Cutting the nation's carbon dioxide emissions by 20 percent within ten years will cost about 0.2 percent of gross domestic product, or around one billion dollars.

Alan Oxley, the chairman of the Australian APEC Study Center, made the remarks Monday in a news conference in Seoul.

Oxley attended a meeting of the Asia Region Climate and Energy Workshop jointly sponsored by South Korea, Australia, Japan and the United States.

He expressed skepticism over the effectiveness of the Kyoto Protocol without the participation of the United States and China, the world's biggest generators of carbon dioxide and global warming.

The protocol is a global environmental treaty to slow global warming by reducing carbon dioxide and other gases. It was implemented in mid-February by 141 countries.

South Korea must cut emissions under the protocol from 2013 because it is considered a developing country.

However, Oxley said the Seoul government should voluntarily observe the emission target of carbon dioxide like nations in Europe.