Emissions of heat-trapping gases from transport in rich nations were 20 percent above 1990 levels in 2003 against a goal under the UN's Kyoto Protocol of a total 5 percent cut in all emissions by 2008-12.

"The growth ... is really quite worrisome," he said. "Clearly much more concerted action is necessary." Transport accounts for about a fifth of all greenhouse gas emissions, mainly carbon dioxide from fuel burnt on the roads by vehicles.

Many scientists say carbon dioxide and other gases are blanketing the planet and may trigger wrenching changes such as more droughts, heatwaves and higher sea levels.

The Bonn talks of senior officials are seeking ways to extend the Kyoto Protocol beyond a first period to 2012.

Kinley said the transport problems in rich nations were mirrored in the developing world. "There's tremendous increase in mobility, in particular in the rapidly industrialising countries where people have access to motor vehicles," he said.

One problem is that transport emissions cannot easily be regulated by a system for trading carbon dioxide emissions, such as a volatile European Union scheme for trading emissions from power plants and factories.

OVERALL EMISSIONS DOWN

And Kinley said there were some positive signs -- China had tighter emissions limits for vehicles than some industrial nations.

And he said efforts to cut emissions of methane -- often to generate power by burning the gas released from manure or rotting vegetation -- were doing well since 1990. Methane is the number two greenhouse gases behind carbon dioxide.

And work to reduce emissions of "F gases", which are powerful greenhouse gases produced by some industrial processes, was also making good process with cuts by aluminium producers.

And in the energy sector, he said some measures already taken would yield benefits in coming years, according to recent reports by governments.

"Projections give a strong indication that in the energy sector the measures in place will start to kick in," he said.

But he faulted many industrial states for failing to submit reports about how they were faring in implementing the Kyoto Protocol -- latest national reports were due by Jan. 1, 2006.

"I'm quite disappointed that we haven't received all of them. I think we're at about half," he said. Among laggards were Germany, Russia, Britain, France, Italy and Canada.

"I'm very hopeful that we will get them in the next couple of months. If it's any later than that I think we want to ring some alarm bells," he added.