Changing Antarctica

Scientific American features an excerpt from Lost Antarctica: Adventures in a Disappearing Land, by James McClintock, a leading Antarctic marine biologist.  I thought this was interesting:

Antarctica boasts some of the largest icebergs ever recorded. In 2000, Iceberg B-15 broke free from the Ross Ice Shelf—a floating platform of ice that can be hundreds or even several thousands of feet thick. (Large icebergs are given designations so they can be tracked.) The Ross Ice Shelf is the largest ice shelf in Antarctica and is about the size of France. Remarkably, a vertical ice wall towering 50 to 100 vertical feet fronts 370 miles of the Ross Sea. The ice shelf was named for Captain James Ross Clark who first sighted the shelf on January 28, 1841. Iceberg B-15 measured twenty-two miles wide and 183 miles long, and was estimated to weigh three billion tons. At 4,200 square miles, the iceberg was eight times the size of the city of Los Angeles. I was fortunate to witness one of these behemoths on a cruise to Antarctica aboard the Explorer II—on whichI was lecturing with a friend, geologist Henry Pollack—in 2007. We sailed for hours, seemingly within reach, of a thirty-one-mile-long iceberg that had grounded itself near Clarence Island off the northern tip of the Antarctic Peninsula. Henry, who had visited Antarctica frequently over a span of eighteen years, was, like me, nonetheless awestruck by this iceberg’s grandeur. Emerging one hundred vertical feet from the sea, the immense iceberg towered above us, dwarfing our ship as we passed.      
As global temperatures rise, icebergs will more often break off, or calve from, the mainland....
A warming Antarctic Peninsula riddled with icebergs has consequences that are hidden from the casual observer. The increased amount and sizes of icebergs scouring the coastal seafloor disrupt the marine communities there. Marine biologists have long known that near-grounded icebergs behave much like earth movers at construction sites, displacing tens of thousands of square yards of seafloor sediment. The exposed portion of an iceberg acts as a sail, transferring the energy of wind and current to motion, causing the berg’s base to plow through soft sediments and scrape over hard rocky bottoms. Massive iceberg scars extend for miles along coastal Antarctic seafloors, and these are devoid of seaweed, sponges, sea anemones, soft corals, sea spiders, starfish, brittle stars, and even fish. Over a period of a few years, the process ecologists refer to as community succession will kick into gear along these iceberg scars. Temporary communities of rapidly settling and fast-growing, but short-lived, seaweeds, sponges and sea squirts will give way to more stable “climax” communities comprised of more competitive seaweeds and marine invertebrates that grow slower and have longer life spans. Climax communities are ecological communities in which populations of bacteria, plants, and animals remain stable and exist in balance with each other and their environment. In the big picture, Antarctic seafloors that are subject to intermediate levels of periodic iceberg scour are checkered with short-term opportunistic and long-term stable communities and, as such, sustain higher overall diversities of species. But just as intermediate levels of iceberg disturbance may increase species diversity, too much iceberg disturbance may actually compromise this diversity. Heavily ice-scoured seafloors, like a graded construction site, can be biological deserts. Climate warming could result in an overabundance of coastal icebergs that regionally decimate near-shore seafloor communities.

While the loss of the arctic environment is a tragedy of sorts, I'm pretty sure the impact of climate change on humans will be pretty immense, and, from our perspective, will obviously be much, much worse outside of the arctic than in it (say in Bangledesh, for instance).  The importance is that Antarctica and the North Pole are the canaries in the coalmine, and as McClintock points out, is already wreaking havoc on life there.