Climate change: warming, cooling, dimming and the consequences

Here is a subject which, at election time, rouses relatively little political controversy. What controversy there is relates to measures to cope with it.

• The Prime Minister has made it one of the two prime points on the agenda of the G8 summit at Gleneagles in July. He set out his views in forthright terms in The Economist of 1 January, and spoke at length on the subject at the World Economic Forum at Davos the same month. More recently Gordon Brown made it his principal theme in addressing Foreign, Finance and Environment Ministers on 15 March. Environment and Development Ministers from the G8 and other countries met discuss the issue a couple of days later.
• Ever since Margaret Thatcher's reign, the Conservative Party has made climate change, and measures to cope with it, as a key element in its policies on the environment. Michael Howard spoke about it last September, and Tim Yeo (the Shadow Secretary of State for the Environment) returned to it in a speech to the Business Council for Sustainable Energy on 14 March.
• Nor have the Liberal Democrats been behind. In many ways they have been the most enthusiastic of all as shown in Charles Kennedy's election statement this week.

In the meantime the science as well as the politics have moved on. The prospects are clearer than ever. Every week seems to bring fresh evidence both about change itself, and the consequences of inaction. This was well brought out in a report of an International Task Force of scientists, policy makers and others in January, and at a scientific conference at Exeter in February. The Financial Times produced a special supplement on Business and Climate Change in February, and the UK Petroleum Industry Association did likewise. At the end of March the New Scientist called for urgent action in a striking editorial.

In the background the first practical international instrument to mitigate the dangers came into effect on 16 February. The Kyoto Protocol to the Framework Convention on Climate Change of 1992 was negotiated with immense difficulty in December 1997, and signed by 84 countries, including the United States. 38 other countries joined later. The circumstances were well stated in a Declaration following a conference of the British and German Governments in November last year. Let me quote two eloquent passages from it.

"The conference agreed that the evidence that human activity was causing climate change, most notably through emissions of greenhouse gases from burning fossil fuels and through deforestation, had been established beyond reasonable doubt. It noted that the atmospheric concentration of the most important greenhouse gas, carbon dioxide, had reached a level not seen on Earth for at least 740,000 years, and that levels were likely to continue to rise during this century."

"The conference reviewed the effects already being felt throughout the world. It recognized that, if unabated, and if we did not adapt appropriately, future climate change could have a devastating impact on human society and the natural environment. The costs of inaction, felt mostly in the developing world, far exceeded the costs of action. The effects of climate change were moving to the centre of social and economic worldwide activity."

How did things reach this point? I do not want to spend too long on the history, but it may be worth flagging what seem to me the main points. Understanding of the relationship between carbon dioxide and the surface temperature of the Earth goes back to the 19th century. But it was work during the International Geophysical Year of 1957 that gave it a new impulse. In the 1960s Rachel Carson's book Silent Spring raised the alarm about environmental problems generally.

Following work at MIT, climate change was recognized as a major issue at the Stockholm Conference on the Human Environment in 1972, and with the creation of the United Nations Environment Programme afterwards came a series of global as well as national climate research programmes. In the 1970s a number of us began to look at the implications for society, although the conventional wisdom then was that change was very slow and could only take place over several generations. In 1979 the first World Climate Conference took place, and in the 1980s there were numerous conferences and increasing scientific awareness of what was at stake.

Perhaps the key transition from science into politics and economics took place when the G7 group of countries took up the issue, and discussed it at their meeting in Downing Street in 1984. Then came its place in the report of the Brundtland Commission on Environment and Development in 1987. The following year the Intergovernmental Panel on Climate Change was set up, and produced its first Assessment in 1990. In the meantime the issues were dramatized in Margaret Thatcher's speech to the Royal Society in 1988, following by another to the UN General Assembly in 1989. In the same spirit she addressed the second World Climate Conference in 1990.

