Home > Environment > Worst case scenarios 3: Climate change

Worst case scenarios 3: Climate change

April 2nd, 2004

The big threat to the worlds environment as a whole is global warming. The best-bet projections prepared by the International Panel on Climate Change suggest that, in the absence of substantial action to mitigate global warming, global temperatures would probably increase by about 1 degree C between now and 2050 and by a further 1 degree C between 2050 and 2100.

This ‘best estimate’ implies environmental damage on a scale sufficient to justify an urgenr response. Of most concern to Queenslanders is the likelihood that rising sea temperatures could cause large-scale bleaching of coral reefs (the process by which symbiotic microorganisms are expelled from corals, leading to the death of the coral). A recent study by Queensland University’s Centre for Marine Studies estimated that 95 per cent of the coral cover on the reef would be lost by 2050, even under conservative assumptions about the rate of global warming.

However, many opponents of action to mitigate global warming have pointed to the uncertainties that surround climate projections to argue that the IPCC estimates may be overstated. Under favourable assumptions about such things as the feedback between climate change and concentrations of water vapour, it is possible that the temperature change associated with global warming will be less than 1 degree C, and might be swamped by natural climatic cycles. There are even some scientists (mostly not experts in the relevant fields) who deny the reality of global warming altogether.

The problem with this optimistic view of things is that it is equally important to look at the possibility that things might be worse than we currently expect on the basis of available scientific knowledge. The worst-case scenarios typically involve some sort of ‘tipping point’, with large-scale melting of the Atlantic ice shelf or a sudden change in ocean currents. Such changes can produce positive feedback leading to rapid climate change. The worst case scenarios typically involve a temperature increase of 5 degrees C.

The best strategy in this case is that of the Kyoto protocol. The reductions in emissions proposed under Kyoto won’t be enough to prevent global warming. But they provide a starting point. If new evidence over the next decade shows that the problem is not as bad as we thought, measures to implement Kyoto will be like an insurance policy on which we have not made a claim. The alternative possibility, of doing nothing, then being confronted with the worst-case scenario will involve far greater economic and environmental costs.

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  1. eric bloodaxe
    April 2nd, 2004 at 22:19 | #1

    the big danger is that there is a tipping point, like “El Nino”, and a really big disaster occurs when Europe becomes uninhabitable by non-eskimos.

  2. kyan gadac
    April 3rd, 2004 at 03:16 | #2

    In a comment in the ‘economic worst case scenario’ I pointed to the significance of the supply side of the economic equation in relation to climate change impacting upon food prices. I strongly suspect that coral plankton are far less vulnerable (as a species) to climate change than are humans.

    Further – the point to make about climate change is that it is already occurring and accelerating rapidly. The last 10 years have seen global temperatures rise faster than the previous 20 years and they rose more then, than in the previous 50 years. Also CO2 levels last year increased by 3ppm which is 0.6ppm faster than expected. It is still an open question as to whether this is due to China’s industrialization or due to outgassing of CO2 from the oceans (which is a consequence of oceanic warming). There has also been some disturbing findings published recently regarding higher than expected rates of warming being found in deep ocean water.

    However all these details pale into insignificance when you break away from the tunnel vision of climate change and consider it in the context of other ecocides. The Amazon rain forest is disappearing at a rate that is faster than the worst nightmares of greenies 15 – 20 years ago for the sake of short term soya bean/cattle ranching operations.

    Desertification due to mining of ground water or to salinity from loss of trees is occurring at a rapid rate in all temperate countries and is synergistic with climate change.This will lead, in short order, to a disruption of human food supplies.

    Ozone depletion due to persistent organo-halogens, of which only the worst culprits have been curbed, is also synergistic with global warming both by decreasing the stratospheric temperature and directly increasing the retention of reflected infra-red. The effects of the resulting increased UV on agriculture are likely to be missed initially. But increased dessication, susceptibility to fungal and viral infection are known consequences.

    Ozone loss in temperate regions is not being reported but you can see for yourself by going here and comparing the monthly global average images over the last ten years, in particular the Xmas months are revealing and troubling.(open up the ftp folder and then complare the relevant .gif files.)

    It is difficult to avoid the conclusion that the four horsemen are stalking us. The only consoling thought is that this has nothing to do with the acts of God and everything to do with the acts of humans and therefore what has been done can be equally undone.

    I doubt whether it can be undone until the crisis is upon us and we have to choose between capitalism and starvation but that point is not that far away. Certainly the current politics of the major parties does not go anywhere near addressing these issues and the Greens, who at least claim an understanding of these matters, have yet to produce a coherent economic alternative roadmap that is more than motherhood statements.

    P.S. I haven’t mentioned other issues such as pollution, war, disease, pestilence etc. I’m assuming that most readers can join the dots.

