(Recasts, adds de Boer interview, details) By Alister Doyle, Environment Correspondent OSLO, Oct 30 (Reuters) - Greenhouse gas emissions by industrialised nations rose in 2004 to the highest levels since the early 1990s, and governments must do more to cut back and fight global warming, a U.N. report said on Monday. "There is a rather worrying increase in the period 2000-04," Yvo de Boer, the Dutch head of the Bonn-based climate change secretariat, told Reuters of the annual study. Emissions of heat-trapping gases by 40 nations, including backers of caps under the U.N.'s Kyoto Protocol and outsiders led by the United States, rose to 17.9 billion tonnes in 2004 from 17.8 billion in 2003 and 17.5 billion in 2000. Economic revival in Russia after a downturn since the collapse of the Soviet Union contributed to stoke emissions, the secretariat said in an annual review. Emissions also rose since 2000 in the European Union, Japan, the United States and Canada. "Countries are going to have to make very significant efforts" to cut emissions, mainly from burning fossil fuels, to reach targets under the Kyoto Protocol, de Boer said. In London, a report on Monday, the most detailed study yet of the economics of global warming, said that ignoring climate change could lead to economic downturns on a scale associated with the 20th century world wars and the 1930s depression. The British report said costs of action would be a fraction of the damage caused by inaction, such as more widespread floods, storms, heatwaves, droughts and rising sea levels. The climate change secretariat said the 2004 rise put overall emissions by industrialised nations, mainly from power plants, factories and cars, 3.3 percent below 18.6 billion tonnes in the Kyoto benchmark year of 1990. World emissions of greenhouse gases, widely blamed for blanketing the planet and raising temperatures, are likely to be at record highs -- the report did not look at the fast-growing economies of nations such as China, India and Brazil. SOVIET COLLAPSE The 2004 emissions by industrialised nations were the highest since just after the collapse of the Soviet Union in 1991, defying efforts at cuts. In 2000, before the revival in Russia, overall emissions were 5.6 percent below 1990 levels. Thirty-five countries have agreed to cut emissions under the Kyoto Protocol to about 5 percent below 1990 levels by 2008-12. Ministers will review Kyoto in Nairobi at annual U.N. climate talks from Nov. 6-17. Britain, France, Germany, Greece, Iceland, Monaco and Sweden were "relatively close" to goals under the Kyoto Protocol, it said. But many others were way off target. Among Kyoto nations, Spain was highest at 49.0 percent over 1990 levels in 2004, ahead of Portugal on 41.0 percent with Canada 26.6 percent over 1990. Further down the list, the United States was 15.8 percent above 1990 levels with the EU as a whole 0.6 percent below 1990. U.S. President George W. Bush pulled out of Kyoto in 2001, arguing it would damage the U.S. economy and wrongly excluded developing nations in goals to 2012. The United States is the world's number one source of emissions. Despite rising emissions, De Boer said Kyoto countries still had a "good chance" of meeting their pledged cuts if they quickly applied planned domestic measures and exploited options such as trading greenhouse gases. Among bright spots, the data showed the amount of carbon dioxide emitted per dollar of economic output in industrialised nations had fallen by 28 percent from 1990-2004 -- meaning growth was not so dependent on burning more energy.
