Einige Leser werden sich vielleicht noch an die Schreckensmeldung erinnern: Schmelzwasser und ins Meer stürzende Eisbrocken lassen die Gletscher Grönlands schrumpfen und zwar schneller als gedacht.
Jetzt stellt sich offenbar heraus, die ganze Aufregung war mal wieder
ein falscher Alarm: One of the most vivid symbols of global warming
used by scientists and campaigners to spur society to curb
climate-warming emissions is photography of gushing rivers of meltwater
plunging from the surface of Greenland?s ice sheet into the depths.
Recent studies have shown these natural drainpipes, called moulins, can
speed up the slow seaward march of the grinding ice by lubricating the
interface with bedrock below. The faster that ice flows, the faster
seas rise. Now, though, a new Dutch study of 17 years of satellite
measurements of ice movement in western Greenland concludes that the
speedup of the ice is a transient summertime phenomenon, with the
overall yearly movement of the grinding glaciers not changing, and
actually dropping slightly in some places, when measured over longer
time spans. The work, the authors and other experts caution, does not
mean that more widespread surface melting could not eventually
destabilize vast areas of the world?s second-largest ice storehouse.
But for the moment, the study, which is being published in Friday?s
edition of the journal Science, throws into question the notion that