Melting at both ends

Arctic sea ice is melting. The Greenland ice sheet is losing mass, and the Antarctic Peninsula is one of the fastest warming parts of the planet. But the main part of Antarctica has often been assumed to be pretty safe from extensive surface melting. It’s very cold, and very high. NASA now reports that in January 2005, large parts of the surface of West Antarctica experienced a week long melt, the first time this has been seen.

“The observed melting occurred in multiple distinct regions, including far inland, at high latitudes and at high elevations, where melt had been considered unlikely. Evidence of melting was found up to 900 kilometers (560 miles) inland from the open ocean, farther than 85 degrees south (about 500 kilometers, or 310 miles, from the South Pole) and higher than 2,000 meters (6,600 feet) above sea level. Maximum air temperatures at the time of the melting were unusually high, reaching more than five degrees Celsius (41 degrees Fahrenheit) in one of the affected areas. They remained above melting for approximately a week.”

The picture accompanying the NASA story clearly shows large melt areas – the size of California (how many Belgiums is that?) – over the West Antarctic ice sheet. There hasn’t been a repeat of the event in the last two years, and the period studied only began in 1999, so it’s not clear how unusual the melt was, or if there is any trend. Given the concerns about the stability of the West Antarctic ice sheet in a warming world, this news will add urgency to this year’s International Polar Year effort (which is getting a bit of help from the International Space Station).

11 thoughts on “Melting at both ends”

  1. Wasn’t there some talk about oil companies eyeing up the Antarctic for possible drilling? It would be interesting to see just what parts of the continent have been exposed.

  2. Found some more info on that. The Madrid Protocol to the Antarctic placed a moratorium on oil exploration until 2041, when it comes under review. There was a lot of talk about opening up Antarctica during the 70s oil crisis, but nothing came of it. And this page
    seems to conclude that the economics aren’t worth it. (At a cost of $200/barrel, this puts it far higher than the current price.)

    Still, you never know.

  3. This was a surface melt on a large ice sheet, so I don’t think it will have done much to make oil exploration easier… The main worry is that – as is happening in Greenland – surface melt water might find its way to the base of the ice and act as a lubricant, helping it to flow towards the sea. The West Antarctic ice sheet is worth somewhere between 5 and 7 m of sea level rise, so signs of increased melting are cause for concern.

    But I’ll ask a petroleum geologist friend where he might want to drill… 😉

  4. It would depend on how the water behaved on the ice surface. If they can find areas where it pools and refreezes in neat layers, then a core might show earlier events. But I’m no ice man, and as the NASA piece says, water tends to flow down through cracks in the ice…

  5. (Evidence of melting was found up to 900 kilometers (560 miles) inland from the open ocean, farther than 85 degrees south (about 500 kilometers, or 310 miles, from the South Pole)

    Um the biggest solar event in 50 years look at the neutron stations!

  6. I was in the affected area at that time. There was some surface icing that played havoc with our logistics, and at the end of the season we had to remove our tents from the snow with crowbars (although that was probably just person heat).
    As I recall some collaborators did a shallow core, and found a succession of ice layers in the top ten meters of firn, so I dont think this was unpresidented.
    The weather was unexpectedly good.

  7. I was participating in the first major airborne survey of Thwaites Glacier, which is the most likely part of the West Antarctic Sheet to go, due to the geometry of the bed. The Amundsen Sea region, which Thwaites feeds into is the part of the main ice sheet that appears to be changing most rapidly; however, atribution of the change to greenhouse gases at this stage is indirect (you would need a hell of a lot of surface water, so air warming is not a factor yet; ocean warming could do it, but the only water mass that could do it hasn’t seen the surface for decades. One possibility is that changes in circumpolar winds, forced by either CFCs or other GHGs, could be dragging this deep warmer water into contact with the ice sheet. However, due to its remoteness, this area is very poorly understood.

    Our collaborator’s core was a very minor part of a major survey, so I dont know if is was done very rigorously. More shallow cores will be occuring in this area over the next couple of years.

    A group of us recently put out a statement here on issues concerning this area.

    Sorry about the Google proofing. [Fixed – G]

  8. Interesting. There’s certainly an intensification of the circumpolar winds – it was cited as factor in the recent paper on CO2 saturation in the southern ocean (Le Quéré et al, blogged here). Thanks for the link to the statement: it preceded the launch of HT…

    And, from my exploration geologist friend:

    There’s an international ban on exploration there. One good reason is that the prospects aren’t too hot – not that much onshore Oz, India, S Africa, so not surprising. Better to leave at least one wilderness on this ravaged planet!

    Nice to know there’s at least one with a bit of heart…

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