The world's most constipated negotiation over an international convention, now going on in Milan, is in search of a laxative. More than a decade after the UN Framework Convention on Climate Change was agreed at the first Earth Summit in Rio, the subsequent deal drafted in Kyoto to make it operational still lacks enough support to kick into action. The announcement in Moscow, by a senior adviser to President Vladimir Putin, that Russia will not sign the protocol "in its current form" makes the prospects for Kyoto gloomier than ever. Warnings of northern Europe being plunged into a big freeze cut little ice (as it were) with Putin. If the global greenhouse switches off the part of the Gulf Stream that warms countries such as Britain and France, why should Russia, with its Siberian wastes, care?
With the US and Australia also out of the Kyoto picture for the foreseeable future, what else can be done? A cheap and increasingly popular option - as global warming offers either drought or floods to swathes of Africa, Asia and Latin America, and as Pacific islands sink beneath the sea - would be for the culprits of global warming to say sorry, as President Clinton did to Hawaiians and Elizabeth II to Maoris and Sikhs during a wave of post-colonial apology. But unless the apology comes wrapped in a multibillion-dollar promissory note to cover the damages, a more likely outcome is that global warming's losers will go to court. The law is one of the few buttons left to press, and it could get the bowels of the climate talks moving.
Using the courts to right historical wrongs and settle disputes between peoples and countries is increasingly popular across the world. As political processes fail, the pursuit of reparations for the guilt of nations and the crimes of corporations becomes more and more a matter for the courts. As well as the actions seeking compensation for slavery and restitution for Nazi looting, the Swiss banks UBS and Credit Suisse have been named in US lawsuits brought on behalf of victims of apartheid in South Africa. An eight-year-old Iranian refugee took a civil action against the Australian government after detention left him with possibly chronic post-traumatic stress disorder. The king of Bunyoro in Uganda sought £2.8bn compensation from Britain for acts of brutality and exploitation admitted in British military diaries dating back to 1894. Perhaps more than anything, the cases against "big tobacco" have made people believe in the potential of the law to tackle great injustices.
The Pacific island of Tuvalu, which could be devastated by climate change effects, has already announced its intention to bring legal action against the world's worst polluters. That is virtually its only option, given its small size and marginal place in world affairs. Its regional neighbour Australia would be first to be taken before the International Court of Justice. Australia, like the US, rejects Kyoto; but unlike the US, it accepts the court. Other low-lying island states, Kiribati and the Maldives, may join Tuvalu to bring the first international class action of its kind.
Such lawsuits reflect the increasing legalisation of international relations. One reason for that is frustration with a complex and constantly undermined United Nations. Another is the success of economic globalisation. As more and more business deals take place across national borders, an increasingly mature and comprehensive body of international law is needed to protect them. Also, wherever the US goes, it tends to take along its uniquely litigious political culture. Around half of all legal cases in the US are tort actions - claims for compensation and punitive damages where injury or harm has resulted from reckless, negligent or improper behaviour. The US is a country where, as Alexis de Tocqueville observed, there is "scarcely any political question . . . that is not resolved sooner or later into a judicial question".
The law is not straightforward. It needs evidence, litigants, appropriate jurisdiction, and the ability to assess compensation commensurate with damages and to constrain the perpetrators of harm. But the law comes down to simple principles: if someone does you harm, they should first stop what they are doing and, second, compensate you for the harm done. The rest is just detail that a queue of hungry lawyers with help from the scientists will help work out.
German interior ministry officials estimated the costs of the great floods that hit Germany in the summer of 2002, affecting a third of a million people, at 9bn euros (£6.3bn). Heatwaves in Paris this year killed about 15,000 people more than the seasonal average, leaving countless aggrieved relatives. The only thing holding back court claims has been the problem of attribution.
Looking at how the insurance market works for the science journal Nature, Myles Allen, an Oxford University physicist, thinks that problem is now largely solved. All you have to do, he says, is work out "a 'mean likelihood-weighted liability' by averaging over all possibilities consistent with currently available information". Unpacked, it means that if past greenhouse gas emissions have increased flood risk tenfold, 90 per cent of the damage caused by a flood can be attributed to past emissions. Because carbon dioxide mixes itself in the global commons of the atmosphere, "an equitable settlement would apportion liability according to emissions", argues Allen.
According to Andrew Strauss, a US professor of international law, people harmed by global warming could sue their own government in the domestic courts; or they could sue the most guilty corporations in either domestic or foreign courts; or they could get governments hauled up before an international tribunal.
Some cases are under way. The US cities of Boulder, Colorado, and Oakland and Arcata, California, together with Greenpeace, Friends of the Earth and affected individuals, are suing the US export credit agency over its funding of fossil-fuel projects. Another action by the International Centre for Technology Assessment and the US conservation group the Sierra Club is trying to apply the Clean Air Act to force the Environmental Protection Agency to impose mandatory greenhouse gas reductions.
A less direct route could prove more effective than any of the above. In the context of world trade agreements - already the locus of disputes between Europe and America over steel tariffs and genetically modified foods - it could be argued that the US opt-out from Kyoto, by avoiding the costs of reducing carbon emissions, is in effect a subsidy to domestic US businesses. The EU could calculate the value of that subsidy and apply countervailing measures or "border tax" adjustments to a selection of US exports until America started to play ball again. The US could then take a complaint to the dispute mechanism at the World Trade Organisation. Trade sanctions, imposed collectively by countries in defence of a multilateral environmental agreement, are, however, entirely legitimate in international law and the decision would very likely go against the US.
If there is a problem with using the law to tackle the slackers over climate change, it is that ad hoc legal processes cannot replace the need for an effective global climate deal. Nothing can replace the need to set a target for shrinking emissions that is sufficient to prevent runaway climate change. Nor can anything substitute for a proper constitutional framework that allows an orderly convergence in the amount of fossil fuel that each person on the planet uses. But as we work painfully towards that end, the litigation laxative might just get things moving.
Andrew Simms is policy director of the New Economics Foundation. A new briefing, Free Riding on the Climate, is available at www.neweconomics.org