Samantha Davison 11 columns
THE FREEZER DEFROSTS Dramatic melting of sea ice due to global warming is having a major impact on the polar region.
Arctic sea ice is set to reach its lowest ever recorded extent as early as this weekend, in “dramatic changes” signalling that manmade global warming is having a major impact on the polar region. Because ice thickness, volume, extent and area are all measured differently, it may be a week before there is unanimous agreement among the world’s cryologists (ice experts) that 2012 is a record year. Four out of the nine daily sea ice extent and area graphs kept by scientists in the US, Europe and Asia suggest that records have already been broken. “The whole energy balance of the Arctic is changing. There’s more heat up there. There’s been a change of climate and we are losing more seasonal ice. The rate of ice loss is faster than the models can capture [but] we can expect the Arctic to be ice-free in summer by 2050,” said Stroeve. “Only 15 years ago I didn’t expect to see such dramatic changes – no one did. The ice-free season is far longer now. Twenty years ago it was about a month. Now it’s three months. Temperatures last week in the Arctic were 14C, which is pretty warm.”
“The ice volume for 31 July 2012 was roughly 10% below the value for the same day in 2011”
Scientists at the Danish Meteorological Institute, the Arctic Regional Ocean Observing System in Norway and others in Japan have said the ice is very close to its minimum recorded in 2007. The University of Bremen, whose data does not take into account ice along a 30km coastal zone, says it sees ice extent below the all-time record low of 4.33m sq km recorded in September 2007. Ice volume in the Arctic has declined dramatically over the past decade. The 2011 minimum was more than 50% below that of 2005. According to the Polar Science Centre at the University of Washington it now stands at around 5,770 cubic kilometres, compared with 12,433 cu km during the 2000s and 6,494 cu km in 2011. The ice volume for 31 July 2012 was roughly 10% below the value for the same day in 2011. A new study by UK scientists suggests that 900 cu km of summer sea ice has disappeared from the Arctic Ocean over the past year. The consequences of losing the Arctic’s ice coverage for the summer months are expected to be immense. If the white sea ice no longer reflects sunlight back into space, the region can be expected to heat up even more than at present. This could lead to an increase in ocean temperatures with unknown effects on weather systems in northern latitudes. In a statement, a Greenpeace spokesman said: “The disappearing Arctic still serves as a stark warning to us all. Data shows us that the frozen north is teetering on the brink. The level of ice ‘has remained far below average’ and appears to be getting thinner, leaving it
more vulnerable to future melting. The consequences of further rapid ice loss at the top of the world are of profound importance to the whole planet. This is not a warning we can afford to ignore.” Longer ice-free summers are expected to open up the Arctic ocean to oil and mining as well as to more trade. This year at least 20 vessels are expected to travel north of Russia between northern Europe and the Bering straits. Last week a Chinese icebreaker made the first voyage in the opposite direction. Every one of the 56,000 Inuits in Greenland have had to adapt to the retreat of the ice,” said CarlChristian Olsen, president of the Inuit Circumpolar Council in Nuuk, Greenland. “The permafrost is melting and this is jeopardising roads and buildings.