All 15 member states of the European Union have ratified the Kyoto agreement on global warming at a ceremony at the UN headquarters in New York.
The protocol - which was signed in Kyoto in 1997 - requires industrialised countries to reduce their greenhouse gas emissions by an average of 5% over the period 2008-2012.
Both the European Union and the United States - the world's biggest emitter of greenhouse gases - are parties to the convention, but President George Bush rejected the treaty, saying it would harm the US economy.
