather event, a natural shift which brings warm waters to the surface of the Pacific Ocean every few years.
Top 10 warmest years since records began in the 19th century, followed by the difference, in degrees Celsius, above long-term average temperatures:
Met/UEA NOAA NASA
(Met office/UEA compare temperatures with a 1961-1990 average; NOAA with a 20th century average, NASA with 1951-1980)
The warmest years according to WMO, excluding 2010: 1) 1998 2) 2005 3) 2003 4) 2002 5) 2009 6) 2004 7) 2006 8) 2007 9) 2001 10) 1997
Most decades in the past century have been warmer than the previous, according to the WMO:
2000-09 14.42 degrees Celsius (57.95F)
1990-99 14.25 C (57.65F)
1980-89 14.09 C (57.36F)
1970-79 13.93 C (57.07F)
1960-69 13.90 C (57.02F)
1950-59 13.85 C (56.93F)
1940-49 13.94 C (57.09F)
1930-39 13.87 C (56.96F)
1920-29 13.72 C (56.69F)
1910-19 13.60 C (56.48F)
1900-09 13.61 C (56.49F)
(NOTE: The global average temperature during 1961-90, the U.N. base years, was 14.0 degrees Celsius (57.20F), according to the WMO)
Compiled by Alister Doyle in Oslo and Gerard Wynn in London; Editing by Janet Lawrence