Kangaroos greenhouse emissions better than cattle
By Robyn Williams on The Science Show
Rangeland cattle produce about 3% of Australia's greenhouse gas emissions. But kangaroos digest their food in a different way to cattle and don't produce the methane. Replacing cattle with kangaroos will save the production of greenhouse gases.
Director, Australian Wildlife Services
Robyn Williams: This week a paper was published by Dr George Wilson of Australian Wildlife Services in Canberra on just how much carbon can be saved if we do switch from cattle and sheep to our other icon, the kangaroo. He says we could save 16 megatonnes if we change how we farm.
George Wilson: We're saying that if one were to manage kangaroo populations upwards and manage cattle down, then you can make a substantial saving in Australia's greenhouse gas debit, and potentially save the livestock industries from having to pay for permits under an emissions trading scheme. You can produce the same amount of meat and do so in a far more environmentally friendly way.
Robyn Williams: You suggest that the cattle produce about 3% of Australia's greenhouse gases. That's more or less the same as planes, isn't it?
George Wilson: In fact cattle themselves produce more than that, we're focusing on the Australian rangelands, the areas in which the existing kangaroo industry operates at the moment, and we're saying that in those lands there are about seven million cattle and about 30-odd million sheep, and if we were to exchange those for kangaroos then you'd save 3%. We're not suggesting that we need to replace dairy cows with kangaroos because it's quite clear that's not going to work. We're focused on the rangelands, and in those areas, by making greater use of kangaroos where the kangaroo industry already exists, you can save 3% of Australia's greenhouse gas liability.
Robyn Williams: How did you work that out?
George Wilson: Well, we looked at the amount of methane they produced and we calculated that up. We also looked at the dry sheep equivalents that cattle are and sheep are on the rangelands, and we said if you remove those dry sheep equivalents, and we know what the equivalent of kangaroos is, if you were to replace that with kangaroos...we used a very conservative figure, a much lower one than is generally accepted, because if you took the higher figure we could probably carry 250 million kangaroos. We're suggesting that in these lands, to be conservative, if you let the population rise by the year 2020 to 175 million then you can produce the same amount of meat and you can make all those greenhouse gas savings that we talked about.
Robyn Williams: Why don't the kangaroos produce methane then?
George Wilson: They have different flora in their guts. Basically they operate on a different system. They have a pseudo rumen and it operates with different flora. Cattle have a full rumen and the flora that they have, the micro-organisms, when they start digesting the cellulose and lignin it produces methane. And of course methane is a very dangerous greenhouse gas, it's much more potent than carbon dioxide, but happily it only stays in the environment for a shorter period of time. So steps that can be taken to reduce methane are a much more effective way of addressing greenhouse gas problems than focusing on carbon dioxide.
Robyn Williams: Which kangaroos are we talking about? Because there are so many, over 50 different species, how would you make sure that people sorted out the rights ones to use and not knock off the yellow-footed rock wallaby?
George Wilson: Indeed, and what we're talking about is the area where the existing kangaroo industry operates at the moment, and of course it's focused on those extremely abundant species which occur on private property. We're talking about red kangaroos, eastern grey kangaroos, western grey kangaroos and euros. The Department of Environment estimates that there are about 30-odd million of these animals out there already. So part of this project is about bringing that to book, letting the landholders on whose properties these animals already occur become involved, grow the industry, and at the same time give them an alternative, because they really don't have many alternatives to address the greenhouse gas issue. There's been quite a bit of work done over the years to try and put kangaroo rumenal flora into cattle but it just doesn't work. The physical structure of the kangaroos' gut system is so different from the cattle that you can't just replace the organisms and expect that you will begin to make a rumen not produce methane.
Robyn Williams: Have you talked to any of the farmers, graziers, about how much easier it might be to have kangaroos culled instead of cattle and how they might do it on a sustainable and indeed practical basis?
George Wilson: What we're doing here is building on overseas experiences. In Southern Africa and in Scotland and indeed in North America iconic wildlife has been brought into the production system. So in Southern Africa the South Africans use springbok, another iconic species, in Scotland they use red deer, and in North America they use bison. These animals, particularly the first two, do roam from property to property, just as kangaroos do, and yet they've been able to develop a regional management process so that all of the landholders in an area that have these animals on their lands are able to benefit from them.
