Political climate

To most of the media, and even some senior scientists, the debate about global warming is over. It has been clearly established to their satisfaction by the intergovernmental panel on climate change (IPCC) that the world is heating at an alarming rate and that the main cause is the rise in man-made greenhouse gases, primarily CO₂. We must therefore act now, the argument goes, to implement the Kyoto protocol and follow it up in 2012 with much more drastic cuts in CO^₂ emissions when Kyoto stage one comes to an end. By 2050, emissions must be reduced to a level 60 per cent below those of 1990. Scientific evidence to support these views is claimed to be as strong as that for the link between smoking and cancer, or HIV and Aids, and the only sceptics left are lobbyists for the oil industry. Indeed, Greenpeace and Friends of the Earth criticise the media for continuing to report the views of sceptics, because they undermine public acceptance of drastic measures to save our planet. (The same NGOs happily ignore the views of the overwhelming majority of plant geneticists, biochemists and molecular biologists who endorse the use and safety of genetically modified crops.)

However, the Bush administration and lobbyists for the oil industry are not the only Kyoto sceptics. In 2004, a conference of some of the world's leading economists, including several Nobel laureates, published what is now known as the Copenhagen consensus. In their list of priorities for dealing with ten big global crises, abatement of global warming was ranked behind action to deal with Aids, malnutrition, trade liberalisation, malaria and access to clean drinking water, among other problems in the least developed countries. In fact, Kyoto came one from bottom of the list. Their report was widely condemned by environmentalists, as was the outcome of the recent G8 summit, because it did not endorse Kyoto in sufficiently ringing terms. Now the economics committee of the House of Lords, advised by the respected environmental economist David Pearce, has published a report, "The Economics of Climate Change," which not only adds its own weighty criticisms of Kyoto, but also questions the objectivity of the IPCC and accuses it of allowing political considerations to influence some of its findings.

The charge of political bias cannot reasonably be made against the IPCC scientists responsible for the technical analysis of climate change. Their report takes care to mention not only the uncertainties and gaps in current knowledge, but developments that seem to contradict the general trend. A good example of the latter is their treatment of the rise in sea levels, which is widely considered to be the most serious consequence of global warming. To the public, some of the clearest evidence of rapid warming is the melting of glaciers. Who can fail to be impressed by dramatic pictures of massive sheets of ice in the West Antarctic peninsula collapsing into the sea? But the scientists point out that while most glaciers are retreating, some are advancing, and that the Antarctic continent, where the overwhelming mass of the world's ice is found, is actually cooling and its ice thickening, with a small negative effect on sea levels. Overall, sea levels are forecast to rise within a range of 0.11 to 0.77 metres in the next 100 years, which could have a serious impact on low-lying coastal regions, but is not perhaps the catastrophic rise predicted in some alarmist scenarios. It will mainly be caused by thermal expansion of the oceans. Melting of the ice sheets is "expected to make only a small net contribution in coming decades." In fact, the IPCC found no acceleration of the rate of sea level rise during the last century, and has lowered its forecast for the present century since its last report because scientists now see a smaller contribution from melting glaciers and ice sheets.



The scientific analysis acknowledges many other uncertainties. One is the impact of aerosols, especially sulphate aerosols, which have a cooling effect—indeed, the gradual reduction of aerosols, as a reaction to the hole in the ozone layer, is likely to increase warming. The scientists concede that levels of aerosols are hard to measure, that our records of them are incomplete and our level of understanding low. However, probably the greatest uncertainty in future projections of climate arises from clouds and their interaction with radiation. Clouds can have either a cooling or warming effect depending on how high or thick they are. (Higher clouds, which trap heat, cause warming; lower ones, which reflect the sun's rays, cause cooling.) Climatologists cannot yet explain why satellite measurements in the troposphere give a lower figure of global warming than measurements on the earth's surface. They are uncertain about the likely effect of changes in land use or the effects of solar factors. One of the main public fears about climate change is that extreme weather will be worse and more frequent. Every hurricane is seen as proof that we are nearing global disaster. A layman might therefore be surprised to find that IPCC scientists predict no increase in storms: "Recent analyses of changes in severe local weather (eg tornadoes, thunderstorms and hail) in a few selected regions do not provide compelling evidence to suggest long-term changes."

