Slashdot Mirror
Huge Freshwater Bulge In Arctic Ocean
New submitter turkeyfish writes "UK scientists are reporting today in the journal Nature Geoscience that a huge bulge of freshwater is forming in the Western Arctic Ocean caused by a large gyre of freshwater. The gyre appears to indicate that the ice is becoming thin enough over the Arctic Ocean that the wind is beginning to affect the motion of water under the ice. A sudden release of this water or its emergence to the surface will greatly accelerate the melting of the remaining polar oceanic ice and likely alter oceanic circulation in the North Atlantic."
Melting sea ice won't lead to a significant increase in ocean levels, it's the land ice you have to worry about.
Read more about the thermo-haline cycle on Wikipedia - http://en.wikipedia.org/wiki/Thermohaline_circulation.
http://en.wikipedia.org/wiki/Jabberwocky
http://science.howstuffworks.com/environmental/earth/geophysics/question473.htm
The main ice covered landmass is Antarctica at the South Pole, with about 90 percent of the world's ice (and 70 percent of its fresh water). Antarctica is covered with ice an average of 2,133 meters (7,000 feet) thick. If all of the Antarctic ice melted, sea levels around the world would rise about 61 meters (200 feet). But the average temperature in Antarctica is -37ÂC, so the ice there is in no danger of melting. In fact in most parts of the continent it never gets above freezing.
At the other end of the world, the North Pole, the ice is not nearly as thick as at the South Pole. The ice floats on the Arctic Ocean. If it melted sea levels would not be affecteÂd.
There is a significant amount of ice covering Greenland, which would add another 7 meters (20 feet) to the oceans if it melted. Because Greenland is closer to the equator than Antarctica, the temperatures there are higher, so the ice is more likely to melt.
The numbers here are likely to be more accurate:
http://www.ipcc.ch/publications_and_data/ar4/wg2/en/spmsspm-c-15-magnitudes-of.html
The complete melting of the Greenland ice sheet and the West Antarctic ice sheet would lead to a contribution to sea-level rise of up to 7 m and about 5 m, respectively [Working Group I Fourth Assessment 6.4, 10.7; Working Group II Fourth Assessment 19.3].
Yet another source: http://nsidc.org/cryosphere/sotc/sea_level.html
Antarctica and Greenland, the world's largest ice sheets, make up the vast majority of the Earth's ice. If these ice sheets melted entirely, sea level would rise by more than 70 meters.
Your move. Let's see what asshole you pulled this "not more than a foot" number from.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
The fact that there was someone there to look at the formation of the plume means that it is not entirely unexpected, as in "someone got their project funded, and thus made a reasonable case for it".
Of course this would be found/discussed in fairly technical papers. If you trust journalists to do science reporting right, I have a bridge on the Moon to sell.
http://www.sciencedirect.com/science/article/pii/0924796395000062 for example dates from 16 years ago.
http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2001.530504.x/abstract is from 11
years ago and directly related. Hint: sciencedirect or google scholar are a better way to get scientific information/papers than plain google.
Predictions are rarely that specific. They're not going to tell you that's there's a fresh water "plume" as TFA so indicates. What predictions do is give you trends, and the effect of these trends on the overall system. The predicted effects are also not specific, but instead the prediction of more trends.
Reality is a little different. There's a lot of noise in the system. The variances of what happens and is expected to happen can be extreme. But the average--the predicted trend--will remain barring unaccounted for variables that may make things much worse or much better. This plume may be a part of the trend. Or it may be one such deviation from the system. Or it could be an unaccounted for variable that's about to accelerate the glacial melt timeline significantly.
Only time will tell whether the initial predictions still hold after this. And if the data doesn't support it, it will be revised. But I can't imagine that 20+ years worth of data supporting the predicted trend will be outright reversed by one event. To even fancy such a notion so would be wishful thinking indeed. More likely, things will either get a little better, or a little worse.
Of course, there actually is a point of no return that we are quickly approaching, and even if things go better than expected for us and the predictions are on the high side, we'll still end up there if we don't change our lifestyles. There's a huge amount of methane stored in the Siberian tundra. Methane is a much worse greenhouse gas than CO2. It's a missile compared to the bullet that the trapped CO2 in glacial ice would be. As the tundra begins to defrost, methane gets released into the atmosphere. When the climate reaches the point where the permafrost is no longer permanent, no amount of CO2 emissions cuts will be able to prevent the sudden release of greenhouse gas into the environment. And at that point, everyone might as well start staking their turf on high ground.
"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
If all of the ice on Greenland and Antarctica (and other lesser ice caps) were to melt it would cause a bit over 200 feet (~65 meters) of sea level rise. However, it would take thousands of years for all of that ice to melt The ice on Antarctica averages ~7,000 feet in depth and it's up to ~12,000 feet in places so it won't melt that fast at any temperature that still supports humans living on the Earth. Current estimates for sea level rise by 2100 are in the 3-6 foot range. 20 feet above the current level isn't inconceivable in 2200.
Regarding what it would take to melt all of it, a paper out recently said that the big ice sheets started to form when CO2 levels dropped below 700 ppmv maybe 30 million years ago. We are currently at ~390 ppmv, up from 280 ppmv in 1830 and ~320 in 1960. At the current rate we would hit 700 ppmv in less than 200 years.
(Undoing moderation to post this)
IPCC 3 WGI Chap 11 Table 11.3 estimates a 61m sea-level rise if all of Antarctica melts, and 7m from Greenland. This could take 1500 years, though other factors like lubrication might speed this.
It's also worth noting that sea levels have already risen 120m since the last glacial maximum.
Why would anyone engrave "Elbereth"?