Science Stunner: Greenland Ice Melt Up Nearly Five-Fold Since Mid-1990s, Antartica’s Ice Loss Up 50% In Past Decade

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"Science Stunner: Greenland Ice Melt Up Nearly Five-Fold Since Mid-1990s, Antartica’s Ice Loss Up 50% In Past Decade"

Based on the new study in Science, this chart shows changes in global sea level due to ice sheet melting since 1992. The background image shows thickening (blue) and thinning (red) of Antarctica’s ice sheets over the same period. Credit: ESA/NASA/Planetary Visions via NBC.

A major new international study reconciles “an ensemble of satellite altimetry, interferometry, and gravimetry data sets” to determine polar ice-sheet ice loss with the highest accuracy to date. The study, “A Reconciled Estimate of Ice-Sheet Mass Balance” (subs. req’d) was published in the journal Science Thursday.

The NASA Jet Propulsion Laboratory news release explains the study’s significance:

An international team of experts supported by NASA and the European Space Agency (ESA) has combined data from multiple satellites and aircraft to produce the most comprehensive and accurate assessment to date of ice sheet losses in Greenland and Antarctica and their contributions to sea level rise.

In a landmark study published Thursday in the journal Science, 47 researchers from 26 laboratories report the combined rate of melting for the ice sheets covering Greenland and Antarctica has increased during the last 20 years. Together, these ice sheets are losing more than three times as much ice each year (equivalent to sea level rise of 0.04 inches or 0.95 millimeters) as they were in the 1990s (equivalent to 0.01 inches or 0.27 millimeters). About two-thirds of the loss is coming from Greenland, with the rest from Antarctica….

“Both ice sheets appear to be losing more ice now than 20 years ago, but the pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s,” [JPL's Erik] Ivins said. “In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade.”

The NBC Evening News had a very good story on this study and the general acceleration of ice sheet melt:

The JPL release is accompanied by this remarkable photo:

Turbulent Water Overflow: Over the course of several years, turbulent water overflow from a large melt lake carved this 60-foot-deep (18.3 meter-deep) canyon (note people near left edge for scale). Image credit: Ian Joughin, University of Washington

The international collaboration that made this study possible was truly unique:

The study was produced by an international collaboration — the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) — that combined observations from 10 satellite missions to develop the first consistent measurement of polar ice sheet changes. The researchers reconciled differences among dozens of earlier ice sheet studies by carefully matching observation periods and survey areas. They also combined measurements collected by different types of satellite sensors, such as ESA’s radar missions; NASA’s Ice, Cloud and land Elevation Satellite (ICESat); and the NASA/German Aerospace Center’s Gravity Recovery and Climate Experiment (GRACE).

“What is unique about this effort is that it brought together the key scientists and all of the different methods to estimate ice loss,” said Tom Wagner, NASA’s cryosphere program manager in Washington. “It’s a major challenge they undertook, involving cutting-edge, difficult research to produce the most rigorous and detailed estimates of ice loss from Greenland and Antarctica to date. The results of this study will be invaluable in informing the IPCC as it completes the writing of its Fifth Assessment Report over the next year.”

Finally, here is a graphic on the astonishing surface ice melt in Greenland this summer:

Extent of surface melt over Greenland’s ice sheet on July 8, 2012 (left) and July 12, 2012 (right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. Via NASA/JPL.

We can’t dawdle much longer if we want to avoid an ice-free planet….

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18 Responses to Science Stunner: Greenland Ice Melt Up Nearly Five-Fold Since Mid-1990s, Antartica’s Ice Loss Up 50% In Past Decade

  1. Mark E says:

    It is worse than that…..

    Not long ago climateprogress posted the following link:
    http://www.uwyo.edu/uw/news/2012/11/uw-professors-delayed-greenland-ice-melt-research-published-in-nature.html

    The gist is that Greenland is getting enough BTUs to melt a LOT more water, but a fair bit is refreezing in the grainy firn below the surface. As that becomes saturated (and becomes more ice-like) presumably more of the meltwater will find its way to the sea. The researchers suggested this firn-buffering effect might last for a measly 20 years.

    • Solar Jim says:

      Concerning BTU’s and ice melt, if I understand correctly, according to J Hansen at NASA GISS, the current energy imbalance from radiative forcing of carbonic acid gas is about 0.6 Watt per square meter over the planet. Sounds small right? Well, with a simple calculator and estimating 8% goes toward ice melt per Hansen, this equates to five times world electric generating capacity operating 24/7/365 (flat out for centuries and rising).

      This implies converting to “clean energy” will be insufficient, but necessary (as of last century).

      • Mulga Mumblebrain says:

        So we must remove greenhouse gases somehow, from the atmosphere. I like trees, so I vote for reforestation and biochar or soil fertility. Albedo restoration, although not by stratospheric geo-engineering seems essential. What is the current state of opinion on reflective roofs and other surfaces. I always liked the sound of it, but it seems not to be mentioned much any more. You’re quite correct, I believe, that things have gone too far already for mere total decarbonisation to suffice.

        • Paul Klinkman says:

          What we call desert now was grassland at the end of the ice age. I suspect that early man was killing off many of the other predators, and so the herbivores multiplied until they ate off the grass.

          African sub-Saharan farmers are planting green banks of desert-stopping trees, with half-moon shaped depressions that capture water for individual trees. We need more carbon-absorbing acreage on earth.

          Once photosynthesis captures some carbon we need to bury the carbon, by whatever means. Megafires putting the carbon back into the atmosphere lead to a mockery of human sequestration efforts.

