A grown moose belches out methane gas equivalent to 2,100 kilograms of carbon dioxide a year, contributing to global warming, Norwegian researchers said yesterday.

The moose's belching is the equivalent of more than twice the amount of CO2 emitted on a round-trip flight across the Atlantic Ocean from Oslo to the Chilean capital Santiago.

"An adult moose emits about 100 kilograms of methane gas a year. But methane gas is much stronger than carbon dioxide, so to get the equivalent you have to multiply by 21," said professor Odd Harstad of the Norwegian University of Life Sciences.

With an estimated 140,000 moose roaming Norway's forests, the country's moose emit a total of 294 million kilograms of CO2 per year.

The Norwegian moose population's contribution to greenhouse gases is dwarfed by the emissions of Canadian moose, who number between 500,000 and one million animals, according to Canadian Wildlife Service statistics.

With more public attention focused on global warming in recent years, the contribution of animals has come under increased scrutiny.

Last year, a report by the United Nations' Food and Agriculture Organization projected that global meat production will increase to 465 million tonnes by 2050, more than double the 229-million tonne level in 1999.

The report said that one-third of the planet's protein consumption comes from meat - and that the cattle, pigs and other animals we eat account for 18 per cent of greenhouse gases.

But Prof. Harstad said that the role moose play in greenhouse-gas production is no reason to begin killing off the moose population.

"Moose have very important functions in nature," he said. "They are ruminants that eat the grass. If we don't have ruminants, we have too much grass and that changes the landscape and has consequences for the flora and fauna."

In Canada, while conservation groups have drawn attention to declining populations in some parts of the country, in other regions moose overpopulation has caused problems.

An overabundance of moose in Gros Morne National Park in Newfoundland was cited by a federal forestry official as a reason for concern in 2004.

Prof. Harstad said his estimate of 100 kilograms of methane gas per moose was based on earlier calculations for cows in Norway.

As is the case with cows and other ruminants, methane is produced from the microbes in the moose's stomach that help break down the roughage they eat.

Both methane and carbon dioxide are so-called greenhouses gases, major contributors to global warming.