- Worst case scenario of 19-inch sea level rise not coming true
- Loss of ice 30% faster than a decade ago
- Contribution to sea level rise will be four inches by 2100
By Rob Waugh
PUBLISHED: 01:44 EST, 4 May 2012 | UPDATED: 04:47 EST, 4 May 2012
Greenland’s glaciers are losing ice – but not at the breakneck pace that scientists once feared, a new study says.
The loss of ice from the glaciers that cover the island is still about 30% faster than it was a decade ago, researchers said.
That means Greenland’s contribution to future sea level rise would be about four inches by the year 2100 if ice loss does not speed up much more, a study author said.
That may not sound like much, but when other causes of sea rise around the globe are added, the total could still be about three feet by the end of the century, researchers said.
‘’Glacial pace’ is not slow anymore,’ said study author Twila Moon, a glacier researcher at the University of Washington.
At the same time, ‘some of the worst-case possibilities that we had imagined are not coming true at this point,’ Moon said. ‘So it’s not good news, but it’s not bad news.’
The scientists relied on a comprehensive satellite-based survey of about 200 glaciers to make their calculations. Their research was published today in the journal Science.
Compared to some past research the findings are somewhat reassuring. A 2008 study had suggested a worst-case scenario that indicated Greenland’s glaciers might contribute up to 19 inches of sea rise by the end of the century.
The glaciers have been melting under warmer summer temperatures in Greenland that on average are up by about two degrees Fahrenheit (one degree Celsius) over the last decade, study authors said.
One famous glacier on northwestern Greenland called Jakobshavn is now losing ice at a particularly fast pace of seven miles (11.3 kms) per year. That means an ice loss of nearly three feet (one metre) of ice every hour. If you stare at the glacier for about 20 minutes you can notice it move, said University of California Irvine glacier expert Eric Rignot.
Even so, that pace does not match the predictions laid out in the worst-case laid out in the 2008 study, research that caused alarm about the effects of increasing greenhouse gas emissions that warm the earth.
‘We’re not seeing kind of runaway effects,’ said study co-author, Ian Joughin.
Rignot said it is unfair to compare this recent study to the more alarming 2008 one, which he said was not designed to be overly realistic. However, he noted that the findings of this new study still exceed computer models and projections by the Nobel Prize-winning Intergovernmental Panel on Climate Change.
NASA Chief Scientist Waleed Abdalati, an ice scientist, called the new work a ‘valuable study that advances our understanding of a very complex wild card of sea level rise’.