Hot and Cold

Summer has a vise grip on Houston. The heat and humidity are relentless, oppressive, and will not abate until sometime in October. Any rain that falls will be graciously welcomed by the plants, but will only add to human misery with mosquitos and heavy “air you can wear.”

So what better time to follow the news from Antarctica about the imminent collapse of the Larsen C Ice Shelf. I was only vaguely aware of this phenomenon, I remember hearing the odd news tidbit, but I’ve doing a little internet research.

Ice shelves are thick sheets of ice that float on the water but are connected to land. They form when a glacier reaches the sea, but the water is cold enough that the flow just continues out into the ocean. We’ve all seen videos of icebergs forming or calving off from a glacier. This is where the water isn’t cold enough to keep an ice flow from melting, so the glacial ice falls and breaks off instead of continuing to flow. Ice sheets will naturally vary in size year to year. Small pieces at the sea edge regularly calve off, and the thickness will vary with temperature and the amount of glacial flow. The largest ice sheets are around the continent of Antarctica.

Photo from the National Snow & Ice Data Center nsidc.org

The Larsen Ice Shelf used to be much bigger, but Larsen A disintegrated in 1995 and a section of Larsen B roughly the size of Rhode Island broke off in 2002. Last November, scientists photographed a rapidly growing rift, or crack, on Larsen C. This crack has grown at an unprecedented rate and scientists are expecting a section the size of Scotland to break off soon. (“Soon” being a very subjective term.)

By NASA photographs by John Sonntag – http://earthobservatory.nasa.gov/IOTD/view.php?id=89257, Public Domain, From wikipedia

So then what happens? Well, no one is sure since this will be the largest ice shelf collapse ever observed. Since the ice is already floating on the water, there won’t be an immediate effect on sea level. Again, ice shelves do grow and shrink, but the Larsen Ice Shelf is unlikely to recover from a collapse of this size. It’s a huge compounding of effects. The rift was at least accelerated by climate change. Warmer air and water temperatures directly contribute to this type of calving. Sea ice floating near the shelf, which helps protect the shelf, continues to diminish. Once the shelf collapses, the flow of the glacier into the water will likely accelerate. All this melting ice will cause sea levels to rise. Which will further damage and reduce the size of ice shelves. Less snow and ice cover in and around Antarctica will contribute to rising air temperatures. Which cause….need I go on…and on and on and on…?

Don’t let trump’s twitter feed distract you from following the news from Antarctica. It’s interesting. It’s important. And maybe it’ll help take your mind off the temperature outside.

https://en.wikipedia.org/wiki/Larsen_Ice_Shelf   Love me some wikipedia.

https://nsidc.org/cryosphere/quickfacts/iceshelves.html  Quick facts on ice shelves from the NSIDC.

http://www.dw.com/en/antarctica-larsen-c-breakoff-could-have-dire-consequences/a-39489181 A rather dismal (tho I believe valid) take on the situation.

http://www.projectmidas.org/  The latest news from MIDAS, a scientific group keeping a close eye on the rift.

 

 

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