April 15, 2008

Sea Level Rise Threatens Millions

According to the Intergovernmental Panel on Climate Change (IPCC), the average rise in global sea levels will be 28 to 43 centimeters (1 "“ 1.4 feet) by 2100. However, according to a new scientific analysis this predicted number is substantially low, and sea levels could actually rise by nearly one and a half meters (almost 5 feet) in that same time frame.

These findings were presented in Vienna at the European Geosciences Union annual meeting by a UK/Finnish team which built a computer model linking temperatures for the last two millennia to corresponding sea levels. The IPCC had been unable to include the accelerated melting polar ice rates because the process to do so was not yet understood.

The new analysis predicts that by the end of the century the sea levels will rise by anywhere from .8 meters to 1.5 meters. "For the past 2,000 years, the [global average] sea level was very stable, it only varied by about 20cm," said the Proudman Oceanographic Laboratory's Svetlana Jevrejeva. "The rapid rise in the coming years is associated with the rapid melting of ice sheets."

She told reporters that the model is able to accurately mimic sea levels observed over the last 300 years by tide gauges.

But according to Simon Holgate, also from the Proudman Oceanographic Laboratory, there is little evidence on what sea levels were for the thousands of years prior. He claimed, "There is some limited archaeological evidence [based on] the sill heights of fish enclosures that the Romans used, that's probably the strongest evidence that there hasn't been any significant change in sea level over the last 2,000 years." Scientists in the field expect to see an acceleration in the rise of sea level; regardless it is currently rising quickly at about 3 millimeters a year.

To further back up this prediction, Stefan Rahmstorf, a German Researcher used a different method but came up with a similar conclusion to Jevrejeva. He projected a rise of between .5 and 1.4 meters by 2100.

Satellite data further proves this theory of acceleration; it indicates that the West Antarctic and Greenland ice sheets are losing mass. If these ice sheets full melt, sea levels would rise by many meters, but the entire process could take centuries.

The University of Colorado's Steve Nerem fully believes that the sea levels will rise by at least a meter in the next century. He noted, "We know what's happening today from satellite data, but trying to predict what that means in the future is very difficult science." Nerem's field of research happens to be global sea levels. "We're seeing big changes in Greenland, we're seeing big changes in West Antarctica, so we're expecting this to show up in the sea level data as an increase in the rate we've been observing," he stated.

If sea levels rise even a meter, low-lying countries could be greatly affected. Holgate noted that countries such as Bangladesh, whose economies are not prepared to build sea defense systems, could be in trouble. He claimed, "Eighty to 90% of Bangladesh is within a meter or so of sea level, so if you live in the Ganges delta you're in a lot of trouble; and that's an awful lot of people."


On the Net:

Intergovernmental Panel on Climate Change

European Geosciences Union

Proudman Oceanographic Laboratory

University of Colorado