Down to the sea

An interview with climatologist Ellen Mosley-Thompson published yesterday in Yale Environment 360is a reminder that for those working with ice there’s not much doubt about where we’re heading. She spent six weeks of the summer on her ninth visit to Antarctica drilling ice cores on the Antarctic Peninsula, one of the fastest-warming places on earth. Its winter temperatures have increased by 6 degrees over the past 60 years and year-round temperatures by 2.8 degrees. As a result, sea ice now covers the western Antarctic Peninsula three months less a year than three decades ago, 90 percent of glaciers along the western Antarctic Peninsula are in retreat, and large floating ice shelves are crumbling.

 

Mosley-Thompson headed a team of six for the drilling, and they were part of a larger group attempting to understand the warming behind the break-up of the Larsen B ice shelf in 2002. Ecologists were looking at an ecosystem on the ocean bottom that until eight or nine years ago had been covered by ice for thousands of years and considering how it is adjusting to the new normal. Glaciologists were looking at how much more rapidly the glaciers are discharging into the ocean with the disappearance of the buttressing ice shelf. A marine group was looking at changes in marine geo-chemistry, collecting new cores in the area that was covered by ice to compare with the cores previously drilled in the ocean bottom along the outer margins of Larsen B when it was in place.

It’s an impressive range of investigation she describes. The ice drilling on the Bruce Plateau was able to get right down to bedrock at 455 metres, and the cores will be closely analyzed back in Ohio for the information they contain about past climate, perhaps to the last glacial period and beyond.

Mosley-Thompson is married to Lonnie Thompson, the highly respected glaciologist. While his wife has been working mostly in Greenland and Antarctica he has done more ice corings of low-latitude glaciers –- in the Andes, Africa, and the Himalayas –- than any other person alive. Yale Environment comments that their work, taken together, paints a sobering portrait of the rapid retreat of most of the world’s glaciers and ice caps in the face of the buildup of planet-warming greenhouse gases.

Here are some of the things Mosley-Thompson has to say in the interview about the overall global picture. In response to the interviewer’s observation that the deep Antarctic ice cores taken at Dome C years show that we have got more CO2 in our atmosphere than at any time in 800,000 years:

“Very clearly. If you look back over the eight glacial/interglacial cycles, you essentially see that CO2 never rises above 300 parts per million and we’re at about 389 now. Methane never rises above about 800 parts per billion, and I think we’re at about 1,700 parts per billion. So we’re clearly outside the range of natural variability. I personally think that graph simply showing the natural fluctuations in those two important greenhouse gases, over almost a million years of Earth history — and then you see the two dots [today] that are so much higher than anything that we see in that near-million history — tells us very clearly that we have a serious problem.”

What does the cumulative ice coring  work show about what we’re experiencing in the last century or so in terms of the warming of the planet?

“ Well, from the tropical work, the cores in the Andes and the Himalaya, the oxygen isotopic ratio in those cores, when you stack those cores together, show very clearly that the last 50 or 60 years have been the warmest in the last 2,000 years.”

The ice cores from the Andes do show a Medieval Warm Period signature and a very distinct Little Ice Age cool signature.  Not surprising, she says, because both those periods are expressed most strongly around the Atlantic Basin and the moisture that builds the glaciers in the Andes of Peru actually comes from the Atlantic.  But the cores from the Tibetan Himalaya show virtually no signature of these periods.

“so when we put these records together, the medieval warming is very modest and the Little Ice Age signature is strongly muted as well. And what really stands out when you put these all together and into the composite, is the last 60 years. The oxygen isotopic enrichment in the tops of the cores [indicating warming] is very striking.”

She notes that particularly in the case of the tropical ice fields the glaciers are retreating very rapidly:

“And, in fact, several of the ice fields, particularly one that we recently published the results [for] in the southwestern Himalaya, it has not gained mass or has no ice that was deposited after 1950. It’s like these glaciers are just literally being decapitated. And it’s very frightening.”

And what about the IPCC error on Himalayan melting?