          We need heat-reflective white parking lots and heat-reflective white breakdown lanes in Florida — at least while Florida still is well above sea level. A number of Floridians are in favor of White everything, so we might as well get some use out of them.

          California promotes white roofs over heat-absorbing roofs. It helps to lower community air conditioning loads a bit in Southern Cal. Far more could be done.

  2. BillD says:

    Thanks NBC, nice job. They did not bring anyone on to say that we don’t need to worry about a relatively slow rise in sea level. Such a rapid increase in the rate of melting is a big concern.

  3. Paul Magnus says:

    “Harris said there is a recent warming trend, but “I don’t understand or know, or I don’t believe anybody really knows, how to place that in historic perspective.” He also said human contribution to climate change “is also a complex question,” and that even if humans are contributing, “can you change that contribution given that we burn a lot of carbon-based products to create the energy we need to run the economy of the world?”

    Here is a guy who can not process plain simple data. Who can not bring it on himself to trust professionals tasked to analys this area. And who just simple can not compute the risk involved here?

    A fin facsimile of what is basically a GOP template. Unfortunately.

    There just appears to be a gapping gap in brain processing in this area for what ever reason. A human tendency that has been observed time stretching back.

  4. David Heintz says:

    Joe, I loved your book and this site sets the standard for eco journalism. I just posted an open letter to the UN Climate Conference in Doha. I’d love your support. David Heintz
    totalglobalreparation.blogspot.com
    thank you all.

  5. Peter Malsin says:

    Best photo to match mind-bending headline 5X pace of ice melt on Greenland since 1990s is from Guardian:
    http://www.guardian.co.uk/environment/gallery/2012/nov/29/polar-ice-sheets-losing-mass-in-pictures
    Greenland’s albedo is crashing with plausible scenarios limited to only steeper trajectories of melt going forward. This stuff is a lot more exciting than The Day After Tomorrow; we need a film of the caliber of the China Syndrome to do justice.

    • Peter Malsin says:

      Note: pic #2 in Guardian series.

      • Lewis Cleverdon says:

        Well spotted Peter.

        In case anyone is puzzled by the blackened ice shown in image #2 of the Guardian series, it is not soot fallout or underlying rock showing through.

        The black material is cryophillic bacteria who are thriving on melting ice, and by darkening the surface and masking its albedo they are accelerating that melt.

        Given that where huge ice cliffs are carving bergs into the sea the newly exposed ice is pristine, and has no dark stripes where bacteria thrived in preindustrial random warm summers, it seems clear that the present colonies covering up to around 1200ms on Greenland (and climbing) are something new.

        Maybe the succession of warm summers is building them up, and maybe unnatural nitrogen deposition is playing a role too. Either way, with their potent impact on the ice-cap’s summer albedo, all bets are off as to how much it would melt this century – if we fail to do more than just end carbon emissions.

        Regards,

        Lewis

    • Mulga Mumblebrain says:

      ‘Exciting’!!??

  6. Solar Jim says:

    The Greenland Ice Sheet holds the equivalent of about 20 feet of sea level rise (700,000 cubic miles of ice). Notice that the melt rate curve is exponentially curving upward. Floating sea ice melting is greatly contributing now due to albedo flip of reflectivity change from white ice to green water.

    “. . the perfect example of something we can all relate to: the progression of almost any tragedy in our lives from initial disbelief to growing uneasiness to final, total awareness.”

    Introduction to The Discovery of the Titanic by Robert Ballard as quoted in Gilded Lives, Fatal Voyage, by H. Brewster, 2012.

    Shall we sink all ships of state?

  7. Colorado Bob says:

    The Mercury Find -
    No atmosphere , no oceans, and no tilt to conduct the heat to the dark parts……… They found ice on Mercury in the shadows of the craters, at the poles.

    This ice find is a real teachable thing . You may not care about the atmosphere , but the atmosphere cares about you.
    Little Mercury sitting there next door to the Sun , and the shady spots have ice houses. What teachable thing about how cool our gas shell is . Step out to Venus it has gas shell . There’s no ice on Venus.

  8. Aaron Lewis says:

    The albedo of the GIS is no longer the issue.

    In the old days, latent heat from the North Atlantic condensed out on the sea ice. Now that water vapor condenses on the GIS. Every gram of water vapor that condenses melts 7.5 grams of ice resulting in 8.5 grams of runoff – that then releases the potential energy of its kilometer or two of height above SL as it falls through some moulin.

    In summer, the whole North Atlantic (and soon the whole Arctic) ocean is a solar collector resulting in heat available to the melt processes on the GIS.

    This is another little issue glossed by the community climate models.

    • Lewis Cleverdon says:

      Aaron – I’d quite agree that loss of GIS albedo may not be The issue, though I understand it’s certainly significant,
      and I’ve been trying to quantify the effect of immense volumes of melt water suddenly dropping 1.5km when the melt lakes break through into the moulin network,
      but I’m puzzled by the delivery of latent heat you describe.

      How does all of the water vapour from the whole North Atlantic get to condense on, or transfer all its resulting heat to, the GIS ?
      Could you clarify this ?

      Regards,

      Lewis

      • Jonathan Brandmeyer says:

        If I understand him correctly, he is referring to an energy transport method similar to that of a heat pipe. Over warm ocean water of 5C, water vapor evaporates, transferring latent heat of vaporization from the ocean to the air above it, and raising the dewpoint to as high as 5C. Over ice, the water vapor condenses/freezes onto it, releasing latent heat of condensation (and possibly freezing). This method of energy transport will work so long as there is both a temperature difference and airflow across the bodies.

        I don’t know how to calculate the strength of the effect, though. It may or may not be as large as the albedo changes.