Catlin Arctic Survey – results
Professor Peter Wadhams, one of Britain’s leading oceanographers and Arctic ice experts, reveals what the findings of the Catlin Arctic Survey tell us about global warming and climate change – and why it matters for the planet as a whole.
“We’ve reached the point in global warming where the winter growth rate [of Arctic sea ice] has been reduced, the amount of multi-year ice has been reduced, and the first-year ice doesn’t reach a thickness that’s enough to withstand the summer melt.
“You can get up to two metres of melt in the summer, and the ice itself is less than two metres thick to start with.” [The average thickness of the ‘undeformed’ flat ice, measured across nearly 600km by the Catlin Arctic Survey, was only 1.72 metres, plus or minus 5cm as an error factor.]
“The measurements confirm that the area crossed by Pen Hadow [leader of the Catlin Arctic Survey] was a first-year ice region [meaning it was open water last summer] – and yet that’s an area of the central Arctic which normally and historically has been largely thicker, rugged multi-year ice.
“It shows we’re getting a big contraction of the ice cover in summer now, which never used to happen. And once it starts happening, it’ll never stop.
“The amount of open water generated is so great that it’s absorbing a lot of radiation in the summer, and it warms up by several degrees. It takes much longer to cool down in the autumn, so the next year’s cycle of ice growth is disrupted, and so it goes on.
Click to watch an animation showing variations in the age of Arctic sea-ice and summer sea-ice extent, 1979- 2007 – from research by Rigor & Wallace.
The red dots show the current location of buoys used to estimate the age of sea ice. The areas of older, thicker ice are shown in white, while younger, thinner sea ice is shown as darker shades of blue.
Prof Wadhams points out: “We’ll never go back now to the sort of summer ice conditions we used to have in the 1970s and 1980s – it’s going to stay at least as open as it is now, and most likely will go further into complete disappearance.
“The computer models predict that in about 20 years [by 2030] it will completely disappear in summer. But in less time than that it will be largely gone, with just a sort of ‘Alamo’ of multi-year ice that will last through the summer, occupying only a relatively small area of the Arctic – and this will itself gradually shrink and disappear.
“That means you’ll be able to have transport across the Arctic Ocean – you’ll be able to treat the Arctic as if it were really an open sea in the summer.
Why an ice-free Arctic is bad news...
“There are lots of problems with it, and a lot of them are unpredictable. Firstly, of course, loss of habitat for polar bears and seals, so they’ll disappear.
“The Greenland ice cap is already starting to melt, but it will melt more rapidly if it’s surrounded by open water instead of sea ice.
“There will be big changes in the marine ecology – one of them is that the Arctic Ocean will become more acidic quite quickly. As soon as you remove the ice cap covering it, you’ll get more carbon dioxide dissolving in the ocean, and the plankton will start to dissolve their shells.
“You’re also warming up the seabed on the continental shelf, and that allows the sub-sea permafrost to melt and release methane, which will increase the rate of global warming.
A global experiment?
“There will be knock-on effects in the whole of the northern hemisphere. Everything changes – evaporation from the ocean, changes in wind patterns and the wetness of the winds, and amount of snowfall in the area – because you’re replacing an ice-covered centre to the northern hemisphere with an ocean-covered centre.
“You’re essentially, for the first time, creating an ocean – which is not a thing you really want to do as a global experiment, because you can’t take the ocean away again after you’ve finished the experiment. You’re stuck with it.
“If it’s a disaster, you can’t put the lid back on again and say, ‘Oh, that didn’t work out, so let’s try something different.’ You’re stuck with what you’ve done.”
Listen to Professor Peter Wadhams
and Catlin Arctic Survey leader Pen Hadow,
in this exclusive interview for WWF,
explaining what the survey data
means for the Arctic – and beyond.