BB on CC

h6. A guest post from Brian Bahnisch on global warming and climate change

On the weekend I decided to revisit the topic of anthropogenically caused global warming and consequent climate change after renewed debate on this site (Parish backs Kyoto) and elsewhere. What follows is some of what I found.

Sir David King, Chief Scientific Adviser to the UK Government, recently advised Tony Blair that climate change was a greater problem for the world than terrorism. While he identifies the range of prospective warming as 1.4 to 5.8C he doesn’t enter into much discussion about its validity. This is a man who doesn’t let the grass grow under his feet, mainly because he can feel the water creeping up his legs already. He points out in an address to the American Association for the Advancement of Science that now something like “10 percent of the housing within England is in flood plains as distinct from 20 years ago”.

In fact the Thames barrier, completed in 1982, at first came into play once in every 3 or 4 years. Now it is used 6 or 7 times a year, each time preventing a flood that would cost $56.7 billion in damage.

His idea is to get ahead of the game, to reduce CO2 emissions unilaterally by 60% by 2050. This will maximize their influence on other countries and make them a mozza through their lead in the appropriate technologies.

He points out that last summer 30,000 people died prematurely in Europe in the heat waves. Mark Lynas in this article reckons that “last year’s heatwave across Europe was so far off the normal statistical scale that climatologists logged it as a once-in-10,000-years event.” That makes it a once per interglacial affair. I’m sure Sir David has worked out that 30,000 is many more than died through international terrorism if you take out state terrorism perpetrated by countries like the US, the UK, Australia and Israel.

Mark Lynas believes that methane burps are a possibility. Since there is calculated to be 10,000 gigatonnes of methane locked up under the oceans and the stuff is 21 times more potent greenhouse-wise than CO2 it is a worry. I’ll just spell that out. Each year we add 6 billion tonnes of carbon to the atmosphere. There is the equivalent of 210,000 billion tonnes of the stuff locked up under the oceans. Is that a worry? Well 251 million years ago according to the work of Michael Benton (see his “When Life Nearly Died: The Greatest Mass Extinction of All Time”, references here, here and here) methane emissions caused about 90% of life on earth to die.

It seems that the temperature may have been 5C or so hotter then. Benton puts the likely cause as a huge volcanic eruption in Siberia. It’s not clear how much the temperature had to do with it, or what might cause smaller burps.

Methane burps may not be a likely scenario, but it seems there is a bias in the way the statistics are collected and presented which favours gradualism and suppresses critical or threshold events associated with ‘abrupt’ climate change.

Of interest is the report of the US National Research Council’s Committee on Abrupt Climate Change (2002). On page 7 of the Executive Summary they say: “Current practices in the development and use of statistics related to climate and climate-related variables generally assume a simple, unchanging distribution of outcomes.” Not being a scientist I don’t understand what that means. I do, however, understand the next sentence: “This assumption leads to serious underestimation of the likelihood of extreme events” a situation that obviously needs rectifying.

A man who understands that there may be critical phases in the process and points of no return is James Hansen. His article ‘Can we defuse the Global Warming time Bomb?’ appeared in the March issue of the Scientific American. A larger version in pdf format is available here.

Hansen reckons the main culprit is coal and the effect to worry about is rising sea levels, especially through ice sheet degradation. He points out that forming ice sheets, glaciers etc is a dry process and takes centuries, if not millennia. Degradation and melting is a wet process and much more rapid. Not enough is known about the process of degradation and when a critical point of no return may be reached.

For me his other important message is that climate forcing operates over a very long time-scale (a century or so to reach a new equilibrium if we stop emission increases now?). Hence we have 0.4 to 0.7C warming already in the pipeline if we stop increases now. We are currently forcing at the rate of about 1 watt per square metre of the earth’s surface, with an additional 2 watts per square metre likely in the next 50 years. As watts per m2 convert to about 0.75C of warming, this gets you, if you add all three, to 2.8C in 50 years. I’m not sure whether you do add all three, the first two components may be coincidental. If so you get 2.05C.

Hansen thinks we should contain additional forcings to 1 watt per square metre, or half what he thinks will happen. Any more could put us in a critical meltdown phase, when the process may be unstoppable with significant consequences for the earth’s capacity to sustain life as now.

