Thirty eight industrialised nations agreed in 1997 in the Japanese city of Kyoto to cut their emissions of the main gases produced by human activities, which are blamed for climate change, writes Denis Staunton.
By 2012, they would have to cut emissions by an average of 5.2 per cent on their 1990 levels. The EU would cut its emissions by 8 per cent and the US by 7 per cent.
Three follow-up conferences in Buenos Aires, Bonn and The Hague, failed to agree on how the cuts should be made. The EU has refused to ratify the Kyoto Protocol until all open questions are resolved.
The US is responsible for about 25 per cent of global emissions of carbon dioxide, the main pollutant covered by Kyoto.
Washington objects to the protocol on the grounds that it concentrates on emissions from industrialised countries, and does not at this stage seek to limit pollution from developing nations.
It was officially opened for signature in 1998. Since then 84 nations, Ireland among them, have signed.