The digestive processes of cows and sheep produce huge quantities of methane, a potent greenhouse gas. Kangaroos, on the other hand, emit little methane. Researchers at the Australian Wildlife Service published a 2008 paper discussing what would happen if Australians ate less livestock and more marsupial meat.
The scientists suggest removing 7 million cattle and 36 million sheep from the country's livestock industry and, over the course of 13 years, bringing the nation's kangaroo population from 34 million to 175 million. This swap would produce the same amount of meat while decreasing Australia's total annual greenhouse gas emissions by 3 percent.