Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 3:03 PM GMT on April 26, 2013
"There's no place on Earth that is changing faster--and no place where that change matters more--than Greenland." So said 350.org founder Bill McKibben, in a 2012 Rolling Stone magazine interview. As Earth Week 2013 draws to a close, I want to draw your attention to a unique effort to learn more about why Greenland is melting so fast--a crowd-funded research project that anyone can contribute to, which aims to answer the "burning question": How much does wildfire and industrial soot darken the ice, increasing melt? The Dark Snow Project, the first-ever Greenland expedition relying on crowd-source funding, hopes to raise $150,000 to mount a field research campaign to find out. The project is the brainchild of Dr. Jason Box, Professor at the Geological Survey of Denmark and Greenland (GEUS), and one of the world's leading experts on Greenland's glaciers. He has set up a website called darksnowproject.org to help raise the funds for the field campaign, and has raised about half of the needed amount as of mid-April.
Figure 1. Over the course of several years, turbulent water overflow from a large melt lake carved this 60-foot-deep (18.3 meter-deep) canyon in Greenland's Ice Sheet (note people near left edge for scale). Image credit: Ian Joughin, University of Washington.
2012: Unprecedented melting in Greenland
Watching the weather events of 2012 over Greenland made all seasoned climate watchers a little queasy. The vast ice sheet on the island holds enough water to raise global sea levels by 7.36 meters (24.15 feet) were it all to melt, and the ice melt season of 2012 gave notice that an epic melting of the Greenland Ice Sheet may be underway. According to NOAA's 2012 Arctic Report Card, the duration of melting at the surface of the ice sheet in summer 2012 was the longest since satellite observations began in 1979, and the total amount of summer melting was nearly double the previous record, set in 2010 (satellite records of melting go back to 1979.) A rare, near-ice sheet-wide surface melt event melted 97% of the surface of Greenland's ice sheet on July 11 - 12. While a similar melt event at the summit occurred 1889, but the 1889 event has no basis in the instrumental record from coastal Greenland. It's instead likely that 2012 was Greenland's warmest summer in at least 863 years, since the medieval warm period (see http://www.meltfactor.org/blog/?p=677 and http://www.meltfactor.org/blog/?p=725). The incredibly warm temperatures have been blamed on highly unusual atmospheric circulation and jet stream changes, which were also responsible for 2012's unusually wet summer weather in England. It would not be a surprise if this sort of summer began occurring more often, since temperatures on top of the Greenland Ice Sheet have been rising six times faster than the global average during the past twenty years. A May 2013 Geophysical Research Letters paper by McGrath et al., "Recent warming at Summit, Greenland: Global context and implications", concluded that by 2025, there is a 50% chance of ice sheet-wide melt events happening annually. The ice sheet reached its darkest value on record in 2012. The darkened surface was due to below average summer snow, soot particles from pollution and forest fires, and record melting. A darker ice sheet absorbs more solar energy, in a vicious cycle that raises temperatures, melts more ice, and further darkens the ice sheet. The amount of melting that was caused by soot from forest fires is important to know, since global warming is likely to increase the amount of forest fires in coming decades. However, the amount of forest fire soot landing on the Greenland Ice Sheet is almost completely unknown, which is why Dr. Box is determined to find out, via the Dark Snow Project.
Figure 2. Smoke from a fire in Labrador, Canada wafts over the Greenland ice sheet on June 17, 2012, as seen in this cross-section view of aerosol particles taken by NASA's CALIPSO satellite. Image credit: Dr. Jason Box, Ohio State University.
Greenland causing 25% of global sea level rise
In a landmark study published in November 2012 in Science, 47 researchers from 26 laboratories reported that the amount of ice being lost from Greenland and Antarctica has tripled since the 1990s, with Greenland contributing more than twice as much to global sea level rise than Antarctica. The study, "A Reconciled Estimate of Ice-Sheet Mass Balance", found that the two ice sheets were responsible for 20% of the global sea level rise of 3.1 mm/year during the 20-year period 1992 - 2011. The remainder of the rise was due to expansion of the water due to heating of the oceans, melting of mountain glaciers, and unsustainable pumping of ground water. Said co-author Erik Ivins of NASA's Jet Propulsion Laboratory, "The pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s." As of 2011, Greenland's contribution to global sea level rise on its own had risen to 20 - 25%, according to an international research group led by the GFZ German Research Centre for Geosciences, in an article published in Earth and Planetary Science Letters on 1 June 2012. If the current exponential ice loss trends continue for the next ten years, Greenland's contribution to sea level rise will double to 1.4 mm/yr by 2022, the researchers said. Many sea level rise researchers expect global sea level to rise by about 1 meter (3.3 feet) by 2100. During the 20th century, global sea level rise was about 0.18 meters (7 inches.)
