Sea surge could threaten a billion people*

 From correspondents in San Francisco

April 20, 2007 07:57am
Article from: Reuters

MORE than one billion people live in low-lying areas where a sudden
surge in sea level could prove as disastrous as the 2004 Asian tsunami,
according to new research.

New mapping techniques show how much land would be lost and how many
people affected by rapid sea-level rises that are often triggered by
storms and earthquakes, a US Geological Survey-led team determined.

Lynn Usery, who led the team, said nearly one-quarter of the world's
population lives 30m below sea level - the size of the biggest surge
during the 2004 tsunami that pulverised villages along the Indian Ocean
and killed 230,000 people.

"What we are suggesting is what kind of areas are at risk (in) a
catastrophic event," Mr Usery told a meeting of the Association of
American Geographers.

"The fact that there are that many people living at that sea level means
there are probably a lot of people potentially in harm's way."

The team also found that a 30m rise in sea level would cover 9.5 million
sq km of land worldwide.

A rise of just 5m would affect 669 million people and 5.4 million sq km
of land would be lost.

Sea levels are rising about 1-2mm each year, making it unlikely such a
scenario would suddenly occur across the globe, Mr Usery said.

But he said that 10,000 years ago, sea levels rose 20m in 500 years - a
relatively short span - after the collapse of the continental ice sheets.

"It can happen in a short period of time if we look at the historical
data," he said.

More importantly, the new mapping technique provided detail previously
unavailable and gave policymakers better tools to prepare for potential
disasters.

"This can be used by nations in the world to put contingency plans in
place," Mr Usery said. "We haven't had data sets at this kind of
resolution before."

The impetus for the project came after the 2004 tsunami and Hurricane
Katrina in 2005 underlined the devastating impact sudden sea level
surges can have on those living in coastal areas, Mr Usery said.