Greenland's ice cap is melting at a frighteningly fast rate

[Richard Tafoya]

SF Chronicle:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/08/11/MELTING.TMP&type=science

The vast ice cap that covers Greenland nearly three miles thick is melting faster than ever before on record, and the pace is speeding year by year, according to global climate watchers gathering data from twin satellites that probe the effects of warming on the huge northern island.

The consequence is already evident in a small but ominous
rise in sea levels around the world, a pace that is also accelerating, the scientists say.


According to the scientists' data, Greenland's ice is melting at a rate three times faster than it was only five years ago. The estimate of the melting trend that has been observed for nearly a decade comes from a University of Texas team monitoring a satellite mission that measures changes in the Earth's gravity over the entire Greenland ice cap as the ice melts and the water flows down into the Arctic ocean.

...

According to the researchers, surface melting of Greenland's ice cap reached 57 cubic miles a year between April of 2002 and November of 2005, compared to about 19 cubic miles a year between 1997 and 2003.


"The sobering thing is to see that the whole process of glacial melting is stepping up much more rapidly than before," said Tapley in a statement.

If the Greenland ice cap ever melted completely -- a highly unlikely event, at least in the foreseeable future -- the scientists estimate it would raise world's sea level by an average of 6.5 meters, or about 21 feet, more than enough to drown all the world's low-lying islands and even some entire nations, like Holland.

The possibility of future sea level rises becomes even more evident when Antarctica's huge ice sheets are considered.

[DoubleEdgeSword]

From what I'm reading, scientists are most concerned about what is called a "feedback loop," a situation in which one event, the ice melting, triggers other events such as exposure of more land which retains more heat and thus speeds more ice melting.

[Java]

Actually there are multiple elements to the feedback loop - more exposeds ocean surfaces at the north pole during the summer months gives the area less reflectivity and therefore more heat absorbtion, thawing tundra lands will emit increaing amounts of methane gas (much worse than CO2) into the atmosphere, rising sea levels getting under antarctic ice and causing it to float up and break off, plus the fact as there is less ice left to absorb BTUs, these BTUs become ever so much more efficient at melting what ice is left until...

...and lets not forget what happens to all those offshore Methane Hydrate deposits once the ocean temperatures become higher - this in itself can be very frightful.

...and adding to this, as more water makes its way towards the equator from the poles, its got to be sped up to match the earth's rotation rate as it approaches the equator. Where does it get the energy to do this? -- It borrows it from the angular momentum of the earth's rotation, and thus slows the earth's rotation rate. This in turn changes the shape of the earth making it less oblate and giving its circumference around the equator less distance to pack in all its existing crust... which leads to more and greater earthquakes to absorb this lost space. I could go on and on... (the unusually high rate of leap seconds over the past few decades can infer a lot of info, etc)

Food for thought: How many BTUs does it take to turn 57 cubic miles of 32 degree ice into 32 degree water? ...and what will these same BTUs do if there was less or (God forbid) no ice left? (and this is just Greenland, mind you) -- Scarey thought if you know anything about BTUs!

Note: I've been feeling like a broken record about this for how many years now? ...and the media is now beginning to publish -just some of- this information from 'bonefide' sources? Honestly it doesn't take rocket science to figure out what's going to happen when we already have more than enough information to work with.

[pinky]

You might have a greater impact if you simply told us how many BTUs are needed to turn ice into water instead of asking what almost seems like a rhetorical question. ;)

[Java]

1 BTU is the amount of energy required to heat or cool 1 pound of water by 1°F.

To raise or lower the temperature of 1 pound of ice by 1°F, it takes only 0.5 BTU.

To change 1 pound of 32°F ice into 32°F water, we have to add 144 BTUs, and coversely taking away 144 BTUs will turn this 32°F water back into 32°F ice.

In other words with the same amount of BTUs to change 32°F ice into 32°F water, once liquified this same amount of BTUs if added will then raise the same weight of already liquid water by 144°F. Now this is a HUGE CHANGE in Temperature!


Now imagine working with over 57 cubic miles of ice a year (and increasing) just for Greenland alone. Latent heat is definitely something worth worrying about. The actual temperatures can do what they will so long as there is ice left to absorb the BTUs. In fact if large ice masses were to break loose and float off into the oceans, the worldwide temperatures may actually decrease for awhile but the BTUs are still coming in to melt more ice. However, once there is too little ice left to moderate the temperature, then things will get very bad, and very fast!

[pinky]

:blueeek: That's huge!

Thanks for the info.