Since we’ve thrown EcoWorld into the global warming debate – and it is a debate – we’ve been trying hard to not just report what everybody else has said, but try to understand for ourselves what the data and the theories really mean. This is basically impossible, but it’s also our obligation both as responsible journalists and as citizens of the world. So we will try.
One relatively easily understood concept is the notion of global warming causing melting of land based polar icecaps which in turn would cause the oceans to rise. In practice, that means the approximately 1.4 mile thick icecap atop Greenland’s 840,000 square miles of land mass, and the roughly 1.3 mile thick icecap atop the 5.8 million square miles of Antarctica.
Since the world’s oceans occupy a surface area of 139 million square miles, it isn’t too hard to figure out how much the ocean surface would rise, if all this land-bound ice melted. There are about 1.2 million cubic miles of ice atop Greenland, and if you pour all that into the oceans (1.2M cubic miles / 139.0M square miles of ocean surface) you get a rise of .083 miles, which is 45 feet. Calculating Antarctica’s frozen ice at a volume of 7.7 million cubic miles (1.32 miles thick x 5.3 million square miles), and pouring that into the oceans (7.7M cubic miles / 139 million square miles of ocean surface) you get a rise of 292 feet.
So our doomsday scenario could involve a rise of the oceans of 337 feet. A scary prospect indeed. One is not calmed if one reads the many reports on Antarctic ice melt. Here are a few: “Antarctic Ice Melting Faster” (BBC), “Antarctic Ice Melting Rapidly” (Washington Post), and “Antarctic Ice Sheet Melting Fast” (ABC).
The landmark Intergovernmental Panel on Climate Change report, in Section 3.3.1, “Antarctic and Arctic Ice and Snow” made the prediction that a warming climate would melt ice at the perimeters of Antarctica and Greenland but would cause increased snow in the interior of those land masses, and that these effects might counteract one another. This is one of the most important premises underlying whether or not sea levels will rise – will the melting ice be balanced by new ice formation through more snow on the icecaps?
Some reports supporting the precipitation increases include “East Antarctica Puts on Weight” (News@Nature.com), and “Snowfall Driven Growth in Antarctica Mitigates Loss of Ice” (Science Magazine).
Now the National Science Foundation has weighed in on this crucial question with a new study released on August 10, 2006 entitled “Overall Antarctic Snowfall Hasn’t Changed in 50 Years”. But in the study, one of the investigators, Andrew Monaghan of Ohio State University, acknowledges “The year-to-year and decadal variability of the snowfall is so large that it makes it nearly impossible to distinguish trends that might be related to climate change from even a 50-year record.”
Bottom line – we don’t know yet. But it would behoove us to pay close attention to this and other fundamental premises of global warming theories.