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."

Comments

Technolog

[Nerdfest]

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.

Re:Technolog

[Nerdfest]

We generally don't even need nature. We seem to do a fine job on our own.

Re:Technolog

[Trepidity]

We're not very good at looking through solid substances yet. Not only don't we know what's under the Greenland ice, we don't even know what's under many of our cities. For example, construction of the Thessaloniki metro recently discovered an entire Roman city center buried beneath the modern-day city center. In limited cases you can find some of this kind of stuff with ground-penetrating radar, but in general mapping out stuff that's covered by solid dirt/ice/etc. is not easy, even in the 21st century.

Re:Technolog

[mevets]

Google Subterrain was voted out by focus groups. The troglodyte minority was trounced by those smug hipsters with their Earth and Streetview apps.

Re:Technolog

[icebike]

Funny thing is, we have Ice Core Samples from all over Greenland, in Multiple Different Databases and they have all missed (or misinterpreted) this data for decades. Some of these were 2000 meters deep. In addition there were dye experiments in some areas.

So it is sort of a surprise that we had no hint of this.

Re:Technolog

[bledri]

Just another example of Man thinking he has everything figured out only to be made a fool of by nature.

Who claims to know everything? Certainly no scientist does. If they knew everything they wouldn't have anything to figure out and figuring out "how life, the universe and everything" work is the what science is about.

Re:Technolog

[Anonymous Coward]

Yeah...Good thing they weren't using them to publish information that's at the core of some public policy or something.

Re:Technolog

[riverat1]

I'm not surprised. It's science, you keep looking and you keep finding new and interesting things. It's not possible to know everything instantly and Greenland is a remote and expensive place to study.

This water is in the firn which occurs down to a depth of around 50 meters before the weight of snow above compresses it to glacial ice which can't hold water like firn. The top of the water table is generally less than 25 meters under the surface (see Figure 2) and can't be deeper than about 50. These aquifers were found in the far south of Greenland near the coast, one of the warmer areas of Greenland. It's unknown as yet if they exist elsewhere but now they know to look for them. I imagine the further north you get the more difficult it would be for them to form.

So you wouldn't likely see this except possibly at the very top of a 2,000 meter+ ice core. Most of those ice cores are drilled from far higher elevations and further north where it doesn't melt much even in summer so there is little water to begin with and in any case the colder temperatures probably cause water that forms to refreeze near the surface. In order for this water/firn mixture to coexist the temperature has to be just right and it wouldn't take much to tip the balance one way or another. If it tipped to warmer I imagine it could lead to rapid collapse of the snow field but we'll just have to wait and see what happens.

Re:Technolog

[Immerman]

No, they believe they know *something*: That the planet *is* warming at an alarming rate, and that human produced CO2 is the forcing factor. Basically all the data collected to date corroborates this, and so that much is considered settled. The exact *implications* of those facts is still very much up in the air. We know the ice caps will melt, that's firmly within the error bars on the model. The exact speed at which it happens, the implications thereof, and the various confounding factors that may arise along the way, *that* is all still very much under examination.

Consider an example - we have a pretty good model of gravity - so if I throw a baseball with a given speed and direction we can model the exact parabolic path it would follow in a vacuum, and that will give us a pretty good idea of where it will land. For a better model we'll have to factor in air resistance and wind velocity, which will give us a much more accurate guess, but still not be perfectly accurate. Then we'd need to factor in any spin on the ball. We could find the exact local gravity (which fluctuates by almost 1% over the Earth's surface) and get even more accurate. If we had a sufficiently detailed weather model (or a large sealed room) we could factor in the fluctuations in air velocity over the course of the balls path. We could even model the exact surface features of the ball and how they influence it's movement as the air drags across it. It *still* wouldn't be completely accurate, but would probably be accurate to within some fraction of an inch. Provided I don't hit a passing bird and totally disrupt the prediction (a totally unexpected major confounding factor) For most purposes though that initial "ball in a vacuum" estimate, with sufficient error bars, is perfectly servicable.

With climate science we're still kind at the level of trying to take the ball's spin into account. There are lots of variables still not understood, and there may even be some giant major confounding factors that end up giving us a "get out of jail free" card. (Aliens swoop in to save us? Rush Limbaugh's head implodes and sucks all the excess hot air out of the world?) The core of the matter though is that, to the limits of our current understanding we are actively creating a situation that is going to have a really drastic impact on our planet's ability to continue supporting us, and the sooner we start facing the problem the cheaper and less severe it will be to make sure we can still support at least a couple billion people by the end of the century. We could have started changing our behaviors 50 years ago to almost completely avoid it, but back then all we had was a crude theory easily dismissed by vested interests. Now we're starting to see the first obvious (to the layman) undeniable signs that the theory was correct, and have fleshed it out to be ever more accurate. Yet people still want to deny that our actions are causing a problem.

Look at it this way - if I were to propose that we restructure our society because in the next fifty years some major confounding factor will be discovered in our theory of gravity that will allow for cheap and simple levitation, you would think I was nuts. Yet when people say we should continue on with business as usual because surely some unexpected confounding factor in climate science will make everything okay, somehow that's okay?

whoosh

[ihtoit]

...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.

Re:whoosh

[Anonymous Coward]

The melting point of water is reduced by 0.007 K per atmosphere of pressure. The effect is of only minor significance, because it is so small. People almost always overestimate it.

If you put water in a real container (as opposed to something indestructible) and put it in the freezer, it will not stay liquid. Instead, it will happily freeze. In doing so it will expand the container, possibly bursting it. To keep the water liquid at just -7 C, you need a container that can withstand 1000 atmospheres, which probably requires a steel pressure vessel. According to the site you linked, there is no pressure sufficient to keep water liquid below -22 degrees.

The pressure under the ice in Greenland is probably about 300 atm at the most (based on the weight of 3 km of ice), so the freezing point is only about 2.1 degrees lower at the bottom than at the top. If there really is pure liquid water at the bottom, that can't be explained purely by regelation. It also has to be quite warm (-2.1 C) at the bottom.

Re:Right

[ihtoit]

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.

Re:Water to be the new Oil?

[riverat1]

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.