for National Geographic News
Replacing much of Australia's beef and lamb with kangaroo meat could significantly cut the continent's greenhouse gas emissions and save its native terrain, according to a new proposal.
A recent study suggests phasing out some 7 million cattle and 36 million sheep from Australian rangelands—semiarid land that doesn't naturally produce the grass livestock requires—and replacing them with kangaroos.
Because of their unique gut microbes, kangaroos emit much less methane than sheep and cattle, said lead author George Wilson, of Canberra consultancy Australian Wildlife Services.
"Methane is a very dangerous greenhouse gas—much more potent than carbon dioxide," he said.
Sheep and cattle are responsible for about 11 percent of Australian agricultural emissions, according to a government survey. Each cow produces 1.84 metric tons of greenhouse gas equivalents a year, and each sheep gives off more than 300 pounds (140 kilograms).
Kangaroos, meanwhile, emit less than seven pounds (three kilograms) of greenhouse gases. Under the study's proposal, that could translate into savings of 16 million tons of greenhouse gases annually—or 3 percent of Australia's total emissions.
The findings were published online last month in the journal Conservation Letters.
Wilson estimated some 30 million kangaroos (including red kangaroos) already roam Australia's rangelands, where farmers typically regard them as pests. His proposal calls for the rangelands to be filled with five or six times that number.
The animals would become an asset to farmers, he said, if Australia includes agriculture—the sector that emits the most methane and nitrous oxide—in its Emissions Trading Scheme, a system the government is devising to impose charges on greenhouse polluters.
The government hopes to implement the scheme by 2010 but says it will not include agricultural emissions for another five years at least because of the difficulty in measuring them.
Wilson said the emissions saved by raising kangaroos could be worth about $650 million Australian (U.S. $570 million), based on current European carbon prices.
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