Gone west


NASA’s Earth Observatory has just published a pair of beautiful images of the Wilkins Ice Shelf showing the ice bridge before and after collapse. The image above, acquired on April 6th, shows the bergs created by the break up moving towards the west. With the bridge gone, the remnant ice from earlier break ups to the east is now free to follow those bergs out to sea.

14 thoughts on “Gone west”

  1. Yes it is very interesting that the Wilkins Ice shelf is breaking up, however completely unrelated to catastrophic global warming, as is implied by including a flurry of articles documenting the progress on this global warming dedicated website.

    For those of you who don’t realise the Wilkins Ice shelf is between two islands off the coast of the Antarctic Peninsula. The Antarctic Peninsula is in the Western Hemisphere, while most of an Antarctica is in the Eastern Hemisphere. Antarctica is a big place, bigger than Europe in fact.

    So let’s put this in perspective. Imagine Europe covered in ice. A shelf between Britain and Ireland melts and collapses. Is Europe warming?

    Given that the bulk of Europe’s land mass is east of Germany, who can say?

    Well research has actually shown growing ice cover in the bulk of Antarctica, so focusing in one piece of antidotial evidence is scaremongering.

    No better than if someone said, Europe had a cold winter this year, so the World must be cooling.

    No evidence for/against long term global warming needs to be two things, global, and long term.

    Please explain to your readers the actual significance off this, and stop using it as evidence that IPCC predictions are already outdated.

    “We show that 72% of the Antarctic ice sheet is gaining 27G29 Gt yrK1, a sink of
    ocean mass sufficient to lower global sea levels by 0.08 mm yrK1”


    WINGHAM Et el

  2. @ Catonz.

    You forgot to mention undersea volcanoes 😉

    But, who are you to say this is completely unrelated to catastrophic global warming..it could well be a symptom of it, alongside the decline in Arctic sea ice, retreating glaciers world wide, melting of permafrost etc etc. As indeed, could increased precipitation in east Antarctica.

    Still, if I put the telescope to my blind eye……..

    PS thankyou for pointing us to a reputable source for the ice mass gain in east antarctica

  3. … Wilkins Ice shelf is breaking up, however completely unrelated to catastrophic global warming,

    Glaciologist with extensive Antarctic experience, are we?

    Well research has actually shown growing ice cover in the bulk of Antarctica, so focusing in one piece of antidotial evidence is scaremongering.

    This is simply not true. For a very good overview of the state of our understanding of the mass balance of Antarctica, I would suggest you read section 3.2 of last year’s USGS report on Abrupt Climate Change [PDF], which reviews all the recent work, including the single paper you cite, and concludes:

    Taken together, these various approaches indicate a likely net loss of 80 Gt/yr in the mid 1990s growing to 130 Gt/yr in mid 2000s. The largest losses are concentrated along the Amundsen and Bellingshausen sectors of
    West Antarctica, in the northern tip of the Antarctic Peninsula, and to a lesser extent in the Indian Ocean sector of East Antarctica.

    Please explain to your readers the actual significance off this, and stop using it as evidence that IPCC predictions are already outdated.

    The significance is clear enough: the Wilkins Ice shelf is not melting from the top down (which is what happened to Larsen B), but from the bottom up. This means that it’s ocean heat driving the break up — and we know that ocean heat is what West Antarctica is most vulnerable to. Check back through earlier posts, if you are really interested. This has important consequences for sea level rise…

    As for the IPCC’s projections being outdated, that’s hardly news. It’s been obvious to anyone with half a brain from the moment that the Arctic sea ice set a new record minimum in 2007.

  4. 1st, I didnt fully explain myself / bad use of words, when I said

    “however completely unrelated to catastrophic global warming”

    I accept your point here. What I meant was, in my humble opinion isolated warming in one part of Antarctica does not get me panicking, I would rather look at science than be driven by emotion.

    Your explanation is warming water, but again this could be a change in currents rather than total warming, maybe not, maybe it is total warming. It just frustrates me when isolated events get jumped on and used as the face of global warming, but for every warm summer somewhere in the world there is a cold winter somewhere else.

    In terms of your report titled “Abrupt Climate Change”, I’m not going to read it. The conclusion is in the title. Hardly an honest investigation I presume 🙂


  5. “In terms of your report titled “Abrupt Climate Change”, I’m not going to read it. The conclusion is in the title. Hardly an honest investigation I presume ”

    catonz it’s a pity you didn’t even get as far as page 1 and discover the report is from the US Climate Change Science Program, which is charged with integrating federal research on climate change. The lead agency in the report was the US Geological Survey and contributing agencies were the National Oceanic and Atmospheric Administration and the National Science Foundation. Dishonesty must be rampant throughout the entire US scientific community. You say you would rather look at science than be driven by emotion. Yet as soon as you are offered some science you excuse yourself from looking at it on the a priori grounds that it can’t be honest.

