Tuesday, January 1, 2013

Is Antarctica Melting?


There are numerous debates over whether the earth’s climate is changing; who or what may be changing it; and what may be some of the symptoms of that change. Amidst that, new research from Ricarda Winkelmann and other researchers from the Potsdam Institute for Climate Impact Research, may shed some light on the foreseeable symptoms of climate change, and dispel one of the more positive myths. 

As our atmosphere warms, its ability to carry greater levels of moisture increases, which has lead to increased snowfall in the Antarctic. Many believe that this would make the Antarctic ice sheet grow.  Many scientists feel that this increased Antarctic snow will counteract the melting of ice sheets in the Arctic, resulting in minimal to zero rise in sea-level, as a result of climate change.  According to Winkelmann and her team, Antarctica may not provide such a counterbalance. 

Winkelmann’s team found that snowfall and Antarctic ice discharge work in concert with each other. Snow falls and piles up on the continent.  This exerts pressure on the ice-sheets below, pushing the ice-sheets out to the ocean more and more as the snow accumulates.  The research team found that thirty to sixty percent of snow collecting on the continent is actually offset by underlying ice being pushed out to sea by that very snow.   This by itself would not be alarming as the influx of new water from Antarctic snowfall is still greater than the flow of ice into the ocean.  Sadly, this is not the only factor that affects how ice sheets melt into the ocean.  

Winklemann explains that this shows, for now, that Antarctica is collecting more ice than it discharges, but not at the level we once thought, and that this will not always be the case. Increasing sea temperatures and shifts in ocean currents also act to speed up ice-melt in the Antarctic.  The research team demonstrates that over the last 10 years the net rate at which Antarctic ice grows has slowly but steadily been shrinking.  They show that as oceanographic processes change in the Southern Ocean, Antarctic ice will melt faster than snow collects.  

This has strong implications for areas sensitive to a rising sea-level.  As sea-level rise becomes a greater concern for coastal communities, it will grow consistently more important to monitor ice discharge from the Antarctic, so that we may gain a better idea of when and how areas will need to adapt to sea-level rise. 

1 comment:

Irene_J said...

There is as much water in all forms in the world today as there were when the world was formed, it,s just a matter of how nature sees fit to distribute it!! and there is nothing man can do to alter the fact.

regrads,
irene of Bear Hunting Alaska