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Huge Pool of Ice-Free Water Discovered Under Greenland Ice
The BBC reports that researchers have discovered a huge pool of meltwater beneath Greenland's ice sheet, trapped "in the air space between particles of ice, similar to the way that fruit juice stays liquid in a slush drink."
From the article, based on research published in Nature Geoscience (abstract): "The scientists say the water is prevented from freezing by the large amounts of snow that fall on the surface of the ice sheet late in the summer. This insulates the water from the air temperatures which are below freezing, allowing the water to persist as liquid all year long. Other researchers believe this discovery may help explain disparities between projections of mass loss by climate models and observations from satellites."
Given our current level of technology, I'm always amazed when we discover large scale things like this. We have out cities mapped and photographed down to the meter, but we keep finding things like this.
...said the physics teacher.
Under pressure, the freezing point of water is lowered. The more pressure, the lower the ice point. To demonstrate:
Assume that a container is indestructible (let's say, a sphere with a perfect seal). It is full of water with no gas in solution or loose in bubbles or anything like that. Just pure water. Now, stick it in a deep freeze. Wait.
Water has the odd property of expanding at around 4C at normal (sea level) pressure. By the time it freezes at 0C under those same pressure conditions, it has expanded to fill 1/8 more volume than it did as a liquid. This is why icebergs float. This is why distilled water ice cubes also float. The liquid water does its thing and... you know the rest. Titanic.
The water in the sphere is prevented from freezing for the simple reason that it has nowhere to go. It has no space to expand into. If it cannot expand, it cannot freeze. How low can you go? I have no idea, having no access to magnetocaloric equipment. But I daresay, you wouldn't meet the conditions required to get the volume of water to contract to the point where it can solidify in the available space, outside of a suitably equipped laboratory or in the shadow of an outer planet.
Further reading suggests temperatures approaching/lower than about 70K (-203C) to achieve this. Further reading.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Isn't that a result of the salinity keeping it from freezing?
Anyways, we have seen supercooling effects like this in the past where the pressure involved allows water to remain below it's freezing point. It's the theory behind an ice dam in the Midwest US that caused a lot of the geographical markings when it burst. I don't really see anything extraordinary here as apposed to theories in history. It's just that is is happening right now in front of us. Water does have that quality, under pressure, it raises the boiling point and can lower the point which it will actually freeze.
it's not true that subsurface water in the Arctic ocean isn't freezing: it is, continually. What salinity does is disrupt the phase equilibrium between liquid and solid so the water phases between solid and liquid at a faster rate than the liquid phasing to solid, ergo the mass remains a liquid. That's only considering salinity. Absent pressure at depth, the entire ocean would be a block of ice right now, but see my other post in this thread (here) as to the other reason the Arctic ocean is liquid.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
So there was a discrepancy between prediction and observation for the AGW model. Why haven't we heard about that before? Only now that the observations are consistent with theory do we find out about it. Yet more evidence that climate scientists are not real scientists.
What makes you think that scientists have hidden this discrepancy? They haven't, and every anti-AGW promoter has been shouting it from the rooftops (while they ignore or misrepresent all the evidence that supports AGW.)
Some privacy policy Slashdot.
There's lots of fresh water on the planet (including all the fresh water stored as ice). The problem is getting to a place where it's useful. Most places have to make do with the fresh water that's available locally. A notable exception being Southern California which imports water from the north and from the Colorado River. I doubt you'll find knowledgeable people saying fresh water would be completely gone (except perhaps for some overtaxed aquifers). Instead they are saying there will be more demand for fresh water than there is supply available to fill that demand in the future. Getting fresh water from Greenland to any place useful would be difficult and expensive.
And yet despite the fact that the global cooling story made the covers of Time and Newsweek in the mid-70's, between 1965 and 1979 there were 6 times as many papers published on global warming from CO2 increases than global cooling in the scientific literature. I was born in 1952 and I don't remember being very alarmed by global cooling in the 1970's.
There is only one thing to do.
Pump it out, bottle it, and sell it.
Then use the resulting cavern to hold raw sewage. Maybe with a little radioactive waste thrown in for good measure.
Sleep your way to a whiter smile...date a dentist!