NASA Data Reveals Mega-Canyon under Greenland Ice Sheet | Hacker News Reader

NASA Data Reveals Mega-Canyon under Greenland Ice Sheet

nasa.gov

63 pointsolefoo22 comments

I wonder how much this new map will effect model predictions of ice velocity and dynamic mass balance. Ice thickness measurements are important for calculating the stresses required to model ice velocity, and these are in turn relevant to predictions for the ice sheet's future because they affect how the ice might respond, for example, to increased melting at either the surface or coastal margins.

I would also be interested in seeing simple calcs of hydraulic potential with the new bed geometry. I wonder if water is still routed along this canyon?

Almost certainly. They even say so in the article. Most glacial melt flow is subsurface - disappears down a moulin and flows out under the overhanging shelf, accelerating melt. Feedbacktastic.

This is true.

Ah ha! Much more detail here: http://www.sciencemag.org/content/341/6149/997.full

Seems that in some parts of the upper canyon, the ice configuration likely leads water away, but in the lower part, it controls the direction of water flow.

It blew my mind to learn a couple weeks ago that many scientists believe that Greenland is actually three separate major islands that together hold up the icecap. http://news.google.com/newspapers?nid=860&dat=19511024&id=pW...

Says at the end that "it may play a major role in transporting melt water...into the Arctic Ocean"

Seems to me, we just need to dynamite it shut and Presto world saved from eventual catastrophic flooding.

Don't everyone thank me at once.

or just let nature do its thing

No, we must nuke it.

Somebody call Bruce Willis.

Just think, within our lifetimes we'll be able to explore this canyon by foot.

Not with current life expectancies, but I was intrigued enough by your comment to look up current best predictions:

http://www.wunderground.com/climate/greenland.asp#IceFree

Well, if we ramp up funding of life extension research, some of us might live another millennium to see it happen.

This is why I want to live forever, to see what Greenland looks like without the ice sheet.

Yay!

Millions might have perished from the global warming and it's adverse weather and sea-line effects, but we could explore Greenland, so who cares about that.

Perhaps with some deep sea diving gear. The surface of Greenland's bedrock is close to sea level in the interior and the discovered canyon appears to in the area that is below sea level.[1]

In addition, it's estimated that a complete melting of the ice sheet would increase sea levels by ~24ft[2] and that's not taking into account the larger impact of the rest of the world melting (Antarctic ice sheet is much larger).

[1] http://commons.wikimedia.org/wiki/File:Topographic_map_of_Gr...

[2] http://en.wikipedia.org/wiki/Greenland_ice_sheet

You're not accounting for rebound: http://en.wikipedia.org/wiki/Post-glacial_rebound.

True, but that would need to be some kind of rebound ;).

Even ignoring sea level rises due to ice loss elsewhere and the fact that the area we're discussing already appears well below sea level, the average ratio of bedrock rise to decrease in ice shelf thickness has been running at about 1:10 in recent years.

I have no idea whether it is accurate or not but as soon as I read this I started thinking about a vastly longer version of Sam Ford Fjord and it's incredible mountain architecture:

http://vimeo.com/33620071

I am not sure if anyone could live long enough, there are some theories that suggest that when a sufficient amount of Greenland's ice cover melts it cools the oceans enough to restart the cooling cycle.

Earth seems to have a lot of built in corrective measures, for both the issues it causes and the ones we think we cause.

That, and chaotic runaways we can't even pretend to understand yet.

I read that as "huge crayon", and for a moment thought all my long held suspicions had proven true.

I read it as both "NSA" instead of "NASA" AND "crayon" instead of "canyon".

I did too and after all the recent NSA articles I thought it was just par for the course.

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