Opinion Predictions that the seas are set to rise by a metre or more this century due to the melting of the Greenland ice sheet are well off the mark, a team of scientists has announced in a new study of the matter.
"It turns out that the ice sheet, in relation to this point, behaves more dynamically and is able to more quickly stabilise itself in comparison to what many other models and computer calculations otherwise predict," explains Professor Kurt Kjaer of Copenhagen uni.
According to Kjaer and his colleagues, the scenarios which predict huge melting and massive resultant sea-level rises are flawed because they rely on a very limited amount of information spanning just a few recent years: the Greenland ice has only been intensively studied for a relatively short period of time. This has led scientists to assume that rapid melting seen lately will carry on uninterrupted, pouring gigatonnes of water into the world's oceans and inundating coastal areas around the planet.
But this is mistaken: it now emerges that periods of rapid melting like the one just seen have happened in the past - but then, rather than continuing, the apparently runaway melting simply stopped.
"We’ve used a combination of old aerial photographs from the '80s and recent satellite data. In this way we’ve been able to gain an overview of the thinning of the ice sheet over the last 30 years in northwestern Greenland," says Shfaqat Abbas Khan of the Technical University of Denmark (DTU), who worked on the study alongside Kjaer.
"We are the first who have been able to show that the Greenland Ice Sheet was on as dramatic a diet at the end of the '80s as it is today. On the positive side our results show that - despite a significant thinning in peripheral regions from 1985-1992 - the thinning slowed and then died out."
Kjaer for his part predicts that the ongoing rapid melting at the moment will cease within a decade, leading to a stable period like the one his team has identified from the early '90s until 2003.
"It is certain that many of the present calculations and computer models of ice sheet conditions that built upon a short range of years since 2000 must be reassessed," states the prof, uncompromisingly. "It is too early to proclaim the 'ice sheet’s future doom' and subsequent contribution to serious water problems for the world."
The new study has been deemed important enough to make today's edition of premier boffinry mag Science, where it can now be read by subscribers.
A related study examining old aerial photos of the Greenland ice was published in June, revealing that in the 1930s the glaciers there were retreating even faster than they are today: but again, the process subsequently stopped on its own. ®