The Kyoto Agreement had been signed by then-US Vice President Al Gore but has never been ratified by the Senate.

Toepfer said he was ‘absolutely convinced that climate change is proven, and is a very serious problem.’ He said the Intergovernmental Panel on ClimateChange (IPCC) had done extensive work, and was carrying out detailed analysis of the definite impacts it had found, especially on developing countries.

‘The US must be integrated into this fight,’ Toepfer said, ‘They are part of the problem, and they are part of the solution’.

Toepfer noted that the annual meeting of the IPCC was to be held on 4 April and he challenged Bush and other holdouts to bring their questions to that meeting. ‘[Members of the IPCC] will vote then on whether to accept the third assessment report,’ he said, ‘and all those who have open questions should join us there and challenge the report. We are always open to questions.’ But, he warned: ‘That can’t be used as a reason for not acting.’

In the past Bush has claimed that the burden of reducing carbon emissions does not fall equally on developing countries, but Toepfer noted that the per capita production of carbon was more than 20t annually in the US, compared to 10t in the EU and other developed countries and less than 1t in most developing countries. ‘We must be aware that the economic development of developing countries will be linked with higher demand’, Toepfer said, ‘Our aim should be to integrate developing countries into the flight against climate change.’ The IPCC’s working group on mitigation, which released its report in early May, suggested that climate change could be addressed with existing technologies for renewable energies and energy efficiency, providing that the technology was used. Asked whether developing countries could be persuaded to use technology from Kyoto signatories, Toepfer said that economic pressure was not the way to bring the US into line. Instead, he said, the IPCC should underline these opportunities. Toepfer said that society at large should start to fight climate change by using these new energy efficient technologies.

Bush’s decision to withdraw from Kyoto, though it broke a campaign pledge, was not unexpected: on 16 March Christine Todd-Whitman, head of the US Environmental Protection Agency, said in a speech that in future US actions to on reducing emissions would focus on SO2, NOx and mercury. ‘California has experienced energy shortages and other Western states must also be worried about price and availability of power. I agree with the President that we must be very careful not to take actions that could harm consumers.’