Japan has long been recognized as one of the global leaders in battling climate change. It is arguably the most energy-efficient country in the world. It uses only one-fourth the amount of energy that China does to make a given quantity of goods.

And it has led the industrialized countries in developing technologies to improve energy efficiency, reduce pollution, and cut greenhouse gas (GHG) emissions.

A recent study conducted by the European Patent Office, the United Nations Environment Program, and the International Centre for Trade and Sustainable Development, found that Japan was "the source of almost 80 percent of all innovations developed worldwide in the field of clean energy technologies", leading the United States, Germany, Republic of Korea, France and the United Kingdom.

Last year, Yukio Hatoyama, then Japanese prime minister, pledged that by 2020 Japan would reduce greenhouse gases by 25 percent, compared with 1990 levels.

The United Nations and others praised Japan for shouldering its responsibilities, unlike many other developed nations.

However, at the start of this week's climate change negotiations in Cancun, Mexico, Japan announced that it would not extend the Kyoto Protocol - the binding international treaty that commits most of the developed countries to emission cuts - when it expires at the end of 2012.

Japan's announcement is ironic given that the only legally binding treaty under the 1997 United Nations Framework Convention on Climate Change is named for the beautiful ancient city of Kyoto.

The Kyoto Protocol has played an effective role not only in cutting GHG emissions but also in spurring technological and innovative research in green development.

According to the recent study, the patenting of green technologies surged after more than 190 countries adopted the Kyoto Protocol in 1997.