BANGKOK: Across the globe, chickens and pigs are doing their bit to curb global warming. But cows and sheep still have some catching up to do.

The farm animals produce lots of methane, a potent greenhouse gas that gets far less public attention than carbon dioxide yet is at the heart of efforts to fight climate change.

Government policies and a UN-backed system of emission credits is proving a money-spinner for investors, farmers and big polluters such as power stations wanting to offset their own emissions of greenhouse gases, particularly carbon dioxide (CO2).

The reason is simple: methane is 23 times more potent than carbon dioxide in trapping heat in the atmosphere and it is relatively simple to capture the gas from animal waste, landfills, coal mines or leaky natural gas pipes.

“A fifth of all greenhouse gas-induced global warming has been due to methane since pre-industrial times,” said climate scientist Paul Fraser of Australia, where ruminant farm animals belch out vast amounts of the gas.

Methane concentrations have increased about 150 per cent in the air since 1750 and now far exceed the natural range of the past 650,000 years, the UN’s climate panel says. And human activities are largely to blame.

The panel will be focusing on ways to curb methane and other greenhouse gas emissions when it releases a major report on mitigating the effects of climate change in Bangkok in early May.

“It’s been argued that the reductions from methane are potentially cheaper than from carbon dioxide,” said Bill Hare, climate policy director for Greenpeace and a lead author of the mitigation report.

“A lot of policy discussion in the United States has focused on methane rather than more difficult problems such as CO2 from coal,” he added.

This is because capturing methane from landfills, mines, or from fossil fuel production or natural gas lines is pretty straight forward and makes economic sense. Methane is a major component of natural gas and can be burned to generate power. Agriculture was a greater challenge, Hare said.

A MATTER OF BALANCE: “There are more difficult areas for methane from livestock and from rice agriculture where, at best, longer time scales are required to change practices in agriculture than you might need in industrial areas,” Hare said.