Polar amplification, again

Posted by William M. Connolley on November 26, 2007
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When I was a wee mustelid, I wrote about this; and there is an RC piece, and as far as I know, its all still valid.

But this post is aimed at those who put an “s” into poles in “What exactly is the mechanism that causes the poles to warm faster than the tropics as a result of climate change?” when they mean the real world, as opposed to a simplified or equilibrium one. Mind you, since the ar4 sez Models of the 21st century project that future warming is amplified at high latitudes resulting from positive feedbacks involving snow and sea ice, and other processes (10.3.3.1) you can hardly blame anyone else for being confused. Traditionally, the IPCC doesn’t pay much attention to Antarctica, and we help them by not publishing :-)

Because, you see, there is only amplified warming at the North Pole; and this is what is predicted. I’m speaking now about the bulk of Antarctica, rather than just the excitingly overheating Peninsula. And by “predicted” I mean, comes out of climate models.

The first plot is the zonal mean of a difference of a 2090-2095 mean and a 2005-2010 mean from the IPCC ar4 sresa1b set, annual mean sfc T. The data have been somewhat crudely processed so don’t publish based on this. Black lines are full zonal means, and the thick blue is the average (including the cr*ppy models). Red lines are the land-only means (which is why they have a gap at 60S and at the NP).

i-ce69c30317f48bc50ac9ee03f08a9f11-warming-ar4.png

Ve zee zat zee North Pole warms nearly 6 oC (all now taken from the avg) and the South 3 oC. Looking at the land-only (red) we see that, apart from the northern high latitudes, most latitudes warm by about 3 oC and there is no SH polar amplification.

Looking at a map of the difference of the average…

i-31c20b296f1e50830cd31cbc86747647-warming-ar4-map.png

It becomes clear that, away from the NP, land warms 2-3 oC, ocean 1-2 oC. The TAR has a similar pic. The commonplace explanation is that the oceans are a nice heat sink and hence delay warming (see-also Rowan Sutton) and there is a nice big ocean all the way around Antarctica.

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Comments

  1. #1 Adam
    2007/11/26

    Does the height of (much of?) Antarctica play a roll too, or is that generally ignored?

    [Its in the models, of course, as a large part of why the sfc is so cold -W]

  2. #2 mugwump
    2007/11/26

    That second pic is a strong argument for global warming being of overall net benefit. The really cold, inhabited places are the ones to warm the most. The north passage through the arctic will open up.

    Couldn’t have designed it better meself.

  3. #3 Alexander Ač
    2007/11/26

    “That second pic is a strong argument for global warming being of overall net benefit” – assuming that changes in temp. are gradual and smooth, assuming that nothing else changes, only temperature. Do you believe that? ;-)
    .
    But I also guess that sceptics in the future will say – OK, GW is bad, but we couldn’t do anything about that anyway… :-)

  4. #4 mugwump
    2007/11/26

    Obviously my assessment is just a gut response, but yeah, I doubt things will be all that much worse in the hotter places and they’ll be a heck of a lot better in the colder ones.

  5. #5 Linzel
    2007/11/26

    Woa!
    Here’s some sarcasm. Could you have been less scientifically vague, general or inaccurate?

    I find it incredible that we can examine ONE map of data. Conclude that overall the world is going to be warmer and suggest ‘Oh thats not so bad!’

    [Who said anything about good/bad? I'm just discussing the form that the warming is likely to take. Certainly one could look in more detail - by season perhaps. But are you disputing the general conclusion? -W]

    I’m truly hoping I misunderstood what you were trying to say but the warming is the secondary cause. The effect of rapid global warming is difficult to say but the threat to habitat and hence food production, ecological stability is possibly the greatest threat to human existence since the development of the atomic bomb.

    You can [I have] that the planet would be better off without us anyway, but the amount of human suffering this potentially threatens is off the charts.

    We have little idea of the final consequences but they are very dangerous. Two options: 1. state we don’t know therefore lets keep up the experiment. 2. The threats are huge, lets try to minimize them. [precautionary principle]

    Climate may be based on physical processes but LIFE is dependent upon them.

  6. #6 Adam
    2007/11/26

    I think Linzel was responding to mugwump.

    BTW my question was on whether the height had an effect in the reduction in warming,…but on thinking about it I can’t see why it would, it would just, as you say, make the starting point lower.

  7. #7 JesusChristHimself
    2007/11/26

    Back in the 1950s they used to publish lots of photographs of Alaska’s gigantic veggies. In this better warmer climate, perhaps they will be able to feed tens of millions of starving Texans with 10 huge Brussels sprouts from that future breadbasket: the Northwest Territories.

    That is, if the Canadians will share their better warmer world with the rest of us.

  8. #8 mugwump
    2007/11/26

    The effect of rapid global warming is difficult to say but the threat to habitat and hence food production, ecological stability is possibly the greatest threat to human existence since the development of the atomic bomb.

    Since you were apparently talking to me, how many net deaths are due to atomic weapons? I believe atomic weapons are still well into positive territory, having saved more lives by avoiding the need for a mainland invasion of Japan than were lost in the bombings of Hiroshima and Nagasaki.

  9. #9 mugwump
    2007/11/26

    That is, if the Canadians will share their better warmer world with the rest of us.

    The Canadians will still be very cold. Most days where I live, I could get a 3C increase by driving no more than 300 miles or so to the South. Where’s the ecological cataclysm in that?

