Five feet high and rising!

Sea.jpg Yesterday, while dissembling, I had what I might loosely describe as a “bugger” moment. Yale’s Enviroment360 web site (which I plugged on its introduction last June) currently features an interview with Robert Bindschadler, a NASA ice expert who is working on the Pine Island and Thwaites glaciers in West Antarctica. The “bugger” moment?

e360: And in the theoretical case that Pine Island and Thwaites glaciers completely dump into the ocean – obviously it’s not going to happen in the near-future – what kind of sea level rise would they contribute to?

Bindschadler: That portion of West Antarctica, that third that flows northward primarily through those two glaciers, has the potential to raise sea level 1½ meters. That’s sort of an upper bound, a worst case. But the time scale is what really matters. Some say that we won’t see these ice shelves disappear in our lifetime – I’m not so sure. I think we might well.

e360: Are you kidding?

Bindschadler: No, no at all.

Bindschadler looks to be about my age. He reports that the ice shelf is melting from the underneath at a rate of about 50 metres per year at the grounding line. And then, a little later, just to make me spill my tea on the keyboard:

e360: I know that the IPCC was saying maybe 1 ½ feet or a half-meter of sea level rise in the 21st century. Is it your opinion that we could be looking at significantly larger sea level rise?

Bindschadler: Yeah, I think there’s sort of an unspoken consensus in my community that if you want to look at the very largest number in the IPCC report, they said 58 centimeters, so almost two feet by the end of the century. That’s way low, and it’s going to be well over a meter. We may see a meter by the middle of the century.

e360: Oh my gosh.

Bindschadler: And if this behavior that we’re seeing in Pine Island, and even Greenland continues – and we don’t see any reason why it wouldn’t continue – well, over a meter by the end of the century, I think is almost certain.

How notably prim the interviewer is. I think I might have managed something a little more Anglo Saxon. A “meter by the middle of the century” is a very long way above most people’s worst case (though not, perhaps, Hansen’s), but it makes our vulnerability to sea level rise much more of a near-term danger than a comfortable reading of AR4 might suggest. It’s a fascinating article — goes into more detail about the WA ice sheet and PIG (yes, that’s what they call it) than anything else I’ve seen in the last few years. Recommended, but not if you have beachfront property.

Meanwhile, a workshop being held at VUW in Wellington is looking at Andrill results, and finding that the WA ice sheet shows signs of repeated meltbacks over the last five million years [Stuff]:

Professor Tim Naish, director of Victoria University’s Antarctic Research Centre […] is co-science leader of the $30 million Andrill project on the ice, with Professor Ross Powell from Northern Illinois University in the United States.

“Antarctica’s ice sheets have grown and collapsed at least 40 times over the past five million years,” Prof Naish said.

“The story we are telling is around the history and behaviour of the ice sheet … as an analogue for the future,” he said.

Not good news, it seems. Expect a rush of papers covering Andrill work over the next few months.

[Johnny Cash]

22 thoughts on “Five feet high and rising!”

  1. Gareth, it might be prudent to show some restraint.

    Note this from the UK Guardian…

    ‘Apocalyptic climate predictions’ mislead the public, say experts…Experts at Britain’s top climate research centre have launched a blistering attack on scientific colleagues and journalists who exaggerate the effects of global warming.

    The Met Office Hadley Centre, one of the most prestigious research facilities in the world, says recent “apocalyptic predictions” about Arctic ice melt and soaring temperatures are as bad as claims that global warming does not exist. Such statements, however well-intentioned, distort the science and could undermine efforts to tackle carbon emissions, it says.

    Wouldn’t want to overstate the case would you ?

  2. Ayrdale: This is a thread about sea level rise, not your preoccupations. You have your own blog, take them there. And this is by no means an “apocalyptic” post: it highlights the concern amongst those closest to the problem. Things are happening faster than expected. That’s bad news it would be foolish to ignore or downplay.

  3. No with respect, you have no clue.

    The point here is that

    “the potential to raise sea level 1 ½ meters. ”


    “an unspoken consensus in my community that if you want to look at the very largest number in the IPCC report, they said 58 centimeters, so almost two feet by the end of the century. That’s way low, and it’s going to be well over a meter. We may see a meter by the middle of the century”

    So you still think you know more than the experts?