We've had some trials going in central Queensland and in western NSW now for a few years to look at this as an issue because we think it is an important long-term issue, that kangaroos really do need to be regarded as part of the main land use and not as pests. In the long term it's not a good position for kangaroos to be in, they need to be part of the system. So what we've done with this study is go on from that generalised observation and say, look, here's another reason, a really strong reason why kangaroos should be part of the production system, why landholders should have a reason for wanting to have them on their properties. And at the same time there are a whole lot of other conservation benefits that flow from this.
Robyn Williams: Yes, one of them being the fact that cattle are very expensive in terms of water, in terms of energy and in terms of just sheer space, ten times the non-cattle alternative of growing crops. Has that influenced farmers at all so far?
George Wilson: Yes, we do have landholders that are sympathetic to those observations. It's another step, the one that we're proposing in this paper, to go on from there and say, okay, that basic premise is accepted but how about going the next step and beginning to regard the kangaroo as their resource rather than the cattle?
Robyn Williams: I'm not talking about them being sympathetic so much as being just hardnosed and practical. If it's going to cost them ten times less in those general expenditures then surely they'll leap for it, because things are tough for farmers these days.
George Wilson: This is right, and harvesting a free ranging animal in the field that doesn't have any of those management inputs (there's no crutching, there's no castrations, there's no...all the other activities that conventional beef operations require), these animals are so successful, they're out there and they breed like mad, nobody does anything...they become a pest they're so successful, surely it's time in Australia that we began to regard this as a resource that should be part of the main production system. So we do have landholders that are coming round to that perspective and they're the ones that we've been working with in the rangelands in western Queensland.
Robyn Williams: How might the kangaroos themselves be affected by climate change?
George Wilson: It will be at both ends. As the country becomes more arid then we anticipate that some areas, particularly in western NSW that are currently in farming and maybe even irrigation may go out of those land uses and they may go back to being rangelands again, as indeed they were before. A lot of the irrigation areas in western NSW and northern Queensland are in areas that used to be rangelands. So it could be that the kangaroo populations in those areas would increase and that you would be able to harvest kangaroos from areas that had previously been used for these other land uses.
At the other extreme, then maybe as land becomes more arid under the effects of climate change, then the range of the kangaroo may contract. But under our proposal if you remove all of those dry sheep equivalents off these rangelands then you create the opportunity for a much larger population to be supported.
Robyn Williams: Of course we eat Bambi and we eat Larry the Lamb and even Jack Rabbit, but what do you say to people who look askance at you and say, 'You really want me to eat Skippy?' What do you tell them?
George Wilson: I tell them that South Africans are not so put off by eating springbok. I worked in Scotland for a number of years and red deer, an equally iconic animal to the Scots, is on the menu there. The French have been known to eat the odd chicken or rooster. Similarly in North America, bison are a very iconic animal. I noticed the other night that they're on the badge of the Department of the Interior, and yet under the sorts of proposals that we're talking about here, private ownership and management has actually increased the number of bison in North America many, many fold. So I believe it's possible with those examples to be able to have your iconic animal, to still love it, but it needn't necessarily stop you eating it. After all, kangaroos were a very important part of the diet of Aborigines for many, many millennia, and of course they had iconic status with them.
Robyn Williams: How is it different from eating whales?
George Wilson: I think it's all about how these animals are killed, I think that's the really important issue, and in fact this is yet another area where I think kangaroo use is important. A head shot in the field at night, I believe, is much less of an animal welfare issue than all of the things that the beef industry subjects cattle to. In other words, moving animals (transport is a major animal welfare issue), the slaughtering of cattle is an issue, there are a whole suite of issues, and I believe the animal welfare issues associated with using kangaroos are far less. If one is not a vegetarian, and I respect people who wish to be vegetarians of course, but if you're not a vegetarian then it really comes down to the way these species are killed and how humanely it's done, and I'm a very strong supporter of humane treatment of animals.
Robyn Williams: That was Dr George Wilson whose report came out on Thursday. He's director of Australian Wildlife Services in Canberra, trained as a vet and worked with kangaroos for many years. And the birdlife in his garden, I can tell you, is spectacular; king parrots, rosellas and gang-gangs. Someone clearly close to animals, as he said.