By that time climate change was firmly on the world's political and economic as well as scientific agenda. One of the products of the Rio Summit Conference on Environment and Development of 1992 was the Framework Convention on Climate Change. This was followed by the Second Assessment of the Intergovernmental Panel in 1995, the signature of the Kyoto Protocol in 1997 and eleven subsequent meetings of the Parties to it. The Third Assessment of the Intergovernmental Panel was published at the end of 2001. The next Assessment will be in 2007: it promises to be much clearer than before, and to reduce many of the uncertainties.

Let us look briefly at the underlying science. It was thoroughly explored and brought up to date at the meeting at Exeter in February. At that meeting a timetable of possible effects in different regions was described, with emphasis on the need for "major investment now in both mitigation and adaptation".

We must first distinguish natural from human-driven climate change so far as is possible.

Natural change

• there has been the roller coaster of natural variations during the past 60 million years; wobbles during the last relatively stable 10,000 years; farming in Greenland in the 10th century, extreme cold in New England in the 16th century; rising temperatures since 1880, and steeply since 1980 with the last few years the warmest yet.
• until recently we believed that all climate change was slow; now we know otherwise with the evidence of cores from Greenland and Antarctic ice caps.
• much work has recently been done to identify natural tipping points or thresholds to mark the onset of change. Among them are:
  • the state of the Amazonian rainforest
  • the direction of the North Atlantic Conveyor current
  • changes in the ozone layer
  • the wind-blown effects of Saharan sand on the chemistry of the Atlantic Ocean and Amazonia
  • the release of methane clathrates from beneath the tundra and ocean bed
  • the frequency and intensity of El Nino and La Nina
  • the melting of the Greenland and West Antarctic ice sheets
  • the behaviour of the Antarctic circumpolar current
  • the behaviour of the Indian monsoons.

Human-driven change

• A periodical visitor from outer space would have no doubt that something strange was going on. He would see more change in the surface of the Earth in the last 20 years than he would have found in the last 200, and in the last 200 more than in the last 2,000. That was one of the most important conclusions of the draft Millennium Ecosystem Assessment published on 30 March.
• Since the industrial revolution, we have been using the sky as a waste unit. As a result carbon dioxide in the atmosphere is a third higher than in pre-industrial times. The process may indeed have started long before, when humans first converted forest lands for agriculture. The last two years has seen the annual rate of increase rise to around 2 parts per million, faster than the l.5 parts per million rise in previous decades. There is a clear relationship between atmospheric carbon and global surface temperature.
• As we learn more from ice cores, the strength of this relationship becomes clearer, as does the extent to which we have deviated from the norm. In the last 800,000 years there have been eight cycles of warming and cooling. During the ice ages atmospheric carbon dioxide levels were at about 190 to 200 parts per million. For each intervening warm period carbon dioxide levels were between 250 and 275 parts per million, until 250 years ago. At the last reckoning they stood at 378 parts per million.
• Methane, a less abundant but far more effective greenhouse gas, has seen its concentration more than double since pre-industrial times.

It is notoriously difficult to distinguish natural from man-made processes, but there is a growing consensus, expressed in successive reports from the Intergovernmental Panel on Climate Change (IPCC), that the human contribution is now having a significant if not decisive effect. Working Group I (Science) of the IPCC concluded in 2001 that

" ... in the light of new evidence and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely to have been due to the [human-induced] increase in greenhouse gas concentrations."

According to the World Meteorological Organization (WMO), 2003 was the third warmest year on record. The warmest year ever was 1998, and the second warmest was 2002. The WMO has stated that late 20th century warmth is unprecedented for at least the past millennium, and in the northern hemisphere the 1990s were the warmest decade and 1998 the warmest year in the past 1,000 years.

What would a warmer world look like? Here the uncertainties, region by region, multiply. Efforts have been made by Working Group II (Impacts) of the Intergovernmental Panel to assess possible impacts by continent, but the results are inevitably sketchy. However interpreted, they suggest a different world and a correspondingly different distribution of human activity as people and the living organisms on which they depend try to adapt to change. Such change includes new patterns of rainfall and drought. The great land masses of Africa, Asia and Latin America could be worst affected. Until recently there was little evidence of the predicted increase in extreme events. But last year saw more people killed by hurricanes in the Americas, and by typhoons in Asia, than for several decades.