It’s worth noting that Hansen considers the IPCC projections unduly pessimistic wrt emissions and temperature change. Possibly we’ll lob in the lower range of their forecasts. He is very clear, however, that the IPCC has underestimated sea level rising. Apparently they discounted melting and concentrated on thermal expansion.

I am impressed with Hansen, especially his care about what we know, what we are uncertain about, what we don’t know and the interactivity between various factors. In particular he appreciates that there may be smoothing in the models that obscures the unlinearity of reality.

So that’s some of what I found rummaging around this weekend. I’m not a scientist but I wouldn’t be surprised if there was a paradigm shift or two around the corner. I do not think we can wait for science to provide final answers, however, lest we find ourselves (well, some of humanity) 5 meters under water or with a mile-high slab of ice over Manhattan (Hansen says it can’t happen, but he too, may be surprised).

There is a debate about what constitutes dangerous anthropogenic interference (DAI) which turns out to be a matter of ethics as much as science. I invite you to have a look at a brief introduction to the subject here. The levels nominated by various authorities are surprisingly low.

Given the science already to hand I find the suggestion that we take no special action difficult, indeed impossible to justify ethically.

30 thoughts on “BB on CC

  1. It’s rather more than overcorrection, it’s the very fact that the pilot is in the loop that alters the feedback. The glider example wasn’t PIO; that comes up with rotorcraft, when it can kill trainees until their reflexes have come right. If you take your hands off the controls of a helicopter, it will crash anyway – but it will save an autogyro.

    To get an idea of the processes involved, try as much of this experiment as you feel safe with:-

    – freewheel a bicycle along, with your hands on the handlebars (stable);

    – take your hands on the handlebars (less stable, but OK if you are fast enough for the gyrsocopic effects to stabilise the bicycle);

    – put your right hand lightly on the left handlebar (and over you go, as your trained reflexes immediately apply corrections of the wrong sign).

    It is subtler than overcorrection, since the issue is that we do not have the analogue of trained reflexes. It’s the same thing that rose up to bite 1960s Keyenesian policies; not simply that they were overcorrecting, but that anything arising from the policy process was bound to both too late and too large a correction (the time lag is also important). It’s an example of the philosophy of free will vs. predetermination in action.

    So, while it makes sense to stop active harm, it does not make sense to take any form of corrective action – particularly because our only hope rests in the idea of a return to a self-stable behaviour regime. If we have already broken the system we can’t get to safety anyway, so it does make more sense not to take positive steps.

    Anyhow, I do think that right or wrong, I have already refuted the idea that there is no ethical basis for refusal – someone could well sincerely belive this to be a greater and more dangerous risk, as I do.

  2. PML I think this then comes back to how you assess the risk. If you think, as Hansen indicates, that with 1C extra warming as there was in the Eemian interglacial, there is any possibility that the oceans would rise by 5-6 meters, as, according to estimates, they did then, you’d be inclined to try to learn the new skills necessary to ‘fly the plane’.

    There are a lot of assumptions here, the first being that we don’t know for sure, apparently, how high the seas were in said Eemian interglacial, and if they were whether they will be so again.

    If you think that the world-wide coordinated action is likely or even certain to be unresponsive enough that it is bound to lead to a stuff-up you might think of a different approach. Rather than manipulate the base circumstances, you might try to improve your adaptability to whatever may occur. For example, you may promote population policies designed to lower the world’s population to safer limits. This can be argued in the terms of green philosophy, where you live in a way that is more responsive to the systems around you and within which you are afterall embedded, not being lords of the universe.

    But then you may think that exercise also beyond us in practical terms, and as a tradesman said to me the other day when we got onto this topic, whatever is left of the human race will probably evolve to suit the circumstances.

    But in relation to planet earth and the biosphere, in the long run, adapt we must. It depends how much will we can muster and how much intelligence we can apply in the process. But also how sensitive we are to our surroundings, how we connect with other people and how we can build institutional organs of co-operation towards common ends BEFORE the threat is so blindingly obvious that we are driven to co-operation.

    But in the end also there is unlikely to be any long-term stability. The situation will be dynamic and fluid. I just wonder whether we can organise the parameters so that we can continue to have ‘human progress’ within them, or whether we are in for a rougher ride.