Figure 3. Monthly smoothed (purple) and unsmoothed (blue) values of the total mass lost from the Greenland Ice Sheet (in Gigatons, Gt) from measurements by the GRACE satellites between March 2002-September 2012. An approximate equivalent global sea level rise figure is on the right axis. Note that the decline in ice mass lost from Greenland is not a straight line--it is exponential, meaning that more ice loss is lost each year than in the previous year. Image credit: 2012 Arctic Report Card.
Will Antarctica be more important than Greenland for sea level rise?
Although melting from Greenland is currently raising global sea level by about a factor of two more than Antarctica melting is, that situation may change later this century. A 2013 study by Dahl-Jensen et al. looked at a new ice core drilled from the bottom-most depths of the Greenland Ice Sheet. The core suggests that the ice in Greenland may have partially survived the warm Eemian period before the Ice Age, approximately 118,000 - 126,000 years ago, when Greenland temperatures were 5- 8°C warmer than present-day temperatures. Global sea level during the Eemian was 4 - 8 meters (13 - 26 ft) higher than the present sea level, and the scientists estimated that melting from Greenland was responsible for 2 meters (6.6 ft) of this sea level rise. This implies that Antarctica was responsible for 50 - 75% of global sea level rise during the Eemian, and thus we might expect Antarctica to take over as the dominant source of sea level rise later this century, when global temperatures may to rise to levels similar to those experienced during the Eemian.
Greenland experiences melting over 97% of its area in mid-July (July 25, 2012)
Record warmth at the top of the Greenland Ice Sheet (July 18, 2012)
Unprecedented May heat in Greenland; update on 2011 Greenland ice melt (May, 2012)
Greenland update for 2010: record melting and a massive calving event
Dr. Jason Box's blog on Greenland and the Dark Snow Project is at http://www.meltfactor.org.
The http://www.greenlandmelting.com/ website looks like a great resource for following this year's melt progression in Greenland.
Video 1. Glaciologist Dr. Jason Box and 350.org founder Bill McKibben plug the Darksnow project in this January 2013 video by Peter Sinclair. There's some impressive footage of the record Greenland snow melt of summer 2012 sweeping away a 20-ton tractor that was attempting to repair a bridge washed out by the raging Watson River on July 11, 2012 in Kangerlussauaq, Greenland. The driver escaped unharmed.
Support the Dark Snow Project
One of Dr. Box's collaborators, photographer James Balog, who created the amazing time-lapse Greenland glacier footage in the fantastic 2012 "Chasing Ice" movie, puts it like this: "Working in Greenland these past years has left me with a profound feeling of being in the middle of a decisive historic moment--the kind of moment, at least in geologic terms, that marks the grand tidal changes of history." On that note, I encourage you all to support the Dark Snow Project. Have a great weekend, everyone!
Dark Snow Project Expedition Plan 2013
Prepare and gather science equipment including a field spectrometer, snow and ice coring device, and snow metrics kit.
Travel to Iqualuit, on Baffin Island, Nunavut from home locales in California, Ohio, Michigan, Vermont and rendezvous with Dash-6 "Twin Otter" ski-equipped airplane and flight crew.
Organize cold weather survival kit.
Ferry team from Iqualuit to Kangerlussuaq, Greenland.
Fly to and land at sampling sites high on the inland ice sheet.
At each site collect snow samples from a snow pit and obtain snow cores to a minimum depth of the previous year's snow surface, and record snow properties.
Transport of team and snow samples to Greenland's capital Nuuk, where the team will rest after hustling at field sites.
Return to Iqualuit, then to respective home locales to start the data analysis and reporting phase of campaign.
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