As greenhouse gas emissions continue to rise, researchers are looking at a source of even more carbon emissions: thawing permafrost. A warming Arctic may cause significant amounts of dead, organic material currently frozen in permafrost to thaw out and decay, releasing more carbon into the atmosphere. How exactly does permafrost store carbon? And what are the consequences if the permafrost thaws?
If gardening in icy Greenland sounds unbelievable, think again. A chef in Kangerlussuaq has started growing tomatoes, peppers, herbs, and even strawberries for his restaurant, and Greenland’s potato production doubled between 2008 and 2012. These agricultural feats would have been impossible only a hundred years ago. The Arctic has been warming over the past several decades at a rate twice as fast as the rest of the globe. As the region warms, several teams of scientists have been tracking changes in Arctic vegetation, trying to see if higher temperatures mean more green. Continue reading
As warming alters the Arctic landscape, people are paying more attention to the changes happening to the Greenland Ice Sheet. The ice is melting more rapidly than before, leaving us to wonder, what’s going on?
To help answer your questions about Greenland, NSIDC’s newest Web site, Greenland Ice Sheet Today, will feature the latest research and imagery that researchers are using to monitor the ice. Scientists are discovering that while the ice sheet is in no danger of instantly melting, it is not immune to the Arctic’s rising temperatures.
Greenland in a warming world
Most recently, during the summer of 2012, nearly 97 percent of the ice sheet surface experienced melting. This extreme melt was unprecedented in the 30-year satellite record; typically only about 40 or 50 percent of the ice surface melts. Scientists chalked this dramatic melt to an unusually warm weather pattern that hovered over Greenland for several weeks. But this unusual event preceded a record low Arctic sea ice extent and occurred in conjunction with other signals of warming in the region. Arctic Ocean temperatures have been rising, and the sea ice that normally blankets those oceans in winter is declining. Outlet glaciers that drain the ice sheet are flowing faster and thinning more rapidly than they have before. Large ponds and other melt features are appearing on the ice sheet surface more frequently, and are lasting longer before refreezing. Consequently, scientists are watching Greenland closely.
Warming in context
Similar to our Arctic Sea Ice Web site, Greenland Ice Sheet Today will feature daily images based on near-real-time data across Greenland. An accompanying graph will illustrate how the current melt extent compares to the longer-term satellite record. We will update the News and Analysis section regularly with background information to help place current Greenland melt conditions into context. Expert contributors will post regularly to discuss the ongoing status of the ice sheet. Greenland Ice Sheet Today helps round out NSIDC’s series of sites featuring data and analysis to keep you updated about Earth’s cryosphere.
For more information and to view data images, visit Greenland Ice Sheet Today.
Previous Icelights posts about Greenland
During the summer of 2012, scientists noticed something unusual in Greenland. On July 8, about 40 percent of the Greenland Ice Sheet surface showed signs of melting. But a mere four days later, 97 percent of the surface was melting, an extent that was unprecedented in the satellite record.
Just how unprecedented was this event? Does it mean that the Greenland Ice Sheet is possibly on the way out, like summer sea ice in the Arctic?
The Greenland block
To be clear, the Greenland Ice Sheet is still very much intact. It will take much more than a warm summer to melt ice that covers 660,000 square miles and averages 1.43 miles in thickness. And surface melt is quite shallow, including only the top several centimeters, according to Thomas Mote, a professor at the University of Georgia. Mote is one of many scientists studying Greenland’s ice, investigating what caused such a dramatic melt. Mote credits last summer’s extreme melt in large part to a weather pattern called the Greenland block. “Greenland blocking is a persistent high pressure ridging over Greenland,” Mote said. “That is when we will see warmer than normal conditions and more melt.” During a normal summer, about half of the ice sheet surface experiences melt. Last summer, this high-pressure block essentially parked over Greenland, creating a lasting dome of heat that rapidly melted nearly the entire ice sheet surface.
Melting in context
Much of the media coverage cited a historical precedent for the melt, focusing on an ice core record from Summit Station, Greenland. This core indicated that such extreme melts are not unusual, and have occurred as frequently as every 150 years. But records from a single location, while invaluable, may oversimplify the history of such a vast ice sheet, and may not account for more recent changes in the broader environment surrounding Greenland.
“You’re talking about a single event at Summit that is quite remarkable but very short-lived, versus this sort of broad warming and increase in melt over much of Greenland,” Mote said. “The increased melt that we’ve seen in Greenland over the past several years is associated with the general warming across the Arctic.” Greenland experienced record warming in 1999, 2007, 2010, and in 2012, mirroring years in which the Arctic as a whole experienced warming, and often, record sea ice minimums.
Mote and others hope to place the extreme event into a larger environmental context, seeing how factors like air temperatures and winter accumulation might play a role. And in spite of the recent warming, Mote cites some positive evidence among the many questions that Arctic warming often raises. “There is some evidence recently that suggests that the Greenland Ice Sheet can recover more easily perhaps than we might have thought,” Mote said. “I think we’re still trying to get a sense of just how inter-related these different cryospheric measures are across the Arctic.”
Nghiem, S. V., D. K. Hall, T. L. Mote, M. Tedesco, M. R. Albert, K. Keegan, C. A. Shuman, N. E. DiGirolamo, and G. Neumann. 2012. The extreme melt across the Greenland ice sheet in 2012. Geophysical Research Letters, 39, L20502, doi:10.1029/2012GL053611.
As the Arctic Ocean becomes increasingly ice-free, many countries are eager to tap into previously inaccessible northern resources. Energy companies seek drilling permits for oil and natural gas, and shipping companies hope to ply newly opened sea routes. Given the unpredictable nature of Arctic sea ice, some wonder if operating in the already inhospitable north will be an economically viable effort. Others believe that even if drilling or shipping is not currently viable, the Arctic is changing fast enough that industry in the Arctic is here to stay. Continue reading