Tokyo ? Japan on Friday launched the first satellite to monitor greenhouse gases worldwide, a tool to help scientists better judge where global warming emissions are coming from, and how much is being absorbed by the oceans and forests.

The orbiter, together with a similar U.S. satellite to be launched next month, will represent an enormous leap in available data on carbon dioxide and methane in the atmosphere, now drawn from scattered ground stations.

“I’m saying Christmas is here,” said an enthusiastic Inez Fung, an atmospheric scientist at the University of California, Berkeley. “Now we get about 100 observations every two weeks. With the satellite we’ll get a million.”

The satellite — named “Ibuki,” which means “breath” — was sent into orbit along with seven other piggyback probes on a Japanese H2A rocket. Japan’s space agency, JAXA, said the launch was a success, and officials said they were monitoring the satellites to ensure they entered orbit properly.

Ibuki, which will circle the globe every 100 minutes, is equipped with optical sensors that measure reflected light from the Earth to determine the density of the two gases.

Carbon dioxide, the biggest contributor to global warming, is emitted by the burning of fossil fuels by power plants, motor vehicles and other sources. Methane has a variety of sources, including livestock manure and rice cultivation.

International science agencies report that carbon dioxide emissions rose 3 percent worldwide from 2006 to 2007. If emissions are not reined in, a U.N. scientific panel says, average global temperatures will increase by 4 to 11 degrees Fahrenheit by the year 2100, causing damaging disruptions to the climate.

“Global warming is one of the most pressing issues facing the international community, and Japan is fully committed to reducing CO2,” said Yasushi Tadami, an official working on the project for Japan’s Environment Ministry. “The advantage of Ibuki is that it can monitor the density of CO2 and methane gas anywhere in the world.”

Scientists currently depend on 282 land-based stations — and scattered instrumented aircraft flights — to monitor carbon dioxide at low altitudes. Ibuki, orbiting at an altitude of about 415 miles, will be able to check gas levels in entire columns of atmosphere at 56,000 locations.

With the current ground-level network, “due to the relatively small number of locations, only large-scale regional averages could be determined” for greenhouse-gas emissions, said Swiss climatologist Fortunat Joos, of the University of Bern.