<div><p>Sea levels were likely eight metres higher around 125,000 years ago when polar temperatures were 3-5 degrees C warmer, says a new study published Wednesday to show the effects of global warming.</p><p>The research by the US universities of Harvard and Princeton was released in the journal Nature as the world's nations met in Denmark to forge a strategy to head off harmful effects of global warming blamed on greenhouse gases.</p><p>To understand the potential effects of a rise in temperature, the researchers reexamined data about the last interglacial stage -- a warmer period within an ice age -- which climaxed about 125,000 years ago, they said.</p><p>At the time, polar temperatures were 3-5 degrees C (37-41 degrees F) higher than today, providing a comparison for current scenarios of future rises of 1-2 degrees C, they said.</p><p>"We find a 95 percent probability that global sea level peaked at least 6.6 metres (nearly 22 feet) higher than today during the last interglacial," the study said.</p><p>"It is likely (67 percent probability) to have exceeded 8.0 metres but is unlikely (33 percent probability) to have exceeded 9.4 metres," it said.</p><p>Previous estimates of sea-level rises for the same period had been at a lower 4-6 metres.</p><p>"The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming," the scientists said.</p><p>The researchers also calculated that during the last interglacial period the average sea level rose six-nine millimetres a year compared to around two millimetres a year during the 20th century.</p><p>That may have accelerated to around three millimetres a year between 1993 and 2003, at least partly because of the melting of the Greenland and Antarctic ice sheets.</p><p>US scientists Peter Clark and Peter Huybers said "the disconcerting message is that the equilibrium response of sea level to 1.5-2 C of global warming could be an increase of 7-9 metres."</p><p>"If their results are correct, the sea-level rise over the coming century will be followed by many more metres of rise over the ensuing centuries," they said in a commentary on the research also published in Nature.</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=65549399&bid=informcom" /></div><div id="copyright"><div>

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