This is because elevated concentrations of greenhouse gases will remain in the atmosphere for decades. The international talks in Bonn, Germany, involve countries which have signed the Kyoto Protocol, the international agreement on tackling climate change. This month's talks are a preliminary to a much higher-profile meeting in November, when there will be pressure for leading polluters to ratify the Protocol, which none has yet done. But environmentalists are accusing some members of the Organisation for Economic Co-operation and Development of trying to undermine the Protocol by exploiting loopholes in its provisions. They say some OECD members, including the US, are trying to avoid cutting their own emissions through greater reliance on nuclear power, and by buying the right to emit greenhouse gases from poor countries which cannot afford them.
Some researchers doubt that human activities are inducing rapid climate change.
They highlight the inconsistencies between the temperature records taken at the Earth's surface, which show rapid warming over the last two decades, and the data produced by satellite and balloon studies. These show little or no warming higher in the atmosphere over the same period, and some scientists say our understanding of climate processes is still too limited to support an acceptance of human-induced climate change.