“…when you look at the breadth of the Intergovernmental Panel on Climate Change reports, and how much information is in there, the fact that this must be the most egregious error, otherwise they would be making more of something else –  I think it’s astounding that the IPCC got as much right as they did because there was just tremendous potential for error.”

And if we don’t begin to rein in CO2 emissions, where is the cryosphere, the Earth’s ice zone, heading?

“To the oceans. Ultimately that’s where all water goes, to the lowest level.”

17 thoughts on “Down to the sea”

  3. "about the IPCC error on Himalayan melting?

    “…, the fact that this must be the most egregious error, otherwise they would be making more of something else – I think it’s astounding that the IPCC got as much right as they did"

    Who said it was the "most egregious error" ? It was simply the earliest reported, but the African agriculture wopper, the Amazon howler, Netherlands geography embarrassment, and the damages from extreme weather events disaster, could each be called more serious. But the important point is that these "errors" were all in one direction. In school we call that cheating. But it is the entirely predictable ourcome of an assessment process driven by preconcieved ideas where evidence that doesn't fit the script is ignored , while anything that looks like it might bolster the catastrophist case gets a handful of Viagra thrown at it.

      1. I am well aware of RC's standard mantra:
        "This is a minor error. It doesn't change the overwhelming consensus. Ignore the man behind the curtain…"

        Meanwhile public trust in these habitual "wolf" callers, continues to collapse.

        Isn't it strange that this "greatest challenge of our times" has been almost invisible in the British election campaign?

      2. I am well aware of RC's standard mantra:
        "This is a minor error. It doesn't change the overwhelming consensus. Ignore the man behind the curtain…"

        Meanwhile public trust in these habitual "wolf" callers, continues to collapse.

        Isn't it strange that this "greatest challenge of our times" has been almost invisible in the British election campaign?

        1. Steve's a big fan of free-enterprise, and I'm amazed how many fans of The Market who are also AGW deniers seem to resort to a kind of simple-minded linearity in analyzing some long-term trends that could lead to some very silly investment decisions if they used similar logic 'at home'.

          When I go to the local ASX site and look at the charts tracking a stock's performance they have this thing called a 'trend line' which shows whether a given stock is actually rising or falling over a longer time interval in order to get rid of some of the outlier day-to-day noise. In the case of climate we need longer – 30 year – trendlines to remove year-to-year noise.

          Now, if this year, next year, or the year after turns out to be the hottest on record – as is strongly likely – will it 'prove' AGW?

          No.

          But by inverting your own simple-linear model there'll be lots of people saying 'right back at ya!' I confidently predict you (collectively) will then revert to a 'nuanced' interpretation.

          Yet anyone with a smidgeon of actual conservatism in their soul – as opposed to the radical reactionaries who have hijacked the name in recent decades – will be thinking 'well, golly, that rather does look like we're heading where all those actual qualified climatologists say, and, heck, we only have the one atmosphere… let's play it safe!'

          Which is what this always has been about, really.

  4. The Himalayan glaciers are still melting it is that in the WGII report there was a typo giving a date as 2050 not 2500. Mistakes happen in any document it does not make a difference to the fact tha tthe globe is warming and it is almost certain that we are doing it.

    I would note that WGI report (the one only done by the climate scientists) there have been no mistakes identified and it does the information it contains about Himalayan glaciers accurately reflects current knowledge.

    Those of us who frequent this blog know all about this. So why does Wrathall come here? It is surely not to impress us as he is just making himself look a pratt. I suggest he stick to the know nothing blogs where they will not laugh at him.

    1. That was 2035 and 2350, Doug. But actually the 2350 was someone's off-the-cuff guesstimate from the mid-'90s and is also wrong.

      The reality is that on present trends the bulk of the Himalayan ice will be gone by 2100, but the glaciers with sufficiently high-altitude accumulation zones will remain indefinitely since it would take a very warm world indeed for temps at 8,000 meters to start spending much time above freezing. In terms of the impact on hydrology, though, it's a distinction without much difference.

      1. Thanks Steve. I mis-remembered the actual figures. Just that the figures had been transposed at some stage and not caught during the editing process.

Leave a Reply