Greenland's Melting Glaciers

Article excerpt

Greenland's melting glaciers were in the news this past summer. In its State of the Climate report for July 2012, the National Oceanic and Atmospheric Administration (NOAA) reported a near-record low (second only to 2011) in Northern Hemisphere sea ice extent and a new record low for the Greenland ice sheet.

In fact, the July 2012 Arctic sea ice volume was 65% below its maximum value in 1979 (see "On the web"). NOAA's Climatewatch website has a video of compiled satellite images that shows visible melting along the Greenland ice sheet near the Jakobshavn Glacier each August between 2000 and 2011. Additionally, the United Nations' Intergovernmental Panel on Climate Change (UN IPCC) plots glacial coverage over time for several large glaciers around the world, and you can watch near real-time change in Arctic sea ice from NOAA (see "On the web").

Despite these data and images, it remains difficult to make predictions about future glacial melting. For example, in April 2012, National Public Radio reported confusion amongst scientists about whether Himalayan glaciers are melting or growing. "Right now, the glaciers that are currently melting are losing one or two feet of thickness every year. ... Some of those glaciers could disappear by the end of the century. But that's too simple a way to look at the problem. That's because our climate is also expected to get wetter as it gets warmer" (see "On the web").

Unfortunately, how much wetter is difficult to predict. Few scientists agree on the future of individual glaciers, but there is agreement that overall trends indicate a general global glacier retreat (UN Environment Programme 2010).

Classroom activities

Participating in data analysis and activities in class will enhance your students' understanding of melting glaciers. First, by accessing glacial data from the United States Geological Survey (USGS) Benchmark Glacier program, students can graph and discover trends for various United States glaciers (see "On the web").

Second, the Changing Planet: Melting Glaciers activity from Windows to the Universe directs students to sort photographs of glaciers and measure glacial retreat to observe how alpine glaciers have retreated over the past century (see "On the web").

Third, take the "Climate Change Tour of Cold Places" with your students using Google Earth. This presentation from the National Snow and Ice Data Center (NSIDC) enables you or your students to overlay images on a virtual globe (see "On the web"). …