A U.S. environmental studies professor said Wednesday in Tokyo that the United States could still meaningfully participate in the framework of the 1997 Kyoto Protocol on curbing global warming.

James Speth said the U.S. was able to achieve energy efficiency following the oil shock in the early 1970s and that "if we pursue these policies (to attain energy efficiency), and begin again to take this very seriously, we could very meaningfully participate in the international regime."

The U.S. has ditched the Kyoto pact, which requires industrialized countries to slash greenhouse-gas emissions from 1990 levels by an average of 5.2 percent between 2008 and 2012.

The pact will only take effect 90 days after being ratified by 55 states representing 55 percent of industrialized countries' carbon dioxide emissions in 1990.

During a speech at the Foreign Correspondents' Club in Tokyo, the dean and professor at Yale University's School of Forestry and Environmental Studies said that rather than looking to Washington on global warming, people should look for action at the local level.

"There is tremendous movement going on at the state level," Speth said. "If we have that kind of pursuit of these issues at the state level and we get more and more states doing things . . . "I think that we will find that Congress will follow along, inevitably."

On Thursday, Speth, along with Harold A. Mooney, a professor in the Department of Biological Sciences at Stanford University, will receive the 2002 Blue Planet Prize.

The prize is awarded annually to individuals or organizations that have made outstanding scientific contributions to global environmental conservation.

Speth will receive the prize based on his devotion to creating and invigorating environmental institutions of extraordinary importance, according to the Asahi Glass Foundation, which established the prize in 1992.