The 2005 rise confirmed an upwards trend in recent years despite efforts at cuts by many governments worried that climate change, widely blamed on fossil fuel use, will spur ever more floods, droughts, heatwaves and rising seas.

"Since 2000, greenhouse gas emissions...increased by 2.6 percent," the Secretariat said.

Emissions by the United States, long the world's top emitter but with China drawing neck and neck, rose to 7.24 billion tonnes in 2005 from 7.19 billion in 2004, according to the first UN compilation of national data for 2005.

Washington has since issued a preliminary estimate that emissions of carbon dioxide, the main greenhouse gas, fell by 1.3 percent in 2006 from 2005 despite robust economic growth.

Revived economic growth in former East bloc nations was a main spur to the overall rise in emissions. Russian emissions rose to 2.l3 billion tonnes in 2005 from 2.09 billion in 2004.

Russia's emissions were still far below 3.00 billion in 1990, just before the collapse of the Soviet Union shut smokestack industries across the former communist bloc.

Among other major emitters, greenhouse gases fell in the European Union and Canada in 2005 from 2004 but were fractionally higher in Japan.

EAST BLOC

Overall emissions by former East bloc states rose to 3.6 billion tonnes in 2005, up from 3.4 billion in 2000 but down from 5.6 billion in 1990. Emissions by Western democracies totalled 14.6 billion in 2005, up from 13.1 billion in 1990.

Industrial nations -- except the United States and Australia -- have signed up for the UN's Kyoto Protocol which obliges an average emissions' cut of at least 5 percent below 1990 levels by 2008-12.

President George W. Bush decided against implementing Kyoto in 2001, saying that it would damage US economic growth and wrongly excluded targets for developing nations such as China and India in a first period lasting to 2012.

Bush this year agreed for a need for "substantial cuts" in emissions in the long term. The world's environment ministers will meet in Bali, Indonesia, in December to start trying to work out a broader successor for Kyoto from 2013.

Among countries covered by the UN data, Latvia had the largest decrease in emissions from 1990 to 2005, of 59 percent, while Turkey's emissions surged by 74 percent.

Overall emissions from the energy sector rose by 0.5 perent from 1990 to 2005 but there were declines in other major areas -- industrial processes, agriculture and waste. Transport had the biggest rise in the energy sector.