If you’re one of the diminishing number of people who don’t believe the world is getting warmer, that headline could be spun to read: “Northwest Passage Finally Found.” That would rank right up there with other facetious headlines, such as: “Spitzer Solves AIG Succession Question.” But, a new report from the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado doesn’t spin its subject. It presents further evidence of the long-term effects of global warming by demonstrating that by the year 2060 the Arctic will be ice-free during the summer months.
All the water locked in the Arctic ice cap will have to go somewhere when it melts. As both Hurricane Katrina and Rita violently demonstrated, coastal cities, like New Orleans, run the risk of major flooding. New York, London, Tokyo, Hong Kong, and a host of other low-lying population centers might be facing the same risk.
In an interview with BBC News NSIDC scientist Mark Serreze said, “September 2005 will set a new record minimum in the amount of Arctic sea ice cover. It’s the least sea ice we’ve seen in the satellite record, and continues a pattern of extreme low extents of sea ice which we’ve now seen for the last four years.”
The new data shows that as of Sept. 19 the area covered by ice fell to 5.35 million sq. kms (2.01 million sq. miles), the lowest recorded since 1978, when satellite records became available. It is now 20 percent less than the 1978-2000 average.
Although he admits that there are still a number of uncertainties in the findings, due to the many variables involved in analyzing climate and weather patterns, Serreze is convinced that at least part of the change is being caused by human acitivities. “I think the evidence is growing very, very strong that part of what we’re seeing now is the increased greenhouse effect. If you asked me, I’d bet the mortgage that that’s just what’s happening,” he told the BBC.
The report confirms findings included in “The Arctic Climate Impact Assessment,” a four-year study, released last year, that involved hundreds of scientists. It projected an additional temperature rise of 4° to 7°C (app. 6° to 10° F) by 2100. This indicates that the Arctic is warming twice as fast as the rest of the planet.
Serreze described his concern that the rapidly melting ice indicates the presence of a “a positive feedback effect, a ‘tipping-point’.” In the case of the Arctic this occurs as ice and snow melt, creating larger and larger areas of dark water that absorb more solar radiation, rather than reflecting it. As these areas increase, the warming effect increases until the point is reached that the trend cannot be reversed.
The BBC described the “idea behind tipping-points is that at some stage the rate of global warming would accelerate, as rising temperatures break down natural restraints or trigger environmental changes which release further amounts of greenhouse gases.” In addition to the Arctic this could also occur if forests switch from being net absorbers of carbon dioxide to net producers, or melting permafrost begins releasing trapped methane.
“This study is the latest to indicate that such positive feedback mechanisms may be in operation, though definitive proof of their influence on the Earth’s climatic future remains elusive, ” the BBC report concluded.