The IPCC predicts that sea levels will rise by between 9cm and 88cm by 2100. But here again the pace of change seems to be increasing. A recent article in the New Scientist looked at evidence from ancient Roman fish pens. In the last two millennia average sea levels have risen with most of this rise in the last 100 years. The change in depth may seem small, but think of this as a volume sloshing across an ocean.

On a global scale effects include:

• impacts on all natural ecosystems about which we remain dangerously ignorant. The patterns of insects and micro-organisms will change;
• impacts on water resources, and in particular increased stresses in many poor countries, with new rivers and lakes;
• impacts on agriculture and thus food supplies. There may be increased crop yields in high and mid-latitudes countries, but decreased yields in lower latitudes.
• impacts on human health. Micro-organisms respond rapidly to changes in temperature and moisture. Old diseases such as malaria could return and new diseases could arise;
• impacts on human population movement, with increased numbers of refugees both within and between countries;
• impacts on business and industry, transport networks, insurance and banking, town planning, and even architecture.

There are two jokers in the pack. They relate to negative and positive feedback.

• There is a possibility that an increase in fresh water in the North Atlantic and Arctic Oceans, caused by melting ice and increased river flow, may weaken the powerful current - the Gulf Stream or North Atlantic Conveyor - that brings warmth to Western Europe and points east. There are already indicators that this process, which happened some 12,000 years ago, may already have started. Thus warming may paradoxically produce cooling. Such cooling might begin in the Northern Hemisphere but to judge from the geological evidence would eventually move to the Southern.
• The other joker is represented by the possibility of a runaway greenhouse effect, as at earlier times in the Earth's history, such as at the Palaeocene / Eocene boundary 55 million years ago. Recent studies of ocean sediments have shown that 55 million years ago the Arctic sea had an average temperature of 20ºC. There was massive die back of marine creatures as carbon dioxide levels soared. In each case vast releases of methane, from melting tundra and the release of methyl hydrates from the ocean floor, may have been the cause.

There is another uncertainty only recently understood. That is the effects of so called global dimming, a 10 percent to 37 percent reduction in sunlight reaching some of the Earth's surface since the 1950s, which results from human-made or human-driven air pollution. Hence the brown clouds covering particularly South East Asia, and the cover of particles of various chemicals covering industrial countries and reaching up into the Antarctic. One paradoxical result could be that the more we reduce pollution, the greater will be the warming. Moreover many of the particles are not of the kind round which rain drops form, so that there could be less rather than more rainfall in the areas affected. It is not good however we look at it.

Of course there is continuing controversy about both climate change and its effects. The contrarians are small in number but exceedingly noisy. Some of them have been financed by industries which believe they would be adversely affected by limitations on carbon emissions. But the genuine argument has been more about the balance between natural and human-driven change, and the rates of change.

Climate change may pose an unprecedented threat to human society, but it does not come alone. For the moment there are five other things for us to think about: human population increase; degradation of land and accumulation of wastes; water pollution and supply; energy production and use; and the destruction of biodiversity.

Of these factors population issues are often ignored as somehow too embarrassing or mixed up with religion and the ideology of development; most people are broadly aware of land and waste problems, although far from accepting the remedies necessary; water issues have had a lot of publicity, and already affect most people on this planet; how we generate energy while fossil fuel resources diminish and demand increases is another conundrum; but damage to the diversity of life, of which our species is a small but immodest part, has somehow escaped most public attention.

One point is worth adding, the product of recent and continuing research. To a considerable extent, and operating on Darwinian principles, organisms tend to create and maintain the living environment most favourable to them. This affects climate as much as anything else. Thus they can offset and mitigate the consequences of catastrophes through complex systems of feedback. The Earth system behaves as a single, self-regulating system, comprised of physical, chemical, biological and even human components. In a word this is Gaia theory. At present we are pressing Gaia hard without understanding the possible consequences.

Together these regulators keep the Earth system in the stable state that has nurtured modern humans. Climate change alone could disturb one, if not all, of these processes and we have yet to reckon with the consequences of disturbing the so-called teleconnexions between them.

