Greenland Warming Lags, But Bound to Catch Up

Discovery News ^ | Michael Reilly

[DBCJR]

One of the world's most important remaining ice reserves on Earth remains deceptively cold.

As the planet's poles thaw out, global sea level rise looms as one of the most dangerous side effects of global warming. Any excess chill may seem like good news for the planet. But a new study suggests that Greenland is lagging behind rest of the northern hemisphere's warming trend and that it's bound to catch up soon.

Air temperatures have been rising steadily in the northern half of the planet since about 1975, when scientists think the effects of human-induced global warming began to dominate the climate. But Greenland was left behind, perhaps kept cool when dust released from the eruptions of Mount St. Helens, El Chicon and Mt. Pinatubo reduced the amount of sunlight hitting the ice.

Around 1985 the icy island started to thaw, and has continued apace ever since. Climate scientists have been alarmed by the speed of the melting, watching as glaciers recede and meltwater pools in lakes on top of the ice.

Still, in an analysis of temperature records in Greenland from 1840 until 2007, Jason Box of Ohio State University and a team of researchers found that the ice sheet remains between 1.0 and 1.5 degrees Centigrade (1.8 to 2.7 degree Fahrenheit) behind the rest of the northern hemisphere. And it should catch up in the coming decades.

"The temperature increase could be three to four times what we've seen already. If that holds it will be far above anything we've seen before," David Bromwich of Ohio State University said. "The ice will continue melting and probably accelerate in the future."

[DBCJR]

Excellent analogy!

[dr_lew]

Around 1985 the icy island started to thaw, and has continued apace ever since. Climate scientists have been alarmed by the speed of the melting, watching as glaciers recede and meltwater pools in lakes on top of the ice.

Here are two views of the meltwater lakes they're talking about, from July 2002 and July 2008, on the 16th of the month. One of these drained suddenly in 2006, when some scientists happened to be on hand studying it, so it made big news. The pattern of lakes in 2002 and 2008 is very much the same, and it looks like the edge of the ice follows the same line very closely, so I don't know about "continuing apace". I can see getting worried about these lakes, though. They are obviously a potentially active agent of erosion. Are there more of them in the 2008 image?

[DBCJR]

Thank you for your post and the satellite map comparison. The type comparison that you ask is one that likely needs computer analysis to identify. The outward range of change one would expect would seem undetectable to the human eye.