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. I believe there’s now some evidence that a dirty great comet smacked into what is now Australia’s north-west shelf around the time of that die-off. That leaves the question of an unfortunate millenium or a hundred about 55 million years ago, when sea life was apparently boiled to death and the mammals of the earth suddenly shrunk to sizes necessary in times of poor nutrition and such. If memory serves, that’s the current favourite for world-historic methane hydrate burp. I got all this off the telly, mind.

    As for the correct attitude to take to global warming; I remember reading a bloke called Cees Hamelink. He reckoned we should treat policy questions based on projections into the future as a form of ‘social gambling’. I am reminded of an economist whose name I think was Roberts, too – on matters of such policy he averred we too often failed to factor the foreseeable cost of our being wrong into the equation. A small chance of a global disaster needs to be weighed against even a probability of relatively inexpensive precautions being wasted.

  2. Rob, according to this BBC site there were arguably 6 mass extinctions, in order as follows:

    1. Late Cambrian ca 500m years

    2. Late Ordovician 440m

    3. Late Devonian 365m

    4. End Permian 250m

    5. Late Triassic 208m

    6. End Cretaceous 65m

    The first two may have been a series of extinctions. The big one (90% plus) was the End Permian. The End Cretaceous is the most famous because it did for the dinosaurs. There’s a theory that it was caused by an asteroid and in fact there is a huge crater off the Yucatan peninsula of Mexico that dates from this period.

    There are lots of other lesser mass extinctions, apparently, and this article by Mark Lynas mentions the 55m extinction event associated with a methane burp. There is a problem, I think, about what is associated with these events and what causes them.

    Michael Benton’s work on the End Permian is recent because scientists couldn’t get into Siberia earlier. There are three links to articles in my post. This one is the TLS review of his book. According to the SBS program I saw the extreme part of the event lasted about 80,000 years.

    I’d better stop there before the geologists kill themselves laughing. But in relation to the global warming/climate change topic it’s likely that these dramatic events are mostly a distraction. It is the slow rising of the water that really matters according to James Hansen.

    What Hansen worries about is that we are ‘forcing’ the climate to a point unknown where ice sheet degradation is unstoppable. He reminds us that during the Eemian interglacial with temperatures about 1C above what we’ve got now the sea level is estimated to have been 5-6 meters higher.

    Hansen is quite sanguine about reigning the whole problem in but says “it surely requires concerted world-wide actions.” Some of it is just good house-keeping, such as cleaning up the whole “black carbon” problem. He says 1m people die every year from man-made air pollution.

    Sounds like good insurance to me.

  3. Rob, I think the idea in your last sentence is pretty good basis for taking action.

    The usual version of the Precautionary idea doesn’t get you far. The realistic scenario is the possibility of some very large disaster with a small probability less some very large current cost. Roughly, taking expected values doesn’t get you far since multiplying the small and uncertain prob by the small and uncertain cost of disaster can give you a net benefit which is positive or negative.

    If you say you just want to avoid the worst possible outcome then its best to do nothing since there is also some chance that the measures you take will be ineffective and produce a warming problem along with the failed high costs of dealing with it.

    A possible approach is to minimise the regret you could imagine yourself experiencing. This is sometimes criticised as ‘crying over spilt milk’ but it says something like your last sentence. You want to minimise the regret you might experience in failing to deal with a terible disaster when you could have dealt with it successfully at relatively low cost.

    It sounds to me like a reasonable human response.

  4. climate change is not a question of probablities – Harry Clarke’s statement “The realistic scenario is the possibility of some very large disaster with a small probability” is simply wrong in fact.

    Climate change is a fact, not a probability. Quite frankly comments like this from otherwise intelligent people smack of a degree of hypocrisy exemplified by their unwillingness to deal in facts and their preference for “fictionalizing” the facts as probabilities!

  5. “smack of a degree of hypocrisy exemplified by their unwillingness to deal in facts and their preference for “fictionalizing” the facts as probabilities!”.

    Kyan, you can accept the fact of global warming (I don’t but take the issue very seriously) but still think of it as having different possible consequences and with small probabilities of catastophic effects.

  6. In my brief exploration of the literarure there seemed to be three main catastrophic scenarios:

    1. The onset of a new Ice-age

    2. A Dansgaard-Oeschger (D-O) event where the Gulf Stream is interrupted by a fresh water flush in the Northern Atlantic, leading to a 5C or more plunge in temperatures for a shorter time period (but up to 1,000+ years) than an Ice -age

    3. Methane burps.

    Hansen discounts the ice-age scenario almost out of hand. They seem to be caused by slight shifts in the earth’s orientation due to the gravitational pull of Venus, Saturn and Jupiter. Hansen says the advent of industrial man and consequent climate forcing has taken this one out of play.

