2008 MARKED BY WEATHER EXTREMES AND SECOND-LOWEST LEVEL OF ARCTIC ICE COVER
Geneva, 16 December 2008 (WMO) – The year 2008 is likely to rank as the 10th warmest year on record since the beginning of the instrumental climate records in 1850, according to data sources compiled by the World Meteorological Organization (WMO). The global combined sea-surface and land-surface air temperature for 2008 is currently estimated at 0.31°C/0.56°F above the 1961-1990 annual average of 14.00°C/57.2°F. The global average temperature in 2008 was slightly lower than that for the previous years of the 21st century due in particular, to the moderate to strong La Niña that developed in the latter half of 2007.
The Arctic Sea ice extent dropped to its second-lowest level during the melt season since satellite measurements began in 1979. Climate extremes, including devastating floods, severe and persistent droughts, snow storms, heatwaves and cold waves, were recorded in many parts of the world.
This preliminary information for 2008 is based on climate data from networks of land-based weather stations, ships and buoys, as well as satellites. The data are continuously collected and disseminated by the National Meteorological and Hydrological Services (NMHSs) of WMO's 188 Members and several collaborating research institutions. Final updates and figures for 2008 will be published in March 2009 in the annual WMO Statement on the Status of the Global Climate.
WMO's global temperature analysis is based on two complementary 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. The other dataset is maintained by the US Department of Commerce's National Oceanic and Atmospheric Administration (NOAA).
Regional temperature anomalies
In March, southern Australia experienced a record heatwave that brought scorching temperatures across the region. Adelaide experienced its longest running heatwave on record, with 15 consecutive days of maximum temperatures above 35°C. Also, several heatwaves occurred in south-eastern Europe and the Middle East during April, associated with a very warm spring observed, not only in this region but also in a large part of the rest of Europe and Asia.
Dry conditions in south-eastern Australia reinforced long-term drought over much of that region, with Victoria having its ninth-driest year on record. These conditions exacerbated severe water shortages in the agriculturally important Murray-Darling Basin, resulting in widespread crop failures in the area. September and October, in particular, were exceptionally dry in this region.
Artic sea ice down to second-lowest extent
Arctic sea ice extent during the 2008 melt season dropped to its second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on 14 September 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million km2. The record monthly low, set in 2007, was 4.3 million km2.
Because ice was thinner in 2008, overall ice volume was less than that in any other year.
A remarkable occurrence in 2008 was the dramatic disappearance of nearly one-quarter of the massive ancient ice shelves on Ellesmere Island. Ice 70 metres thick, which a century ago covered 9 000 km2, has been chiselled down to just 1 000 km2 today, underscoring the rapidity of changes taking place in the Arctic. The season strongly reinforces the 30-year downward trend in Artic sea ice extent.
WMO is the United Nations' authoritative voice on weather, climate and water
For full 2008 preliminary report go to http://www.wmo.int/pages/mediacentre/press_releases/pr_835_en.html