We are in an unprecedented situation, well expressed in the title of a recent book Something New Under The Sun. The scale of the problem was brought out in a Declaration made by over 1,500 scientists from the four great global research programmes at Amsterdam in July 2001. There it stated squarely that the Earth was currently operating in a no-analogue state, and that the business-as-usual way of dealing with the Earth's system was not an option. That judgement has been brought out with still more force in the draft report of the Millennium Ecosystem Assessment of 30 March.

Let us go back to that interesting moment when science moved into politics and economics asset out in the Framework Convention on Climate Change of 1992. Its broad objective was there defined as the stabilization of "greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system".

How this should be done has been discussed at successive meetings of the Parties to the Convention. Recent meetings have concentrated on the implementation of the Kyoto Protocol. This committed 38 industrial countries, including the United States, to a global carbon dioxide emissions reduction target of 5.2 percent by 2008-2012. The methods to be used included what are called in the jargon Joint Implementation and the Clean Development Mechanism.

Together these methods mean that non-industrial countries can benefit from investment in clean technologies. For their part the industrial countries will benefit by having some of their own emissions offset through helping non-industrial countries. The prime need remains for industrial countries to cut their emissions, and create low carbon economies, persuading the rest of the world to do likewise.

This is horribly complicated, and may sound unrealistic. It depends on some somewhat uncertain science on the nature of carbon sources and sinks. But it remains to be tested, and no doubt modified through experience. It is at least a start.

So far there have been ten meetings of the Parties to the Protocol. The last of them at Buenos Aires last December marked the tenth anniversary of the entry into force of the Framework Convention. It was not a happy occasion. On the positive side it looked forward to implementation of the Kyoto Protocol and the period after 2012; on the negative side it was marked by obstruction from the United States, whose representatives played a somewhat mischievous role throughout.

Until recently the rest of the world, including India and China, regarded the problem as one for the industrial countries. But increasingly such countries realize how much their own future welfare is involved. India is substantially dependent on the regular behaviour of the annual monsoon. For its part China is very vulnerable. With its massive population, it is predicted to overtake the United States as the world's largest emitter of carbon dioxide.

The Chinese claim to have reduced their carbon emissions in real terms over the last five years. Some have accused China of overstating the reduction, but even research funded by the US Department of Energy has found that, due to a combination of the restructuring of Chinese industry, improvements in efficiency, less burning of high sulphur coal, and other environmental measures, there has been a genuine decrease in emissions.

Even if the Kyoto commitments were met (itself highly doubtful), greenhouse gas emissions would still be some 30 percent up on 1990 by 2010. Thus it is no more than a first step. But even that has not been taken by the biggest polluter of all. The United States, with less than 5 percent of the world's population but over 20 percent of its greenhouse gas emissions, is a major villain of the piece. Its unwillingness to accept binding treaty obligations is not new. With American society still based on cheap energy (gasoline prices are still lower than bottled water) and vested interests being close to the heart of the current US Administration, it is no surprise that President Bush has refused to ratify the Protocol.

In the United States many are ignoring the federal Administration. The nine North East states, including New York, New Jersey and Massachusetts, are working toward creating a regional greenhouse gas market. Meanwhile, California has enacted legislation to limit carbon dioxide from cars and sports utility vehicles. These state initiatives are important not only because they can help pave the way for federal action but also because US states are themselves large emitters of greenhouse gases. California's emissions exceed those of Brazil. Ohio's emissions exceed those of Turkey, and those from Illinois exceed of the Netherlands.

The European Union countries, including our own, ratified the Protocol in New York on 31 May 2002. The European Union now has an overall emissions target of 8 percent below 1990 levels for the period between 2008 and 2012. The British government has decided to do still better and has adopted a legally binding target of 12.5 percent. Since then, as global warming seems to be proceeding faster than expected, the government has also adopted a voluntary target of 20 percent reduction by 2010. At present it seems unlikely to do better than 14 percent. Indeed British emissions actually increased in 2003. More recently the government has set itself a still more ambitious target in line with the recommendations of the Royal Commission on Environmental Pollution: a 60 percent reduction by 2050.