    The D-O scenario seems to depend on a sudden flush of fresh water as when a huge Canadian ice dam broke 8200 years ago and caused a mini ice-age for 200 years. As George Monbiot explains in Born yesterday there are no sources a similar sudden fresh water flush anywhere at present.

    Methane burps, as in 55m and 251m years ago are little understood and it is not clear to me whether they were a cause of a major event or caused by and an amplifier of such an event. They seem more likely to occur, however, when the climate is warmer.

    Leaving these three to one side, kyan is right IMO. Evidence of global warming and climate change is all around us. Annabel Day’s article ‘The rising cost of global warming’ in todays AFR (subscription required) describes how many companies (banks in their lending risk calculations, for example) are already factoring in GW and CC as a fact. It’s the major reason I don’t invest in insurance companies carrying reinsurance on their books.

    Here’s a dilemma. I’ve heard that the drier weather we’ve been having in Australia in recent times is in large part due to the large anti-cyclones just south of the continent we have been seeing on our TV weather maps every night for about the last 5 years. They are, I understand, unusual. This phenomenon seems to be associated with (caused by?) the ozone hole which is pulling polar circulation systems in tighter around the south pole. This has the effect of preserving ice sheets in Antarctica except for the peninsula, where there were dramatic Rhode Island sized lumps break off in 2002.

    We all would like to see the ozone hole closed. But if it does close and the West Antarctic ice sheet melts as a result of climate forcing already in the system together with unavoidable momentum increases in forcing, well then we could be in big trouble even though the scenario is likely to play out over centuries.

    I say you can see dangerous anthropogenic climate interference by looking out the window, or more particularly watching the TV, if you know what you’re looking for.

  7. Just one thing Brian, you missed one of the extinctions, being the holocene one.

    If/when there is significant climate change, the biota, which has adjusted and evolved in response to similar changes in the past, will this time have already been put into a highly stressed situation, with habitat fragmentation across much of the landscape meaning there is limited opportunity to adjust.

    Say goodbye to the biodiversity we’ve come to appreciate.

  8. wilful, for the uninitiated by ‘holocene’ you mean, of course, the present one. It did cross my mind, but not being a scientist I just followed the BBC site information. This site gives a quick overview, and this one gives a brief overview of the rest, unlike the BBC site, in the right order.

    On the holocene I heard an American researcher a few years ago talk about his research into island ecologies. They are inherently less adaptable over long periods of time. He was making the point that our land use activities and national parks have pretty much replicated the island concept everywhere.

    Also I understand there is a concept of ‘critical species’ the disappearance of which not only destabilises a food chain, at times it can destabilise related webs of life not directly in the food chain. With land clearing and monocultures we are bound to be destroying some of these before we know they exist or appreciate their importance.

  9. Thanks, wilful. Very depressing!

    This BBC site addresses the extinction implications of global warming.

    At the end of the post I mentioned ethical considerations. These are typically considered in terms of winners and losers in the human domain, as there will most likely be some of both with global warming.

    I believe we should take the welfare of other species into respectful consideration. I can’t see any logical reason why we should privilege the most destructive of the lot, ie us.

    Hence, the ethical position most easy to defend would be to return the atmosphere as near as possible to how we found it before the industrial age. This is no doubt impossible but it perhaps represents the direction we should be heading.

    I will certainly be told by some that this is economically unacceptable and impossible. However, as Jeff Harvey so aptly warns us :

    ” The inevitable conclusion … from the empirical evidence is that a combination of human activities are leading to fraying food webs, the transformation and simplification of terrestrial and aquatic ecosystems, a signficant loss of species and populations, falling water tables, and a disruption of biogeochemical cycles over immense spatial scales. In other words, we face a number of serious and growing problems worldwide that need urgent attention, if there are not to be consequences.”

    It seems as though we have been cheating by not paying for the true externalities of our life-style. Sooner or later we will have to pay our debt and reach a new equilibrium with the world around us. Better we engineer it for our comfort than have it forced upon us.

    We could start by trying to stabilise the climate.

  10. “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.”

    Sir David King is misinformed, ignorant, or a liar. The midpoint of his global his global projection is 3.6C. Only someone who is misinformed, ignorant, or a liar would maintain that there is a 50/50 chance of global surface temperatures warming by 3.6C from 2000 to 2100.

