Science is increasingly pointing a finger at human actions as being responsible for the perils of climate change. This is an ineluctable consequence of improving the computer models of climate change. Of course, there are still large uncertainties. But it is clear the human hand is indispensable in understanding what has happened.

The more certain is the attribution for blame, the more justified many developing countries will feel in protesting about the impact of rising sea levels on small island states such as the Maldives and Fiji or low-lying delta cultures such as Vietnam and Bangladesh. Fair-minded democracies will find the call for compensation hard to resist at home.

The science also opens up the possibility that the victims of climate change could begin to take international legal action against the countries responsible, particularly the early industrialisers, such as Britain, Belgium and Germany, whose carbon continues to warm the planet a century after it was emitted. Legal action is not a substitute for politics, but it could highlight the evidence in an uncomfortable way.

The UN framework may not be ideal, precisely because it is dominated by the historic five powers, who have their own interests. But the International Tribunal for the Law of the Sea may be a forum that would hear the matter.

It is not a defence that we did not know what we were doing, nor does a case have to target everyone who might have historic responsibility: countries are jointly and severally liable.

The historical emitters can argue that the global political processes underway since 1992 are proof that the need for action has been responded to and preclude the need for lawsuits. But that implies that such processes must hold out a real possibility of delivering change. — © Guardian Newspapers Limited, 2013

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