kanga

Dr Henry is at odds with prominent ecologists, as well as the economist Ross Garnaut. Professor Garnaut's 2008 climate-change review made the case for an increased diet of roo displacing cattle and sheep consumption. The Garnaut report cited a study by George Wilson and Melanie Edwards that predicted a 3 per cent drop in greenhouse emissions if roo numbers rose from 25 million to 175 million, pushing cattle and sheep of rangelands, and displacing some red meat consumption. Critics on the Henry side question the numbers, unconvinced kangaroo meat could ever replace red meat consumption in Australia to any significant degree.

"A lot of the environmental movement supports eating kangaroos, because people think it is green," said Daniel Ramp, a biologist at the University of NSW helping set up a think tank on the roo industry with the Institute of Sustainable Futures at the University of Technology, Sydney.

"But we need to follow that argument through and ask how many sheep or cattle we could displace with meat from a kangaroo."

On Dr Ramp's figures, if every Australian were to start eating roo regularly, its population would need to swell from about 25 million well into the hundreds of millions and possibly billions.

Industry estimates put the average amount of meat derived from a single roo at 12 kilograms. If a 12-kilogram meat yield provides 48 people with one 250 gram meal, 24 million roos would be needed for everyone in Australia to have one meal a week.

But quotas prevent the industry harvesting more than 15 per cent of the roo population a year, making a population above 160 million necessary. Providing fillets would require many more roos, while maintaining the existing amount of meat that is used for pet-food could push the required population into the billions.

"Imagine if we had 175 million kangaroos running about?" said Dr Ramp. "The environmental degradation would potentially be large and it would not be safe to drive on rural roads for the sheer number of kangaroos.''