    The alternative is surely that we continue on our individualistic, hedonistic path and eat, drink and be merry.

  3. You misunderstand me.

    It isn’t a matter of learning the new skills and then it will work – at the start you just don’t have the skills, and learning them is fatal itself. You are part of the problem at that point. To learn the new skills by being thrown in at the deep end is to require a catch 22, making the undesired fatal mistake as part of the learning experience.

    Any deliberate positive steps are likely to be wrong. It is not a matter of “let’s try something else then”, it’s “when in a hole stop digging”. We don’t have the option of a mixed strategy of trying it your way first, then leaving well enough alone.

    The argument that we should try other things since there are correct options out there misses the point; there are no correct options attainable by us, since the path to the correct options goes through a fatal learning experience. It’s very like early socialists accurately pointing out that a command economy would work if they once had the right things to do – it missed the point of the rebuttal that it was not humanly possible to run a command economy to the desired performance level. That’s where the “socialism was never tried” argument is both right and wrong – it was never tried because all attempts to launch it, in this vale of tears, attain something else.

    And so also with attempts to fix the environment. If nothing else, managed nature isn’t nature. But merely in terms of survival, our only hope rests in there still being automatic mechanisms, in which case we have to stand back and allow them. If there aren’t any anyway, there’s no point managing nature and we might as well just attempt to salvage what we can in an exploitative way. But there’s time enough to find out if that is what faces us.

    This links to some PIO issues:

  4. I did have a hunch that you were not going to allow me to relearn riding a bike from scratch using my right hand on the left handlebar. I’ll look up the references and comment further a bit later.

    As to nature being nature, I think we’ve gone past that point. Yesterday I heard that we should only eat three serves of small fish per week, or one serve of big fish plus no other fish. The reason was mercury. btw much less of both if you’re pregnant!

  5. PML, you could be right. The climate forcing we have already done could be the equivalent of the “pilot’s abrupt liftoff during takeoff, and his failure to correct a pilot-induced-oscillation during takeoff initial climb which resulted in the main rotor blades striking the tail mounted rudder, and an in-flight loss of control” in the example you gave.

    I’m not sure whether the pilot was doomed because he jerked the take-off or whether he actually had just one shot at getting the correction right and missed it. If the latter is the case we could be at the point where we have jerked the take-off and NOW have just one shot at retrieving the situation. Or maybe we’re gone already. The difference could be whether we lose a few hundred million people or a few billion.

    It would take some-one more knowledgeable about climate modelling and I think some-one who didn’t particularly care which way the answer came out to give you a decent guestimate. Nevertheless I suspect the analogy has got problems. We are only forcing 1 watt in 340 per square meter and a few watts here and there is not, I think, going to crash the system. It seems far more stable now than it was 600 million years ago (thankyou plankton!) so I suspect we’ve just got a bit of a wobble. After the wobble there will be a new equilibrium which, while it may not support billions of humans, will almost certainly support a quite diverse range of life on the planet. The planet and life on it will go on.

    If I may I’d like to put the analogy to one side and look at the actual problem.

    James Hansen reckons the net increase of emissions is tapering. He thinks this may because of the reduction of CFCs following the Montreal protocol and the tendency to use natural gas rather than coal. He thinks this may be why we appear to be undershooting the bottom of the IPCC range. Too early to say, it may be a fluke, he says.

    In Hansen’s paper (link given several times earlier) from p18 he outlines “A Brighter Future”. His ‘alternative scenario’ does look doable, which he thinks will limit emissions to an additional one watt per square meter of forcing which should limit effects at something less than dangerous. Our emissions need to be stabilised in about 50 years.

    Coal is the big one. We need to find a cleaner replacement (or part replacement) or do a lot of carbon capture and sequestration. Here again I don’t have the expertise, but having listened to copious experts a 10 to 20 year time frame to make significant inroads seems possible and thereabouts on Hansen’s timetable. The natural cycle of decommissioning and replacing old power stations helps.

    In truth I’m starting to worry more about the other major systems on the planet which we are stressing such as fresh water and our fisheries. Jeff Harvey briefly outlined some of the problems and suggest we read the scientific literature. For me it called to mind a special issue of Time Magazine of April-May 2000 for Earth Day, much of which is here on the net.

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