Dedicated to the balanced discussion of global warming
Washington Post – January 14, 2008
Changes to the ice mass on Antarctica could be the tipping point for a wide range of calamities caused by global warming. This news of escalating ice loss is very disconcerting. We need to monitor this situation closely to understand if it is within the realm of variability or if this is significant on-going trend.
I don’t typically jump on to the sky is falling bandwagon. However, significant changes in this ice mass or so concerning that caution is called for. Even if the root cause of global warming is not man but rather it is nature, the events of Antarctica are extremely noteworthy and anything that we can do to reverse this trend is likely to be worthwhile.
It is a little disconcerting that again we find that we don’t understand what is going on. I point to the statement “less-well-understood dynamics of the submerged current” as being particularly appalling. Once again, I call on the academic and political world to spend more money and time on the science of understanding our world and environment.
It is also fair to point out that the author of the study, Eric Rignot, says that the loss of ice started 40 years ago so saying that this is solely a man-made catastrophe falls a little short of reality.
Climatic changes appear to be destabilizing vast ice sheets of western Antarctica that had previously seemed relatively protected from global warming, researchers reported yesterday, raising the prospect of faster sea-level rise than current estimates.
In addition, researchers found that the rate of ice loss in the affected areas has accelerated over the past 10 years — as it has on most glaciers and ice sheets around the world.
The cause, Rignot said, may be changes in the flow of the warmer water of the Antarctic Circumpolar Current that circles much of the continent. Because of changed wind patterns and less-well-understood dynamics of the submerged current, its water is coming closer to land in some sectors and melting the edges of glaciers deep underwater.
The new Antarctic ice findings are based on mapping of 85 percent of the continent over the past decade using radar data from European, Japanese and Canadian weather satellites. Previous studies had detected the beginning of ice loss in West Antarctica and substantial loss along the peninsula, but the current research found significantly greater changes.
In all, snowfall and ice loss in East Antarctica have about equaled out over the past 10 years, leaving that part of the continent unchanged in terms of total ice. But in West Antarctica, the ice loss has increased by 59 percent over the past decade to about 132 billion metric tons a year, while the yearly loss along the peninsula has increased by 140 percent to 60 billion metric tons.
Rignot said there has been evidence of ice loss going back as far as 40 years.
Thompson, who has studied the Quelccaya glacier in the Peruvian Andes for 30 years, said that for the first half of that period, it retreated on average 20 feet per year. For the past 15 years, he said, it has retreated an average of nearly 200 feet per year.
Martinson said the current, which flows about 200 yards below the frigid surface water, began to warm significantly in the 1980s, and that warming in turn caused wind patterns to change in ways that ultimately brought more warm water to shore. The result has been an increased erosion of the glaciers and ice sheets.
… researchers do not have enough data to say for certain that the process was set in motion by global warming, but “that is clearly the most logical answer.”
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