Science talks

Report from AGU meeting: One meter sea-level rise by 2100 ‘very likely’ 4

Why so many geophysics-related posts this week?  First, all of the major groups that track temperature and climate put out their news-making annual reports this week—and I don’t think the media is doing a terribly good job of focusing on the important issues.

Second, this week, the American Geophysical Union has its big fall conference where all the leading geophysicists go to report their latest research.  Here, I have glommed on to a roving reporter, Jeff Goodell, author of the terrific book, Big Coal.

Goodell reports that Dr. Eric Rignot, principal scientist for the Radar Science and Engineering Section at NASA’s Jet Propulsion Laboratory, “rocked the house tonight (Tues.) with his talk on polar ice melt”:

The room was packed, SRO, spilling out into the halls.  I only caught the tail end of the talk, unfortunately, but he concluded that one meter sea level rise by 2100 is “very likely” if the rate of ice melt just stays the same, leaving unsaid the fact that it is likely to rise even higher if rate of melt accelerates.  Said that the way we are studying ice in the poles today is “like climbing Mt. Everest in tennis shoes,”  because our monitoring and measurement is so bad.

Rignot is one of the world’s top ice sheet and sea-level rise experts (see “The Antarctic ice sheet hits the fan”), so that’s why he packs them in.

If Rignot is right, then Hansen and Gore are right—our target must be 350 ppm or lower (see “Stabilize at 350 ppm or risk ice-free planet, warn NASA, Yale, Sheffield, Versailles, Boston et al”).  That’s because, thanks to lags in the climate system, we are going to warm more than another 0.6°C even if greenhouse gas emissions were zeroed out tomorrow—and that will surely speed up all ice-loss processes.

One small critique of the AGU meeting:  They should put far more of their talks online.  This stuff is incredibly fascinating and important to a great many people.

This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.

Joseph Romm is the editor of Climate Progress and a senior fellow at the Center for American Progress.

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  1. Delay And Deny's avatar

    Delay And Deny Posted 1:00 pm
    18 Dec 2008

    More Ice Please...

    There's not enough ice in the Arctic for a 1 meter rise.
    My calculations show maximum melted volume would give a 0.3 meter rise.
    Also, you're not accounting for arid areas that would soak up the increased water as precipitation.
    (Note recent precipitation trends in Arizona -- in last week 600% of normal!)

    "This is the essence of science...you ask an impertinent question and you're on your way to a pertinent answer." -- Fox Mulder, S1E4, "Conduit"
  2. undyau Posted 2:01 pm
    18 Dec 2008

    jabailo calculationsMy calculations show 2 polar areas, maybe you need to revisit your maths with this in mind.
  3. Sam Wells Posted 5:00 am
    19 Dec 2008

    Local versus average sea riseI don't know about one meter - it might be a high or low estimate because we just don't know. So far, most areas in the US are experiencing regressed sea level rise rates of 1-4 mm per year.
    Noted it that Arctic sea ice is already floating in the water, so by itself, sea ice melting is no big deal. When land ice and glaciers go, I'd be very concerned, since they don't displace ocean water right now. That's more of a heat-sink issue (I hate the term "feedback loop").
    Back to my point, sea rise will NOT be uniform over all the oceans at varying rates. Additionally, different areas will be impacted especially if they are experiencing subsidence and coastal erosion, which can be highly variable.  Never trust one number!

    Onward through the fog
  4. Michael Tobis's avatar

    Michael Tobis Posted 10:23 am
    19 Dec 2008

    arithmeticIf you multiply the area of Greenland by the average ice depth in Greenland and divide by the total surface area of the ocean you should get about seven meters, essentially the maximum ice melt contribution to sea level from the northern hemisphere alone.
    If you are not in that ballpark, you have a mistake in your data or your calculations.
    Everyone note please that sea level rises under warming even if the glacial balance is neutral due to thermal expansion of the water.

    mt

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