Carbon dioxide emissions can be cut by 70 percent by 2050 in Japan even without adding nuclear power plants if the country improves energy efficiency and increases natural energy generation, a governmental environmental institute said.

The government aims to build more nuclear plants to cut carbon dioxide emissions, but the alternatives are "worth trying for future generations' sake," Junichi Fujino, a researcher at the National Institute for Environmental Studies, said last week.

According to research by the institute under the Environment Ministry, Japan can cut carbon dioxide emissions by increasing use of fuel cells, wind power generation and other new types of energy.

Britain and Germany have already come up with goals to cut nearly 60 percent of carbon dioxide emissions by 2050 in the runup to international negotiations beginning this year on long-term global warming gas reduction goals after the Kyoto Protocol expires in 2012.

The research shows placing solar battery panels on the roofs of half of houses and buildings and constructing as many windmills at parks and other places as possible could generate 120 million kw, equivalent to the electricity generated by dozens of nuclear reactors.

In addition, Japan should produce hydrogen out of natural fuels in and outside Japan and supply hydrogen to fuel cells used in automobiles and home appliances.

The country also should reduce energy consumption by refining city structures and the traffic system, the institute said.

In a combination of all the above measures, Japan can reduce carbon dioxide emissions to less than 400 million tons a year, or 30 percent of what they are currently, the research shows.