ScienceDaily (Dec. 13, 2007) — The decade of 1998-2007 is the warmest on record, according to data sources obtained by the World Meteorological Organization (WMO). The global mean surface temperature for 2007 is currently estimated at 0.41°C/0.74°F above the 1961-1990 annual average of 14.00°C/57.20°F.
The University of East Anglia and the Met Office’s Hadley Centre have released preliminary global temperature figures for 2007, which show the top 11 warmest years all occurring in the last 13 years. The provisional global figure for 2007 using data from January to November, currently places the year as the seventh warmest on records dating back to 1850.
Other remarkable global climatic events recorded so far in 2007 include record-low Arctic sea ice extent, which led to first recorded opening of the Canadian Northwest Passage; the relatively small Antarctic Ozone Hole; development of La Niña in the central and eastern Equatorial Pacific; and devastating floods, drought and storms in many places around the world.
The preliminary information for 2007 is based on climate data up to the end of November from networks of land-based weather stations, ships and buoys, as well as satellites. The data are continually collected and disseminated by the National Meteorological and Hydrological Services (NMHS) of WMO’s 188 Members and several collaborating research institutions. Final updates and figures for 2007 will be published in March 2008 in the annual WMO brochure for the Statement on the Status of the Global Climate.
WMO’s global temperature analyses are based on two different sources. One is the combined dataset maintained by both the Hadley Centre of the UK Meteorological Office, and the Climatic Research Unit, University of East Anglia, UK, which at this stage ranked 2007 as the seventh warmest on record. The other dataset is maintained by the US Department of Commerce’s National Oceanic and Atmospheric Administration (NOAA), which indicated that 2007 is likely to be the fifth warmest on record.
Since the start of the 20th century, the global average surface temperature has risen by 0.74°C. But this rise has not been continuous. The linear warming trend over the last 50 years (0.13°C per decade) is nearly twice that for the last 100 years.
According to the Intergovernmental Panel on Climate Change’s 4th Assessment (Synthesis) Report, 2007, “warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.”
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