Greenland is losing 100 Gigatons of ice a year

[n2doc]

Gravity satellites see ice loss


Much of the ice is being lost from southeast Greenland

Greenland is currently losing about 100 billion tonnes of ice a year.

US space agency (Nasa) scientists have undertaken a new assessment of the rate of melting occurring on the great ice sheet that covers the region. Their data comes from satellites that detect changes in mass by monitoring tiny fluctuations in the pull of gravity as they fly over the Earth. Scott Luthcke, from the Goddard Space Flight Center, and colleagues report their study in the journal Science. The rate of ice loss observed using the Grace (Gravity Recovery and Climate Experiment) spacecraft is much lower than other recent research using the same data has suggested. The Luthcke team says it has used a different analysis technique - one that enabled the group to determine the behaviour of individual drainage systems instead of looking at the ice sheet as a whole.

The results indicate that Greenland lost about 100 billion metric tonnes (or gigatonnes, Gt) of ice per year from 2003 to 2005. Other estimates for the same period have been close to 240 Gt of ice. Both figures, however, contrast with findings showing that the ice sheet's overall volume was roughly constant during the 1990s.

Reducing uncertainties

The Science authors also found, as others have, that the ice sheet is thinning at the margins while growing a little in the interior. This fits with climate models of a warmer world which expect increased melting at the edges of Greenland and increased snowfall on more central, higher locations. According to this study, though, Greenland is now losing 20% more mass than it receives from new snowfall each year. "This is a very large change in a very short time," said co-author Jay Zwally. "In the 1990s, the ice sheet was growing inland and shrinking significantly at the edges, which is what climate models predicted as a result of global warming. Now the processes of mass loss are clearly beginning to dominate the inland growth, and we are only in the early stages of the climate warming predicted for this century."

The contribution to global sea-level rise of the ice loss observed in this study is about 0.3mm per year.

Commenting on the Grace research, Anny Cazenave, from the Observatoire Midi-Pyrenees, France, said scientists still had much work to do, to pull all their observations together and build a full picture of ice mass trends. "Because of these contrasting behaviours - mass loss in coastal regions and mass gain in elevated central regions - ice-sheet mass loss exceeds mass gain only slightly," the Toulouse-based researcher said. "Thus according to the recent mass-balance estimates, the ice sheets presently contribute little to sea-level rise. However, great uncertainty remains, mainly because of incomplete coverage by remote-sensing surveys, spatial and temporal undersampling, measurement errors, and perturbation from unrelated signals."

link:
http://news.bbc.co.uk/2/hi/science/nature/6069506.stm

[acmavm]

1. I do not find it comforting that soon we'll be able to purchase

beach-front property on the island of Greenland.

[EST]

2. Shit-no more scotch rocks in G--land, I guess.

Soon they will have to give up the title for the most original military ordnance. The icy BM.

[nam78_two]

3. k&r :-/ /nt

[file83]

4. Can I get that figure in "Ice Skating Rinks" or something? Gigatons?

Having...a difficult... time processing... "Gigatons".

[n2doc]

6. 1 Gt of ice is roughly 10to the 14th power liters of water

One 40x20 footx5 foot deep swimming pool is about 1x10^5 liters, so we are talking about 1 billion such swimming pools a year. 1 for every family in the world.

Or, if you like, about 1x10^15th ice cubes. enough ice to give each person on earth 150,000 ice cubes a year. or 400 ice cubes every day.

[file83]

8. Hey thanks! Hmm... that's a LOT of ice.

[frogcycle]

11. here's another visual

picture yourself waiting at a grade crossing for a unit coal train - they are typically ~100 cars , about a mile long

ice weighs about 60% what coal does, so each of those 100-ton coal cars would hold about 60 tons of ice.

it would take 167,000 of those trains to haul a billion tons of ice. going past at 60 mph, end-to-end, they would take roughly 117 days to clear the crossing.

[Teaser]

5. This is quite good news.

Soon the frost giants will have nowhere left to hide. Forced out into the open, they will be sitting ducks.

[HiFructosePronSyrup]

7. Hmm, yes.

We fight Ragnarok over there so we don't have to fight it over here.

[Gregorian]

9. "and we are only in the early stages of the climate warming predicted"

I've been spouting off on these posts. Saying that we are just beginning. But it seems so much more frightening to see others saying the same thing.

And I might add that this process is going to accelerate. Due to growth of modern lifestyle populations, and due to the loss of "ground" (cold mass), and due to more liquid (which can aid conduction).


This is a crisis. And fortunately people are beginning to wake up to it. I'm still not sure how we're going to make any changes. Most of the problems we face are not due to our personal behavior. But more along the lines of commercial activity done on our behalf. Now that is my own guessing. I'm not informed enough to state that as fact. But it is very probable. Transportation, manufacturing, energy production. What I mean is it's not going to be effective to just change cars from one form to another. It's going to take a quantum change in society itself. Something like a reversal back to communal living. I mean that the answer is going to come from getting closer to nature rather than further, as we are today.

And it does translate to sacrifice. And it is related to population. I cannot believe the people I encounter who don't see that, and who are on the fighting front of trying to save the planet. They of all people should know better.

[Chulanowa]

10. Holy sheep shit

I don't know whether to look forward to being able to tell my children what a glacier looked like, or whether I should dread it.

[AlienGirl]

12. If that meltwater ends up stalling the Atlantic conveyor...

There will be plenty of glaciers, everywhere...

Tucker