Lewis Smith / The Daily Mail – 2013-01-07 23:50:14
http://www.dailymail.co.uk/sciencetech/article-2258398/Climate-change-Sea-level-rises-worse-feared-say-leading-scientists-tens-millions-likely-driven-homes.html
Sea Level Rises Will Be Much Worse
Than We Feared, Say Leading Scientists,
With Tens of Millions Likely To Be Driven from Their Homes
Lewis Smith / The Daily Mail
LONDON (January 7, 2013) — Almost 200 million people could be forced to leave their homes by the end of the century because of sea level rises, researchers have warned. Sea level rises are now feared to be significantly worse than forecast by the Intergovernmental Panel on Climate Change (IPCC) just six years ago.
Melting of the polar ice sheets could be so severe that seas could rise a meter by 2100, a level that would be considered ‘catastrophic’.
The latest findings were made by a specially-selected team of 26 leading experts who concluded the risks were ‘potentially severe’ after being asked to assess what sea level rises can be expected.
It is most likely, they found, that there will be an increase of 29cm this century but they also concluded there is a one in 20 chance that it could exceed 84cm with a ‘conceivable risk’ it will be greater than a meter.
Projections from each of the experts were combined using the mathematical technique expert elicitation (EE) to provide a pooled estimate.
Even with sea level increases limited to 29cm there would be serious consequences not just to low lying countries such as the Maldives and Bangladesh but to some of the biggest cities in the world.
Many big cities, including London and New York, have river or coastal ports and even small rises significantly boosts the risks of flooding from storms and tidal surges.
Flooding and the threat of inundation is likely, concluded the team, to force up to 187 million people to leave their homes.
The forecasts, published in the journal Nature Climate Change, are higher than the projections published by the IPCC in 2007 when it was estimated that sea levels would rise by as little as 18cm and as much as 59cm.
Professor Jonathan Bamber, of the University of Bristol, said: ‘This is the first study of its kind on ice sheet melting to use a formalized mathematical pooling of experts’ opinions.
‘It demonstrates the value and potential of this approach for a wide range of similar problems in climate change research, where past data and current numerical modeling have significant limitations when it comes to forecasting future trends and patterns.’
The findings are in line with other studies which have shown sea level rises are likely to be much worse than had been thought just a few years ago and that the rate of increase has speeded up in the last decade.
In the study the team of researchers recognized that there remains considerable uncertainty over the likely extent and even the causes of melting in polar regions.
‘On the critical question of whether recent ice-sheet behavior is due to variability in the ice sheet–climate system or reflects a long-term trend, expert opinion is shown to be both very uncertain and undecided,’ they said.
‘We find an overwhelming lack of certainty about the crucial issue of the origin of recent accelerated mass loss from the ice sheets. The present expert elicitation findings suggest a smaller contribution from the ice sheets than implied by semi-empirical models, but larger than proposed in the last IPCC report.’
Arctic and Antarctic ice sheet melting is one of several contributors to sea level rises and is likely to make up an increasing proportion as the century progresses.
A recent study found that melting ice sheets now contribute to 30 percent of sea level rises, compared to 10 percent in the 1990s.
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