2005 warmest year for the northern hemisphere since records began
Mon 23 January 2006
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According to the UN’s World Meteorological Organisation, 2005 can boast to the hottest northern hemisphere since data collection began in 1861. In the southern hemisphere is expected to be the fourth warmest year ever. October and June were globally the warmest recorded. 2005 was also the most active year recorded for hurricanes and tropical storms.
The effects of global warming are now being reported with increasing frequency. A WWF study has found the Artic Mountain glaciers are retreating and snow cover reducing. A thinning of the Greenland ice sheet and Artic sea ice cover is also being linked to an increasing frequency of drowning by polar bears. Dr. Charles Monnett, a marine ecologist at the American government’s Mineral Management Service, said that “drowning –related deaths of polar bears may increase in the future if the observed trend of regression of pack continues.”
Research published by the University of Colorado suggests that global warming could melt almost the entire top layer of Artic permafrost by the end of the century. The release of carbon with the melting of permafrost occurs because warmer temperatures allow bacteria to degrade previously frozen dead vegetation releasing large stocks of carbon into the atmosphere.
Recent warming has degraded large sections of surface permafrost across central Alaska, with pockets of soil collapsing as the ice within it melts. The effect has buckled roads, destabilised houses and caused ‘drunken forests’ in which trees lean at wild angles. Sections of the Alaskan Artic oil pipeline buried in sensitive areas are refrigerated to keep the permafrost around it solid.
David Lawrence, a climate scientist with the US National Centre for Atmospheric Research, believes the melting of permafrost is one of several climate “tipping points” as carbon released from the soil would accelerate global warming. This is because much of the world’s soil carbon stock is stored in the northern hemisphere. Tests conducted at the university showed that, assuming that emissions of carbon dioxide and other greenhouse gases from the usual sources continued to rise, the area holding permafrost within about 3.5 metres of the surface will shrink from 4m square miles to a little over 1m square miles by 2050. By 2100 the area of surface permafrost will shrink to about 400,000. The results appear in the journal Geophysical Research Letters.
The computer model used by the university also predicted a massive thaw would significantly increase the amount of fresh water draining into the Artic Ocean. Water runoffs from permafrost to the ocean have increased by 7% since the 1930s. The computer predicted a further increase of 28 % by 2100. Half of this is due to the ice melting within the surface soil, with the rest because of increased rainfall, snowfall and increased drainage.
Related Links
WWF Press Release
NSIDC Website
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