Such frank admissions of doubts and uncertainties increase one's confidence in the scientists' objectivity and lend credibility to their conclusions. These are that, despite the uncertainties, the models they use that form the backbone of the IPCC's predictions have become more reliable, that global warming is happening, that it has speeded up in the last few decades and that "a significant anthropogenic contribution is required to account for [global weather] trends for at least the last 30 years." In fact, the physics of global warming seems to be generally accepted: other things being equal, CO^₂ causes warming and the main cause of the rise in CO₂ is our increased use of fossil fuels. It should also be noted that new evidence since the last IPCC report tends to reinforce its main conclusions. Most important is a recent finding of the Scripps Institution of Oceanography—that the significant ocean warming that has taken place can only be the result of man-made greenhouse gases.

However, two important questions remain unanswered. How much warming can we reasonably expect? And what should we, or can we, do about it?

The IPCC "Third Assessment" report lists a range of possible temperature increases for the next 100 years, from a rise of 1.4 degrees Celsius—two and a half times the rate of warming of the 20th century, but still as likely to be beneficial as harmful—to 5.8 degrees Celsius, which would have severely damaging results for most of the world. It gives no indication where the balance of probability lies. As might be expected, most attention has been focused on the more pessimistic scenarios.

The House of Lords report criticises the IPCC's presentation of future warming. It argues that some indication should be given of the likelihood of different scenarios. It further questions the assumptions and methodology on which the most pessimistic scenarios are based. In addition it alleges that the IPCC tends to exaggerate dangers and lacks objectivity.

Three examples appear to support the Lords' charge. First, no mention is made of the possible benefits of global warming, such as the positive effects of CO₂ on some crops, the increased opportunities for tourism and the advantages of milder winters for northern Europe, which are likely to save more lives than will be lost through hotter summers. In one significant respect, the IPCC summary for policymakers (approved by political representatives) differs from the expert report on which it was based. The expert report states that whereas current estimates may understate the true cost of climate change because they tend to ignore extreme weather events, "they may also have overlooked positive impacts of climate change." The IPCC summary ignores this key sentence and simply states that "omissions are likely to result in underestimates of economic losses and overestimates of economic gains."

A second example is the IPCC's warning that we will face a marked increase in vector-borne diseases, such as malaria, and that this is already happening. No malaria expert, it seems, endorses this claim. Paul Reiter of the Institut Pasteur in Paris, an authority on malaria who was a member of the relevant expert group, has pointed out that malaria is not a tropical disease and was widespread in northern Europe during the "little ice age," from the mid-15th to mid-18th century, when temperatures were lower than today. Warmth is a factor in its transmission, but local factors are more important. Reiter told the Lords committee that none of the authors of the relevant section of the IPCC report has published a paper on malaria, and that the report contains serious errors.

The third and perhaps most important example is the IPCC's errors and dubious assumptions about future emissions of CO₂. The rise in these emissions depends partly on the rate of future economic growth, partly on population growth, energy mix, energy efficiency and technology. Overestimates of economic growth rates lead to overestimates of the rise in global warming. Yet the IPCC's special report on emission scenarios (SRES) bases its various projections on a questionable assumption and a flawed methodology. The assumption is that the gap between the wealth of rich and poor countries will be rapidly diminished. The methodology used exaggerates the present-day gap by using market exchange rates as the basis for comparison of wealth rather than the more common measure of purchasing power parities. The result is that all the predictions in the SRES are for a very high rate of growth, exceeding any historical experience. Indeed, the assumption of rapid convergence was based not on evidence, but on what would be equitable. The result is a big upward, alarmist bias in projections of global warming.

When these criticisms of the SRES were first raised with the IPCC by two eminent economists, David Henderson, former head of the department of economics at the OECD, and Ian Castles, former head of the bureau of statistics in Australia, they were contemptuously dismissed. When the Lords committee suggested to a representative of the IPCC that it might reappraise the SRES in its next assessment, he said they had no intention of doing so. Not surprisingly, the committee recommends that political factors should not be allowed to influence scenarios, whether over the issue of convergence or indeed in any other context. It also criticises the IPCC for its lack of appropriate economic expertise and is concerned about political interference in the nomination of scientists, which should rest solely on their scientific qualifications for the tasks involved.

The most important findings of the Lords report are those about the Kyoto protocol. On this it joins forces with the Copenhagen consensus. The targets for the first stage of Kyoto, which ends in 2012, will, it seems generally agreed, have little effect on global warming. Even if the US signed up to Kyoto, which it will not, Kyoto stage one would postpone the degree of warming now forecast for the year 2100 by only seven years, or to put it another way, would lead to a decrease in warming of 0.1 degrees Celsius in a hundred years' time. The 2012 targets for a reduction in emissions are relatively modest: for the 15 pre-enlargement EU states, emissions must be on average at least 8 per cent below those of 1990. Yet they could still prove costly. The target for 2050 set by the government's white paper (conditional on other countries pursuing similar goals) is a reduction in emissions of 60 per cent compared with 1990, which would involve vastly increased costs. The treasury, surprisingly, has not calculated what the costs of meeting either target might be.