  6. Cheers Doug, great article you sent me.

    Quote from the article:

    “Over the time period of our survey, the ice sheet as a whole was certainly losing mass, and the mass loss increased by 75% in 10 years. Most of the mass loss is from Pine Island Bay sector of West Antarctica and the northern tip of the Peninsula where it is driven by ongoing, pronounced
    glacier acceleration. In East Antarctica, the loss is near zero, but the thinning of its potentially unstable marine sectors calls for attention. In contrast to major increases in ice discharge, snowfall integrated over Antarctica did not change in 1980–2004 (ref. 27) and even slightly increased in areas of large loss17.We conclude that the Antarctic ice sheet mass budget is more complex than indicated by the temporal evolution of its surface mass balance. Changes in glacier dynamics are significant and may in fact dominate the ice sheet mass budget.”

    Both articles point out the large uncertainties in determining overall balance, and the regional differences in melting rate.

    For sure, global warming will cause increased melting in Antarctica, and sea level rise. But I stand by my original premise, that this article is misleading, and that regional warming can not be touted as global warming:

    “evidence for/against long term global warming needs to be two things, global, and long term.” – this is neither so should not be touted as such.

    Now onto the other article,

    You provide the article to refute my claim that ice cover is growing in east Antarctica, which makes up the bulk of the continent,

    I said I didn’t want to read an article with such an obviously biased origin given its title. But, OK I will read the part on Antarctica,

    Now after I have read it I have to wonder, have you read it???

    It supports my claim!

    “In the peninsula, the mass loss increased to 60±46 Gt a-1 in 2006 due to the massive acceleration of glaciers in the northern peninsula following the breakup of the Larsen B ice shelf in the year 2002. Overall, the ice sheet mass loss nearly doubled in 10 years, nearly entirely from West Antarctica and the northern tip of the peninsula, while little change has been found in East Antarctica”

    “Results show that interior parts of East Antarctica monitored by ERS-1 and ERS-2 thickened during the 1990s,”

    “Zwally et al. (2005) estimated a West Antarctic loss of 47±4 Gt a–1, East Antarctic gain of 17±11 Gt”

    The article then concludes “In East Antarctica, with the exception of glaciers flowing into the Filchner/Ronne, Amery, and Ross ice shelves, nearly all the major glaciers are thinning” – however no source is given, very strange considering all through the paragraph sources are given that cite East Antarctica is gaining.

    I will end on question for you Gareth, I listened to your submission today, you stated that warming has a lag affect of 20-30 years, so even if we stopped emitting we would experience warming.

    Does this apply for all gasses or are you only meaning CO2, and other long life gasses? Would methane create warming in 20-30 years? if this does not include CH4 could you please include a correction in your follow up document, it is very important the select committee is aware of the differences between gasses as they are making recommendations on important policy, and methane makes up a large amount of NZ’s inventory.

  7. Now after I have read it I have to wonder, have you read it???
    It supports my claim!

    You claimed on the basis of one paper that the Antarctic is gaining mass. The thorough review of all current work that I pointed you at says otherwise. The balance of evidence is that Antarctica is losing substantial ice mass.

    Very diligent of you to listen to my oral submission. Were you there on business or just out of interest?

    The committed warming is not tied to any one gas. It depends on the total forcings acting on the system. It doesn’t matter what gas is doing the heat trapping – it’s the heat trapped that’s important. If you look at the AR4 projections (WG1, Chap 10), they include a “commitment” scenario, based on forcings held constant at 2000 levels. Most of the “catching up” takes place in the first 20 years as the oceans warm up and the planet achieves thermal equilibrium (incoming radiation matched by outgoing). No need for me to “correct” anything in my statement… 😉

    NZ agriculture’s primary vulnerability is to action taken overseas to address climate change. Not acting to reduce emissions (inside or outside an ETS or other regulatory framework) will put farmers at a disadvantage in key markets. Recent work suggests that a substantial chunk of emissions reductions can be achieved at zero cost or better. It’s worth noting too that land use change is a valid way to reduce emissions: we don’t have to have dairy farms everywhere…

  8. The mass loss in Antarctica is a regional phenomena.

    Recent work or recent interpretations by Simon Terry? None of the options are currently recognised by UNFCCC, all technologies are in the pipe line I think and yet to be proven, but it would be great if in 3 years time he is right, wait and see.