    If he truly believes that there is a 50/50 chance that global warming will be 3.6C from 2000 to 2100, that means that the temperature would increase by an average of 0.36C per decade.

    I’ll be happy to bet him $200 that global surface temperatures (or even better, lower tropospheric temperatures!) will not increase by 0.36C from 2000 to 2010. And then, even if I lose the bet, I will be happy to renew the bet for the next decade (i.e., that the increase will be less than 0.72C from 2000 to 2020), and the next decade (that the increase will be less than 1.08C by 2030), and the next, throughout the entire 21st century (i.e., a total bet of $2000).

    There is even a website specifically set up for such bets:

    “His idea is to get ahead of the game, to reduce CO2 emissions unilaterally by 60% by 2050.”

    He and his fellow idiots should reduce their own *personal* emissions by 60%, and leave the rest of humanity alone; we have *real* problems to deal with, not computer-generated fantasy problems.

    Mark Bahner (environmental engineer)

  11. “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.”

    Not to mention the ~300,000 Iraqi people that are estimated to have been murdered during Saddam Hussein’s reign of terror. (Why don’t they count in your evaluation of state terrorism?)

    And you’re apparently also not counting the over 1 million people who have ***starved to death*** in North Korea in the last decade. I’ll bet they were plenty scared as they watched their bodily functions gradually shut down.

    You can read a little of what it’s like right here:

    Hungry Ghosts, by Jasper Becker

  12. “Mark Lynas believes that methane burps are a possibility.”

    Let’s see…Mark Lynas appears to have a bachelor’s degree in history and politics. Why should anyone attach much weight to his (religious?) beliefs about methane burps?

    More importantly, what odds does he assign to this “possibility”? (After all, there is a “possibility” that an asteroid/comet could eliminate over half of the earth’s human population in the next 100 years.)

  13. “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).”

    Science has already provided answers to those particular questions. There is virtually no chance (less than 1 in 10,000) that the oceans will rise by 5 meters in the next 100 years. And the odds of New York being under a mile of ice by 2100 are probably even lower than 1 in 10,000. (Mainly because humans wouldn’t allow that to happen.)

  14. “climate change is not a question of probablities”

    Climate change IS a question of probabilities. What is the probability that the sun’s output will decline in a matter significant enough to cause a “little ice age”?

    Conversely, what is the probability that the sun’s output will increase to cause additional warming?

    Finally…what is the probability that the sun’s output will stay essentially the same (i.e., neither contributing to significant cooling or significant warming)?

    Not to mention the question of what the probability is that we will discover that CO2 and methane have little or nothing to do with global warming, and that global warming is caused almost completely by black carbon (i.e. “soot”)?

  15. Mark, that’s six comments in a row from you. In the interests of productive discussion, I request that you take a break until some others have responded.

  16. “But if it does close and the West Antarctic ice sheet melts as a result of climate forcing already in the system together with unavoidable momentum increases in forcing, well then we could be in big trouble even though the scenario is likely to play out over centuries.”

    The worldwide average (arithmetic mean) income in 2000 was on the order of $5000.

    What do you think the worldwide average (arithmetic mean) income will be in 2100?

    What do you think it will be in 2200?

  17. Oh, my questions were all in year 2000 U.S. dollars.

    That is, what will be the worldwide average (arithmetic mean) income in 2100 (in year 2000 U.S. dollars)?

    In 2200 (in year 2000 U.S. dollars)?

  18. Mark, concerning your last question, I have no idea what the worldwide average income will be in 2100. I’d hazard a guess that we won’t be quoting it in US$. Maybe in euros, rupees or yuan. Most likely none of the above.

    I’m not a forecasting nut. I’m more concerned with flows, dynamics, processes and relationships, together with the ontological, teleological and ethical bases of these, if that’s not too pompous.

    Should we care about what happens in 100 years time? Yes, definitely, if our actions or lack of action have any bearing. Which, inevitably, they do.

    I’ll comment on your other points by and by.

  19. On the ethical issue, as I have said in comments once or twice before, we need to consider the fact that one good way of making yourself sustainable is to rob your neighbours.

    Environmentalists often insist that preservation of a sustainable environment will benefit everyone, and appear to believe that this is a good reason for preserving sustainability. To many, it isn’t.

    To many people, and I suspect to at least some national governments, the short road to sustainability of a personal/national lifestyle is theft, not working to preserve the natural endowment of all mankind. To such people, diminution of resources and degradation of ecosystems is just a better reason to steal, because the “swag” is worth more.