When challenged with the limited benefits from Kyoto, its advocates reply that it is the framework that matters and that stage one is only the first step on a path of further agreements. Yet it is unlikely that even the limited 2012 targets will be met by all signatories. If they are not met, the Kyoto protocol imposes sanctions: countries which do not achieve their 2012 targets must make up the shortfall in stage two (to be negotiated) and must also, as a penalty, achieve an additional 30 per cent reduction. So why should they sign up to a further stage?

The Kyoto process is an extraordinary exercise in make-believe. Stage one will have no significant effect on global warming. Neither the US, India nor China, all of which are building many new coal-fired power stations, and which between them will emit most greenhouse gases, have any intention of joining either stage one or stage two. Several nations which have signed the Kyoto treaty are likely to be in breach. They too are unlikely to sign up to stage two because the compliance mechanism is a disincentive to do so. At the same time, the costs of Kyoto will have a negative effect on economic growth. One does not have to be a Nobel prize-winning economist to agree that Kyoto's costs outweigh its benefits and that it should come close to the bottom of the list of realistic global solutions for global crises.

The Copenhagen economists did not specifically consider the IPCC's scientific analysis or challenge its central conclusion that global warming is happening and has an important man-made element. Their views were based on a cost-benefit analysis. However, some contributors made further comments. One was that future generations will be much richer and smarter than us and that it makes no sense to make current generations pay for the problems of future ones. It was also argued that Kyoto supporters make no allowance for future technical changes that will allow the world to cope with climate change.

What, then, would be a more constructive response to global warming than Kyoto's reliance on targets and penalties? No one suggests that the problem should be ignored. At first sight, there is a case for precautionary measures to prevent possible catastrophe even if the prospect of disaster is remote. But a balance still has to be struck between cost and probability. If we are hit by a large asteroid, the damage will be huge, but the chances of its occurrence are so slight and the costs of a programme to divert its course would be so large that precautionary measures would be irrational. On the other hand, if the cost is not prohibitive, it makes sense to pursue policies that reduce CO₂ emissions.

What the Lords committee proposes is a balanced programme of mitigation and adaptation. The latter has been generally neglected in the debate. However, if a rise in sea levels, which cannot be reversed within many decades, threatens low-lying coastal regions, it makes sense to enable Bangladesh to prepare sea defences as the Dutch have done. They will also be much better able to help themselves if they are wealthier. Indeed, the reasoning that lies behind the priorities chosen by the Copenhagen consensus is that if rich countries can cope with most of the likely problems of global warming, policies that reduce poverty will help poor countries to do the same.

Nevertheless, if we accept that the scientific conclusions of the IPCC must be taken seriously, mitigation must remain a high priority. The House of Lords has little time for the government's main response: the emphasis on renewables, particularly wind energy. It favours a carbon tax instead, to provide market incentives for non-carbon technologies. While the prospects of an internationally harmonised tax are acknowledged to be remote, it argues that its introduction in Britain would be preferable to the climate change levy that offers electricity generators no incentive to switch between high and low-carbon fuels. The committee also recommends that the nuclear option should not be closed and that current capacity should be retained.

However, its central and final recommendation is to focus on technology and research and development. Some people will complain that this echoes the approach of the US, which has long been regarded as the main obstacle to international co-operation on climate change. The G8 summit, according to environmental pressure groups, is a triumph for Bush and a defeat for effective action. Instead, perhaps the summit should be regarded as a triumph of realism over illusion. As Tony Blair said, "If we don't have America, China and India taking the action necessary to reduce greenhouse gas emissions, then we don't solve the problem of climate change." In practice, even if it were proved, contrary to the arguments of the Copenhagen consensus, that developing countries should curb their economic growth in the interest of our planet's future, there is no chance that they will do so. Nothing will stop China and India building new coal-fired power stations. The main answer must lie in the most rapid application of the best technologies. Yet it is America, not Britain and Europe, that is investing heavily in new technologies such as carbon sequestration and hydrogen-fuelled transport. An international agreement on technology and its diffusion would be a far more effective response to the IPCC than the Kyoto route of target reductions, penalties and cost-restraints on economic growth.