| 'We risk burdening the global community with a cost much higher than that of global warming.' |
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Global warming has become the great environmental worry of our day. There is no doubt that mankind has influenced and is still increasing atmospheric concentrations of CO2, and that this in turn influences temperature - but we need to separate hyperbole from realities in order to choose our future optimally.
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The global average temperature has increased by 0.6 degrees Celsius over the past century, and it is likely that this is partly due to an anthropogenic (man-made) greenhouse effect. However, the impression of a dramatic divergence from previous centuries is surely misleading.
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The sensitivity of the climate to greenhouse gas emissions that is predicted by the Intergovernmental Panel on Climate Change (IPCC), of 1.5 - 4.5 degrees C, has not changed over the past 25 years  . This indicates a fundamental lack of model adequacy, because we still do not know whether we live in a world where doubling the CO2 concentrations will mean a rather small (1.5 degrees C) or a dramatic (4.5 degrees C) temperature increase.
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All the IPCC predictions are based on the simulation of the climate on supercomputers with so-called Atmosphere-Ocean General Circulation Models (AOGCMs, sometimes known as GCMs) . , but there are still crucial problems with the representation of aerosols, water vapour feedback and clouds. In all three areas, research points towards a smaller than predicted climate sensitivity to CO2.
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With the 40 new scenarios, the IPCC has explicitly rejected making predictions about the future. Instead it gives us computer-aided storytelling, basing the development of crucial variables on initial choice and depicting normative scenarios 'as one would hope they would emerge'.
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While the spread of scenario profiles are wide, three scenarios stand out as securing a much richer world. The total extra benefit is above $107trillion, which is 20 times more than the total cost of global warming.
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For comparison, we spend between one and two percent of Gross Domestic Product (GDP) today on the environment. If we continued to spend the high end of two percent of an ever-increasing GDP, we would end up spending about $18trillion on the environment throughout the twenty-first century.
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Reasonable analysis suggests that renewables - and especially solar power - will be competitive to, or even outcompete, fossil fuels by mid-2001. This means that carbon emissions are much more likely to follow the much lower of the IPCC scenarios, causing a warming of about 2 - 3 degrees C.
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Global warming will not decrease global food production; it will probably not increase storminess or the frequency of hurricanes; it will not increase the impact of malaria or, indeed, cause more deaths. It is even unlikely that it will cause more flood victims, because a much richer world will protect itself better. However, global warming will have serious costs - the total cost is about $5trillion.
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Moreover, the consequences of global warming will hit developing countries hardest, while industrialised countries may actually benefit from a warming lower than 2 - 3 degrees C. Developing countries are harder hit primarily because they are poor, giving them less adaptive capacity.
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Despite our intuition that we naturally need to do something drastic about such a costly global warming, economic analyses show that it will be far more expensive to cut CO2 emissions radically than to pay the costs of adaptation to the increased temperatures.
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The economic analysis indicates that, unless Kyoto is implemented with a system of global carbon emissions trading . , in which nations can trade permits to emit a certain amount of CO2 equivalents - thus ensuring a commitment from the developing countries - the world will be worse off. Moreover, the effect of Kyoto on the climate will be minuscule - in the order of 0.15 degrees C in 2100, or the equivalent of putting off the feared temperature increase for just six years.
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In the longer run, a Kyoto Protocol with global carbon emissions trading will be less efficient than an economically optimal policy (where there is an optimal trade-off between the impact of restricting global warming and the impact of global warming), but even that policy will only cut 11 percent of the CO2 emissions and only diminish the temperature increase slightly.
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If, on the other hand, Kyoto is implemented without global carbon emissions trading - even if it ends up allowing trade among all the richer nations (so-called Annex 1 countries) - it will not only be almost inconsequential for the climate, but will also be a poor use of resources. The global cost of such a Kyoto pact for just one year will be higher than the cost of providing the entire world with clean drinking water and sanitation - something that it is estimated would avoid two million deaths and prevent half a billion people becoming seriously ill every year. If no global carbon emissions trading mechanism is implemented for Kyoto, the global costs could approach $1trillion, or almost five times the cost of worldwide water and sanitation coverage.
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If we were to go forward as many have suggested, seeking to curb emissions to the global 1990 level, the net cost to society would escalate to about $4trillion - comparable almost to the cost of global warming itself. Likewise, a temperature increase limit would cost anywhere from $3trillion to $33trillion extra.
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This shows that we need to be very careful in our willingness to act on global warming. If we do not ensure global trading of carbon emissions permits, the world will lose. If we go much beyond an 11 percent global CO2 reduction, the world will lose. And this conclusion does not just come from the output from a single model.
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Almost all the major computer models agree that even when chaotic consequences have been taken into consideration, 'it is striking that the optimal policy involves little emissions reduction below uncontrolled rates until the middle of the next century at the earliest'. Equally, another study concluded that 'the message of this admittedly simple model seems to be that it matters little whether carbon emissions are cut or not, only that protocols to stabilise emissions or concentrations are avoided'.
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A recent overview concluded that the first insight gained from these models was that 'all appear to demonstrate that large near-term abatement is not justified'. A central conclusion from a meeting of all economic modellers was: 'Current assessments determine that the "optimal" policy calls for a relatively modest level of control of CO2.'
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Finally, it is asserted that the efforts to combat global warming are an insurance policy against extreme events. When included in the computer models, these do not alter the results appreciably, but the insurance mentality can be justified by those who harbour an intense dislike of risk-taking. But this doesn't change the fact that the investments would be far better made elsewhere - like in the developing world.
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The point in this case is that with the best intentions of doing something about global warming, we could end up burdening the global community with a cost much higher or even twice that of global warming alone. As the Kyoto Protocol is unlikely to be implemented with global trading, simply because of the staggering amounts involved in distributing the initial emission rights and the subsequent redistribution, Kyoto represents a waste of global resources. If we want to do good, we have to spend our resources more wisely.
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The above is adapted from Part 5, Chapter 24 of The Skeptical Environmentalist, pages 317-318. Buy this book from Amazon (UK) or Amazon (USA).
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