Prime Minister Yasuo Fukuda was expected to unveil on Monday a target to cut Japan's greenhouse gas emissions by 2050, but also faces pressure to set an interim goal to show leadership as host of a G8 summit next month.
Japan hopes to clinch agreement to halve global emissions by mid-century at the Group of Eight summit, where a climate change session will also be attended by big emerging countries such as China and India.
The European Union, which has already set a target of reducing emissions by 20 percent by 2020, and developing countries argue rich nations should take the lead by setting bold 2020 targets for reducing emissions that cause global warming.
But the United States, a top emitter along with China, has said it will only accept binding emissions curbs on condition major emerging countries also agree. So far, they have refused to do so.
Fukuda is likely to set a target to reduce emissions by 60-80 percent by 2050 and acknowledge the need for mid-term targets. But Japanese media have said he would stop short of announcing firm figures for a 2020 goal.
The Yomiuri newspaper said over the weekend, however, that he would introduce a preliminary figure estimating how much Japan could reduce emissions by around 2020-30 from 2005 levels.
The paper also said Fukuda would announce that a trial scheme for carbon trade, seen as one way to fight global warming, would begin in the autumn.
Japanese steel makers and power companies have opposed a mandatory cap-and-trade scheme out of fear it would harm their competitiveness.
Opposition party lawmakers and environmentalists say Fukuda should take a bold stance on an interim target to persuade industry and voters to get serious about global warming and convince emerging countries to join a new international framework.