  10. #10 cce
    2007/11/26

    A 300 mile shift northward in isotherms is a major change in the climate, with major implications for ecosystems. Or, put in a humans-first perspective, for those of us who depend on snowpack for much of our water, it won’t last through the summer.

  11. #11 Eli Rabett
    2007/11/26

    The latest EOS has an interesting article on the WAIS warming. their bottom line is that the circumpolar deepwater is warming the ice sheet. Of course, this really is the end of the earth and there are very few observations. Even the satellite data is sparse.

  12. #12 jesusChristHimself
    2007/11/26

    “Where’s the ecological cataclysm in that? …” – mugwump

    I don’t know. Perhaps it’s hiding in the same dark hallway as the so-called economic cataclysm that would be caused by doing things to avoid it?

  13. #13 James Annan
    2007/11/26

    this really is the end of the earth

    Even by your standards, Eli, this is somewhat alarmist

    :-)

  14. #14 mugwump
    2007/11/26

    for those of us who depend on snowpack for much of our water, it won’t last through the summer.

    Gosh darnit, we’ll just have to build a dam or two. Or heaven forbid, lay some pipes.

    Still not seeing an ecological cataclysm. At least, not one that isn’t dwarfed by humanity’s existing impact.

  15. #15 David B. Benson
    2007/11/26

    I am under the impression that (much of) Antartica is protected not only by altitude, but also by the circum-polar winds which (almost) continuously blow from west to east. Thus, for example, little moisture reaches far inland making (much of) Antartica extremely dry and cold…

  16. #16 cce
    2007/11/26

    Our “existing impact,” as in all the dams we’ve already built, and all the aquifers we’ve already tapped? There’s apparently nothing wrong, ecologically speaking, with a Grand Canyon with no water in it, as long as there’s a puddle left in “Lake” Mead.

  17. #17 Chris O'Neill
    2007/11/27

    Most days where I live, I could get a 3C increase by driving no more than 300 miles or so to the South.

    Lucky you. Where I would like to live when it’s not too hot, I need to travel 600 miles to the south-est along the coast to get somewhere 2C cooler. But I guess all those corals on the Great Barrier Reef can just get in their boats and sail south when they think it’s getting too warm.

  18. #18 mugwump
    2007/11/27

    But I guess all those corals on the Great Barrier Reef can just get in their boats and sail south when they think it’s getting too warm.

    Not quite the mechanism, but the effect will be the same. If humans were causing cooling you’d be complaining about coral moving North. Fact is, the Earth climate changes all the time; just because we humans may be behind some of the current change seems immaterial to me, unless we are putting ourselves in peril.

    [http://mustelid.blogspot.com/2004/12/why-do-people-say-climate-change-is.html -W]

  19. #19 outeast
    2007/11/27

    Please stop feeding mugwump.

  20. #20 Eli Rabett
    2007/11/27

    Eli has standards? Where did you hide them?

  21. #21 Chris O'Neill
    2007/11/28

    the effect will be the same.

    I believe you. Thousands wouldn’t.

  22. #22 mugwump
    2007/11/28

    “[http://mustelid.blogspot.com/2004/12/why-do-people-say-climate-change-is.html -W]”

    Yep. And we also know that sea-level rose by 5m a century once-upon-a-time. So sometimes climate change is fast, sometimes it is slow, sometimes a dirty great asteroid hits the Earth and really f*cks things up.

    My point: we’re in the geological age of the humans. The Earth is already undergoing a transformation way beyond anything that could be regarded as “Business As Usual”, even before you look at climate change.

    Humans are by far the most interesting thing to happen to Planet Earth – apart from Roswell of course :). We’re just at the very beginning of a technological revolution that within a few hundred years will give us virtually unlimited control over our environment. Let’s have a bit of perspective folks.

  23. #23 Zeke
    2007/11/28

    “We’re just at the very beginning of a technological revolution that within a few hundred years will give us virtually unlimited control over our environment.”

    Our past efforts certainly inspire hope…

    As far as the impacts of climate change, it really depends on the degree. At less than 2 degrees C warming (most likely the least we can expect), there -might- be net positive economic gains for the U.S., and certainly for Russia. Any climate change would be unambiguously negative for countries like Bangladesh and India. Once you get up to and beyond 3C, however, its pretty much bad for everyone no matter which economist you trust (e.g. even Mendelson).

  24. #24 Chris O'Neill
    2007/11/28

    Let’s have a bit of perspective folks.

    Sure, let’s deliberately ignore reality because deliberately ignoring reality is merely having a bit of “perspective”.

  25. #25 mugwump
    2007/11/28

    Once you get up to and beyond 3C, however, its pretty much bad for everyone no matter which economist you trust

    In which case I trust none of them. At the very least the Canadians should be better off well beyond 3C. It’s frigging cold up there most of the year.

    Chris, it’s impolite to resurrect an old argument from another blog here. Nevertheless, Annan posts here so why don’t you ask him to resolve the issue: did he rely on climate models when deriving his sensitivity estimate, or was it purely data driven (as you wish to claim)?

  26. #26 Chris O'Neill
    2007/11/29

    it’s impolite to resurrect an old argument from another blog here.

    What a hypocrite.

    Nevertheless, Annan posts here so why don’t you ask him to resolve the issue

    Unlike mug.., I don’t need an author to read his paper to me.