Dr. Jeff Masters: Support Dark Snow Project

April 27, 2013

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.

Jeff Masters at Weather Underground:

“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 boxglasseswildfire 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.

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).

textdarksnowsmall

It would not be a surprise if this sort of summer began occurring regularly, since 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.

-

Jeff Masters is a founder of Weather Underground, and one of the most respected and oft quoted meteorologists in the country. I interviewed Dr. Masters in January for his thoughts on current observations of Arctic Ice, Jet stream changes, and the outlook for 2013.

About these ads

One Response to “Dr. Jeff Masters: Support Dark Snow Project”


  1. But perhaps it would be worth to cite accurately.

    First paper (for the last two), is also such applications:
    “The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear.
    On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 +/- 4 degrees Celsius above the mean of the past millennium …”,
    “… show only a modest ice-sheet response to the strong warming in the early Eemian.”

    Related:

    http://www.iceandclimate.nbi.ku.dk/research/climatechange/glacial_interglacial/eemian/:

    “Close analysis of δ 18 O values in the Eemian ice does indeed suggest that the Eemian Greenland ice sheet was not dramatically smaller than today.”

    Second reference:
    “The good news from this study is that Greenland is not as sensitive as we thought to temperature increases in terms of disgorging ice into the ocean during interglacial periods,” said Dahl-Jensen.
    “The bad news is that if Greenland did not disappear during the Eemian, Antarctica, including the more dynamically unstable West Antarctica, must be responsible for a significant part of the 4-8 meters of sea-level rise.”

    It is worth remembering that:http://www.sciencedaily.com/releases/2012/12/121206094505.htm:
    “This means that researchers cannot predict how water levels will change in the future with any large degree of certainty.”
    “It is therefore probably a change in the ocean circulation in the Amundsen Sea that has caused this increased melting,” continues Arneborg.”

    “… 4-8 meters of sea-level rise …” in Eemian …
    … its, most probably, no effect of melting West Antarctic, but the results another post-glacial (isostatic) rebound (http://www.ouramazingplanet.com/390-glacier-ice-loss-less-than-thought-study-suggests.html). Range of glaciations – ice mass global, was much higher before the Eemian, than before the Holocene.


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 1,627 other followers

%d bloggers like this: