Doomsday Delayed: Greenland’s Ice Sheet Slows Down

One of the real (as opposed to the many imagined) threats from climate change is the risk of sea-level rise.  Raise the oceans too much and not only will beach dwellers be flooded out of their sea-side cottages, but fisheries could be disrupted, limiting vital food supplies, and entire ecosystems could be wiped out.  For instance, salty sea water could permeate through the porous bedrock under the Florida Everglades and permanently destroy that one of a kind freshwater system.

As NPR reports, though, the most dire sea-level rise might be farther away than once thought.  New evidence shows that the rate at which Greenland’s glaciers are flowing in to the sea has slowed, causing scientists to reassess their predictions:

[G]iven what’s happening in Greenland, the worst-case scenario, for 6 feet of sea level rise this century, is looking very unlikely to [Ian] Joughin [of the University of Washington’s Polar Ice Center].

“My guess, and it is a guess, is probably a meter or less — 3 feet or less.”

Glacier are pretty cool.  They’re basically sluggish rivers of ice that slowly flow across the land, shaping and scraping it in all sorts of interesting ways.  We see in the news all the time stories about glaciers breaking off into the sea, complete with dramatic video aimed at stirring just the right emotions to make us feel bad, if only for a minute, about driving a car to work that morning.

But ice flows, so every little piece that makes it to the sea isn’t that big of a deal.  It’s the cumulative whole you have to worry about, and the biggest part of the whole is the ice sheet covering Greenland.  Melt that thing and you’ll never get rid of Kevin Costner.

We also hear a lot about the polar ice caps melting, but you don’t necessarily have to worry about them in terms of sea-level rise.  The ice cap at the South Pole is pretty much all on land, and if it melted, that would be a problem like melting the Greenland ice sheet.  The North Pole, on the other hand, is covered mainly by sea ice, and that stuff has been melting like crazy every summer for the past few years.

I’ve heard people talk about icebergs melting and causing oceans to rise, but that’s just not true.  Icebergs and the arctic sea ice are already in the water, so when they melt they don’t add to the volume of the oceans, which means sea-level doesn’t rise.  It does mean, however, that there is less white ice to reflect solar radiation and more dark water to absorb that solar radiation, setting up a potential feedback loop that could help perpetuate a warming trend.  Or it could mean that Barrow, Alaska, is poised to become a hot new vacation spot.  Buy your land now!

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s