Time for an ice update. There’s more bad news about the Arctic sea ice, some interesting video from Greenland, and confirmation that the Antarctic is losing significant amounts of ice. A team lead by James Maslanik of the University of Colorado at Boulder’s Center for Astrodynamics Research has tracked the age of perennial Arctic sea ice (the stuff that survives through summer), and found that since the 1980s the ice has become thinner and younger. Of the ice that survived last year’s melt back, 58% is thin and only 2 to 3 years old:
The portion of ice more than five years old within the multi-year Arctic icepack decreased from 31 percent in 1988 to 10 percent in 2007, according to the study. Ice 7 years or older, which made up 21 percent of the multi-year Arctic ice cover in 1988, made up only 5 percent in 2007, the research team reported. [Science Daily, UC release]
This sets the Arctic up for more rapid ice loss, and makes it much harder for the sea ice to recover to its historic size. Meanwhile, Andy Revkin at the New York Times describes what’s been happening in Greenland [you might have to register, but it's worth it]. The video from a camera being lowered down a moulin is amazing. That’s our world going down the gurgler (as I said at the HT launch). More from Revkin (and more video) at his Dot Earth blog supporting the article.
In our neck of the woods the news isn’t flash, either. A new study confirms that Antarctica has been losing ice over the last 10 years, and finds that the rate of loss has increased by 75% over that time [Herald]. The East Antarctic ice sheet remains more or less stable, but the West Antarctic and Antarctic Peninsula are losing significant amounts of ice mass – a total of 192 billion tonnes of ice in 2006. Perhaps the most interesting finding is that the mass loss is down to increased glacier flow:
Changes in glacier dynamics are significant and may in fact dominate the ice sheet mass budget. This conclusion is contrary to model simulations of the response of the ice sheet to future climate change, which conclude that it will grow due to increased snowfall.
The Christian Science Monitor provides a good overview of what’s going on south of us here.
Meanwhile, to quote a Prebble, I’ve been thinking, and before too long I shall blog about the implications of what’s happening in the Arctic. More questions than answers – but perhaps we can start thinking about how to get the answers we need. More soon…