Japan has pledged to reduce emissions of greenhouse gases to 6% below the 1990 level by 2010. It made that pledge at the Third Session of the Conference of the Parties to the UN Framework Convention on Climate Change (COP3), held in Kyoto in 1997.

Carbon dioxide makes up more than 80% of the total of all greenhouse gases, and the best way to reduce carbon dioxide emissions is to use less energy. To conserve energy and use it more efficiently, a number of techniques are now available. They include:

Developers are now working on a small, highly efficient battery called a proton exchange membrane fuel cell, which produces electricity from hydrogen. The fuel cell does not pollute the atmosphere, and the only emission is water.

Fuel cell hybrid vehicles (FCHV) will use hydrogen as a fuel, plus a battery to use surplus kinetic energy as electricity. The FCHV is expected to have about three times the overall efficiency of today's gasoline-powered vehicle. By 2040, there could very well be about 9 billion people in the world and three times more cars on the road than now (2 billion!), and yet all of those cars could use about the same amount of energy as today.

Of course, by that time there will be less oil available for production. But other types of energy will also be available to supply pollution-free hydrogen, so CO2 emissions will be lower than today.

More renewable energy is being produced as well—the sun shines on solar panels and makes electricity, the rays of the sun provide heat that is used effectively, the wind generates electricity. Solar panels convert the sun's rays into electric energy, and are now achieving efficiency rates of close to 20%. Data for the last 20 years show that, for each doubling of accumulated electricity production, costs fall to around 82% of the previous level. If this trend continues, electricity from solar panels will one day cost no more than from conventional sources. Then, people who own vacant land in sunny locations in Japanese cities will have another choice besides growing vegetables or developing a parking lot—they could also decide to construct solar panels and use or sell the electricity. Wind turbines in Japan already have the capacity to generate 460,000 kW of electric power, and the number under construction is growing. Farm waste and other organic matter may one day be used as biomass, converted into a material that is mixed with gasoline or some other fossil fuel to make a bio-fuel for motor vehicles.

In recent years, many Japanese companies have released annual reports on how much they are reducing their CO2 emissions. But more time is needed to replace today's energy systems with environmentally friendly ones. If, in addition to the introduction of new technologies, there are tax incentives, improvements in the social infrastructure, and campaigns to modify lifestyles, people will surely use energy more efficiently and embrace smaller, more environmentally friendly energy systems.