Times of India , 24 March 2006

Sea levels could rise by six metres: Study

WASHINGTON: The Arctic and Antarctic ice sheets could melt more quickly than previously thought, boosting sea levels by up to six metres by 2100, according to a US study.

That would raise oceans to levels last seen nearly 130,000 years ago, because of warmer Arctic temperatures caused by greenhouse gases, scientists at the National Centre for Atmospheric Research (NCAR) and the University of Arizona said in a paper in the journal Science.

The last time temperatures were that high, sea levels rose by up to six metres, according to the study funded by the National Science Foundation, an independent federal agency created by the US Congress.

"The ice sheets have melted before and sea levels rose. The warmth needed isn't that much above present conditions," said NCAR researcher Bette Otto-Bielsner.
  In the past few years, sea levels have risen rapidly at a rate of 2.5 centimetres per decade, said co-author Jonathan Overpeck.

The scientists calculated their research with a model that simulates past, present and future climates by analysing data of previous temperature rises in the Earth's history which are recorded in ice cores and coral reefs.

Looking at data from the period between the last two Ice Ages, the researchers concluded that one factor that contributed strongly to rising sea levels was that Arctic warming and melting eventually led to a collapse of Antarctic ice sheets.

If the same happened today, this process would only be accelerated by the fact that greenhouse gases have led to higher global temperatures year-round, the scientists said.