Last night our PBS station presented “Journey to Planet Earth”, narrated by actor Matt Damon. Lots of scenes showing Matt superimposed on the scene as he narrated (like with Julia Roberts, she was saving the orangutans I believe). The 1st part was gripping, concerning the collapse of cod fisheries worldwide; showing how this has devastated a village in Portugal, and their relatives, the Portu.-American community in New Bedford, Mass.
I had hoped they’d then go into what can be done to remedy this disaster (if anything): treaties to limit the catch, chances for the cod to recover, etc. Instead the focus shifts to… global warming, of course. Well, that’s a very important matter (maybe more important). They illustrate it with scenes of glaciers in southeast Greenland melting away, slipping into the sea. Scenes of the meltwater lakes which grow in the summer, water cascading in mini-Niagaras thru holes in the ice– where it then lubricates the underside of the glaciers, making them slide off into the sea at a faster rate.
Alarms have been raised about this for some time. However I remembered reading that some studies show that the alarm is overdone! So I rushed off to Google the matter and found this, an article in the British magazine New Scientist from 3 July 2008 entitled (see link) “Greenland ice sheet slams the brakes on”. Some excerpts from that:
Much noise has been made about how water lubricates the base of Greenland’s ice sheet, accelerating its slide into the oceans. In a rare “good news” announcement, climatologists now say the ice may not be in such a hurry to throw itself into the water after all…..
…They found that meltwater pouring down holes in the ice – called “moulins” – did indeed cause ice velocities to skyrocket, from their typical 100m per year to up to 400m per year, within days or weeks.
But the acceleration was short-lived, and ice velocities usually returned to normal within a week after the waters began draining. Over the course of the 17 years, the flow of the ice sheet actually decreased slightly, in some parts by as much as 10%.
The article does close with a caution from Jay Zwally of NASA-Goddard –yes, that bunch of alarmists (just kidding): Zwally told New Scientist that unpublished data from the eastern edge of the ice sheet suggests between 3% and 5% more ice is being lost because of lubrication than would otherwise happen. That is less than the 25% that was previously calculated, but still significant, he says.
So, maybe sea levels won’t rise by 20+ feet after all? But who has time, in a documentary devoting to saving our precious planet, to present both sides of a scientific controversy?
Oh, I know: one noted expert has told us: “the science is settled”. (Al’s specialty was applied political science, of course)