  3. Tom Davies
    April 3rd, 2004 at 09:05 | #3

    As Kyan says, history indicates that you can have capitalism, or you can have starvation, but you can’t have both. ;-)

  4. April 3rd, 2004 at 13:03 | #4

    im going to play devils advocate.

    even if the temperature rose by 2 degrees i dont think this would change much. sure there might be very different weather patterns, and even land mass would change, but humans would not starve.

    human civilisation isnt going away anytime soon, you could raise the temperature ten degrees and thered still be large numbers of us.

    we are already an extremely adaptable species, living in climates ranging from permafrost to tropical, coupled with technology we could live on any climate on earth in the next few hundred years including worst case scenarios. (the real worst case scenario would be a massive nuclear winter, but still hundreds of thousands of humans would be able to survive through this)

    this doesnt mean we should try to stabilise the environment, and create less pollution etcetera, but its not going to be a catastrophe.

  5. April 3rd, 2004 at 13:05 | #5

    the last sentence should read “this doesnt mean we shouldnt try to stabilise the environment…”

  6. PK
    April 3rd, 2004 at 22:25 | #6

    “The problem with this optimistic view of things is that it is equally important to look at the possibility that things might be worse than we currently expect on the basis of available scientific knowledge.”

    Or things could get better, or they could stay the same. Is this really the best argument you can provide? Does that mean we should spend resources on attempting to avoid every imaginable catastrophe no matter how improbable?

    There’s plenty of problems we KNOW exist such as poverty and disease. Let’s spend resources on them rather than on something that may or may not even be a problem.

  7. kyan gadac
    April 3rd, 2004 at 23:45 | #7

    Without wishing to get into the interminable debate about whether climate change is real. PK is wrong in suggesting that it may have less reality than poverty or disease. Please re-read what I wrote and you may understand that poverty and disease are symptoms of ecological crises and have always been symptoms of ecological crises. Climate change is due to our unthinking consumption of fossil fuels. More pointedly our hubris that suggests that the european scientific revolution is the answer to all problems when in fact it is posited upon the rape of the earth is the cause of the ecological crises that will inevitably lead to increasing poverty and disease.

    c8to writes through the rose coloured glasses that they supply to all of us in high school when it comes to proselytising the scientific agenda. If the global temperature was to rise by 10 degrees it would not only trigger massive tidal waves as Antarctica melted, wiping out most of the coastal lands, it would also presage a runaway greenhouse effect that would be likely to result in temperatures on earth in the vicintiy of 100 degrees plus which would gaurantee the extermination of most terrestrial life. Like I said the plankton have got a better chance.

    Just to reinforce the point that this is not alarmist speculation. Climate scientists have been refining their computer models of future temperature rises given the various scenarios (business as usual, Kyoto etc.). These models are becoming increasingly reliable and accurate. Forecasting day to day weather patterns is a copmletely different proposition to forecasting trends based upon changes in the climate due to changes in the heat balance of the earth.

    The latest of these models was released early in 2003 and it worked fine up until 2050 at which point it ‘broke’ because it showed a rapid drying out of the tropics and that the climate become really unpredictable after that. This indicates that a cusp (in the mathematical sense of chaos maths was reached). This model contained no far fetched assumptions about 10 degree rises but was based upon current estimates of a 1 degree rise in the next fifty years.

    Climate physicists, because of the opposition to the work, make very conservative assumptions to ensure that their figures are solidly defensible. That is why many of them are alarmed about the unexpected increase in CO2 levels last year.

    Play devils advocate all you want and wear rose glasses all you want. But if you have children then I’d suggest you think long and hard about them before you treat climate change as a flippant unreality.

  8. John Quiggin
    April 4th, 2004 at 06:32 | #8

    As Kyan says, history indicates that you can have capitalism, or you can have starvation, but you can’t have both. ;-)

    Try telling that to the Irish!

  9. gordon
    April 4th, 2004 at 11:03 | #9

    The dangers of global warming are much exacerbated by what I believe is a tendency by some to regard it as a game which certain countries, eg. the USA, can win. Nordhaus and Boyer (“Roll the DICE again: Economic models of Global Warming”) for example, estimate much worse impacts of global warming in Europe than in North America. A US Govt. study “CLIMATE CHANGE IMPACTS
    ON THE UNITED STATES:The Potential Consequences of Climate Variability and Change” is remarkably sanguine about the outcomes in the US. I can’t help feeling that these attitudes effectively prevent international cooperation to mitigate and manage the impacts of global warming. Looked at from this point of view, the Australian Govt. attitude is profoudly silly, because the only projections of climate change impact on Australia that I have found are definitely negative. Whoever else might “win”, we will lose.

    Web reference for Nordhaus and Boyer is http://www.econ.yale.edu/%7Enordhaus/homepage/web%20table%20of%20contents%20102599.htm and for the US Govt. study is http://www.gcrio.org/NationalAssessment/

  10. Brian Bahnisch
    April 4th, 2004 at 12:42 | #10

    Gordon, yes, I’d heard that too about the USA v Europe. I think the Europeans are very aware that some nasty scenarios are possible. For example, an initial warming could trigger a rapid cooling that would give Europe a climate similar to the present Siberia (see Paul Monk ‘A cool change for the clever animal’ Australian Financial Review, August 8, 2003 – subscription required).

