TOKYO, OCT. 23 -- Japan's government established a multifaceted program to combat global warming today, setting targets to stabilize emissions of so-called "greenhouse gases" at current levels by 2000.

The Japanese program, announced just in time for the second World Climate Conference, which convenes next week in Geneva, leaves the United States as one of the few developed countries that has not set targets to control the gases that may cause global warming.

"They pushed this out in time for the conference, which means we'll be all by ourselves in Geneva," said a U.S. Embassy official. "But our position is that the scientific community has still not made up its mind about global warming, and we are not setting targets in an unsettled situation."

The Japanese plan expresses no doubt about the concept of global warming -- the theory that the burning of fossil fuels has changed the earth's atmosphere and is gradually raising average temperatures.

"Global warming is a grave concern which is likely to pose a serious threat to the very foundation of human life," the report says, citing the risk of environmental changes and possible social consequences. It stresses the prediction -- rather fearsome to an island nation with many big cities on the coast -- that global warming could melt polar ice packs and raise the level of the oceans, submerging low-lying areas.

Japanese emissions of carbon dioxide, the most important of the greenhouse gases, already are low compared to other industrialized countries. According to the Organization for Economic Cooperation and Development, Japan's emissions in 1988 came to about 2.5 tons per person, lower than most other wealthy countries. The U.S. rate was more than twice as high, at 6.14 tons.

Under the program announced today, carbon dioxide emissions will be capped in 2000 at 1990 levels, increased only to match population growth. Officials here estimated that Japan's economic growth would increase carbon dioxide emissions by 5 to 10 percent over the next decade, if no corrective steps were taken. There would be no assurance that the current level will be maintained through the 1990s, however.

The Japanese program calls for various steps to reduce the use of fossil fuels, which release carbon dioxide when burned. In particular, the plan calls for cutting oil's share of total energy consumption from the 1989 figure of 58 percent to 51 percent by 2000 and 45.3 percent by 2010.

To achieve those reductions, the government said Japan should increase construction of nuclear-powered generating plants, which do not emit significant greenhouse gases. The plan also calls for increased use of hydrogren fuels, although it is not clear that the technology exists to do so within the next decade.

Also mandated is more use of mass transportation, which may be an ambitious goal in a country where trains and subways are already the main form of daily transport for a large majority of the population.

The government is to use "administrative guidance" -- a sort of official nudging that is often highly effective -- to make auto manufacturers produce lighter cars that use less gasoline. In 1988, according to Japan's Environmental Agency, cars here averaged 27.2 miles per gallon, about 30 percent higher than the American average. The plan says this figure should increase by 10 percent before 2000 and 15 percent by 2010.

The program also calls for Japan to switch to daylight saving time, known here as samma tymuh or "summer time." That would save energy now used for air conditioning in the morning and lighting offices in the evening.

Japan's global-warming targets represent a compromise between proposals by the Environmental Agency and the concerns of the Ministry of International Trade and Industry, which protects business interests. The two agencies squabbled for months over the plan, according to reports here, and finally settled their differences so that Japan could present formal targets at the Geneva conference.

"Europe has already settled on targets, and now Japan has decided," said Taku Omura, a planning official in the Environmental Agency. "The U.S. has been behind the others in this area."