Sea ice along the Greenland coast. New research suggests Arctic sea ice could all but disappear in summer by 2040.
Credit: iStockphoto
WASHINGTON: The worrying shrinkage of the Arctic ice pack could leave the northerly ocean virtually devoid of ice in summer by 2040, according to an international study.
The research, which appeared on Tuesday in the U.S. journal Geophysical Research Letters, mainly pointed at greenhouse-gas emissions as the culprit.
It warned that if carbon pollution continues to increase at present rates, the Arctic's normal cycle of freezing and thawing faces catastrophic disruption.
A simulation run by scientists at the National Centre for Atmospheric Research (NCAR) and Canada's McGill University predicted that the area covered by ice in September - before new ice begins to form each winter - could shrink from about 5.9 million square kilometres to 1.9 million square kilometres within a decade.
By 2040, "only a small amount of perennial sea ice" would remain along the north coasts of Greenland and Canada in summer, said NCAR in a statement.
In winter, ice thickness would be reduced from about 3.5 metres to less than a metre.
"We have already witnessed major losses in sea ice, but our research suggests that the decrease over the next few decades could be far more dramatic than anything that has happened so far," said NCAR scientist and lead author of the study, Marika Holland.
Greenhouse gases trap the Sun's heat, gradually forcing up Earth's surface temperature. But several peripheral factors could be contributing to the accelarating ice melt.
Open water absorbs more sunlight than ice, so as more open water becomes uncovered, the remaining ice will melt more quickly. This will itself accelerate the rate of warming and lead to more ice loss. In addition, global climate change is likely to drive warmer ocean currents into the Arctic region.
"This is a positive feedback loop with dramatic implications for the entire Arctic region," Holland said.
The shrinkage of the Arctic ice cap is viewed with alarm by scientists, as it appears to perturb important ocean currents elsewhere, notably the Gulf Stream, which gives western Europe its balmy climate.
It also threatens animals such as polar bears and seals that depend on ice - as well as Inuits and other native peoples who hunt these animals.
There are geopolitical implications, too, as Canada, Russia and the United States jockey to claim rights over transpolar passages that open up within their newly ice-free waters.
In September, European scientists unveiled satellite images from late August showing that perennial sea ice - thick ice normally present year-round and not affected by the Arctic summer - had disappeared over an area bigger than the British Isles.
The study concludes that reduced rates of greenhouse gas emissions could slow the ice loss. "Our research indicates that society can still minimise the impacts on Artic ice," Holland said.