The government has adopted a whole raft of measures on energy to reduce emissions. First is the European emissions trading scheme which began on 1 January 2005. Under the scheme European Union member state governments are required to set an emission cap for all installations covered by the scheme which include: the electricity generating industry; oil refineries; the iron and steel industry; the minerals industry; and paper, pulp and board manufacturing. So far aviation and bunker fuel are missing.

There is still a big question mark over whether Kyoto will much affect the British economy. Will it help the government achieve its targets? Much will depend upon the price of tradable emission permits. Here the Government has been less than resolute. To cushion industry from changes that will inevitably have to come, the Government tried to relax its intended carbon dioxide cap from 736m tonnes over the next three years to 756m tonnes. This decision was immediately challenged by the European Commission. It sat strangely with the Prime Minister's continuing efforts to show leadership on climate change both within the G8 group and within the European Union (whose Presidency Britain assumes on 1 July), and it has since been rescinded with vague threats of legal action in the air.

The road from Kyoto is pretty clear. The key question is what should follow the Protocol after 2012. There are many ideas around, including new arrangements for methane. A lot depends on how the issue can be managed within the G8, and whether the Prime Minister will at last be able to persuade President Bush to join the rest of the world.

In my own view much firmer action should now be considered. When I first thought about the problems in the mid 1970s, I then wondered whether some sort of trade sanctions might be imposed on countries that failed to adopt the necessary policies, but took commercial advantage of countries that did so. I hope that no such measures will be necessary. We can already see US industries deciding to take their own measures, and the insurance and reinsurance industries, like many banks, are beginning to apply new criteria in establishing future premiums and investments. We shall have to see what happens. Too much pussyfooting at this stage will not help.

In conclusion if we are to tackle climate change and the wider environmental crisis developing around us, we must all learn to think and behave differently. Even those who accept the premise of the need for change have very different priorities. For what it is worth my own are as follows:

• Obviously we need urgent action on climate change and clearly this means urgent action on energy policy. There is never going to be a shortage of energy. The only problem is how we generate it, and there are many choices. So much has been said on this that I will not repeat it.
• We need to do far more to understand the Earth system. We are often ignorant of our own ignorance. Last week's draft report from the Millennium Ecosystem Assessment will help. But the complexity of all living things and their mutual dependencies at present passes human understanding. Yet we damage it at our peril.
• We need to look again at economics and the way we measure wealth, welfare and the human condition in terms of the Earth's good health. The key question is how to establish true costs. Failure to tackle climate change carries an enormous financial penalty. Traditional measurements of economic growth are dangerously misleading. Here the Chinese government has recently taken a lead. It has actually applied the principles of "clean green growth" in the province of Shanxi. Governments have a particular responsibility to determine what is in the public interest, and to use fiscal instruments to promote it.
• Nowhere is this more true than in the field of technology. Carbon sequestration should have its place, but let me say simply that I do not think that technical wheezes - mirrors in space, windmill extractors, iron sprays in the oceans, cloud whitening and the rest - could ever do the trick, and would probably create more problems than they solved. We need to make much better use of technology and its myriad applications. We also need to understand the hazards, particularly over pollution. Risks are hard to assess. The short term must not be allowed to defeat the long term.
• We need to apply the principles of common but differentiated responsibility, accepting that industrial countries have much bigger responsibilities for what has gone wrong as well as what has gone right, and should give the example in their domestic policies. Getting rid of perverse subsidies, especially those supporting the fossil fuel industries, would be a good start.

How will these changes come about? Change usually takes place for three main reasons. First through leadership from above by institutions or individuals; secondly through public pressure from below; and thirdly - however regrettably - through some useful catastrophes to jerk us out of our inertia into more sensible courses.

The Astronomer Royal, just elected President of the Royal Society, has rated the chances of our civilization surviving until the end of the century as no more than 50 percent. The stakes are indeed high but the odds should lengthen as public understanding increases. All over the world people have to change their ways and remodel their thinking. Otherwise nature will do what she has done to over 99 percent of species that have ever lived, and do the job for us.