The European Union has urged Japan and the United States to reduce their greenhouse gas emissions by 24 percent each by 2020 from 1990 levels in an attempt to ensure that developed countries pull their fair share in the fight against climate change.

The EU figure could influence debate on Japan's emissions reduction target for 2020, which Prime Minister Taro Aso says he will unveil by June prior to a Group of Eight summit in Italy in July and a key U.N. climate change conference in Copenhagen in December.

Japan is studying six options for its 2020 target. Compared with 1990 levels, they are growth of 6 percent, a range from a 2 percent decrease to a 7 percent increase, a 4 percent decline, a 1 percent to 12 percent contraction, a 16 percent to 17 percent cut and a 25 percent reduction.