    Went out of interest, but didn’t realise you would be submitting. They are not very good at publishing who is up each week. Maybe you get work out a way to publish the info on your website? Now that you are in contact with the secretariat?

    I don’t think you really answered my question, will methane released now still be creating warming in 20 years?

  9. It would be better if agriculture was doing more than “waiting and seeing” (and I know that in some respects it is, at least in research terms), but instead of expensive ad campaigns promoting dairying as clean and green, it would be better to start on some serious emissions reductions.

    On the hearings: Carbon News does a pretty good job. I know it’s behind a paywall, but Hot Topic regulars get a discount… 😉

    You originally phrased your methane question in the context of committed warming, and the lifetime of CH4 in the atmosphere is broadly irrelevant to that. However… from memory, any given CH4 molecule is likely to be oxidised to CO2 and water in 12-15 years. The total amount of CH4 at any one time is determined by the balance between the “sinks” — mainly atmospheric oxidation by OH radicals — and emissions from wetlands (natural and artificial (rice)), permafrost and hydrates, mining and oil/gas extraction, ruminant animals etc. When emissions exceed sinks, the amount rises.
    Bottom line: methane emitted today will not itself be causing warming in 20 years time, but the CO2 it leaves behind will – and CO2 hangs around for hundreds of years…

  10. Alright, but how is methane produced in a cows stomach? CO2 is required in the initial reaction, so its a bit like bio fuels, although CO2 is emitted it is also sequested so the CO2 part of the equation is balanced (although methane concentrations will be increased).

    And only other point because way off topic to this article, your life time of methane is on the high side,

    “Once emitted, CH4 remains in the atmosphere for approximately 8.4 years before removal” – IPCC AR4 Sec 7.1

    The GWP calculation uses 12

    (why? Because they figure methane lifetimes will increase as more as emitted, and the hydroxyl radical concentrations are reduced. Section 2.3.5 gives an overview of hydroxyl radical concentrations,

    “IPCC/TEAP (2005) concluded that the OH concentration might change in the 21st century by –18 to +5% depending on the emission scenario.” – IPCC AR4 sec 2.3.5


    “Short-term variations in OH were also recently deduced by Manning et al. (2005) using 13 years of 14CO measurements in New Zealand and Antarctica. They found no significant long-term trend between 1989 and 2003 in SH OH but provided evidence for recurring multi-month OH variations of around 10%” – IPCC AR4 Sec2.3.5)

  11. Ha! If you know so much, why ask in the first place?

    The OH concentration side of the equation is interesting, because OH is the atmosphere’s “cleaner”. It’s not just methane that can/could overwhelm OH, industrial particulates and aerosols can do the same. In other words, if OH is being used up dealing with pollution, that could decrease the rate of methane oxidation, and lead to a rise in atmospheric CH4 even if emissions aren’t increasing.

    As far as cows are concerned, the important point is not the CO2 “tail” (which could be considered as not additional, as you say), but that the carbon is converted to a far more effective GHG.

    From the perspective of the dairy/pastoral industry in NZ, rather than argue “it’s all too difficult, so let’s not bother”, it would be far better (if only from a marketing perspective) to be proactive about grabbing the emissions reductions that are available now, and perhaps embark on a programme of carbon and biodiversity offsets to deal with the rest.

  12. OK, so back to the original point, will methane cause warming in 20-30 years?

    – Also if gasses other than methane cause an increase in methane lifetime, is it equitable for the IPCC to place the burden for this on methane emitters such as New Zealand, through GWP calculations?

  13. I thought I’d answered your first point. A molecule of methane emitted today is unlikely to be around to “cause” warming in 20-30 years, but it will have caused plenty of warming over its time in the atmosphere, and that warming is cumulative, at least until GHG concs stabilise and the planet reaches thermal equilibrium.

    The IPCC doesn’t impose anything. The GWP calculations are used to allow emissions to be compared. As methane is “worth” 25 times more than CO2, a nation could choose to reduce methane by a small amount, perhaps allowing some room for CO2 emissions to grow. That’s not so easy for NZ, of course, because methane has always been a large part of our emissions profile.

    As I’ve said before, however, we could reduce our agricultural emissions by choosing to grow something other than milk, meat or wool. There are plenty of choices available… Farmers make decisions on what crops to grow based on costs versus returns. If one of the costs is carbon, then they can choose to either manage that cost, or change to a lower-carbon crop.

    If you’ve read my ssubmission to the ETS Review, you’ll know that I recommend a national topoclimate effort, to allow for crop optimisation at farm level. That’s adaptive, and profitable.

Leave a Reply