    Students of colonial history should find such a course of events familiar and probable; in a sense it has all happened before.

    Environmentalists seeking to persuade people to cooperate in order to preserve a sustainable natural world need to consider the “theft option” more seriously. Unless/until a convincing response is found, environmental arguments have a hollow ring.

  20. Sorry, I’ve been busy.

    In thinking about the series of questions you raised and the points made, Mark, I came to several conclusions.

    First, if I answered each in turn I’d be here a long while. Funnily enough, given my lack of scientific and technical qualifications, I think I could make a fair fist of quite a few, mostly by using the findings and ideas of other experts. But you have already indicated you don’t rate mere gatherers of other people’s ideas by your comments on Mark Lynas.

    Secondly, a fair few hares were set running on topics other than global warming. From this I saw that ideologically we were likely to disagree on many things. On many of these we would have a small probability on changing each others views.

    Third, I had a feeling that by your questioning style you were playing a cat and mouse game, where I or others might slip up and then you could cry “Gotcha!”

    Maybe not, but I decided to have another look at your site.

    From internal evidence I got the impression you had not sat down and read it word for word for some time. I then wondered whether you still hold all the positions you put there, for example the relative weight you would give to CO2 and methane on the one hand and black carbon (“soot”) on the other.

    The information is very clearly presented. However, in a couple of cases you present it in a manner that could easily mislead. For example the graph in Figure 1 in the section “What will happen to us?” shows the decreasing decadal percentage INCREASES in CO2 emissions. This shows the bars decreasing and gives the visual impression to the non-mathematical among us that the problem is as good as solved. A fairer way of presenting the same trend is in Figure 11 on page 19 of James Hansen’s paper which shows TOTAL global fossil-fuel CO2 emissions as a rising, albeit plateauing line graph.

    In Figures 3 and 4 you use 4 different kinds of line to represent 6 lines on the chart, doubling up on two of them. This muddles your projections with the IPCC projections. Also the heavy lines represent the 50% probability lines which are actually the mid values between 5% and 95%. Hence the 50% line, being heavier, visually appears the more likely. If this is how mathematicians present probabilities to non-mathematicians, I suggest they consider changing it. To my simple mind 95% would seem the more likely.

    This seems to leave you with quite a lot of carbon in the air at about 610ppm in 2100, quite an increase on 369ppm in 2000.

    The most serious problems, though, are in what you claim you don’t know. For example, you say you are not an expert in modelling. This does not prevent you from having a swipe at those who do have such expertise. To me “40 stories” do not seem excessive when you are plotting the complexities of how many people will live where, under what circumstances and how much they will generate of the 7 main emission categories which Hansen identifies.

    Then you also disqualify yourself from expertise in positive feedback, which Hansen identifies as a significant problem in future ice melting. Rather than defer to those with the requisite expertise you fall back on your ‘black box”. This seems like linear projections on past and present trends to me in a field that seems to be distinctly non-linear.

    To tell the truth, that’s when I lost interest a bit.

    Finally, you do suggest that CO2 and methane are the main game. Hansen, by contrast, identifies 8 factors in the past, both negative and positive (see p.9) and 7 for the future (see p. 16). This seems a much more competent and thorough approach.

    So why then would Hansen be so wrong in suggesting there is a problem, albeit less than the IPCC in some ways? Do we infer that he cooks the books so that he can attract increased funding?

    I’d like to conclude by addressing the question of qualifications. Mark Lynas has an honours degree in history and politics from Edinburgh University. He has written what appears to be a well-researched book, “High Tide” taken seriously in reviews in The Guardian and the Times Literary Supplement. His own original contribution seems to stem (I haven’t read the book) from his visits to five continents to talk to those experiencing first hand the effects of climate change.

    Sir David King, Chief Scientific Advisor to the UK Government has a distinguished academic career that speaks for itself.

    Neither of these gentlemen is pushing out the barriers of scientific knowledge. Both are seeking to convince us of a concern that they have and use rhetorical techniques in the process. This does not mean they are wrong. Nor are they idiots or knaves.

    For laymen like myself there is always an issue as to how we judge the quality of experts. Every-one faces this problem in selecting doctors, dentists, tradesmen etc. Of those I read I felt that James Hansen of the NASA Goddard Institute for Space Studies had most of the bases covered and seems to be committed to the spirit of science. Certainly he has no noticeable lacunae in his armoury, unlike your good self.

    The Hansen paper I referred to above contains answers to all the questions you raise in so far as they relate to global warming and climate change and more besides. But with greater knowledge he lays less certain claims as to what actually will or will not happen.