    So what degree do you have… none… then shut up please! With respect.

  4. Perhaps ‘apocalyptic predictions’ about Arctic ice-melt aren’t helpful because it’s sea ice so melting which won’t have an effect on sea levels. What is in question here is parts of Antarctica, which has plenty of scope to affect sea level rise…

  5. jonno, don’t you think the general public needs to be aware of the situation ? and that cooperation is essential ?

    [This is still off-topic. Take the discussion to your blog. Restrict your comments here to sea level rise, please. GR]

    It’s all about accuracy, honesty and community cooperation jonno…

  6. Gareth, in the first quote he refers to the *shelves* disappearing in his lifetime (meaning the next @25 years based on his apparent age). The bulk of the ice loss would occur subsequent to that. So… things could be even worse!

    Just a few months ago Mark Serreze said the consensus was at a meter. Now it’s over a meter, with that much being possible as soon as mid-century. Considering that just a few years ago this ice was considered to be essentiually static on these time scales, one wonders what we’ll be looking at in another few years. If the Antarctic winter vortex starts getting broken up the way the Arctic one already is (and see my belated comment in that thread), even larger changes may be in store.

  7. No courage behind your convictions ?

    Plenty… But you have to recognise that at Hot Topic I set the agenda. I will not allow you to derail what I hope will be an interesting discussion about SLR.

    You have your own blog. You control the agenda there. If you want to talk about that story, you can do so with your readers. But you don’t seem to have many prepared to comment…

  8. Gareth, reading and re-reading this exchange, with the “snips” imposed by you, I’m so aware of what more could be said.

    This is a truly fascinating topic, the most important in our lifetimes probably and it is such a shame to limit and/or inhibit it.

    Every poster has at his/her fingertips the opinions of dozens/hundreds of people…it seems to me to be such a shame to limit the discussion only to those who agree. Preaching to the converted can’t really be rewarding in the long term.

    Don’t you agree ?

  9. This is pretty startling stuff.
    I was aware of the Pine Island and Thwaites Glaciers and the fact that they are under stress, but I didn’t realize that they are such big players. I thought the Ross Ice Shelf was the one to watch…
    To borrow a line from Brendan Fraser: This just keeps getting better and better.

  10. Ayrdale #15

    I thought the discussion was about the loss of West Antarctic ice. Have you got a scientist whose evidence contradicts Bindschadler’s analysis or who finds the analysis faulty? I’m sure we’d all be interested to hear if you have.

  11. I see another recently posted article on the same website by science writer Michael Lemonick includes reference to the Greenland ice sheet’s glaciers displaying the same phenomenon as the Pine Island and Thwaites glaciers. He reports other scientists who also see us looking at the possibility of up to two metres sea level rise. It’s a very lucid article. As well he deals with the loss of Arctic sea ice and the increases in the annual global CO2 emissions levels. It’s all in the context of his main point – that the IPCC report is already out of date in some serious areas. Excellent for non-scientist readers.

  12. Bryan, the upshot of the Pfeffer paper (discussed extensively at RC) is that this glacial undermining effect is limited in Greenland since once the glaciers retreat to a certain point their channels gave gotten so shallow that the effect stops. There are some large glaciers with deep channels that extend far into the interior, but Pfeffer did a calculation showing that for those glaciers the narrowness of the openings (mountains on both sides) places a mechanical limit on how much calved ice can get out. At least at present, rapid ice loss seems to require calving since the melting process just doesn’t add up to enough. I assume other scientists will be examining their assimptions, so probably this is not the final word on the subject.

    Another assumption Pfeffer made in limiting 2100 SLR to six feet maximum is that the WAIS (which they didn’t study) would stay relatively stable even though the grounding line would stay deep all the way inland and there are no limning mountains. Bindschadler obviously thinks these are not good assumptions.

    Putting all of this together, we may be looking at more like a three meter worst case for 2100. It’ll be interesting to see what synthesis they come up with next month in Copenhagen.

  13. Thanks Steve. Your explanation reminded me that I had somewhere fairly recently seen reference to Pfeffer’s calculation, though without remembering his name. I recall wondering whether one could take comfort from it. Not much, by the look of the Real Climate discussion and your own comments here.

    Fearful prospects. One would hope serious political action can’t be much longer delayed.

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