Arctic ice twice the area of the UK melted last week

[BobLibDem]

Looks like bad news for polar bears. Yet still the corporations find scientists willing to sell their integrity and pay them to manufacture doubt where there should be none.

[BrainGlutton]

@Shamozzle

Wait a minute here: “Experts say they are “stunned” by the loss of ice, with an area almost twice as big as the UK disappearing in the last week alone.” Is that for real? Is that accurate? Cause that sounds like a WHOLE BUNCH of ice, REAL fast… I know we are losing ice fast, but that fast??

Well, keep in mind, they’re talking about an annual summer melt; and then ice forms again in the winter. But it appears a lot more is melting this year than in previous years, and less of it might re-freeze.

[XT]

@Bricker

While I appreciate panic as much as the next guy, I must ask, with respect to this business of “twice the size of the UK:” how much ice melted in an equivalent time period 20 years ago? Fifty years ago? And what’s the delta betwen those figures and now?

I don’t know how reliable this site is, but according to the National Snow and Ice Data Center :

For the fourth consecutive year, NSIDC and NASA scientists using satellite data have tracked a stunning reduction in arctic sea ice at the end of the northern summer. The persistence of near-record low extents leads the group to conclude that Arctic sea ice is likely on an accelerating, long-term decline.

“Considering the record low amounts of sea ice this year leading up to the month of September, 2005 will almost certainly surpass 2002 as the lowest amount of ice cover in more than a century,” said Julienne Stroeve of NSIDC. If current rates of decline in sea ice continue, the summertime Arctic could be completely ice-free well before the end of this century. (Figure 1: September extent trend, 1978-2005).

Arctic sea ice extent, or the area of ocean that is covered by at least 15 percent ice, typically reaches its minimum in September, at the end of the summer melt season. On September 21, 2005, the five-day running mean sea ice extent dropped to 5.32 million square kilometers (2.05 million square miles), the lowest extent ever observed during the satellite record (Figures 2 and 3: Five-day running mean).

I can’t reproduce it here, but this is a pretty good visual of how the sea ice has changed since 1978. I don’t pretend to know if that is a long enough trend to be meaningful (its apparently how long we’ve had satellite imagery of the area), but you can see where the sea ice was in 1978 compared to where it is as of 2005…and according to other things I’ve seen its retreated even more this year. Whats interesting to me is how the areas effected have seemed to shift. If you look at the 2004 graphic and compare it to 2005 there are large areas that were ice free in 2004 that are covered now…and vice versa. I have no idea why that would be (again, I don’t even pretend to play a climatologist on TV, let alone actually understand this stuff)…but it is interesting in light of the OP’s cited article.

The long term trend seems to be pretty clear though (even taking out the sensationalist stuff from the OP)…the sea ice is gradually melting over all, even if it tends to melt more or less in a given place. This figure shows the general trend downward, and claims that there is more than an 8% decline per decade.

-XT

[BrainGlutton]

Also from The Guardian: The melting is triggering earthquakes in Greenland.

[DrDeth]

@DrDeth

At the current much faster rate of sea level rise, how long do you think before the sea level rises 1 meter? :dubious:

You haven’t answered my question, BrainGlutton.

[BrainGlutton]

The IPCC’s third assessment report in 2001 predicted a sea level rise of 9 to 88 centimeters by 2100. But a lot of news we’ve seen since then, this story included (and see also here) indicates the process is happening a lot faster than previously expected.

(One thing I have seen nowhere is an estimate of the maximum possible rise – i.e., where sea level would be if all the icecaps melted completely and the world ocean’s average temperature were the highest it has been since the Paleozoic.)

[XT]

So…to nail you down here BG, you think a meter rise is possible or probable within the century?

-XT

[An_Gadai]

Hopefully nuclear winter will cancel out global warming.

[BrainGlutton]

@xtisme

So…to nail you down here BG, you think a meter rise is possible or probable within the century?

-XT

I think it’s definitely possible. Too many unknown variables to say more. At any rate, I won’t be buying any beachfront property. (What’s the job market like in Denver?)

[Sunspace]

@BrainGlutton

(One thing I have seen nowhere is an estimate of the maximum possible rise – i.e., where sea level would be if all the icecaps melted completely and the world ocean’s average temperature were the highest it has been since the Paleozoic.)

I have read that a maximum melt–Greenland, Antarctica, everything–would yield a 100-metre rise in sea level. But I don’t know where I read that.

Edit: here’s a USGS site that quotes data from another study as yielding a maximum 80-metre rise. Hmm. My apartment would be on the beach rather than underwater, then.

[jshore]

@Sunspace

I have read that a maximum melt–Greenland, Antarctica, everything–would yield a 100-metre rise in sea level. But I don’t know where I read that.

Edit: here’s a USGS site that quotes data from another study as yielding a maximum 80-metre rise. Hmm. My apartment would be on the beach rather than underwater, then.

That sounds about right. Greenland alone would yield something like a 7-m rise and it is actually a realistic scenario that it could completely melt especially if the mid- to high-range scenarios for temperature rise predicted by 2100 play out. The thinking originally is that it would take millenia to actually do so although now there are indications that the process might be able to happen more quickly because ice sheet disintegration seems to be a highly nonlinear process in which a lot of it can occur by ice sliding and disintegrating rather than melting.

I am not sure how much of Antarctica could realistically melt. I believe the amount that some think might be reasonable gives a number pretty similar to the rise from Greenland’s melting.