  21. On Brian’s point as to how we judge the quality of experts, and indeed the broader issue of people whose vision is so narrowed by technical expertise, Weber had something to say about such a society:

    No one knows who will live in this cage in the future, or whether at the end of this tremendous development entirely new prophets will arise, or there will be a great rebirth of old ideas and ideals or, if neither, mechanized petrification embellished with a sort of convulsive self-importance. For of the last stage of this cultural development, it might well be truly said: ‘Specialists without spirit, sensualists without heart; this nullity imagines that it has obtained a level of civilization never before achieved” ( 1930, p. 182).

    Weber, Max. 1930. The Protestant Ethic and the Spirit of Capitalism. Translated by Talcott Parsons. New York: Charles Scribner’s Sons.

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

    BB, have a look at what happens with Pilot Induced Oscillation. It is entirely possible that positice corrective intervention may be the very worst thing possible (as opposed to taking our hands off the controls and allowing natural stabilisers to operate – if they’ve already collapsed, we’ve had it anyway).

  23. PML that’s an interesting concept. Forgive a longish reply, but I think it’s important.

    By Pilot Induced Oscillation I think you mean the possibility of overcorrection. You will note in this example that the glider bounced four times in landing, but the pilot did regain control and and the landing was completed albeit with some damage to the plane. This is probably the best we can hope for in GW and CC.

    To work the analogy further, each bounce is maybe a hundred years or more. At the moment we have 340 watts per square meter in from the sun and 339 watts out. James Hansen reckons that if we hold emissions at present levels we will probably incur 0.4 to 0.7C warming in the next 50 years. The problem then is that such warming is likely to cause ice sheet degradation which will work its way through to a new stability over the following 50 years or more. No-one can tell for sure.

    But the problem of over-correction had crossed my mind, which may be why flatlining emission levels is a reasonable first step, which has a beautiful analogy in what the glider pilot really should have done.

    The alternative of taking your hands off the wheel probably would have killed the pilot and in GW and CC may largely, at worst, considerably depopulate the earth.

    Hence our ethical horizon needs to be opened up to embrace the notion of optimum sustainable living conditions in the next couple of centuries. This is a long time-span for us, but a blink of the eye for the planet.

    This raises the charge as to whether trying to find a new equilibrium for the earth’s climate is not a giant act of hubris. I’m sorry but we are already into that game. Our past hubris and assumptions of eternal progress through the application of technology mean we have already wrested controls from the natural systems, albeit at the margins.

    By “at the margins” I mean that we have taken out of play, it seems, variations in the sun’s output, which may have caused the mini-ice age roughly between 1300 and 1800AD. The deeper stability seems to have been laid down about half a billion years ago. 600 to 700 million years ago, according to this article we had a series of glacial periods when sea ice reached the equator and there is evidence of sea-level glacial activity close to the equator. Each glacial period “ended violently under extreme greenhouse conditions. These climate shocks triggered the evolution of multicellular animal life…”

    This article Plankton may protect Earth from icy fate
    indicates that these little tackers by carrying carbon deep into the ocean when they die ended the violent oscillations, allowed life as we know it to evolve and allowed the seams of coal and the wells of oil and gas to be formed. The are my new No.1 heroes in the biosphere ahead of earthworms.

    So the oscillations we are dealing with are relatively minor by comparison.

    James Wolfensohn in an article ‘Hurry, we may save the planet’ in the AFR 26 June 2004 (subscription required) says we need to act urgently on global warming. He points out that the Montreal protocol has possibly avoided “up to 20 million cases of skin cancer and 130 million eye cataracts”. We are now in danger of losing “12 per cent of birds, 24 per cent of mammals and 30 per cent of fish [which] are either vulnerable or in immediate danger of extinction”.

    In terms of north-south equity “poorer countries pay much of the “costs” [of advanced country’s emissions and therefore life-style] – losing up to 8 per cent of their GDP per year due to environmental degradation, as well as suffering devastating effects on health and human welfare.” He concludes: “It will be too late 25 years from now to make the right choices. For the sake of our children and our children’s children, we must act now.”

    Some of what Don Henry (formerly Moreton Island Protection Society and now Australian Conservation Foundation) taught James in his spell at the World Bank must have rubbed off.

    So our ethical concern must extend in three directions – to the less well off in the world, to other species and into the future, not just our children and our children’s children but way beyond that.

    We have a choice.

  24. 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.

  25. 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.

  26. 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:

  27. 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!

  28. 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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