    European weather seems to be critically dependent in the operation of the Gulf Stream, which can’t be totally taken for granted.

    Another “tipping point” is if the Western ice sheet melts in Antarctica, giving a rise in sea levels of 4 to 6 meters.

  11. April 4th, 2004 at 13:39 | #11

    Irony alert.

    JQ, didn’t you know that capitalism increased food availability even when it made the Irish starve? It was the others in other countries who got the food exported from Ireland and starved less. If only you were an economic rationalist and willing to net those off against the starving Irish…

  12. Brian Bahnisch
    April 4th, 2004 at 16:18 | #12

    There is an interesting phenomenon in the citadel of capitalism – the US of A. While starvation is rare, the less severe conditions of ‘hunger’ and ‘food insecurity’ are not. This report from the Food Research and Action Center indicated that in 2002 there were 12.1m households in the US that were food insecure, that is 34.9 million people. Fully 3.8m households were hungry.

    This article by Jay Shaft tells us about the difficulty experienced by single mothers in the US. It also tells us that 18m children miss at least one meal each day.

    That article was mostly case studies. Shaft addresses the general problem of poverty in the US here.

    Margo Kingston republished the first Shaft article together with my commentary here. (Scroll down to ‘Poor fellow, America’).

    This situation is made worse by the notion that if you are in the bottom decile of incomes in the US you have virtually no hope of getting yourself out. (I had a Will Hutton reference on this, but I think Pr Q has said the same thing.)

  13. Andrew
    April 4th, 2004 at 23:19 | #13

    c8to, if you think of an minor increase in average temperature of the earth’s atmosphere as a staggeringly huge increase in the total amount of energy being held in the weather systems, it’s easier to comprehend the dangers.

    It doens’t mean that you will need to wear a jumper for a week less over winter. It’s all those little concentration points (like storms, tornadoes and cylcones) that will have quite a deal more extra power to play with.

  14. gordon
    April 5th, 2004 at 11:56 | #14

    Brian, do you (or any other interested commenter) have any views on the Nordhaus and Boyer modelling or are aware of other interesting and perhaps policy-influencing estimates of regional/National global warming impacts? Eg. perhaps the Mendelsohn and Neumann (1999) study quoted by Nordhaus and Boyer (which I think was also pretty sanguine about US impacts)? From the few attempts at large-region comparative projections that I have found, it seems that outcomes seem to depend a lot on how economic “adaptatability”, and the effects of CO2 on crop growth are modelled. Which makes Prof. Quiggin’s “Snippet on Economic Modelling” pretty apposite!

  15. Brian Bahnisch
    April 5th, 2004 at 22:51 | #15

    I’m not into the topic in that sort of depth, Gordon. I keep hearing things of interest on Radio National. I’ve often heard it said that the number of exceptional events, ie breaking records, is increasing. I heard that last year was an exceptional year for tornadoes in the US. A quick google yielded this, which only goes to 1998, but the graph does seem to be telling us something!

  16. Tom Davies
    April 5th, 2004 at 23:57 | #16

    Brian, this suggests that the apparent trend is just better reporting of small tornadoes (in Illinois, anyway)

  17. Brian Bahnisch
    April 6th, 2004 at 00:08 | #17

    Thanks, Tom, I wondered about that.

  18. kyan gadac
    April 6th, 2004 at 00:40 | #18

    Nordhaus and Boyer modelling should be taken with a large grain of salt. There are several critiques available on the web. Basically they all suggest that many of their models assumptions are too broad to enable the kinds of predictions that they make. In particular the time period they use has been criticised as well as assumptions they make about economic welfare. They are quoted by environmental sceptics like Lomborg and the BUsh adminsitration as saying that Kyoto would cost $5 trillion to implement. Needless to say I think this sort of mathematics is farcical.

    For a different perspective on the economics of climate change try Steven Schneider Climate Change Site at Stanford University

  19. April 6th, 2004 at 08:05 | #19

    kyan: i said an increase of 10 degrees not 100 degrees. i know what you are trying to say, is that an increase of 10 degrees may lead to an increase of 100 degrees later on, but lets just stick to what i said: global temperatures being 10 degrees higher in 50 years.

    furthermore, i didnt say anything about whether it will be fun, or whether your children will die, or whether billions will die. i just said humanity will survive.

    stop getting hysterical.

  20. gordon
    April 6th, 2004 at 09:23 | #20

    Kyan, thanks, Schneider looks interesting and I will try to find the critiques of Nordhaus & Boyer you mentioned. But aside from the validity of this sort of modelling is the issue of its influence, which I am also trying to investigate.

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