BANGKOK, Thailand — UN-sponsored scientists who warned of the dangers of a warming Earth will issue a new study next month describing how to avert the worst.

They say that everyone must embrace technologies ranging from nuclear power to manure control. A draft copy of the panel's report says that under a best-case scenario, the global economy might lose as little as three percentage points of growth by 2030.

That is if technologies to reduce greenhouse-gas emissions are used.

But the draft report, obtained by The Associated Press, says it won't be easy to achieve.

One of the report's authors, British researcher Rachel Warren, says: "Governments, businesses and individuals all need to be pulling in the same direction."

For one thing, the governments of such major emitters as the United States, China and India will have to join the Kyoto Protocol countries of Europe and Japan in imposing cutbacks in carbon dioxide and other heat-trapping gases emitted by industry, power plants and other sources.

The U.S. administration rejected the protocol's mandatory cuts, contending they would slow U.S. economic growth too much. China and other poorer developing countries were exempted from the 1997 pact, but most expected growth in greenhouse emissions will come from the developing world.

The draft report from the Intergovernmental Panel on Climate Change, or IPCC, whose final version is to be issued in Bangkok on May 4, says emissions can be cut below current levels if the world shifts away from carbon-heavy fuels like coal, embraces energy efficiency and significantly reduces deforestation.

"The opportunities, the technology are there and now it's a case of encouraging the increased use of these technologies," said International Energy Agency analyst Ralph Sims, another of the 33 scientists who drafted the report.

Two previous IPCC reports this year painted a dire picture of a future in which unabated greenhouse emissions could drive global temperatures up as much as six degrees Celsius by 2100. Even a two-degree-Celsius rise could subject up to two billion people to water shortages by 2050 and threaten extinction for 20 per cent to 30 per cent of the world's species, the IPCC said.

The third report makes clear the world must quickly embrace a basket of technological options - both already available and developing - just to keep the temperature rise to two degrees C.

The draft notes that significant cuts could come from making buildings more energy-efficient, especially in the developing world, through better insulation, lighting and other steps, and by converting from coal to natural gas, nuclear power and renewable energy such as wind, solar and biofuels.

Less significant but also important would be steps to make motor vehicles more fuel-efficient, reduce deforestation, and plant more trees as a carbon "sink," absorbing carbon dioxide. Even capturing methane emitted by livestock and its manure would help, the report says.

Over the next century, it says, such technology as hydrogen-powered fuel cells, advanced hybrid and electric vehicles with better batteries, and carbon sequestration - whereby carbon emissions are stored underground - will become more commercially feasible.

It says taking "optimal" mitigation measures might by 2030 stabilize greenhouse-gas concentrations in the atmosphere at 445 to 534 parts per million, up from an estimated 430 ppm today.

Achieving the 445-534 ppm range might cost under three per cent of global gross domestic product - or GDP - over two decades, the draft says.