by Judith Curry
In all, livestock farming produces 8-18% of greenhouse-gas emissions. It is the main contributor to the build-up of nitrogen and phosphorus in the world’s soils, producing too much ammonia (which is caustic), nitrous oxide (a greenhouse gas) and dead zones in oceans (the result of excess phosphorus). – The Economist
A paper recently published in PNAS [link]:
Biomass use, production, feed efficiencies, and greenhouse gas emissions from global livestock systems
Mario Herrero, Petr Havlík, Hugo Valinc, An Notenbaert, Mariana C. Rufino, Philip K. Thornton, Michael Blümmel, Franz Weiss, Delia Grace, and Michael Obersteiner
Abstract. We present a unique, biologically consistent, spatially disaggregated global livestock dataset containing information on biomass use, production, feed efficiency, excretion, and greenhouse gas emissions for 28 regions, 8 livestock production systems, 4 animal species (cattle, small ruminants, pigs, and poultry), and 3 livestock products (milk, meat, and eggs). The dataset contains over 50 new global maps containing high-resolution information for understanding the multiple roles (biophysical, economic, social) that livestock can play in different parts of the world. The dataset highlights: (i) feed efficiency as a key driver of productivity, resource use, and greenhouse gas emission intensities, with vast differences between production systems and animal products; (ii) the importance of grasslands as a global resource, supplying almost 50% of biomass for animals while continuing to be at the epicentre of land conversion processes; and (iii) the importance of mixed crop–livestock systems, producing the greater part of animal production (over 60%) in both the developed and the developing world. These data provide critical information for developing targeted, sustainable solutions for the livestock sector and its widely ranging contribution to the global food system.
Additional background on this topic is provided by a 2006 FAO report entitled Livestock’s Long Shadow.
The Economist has an article on the Herrera et al. paper entitled A lot can be done to make meat eating less bad for the planet. Excerpts:
Around the world 1.3 billion people, most of them poor, raise animals, accounting for a third of total agricultural GDP. More acres are given over to feeding animals than to any other single use. Meat accounts for a sixth of humanity’s calorific intake but uses roughly a third of its crop land, water and grain. Producing a kilogram of grain takes 1,500 litres of water; a kilo of beef takes 15,000 litres. A fifth of the world’s pasture has been spoilt by overgrazing.
So what sort of livestock farming can satisfy growing demand while using land, water and crops more rationally? Recent papers by Mario Herrero of Australia’s Commonwealth Scientific and Industrial Research Organisation and colleagues argue that the answer is intensive livestock farming, which is more efficient and environmentally friendlier than small-scale, traditional pastoralism of the sort beloved by many greens. But to avoid turning more wilderness into pasture and using more water that the world cannot spare, “factory farming” must be reformed.
Switching from pastoralism to feeding cattle with grain would dramatically improve efficiency. This switchover would also reduce the damaging build-up of nitrogen and phosphorus in soil, since intensive methods turn the nutrient in feed into meat more efficiently. And it would slash greenhouse-gas emissions. Cattle on dry rangelands produce 100 times as much per unit of meat as cattle in America or Europe.
Industrial-scale livestock farming can encourage the spread of diseases that humans share with animals. And animals may suffer in factory farms (though they bear a big burden of endemic diseases in pastoral systems). Such downsides are cited by environmentalists who would prefer less factory farming and more traditional pastoralism. But efficient livestock farming makes better use of scarce basic resources—and is far better for the planet.
From the comments on the Economist article:
Dear The Economist
My livestock research colleagues and I welcome the Economist’s coverage of these important livestock issues, and the acknowledgement that the global livestock sector can become more efficient, equitable and environmentally sustainable.
We see the greatest opportunities for increasing livestock productivity in the smallholder livestock production sector in the tropics, which currently produces the bulk of livestock products globally. These production systems, with adequate investments, support and technology (better use of feeds, breeds, and markets for example) could increase their productivity, sometimes by a factor of two or more. These practices would lead to a triple win: improved livelihoods and incomes for poor producers, improved food security for consumers and more efficient use of natural resources, including reductions in greenhouse gas emissions. This is not equated in anyway to factory farming, but to sustainably intensifying the smallholder sector.
Our research does not suggest that we should get rid of pastoralism. On the contrary, even when these systems might be seen as inefficient from a greenhouse gas perspective, we should support the sound management of pastoral lands as they help maintain vital ecosystems services, such as cleaning water, storing carbon and protecting biodiversity, as well as supporting the livelihoods and food security of many highly vulnerable people in the world.
Factory farming, if well regulated, has its place in helping to meet the demand for livestock products, but this cannot be the sole livestock avenue for simultaneously meeting the global sustainability concerns while feeding 9 billion people in the future. It is simply too risky to put ‘all the eggs in this basket’ for the sake of increases in resource use efficiency due to millions of smallholder and pastoral livelihoods at stake, significant risks of zoonoses, animal welfare concerns, potential pollution problems and disruption of global nutrient cycles, amongst others.
Commonwealth Scientific and Industrial Research Organisation
AMATERJan 30th 2014 13:51 GMT
Dear Dr. Herrero,
I take your commentary for a kind of excuse and an attempt to attenuate The Economist’s harsh judgment on meat production and consumption, particularly as far as extensive, ruminant based production systems are concerned. However, the disastrous effect on the reputation of domestic livestock in general and pastoral systems in particular, and even on world-wide food security which produce such kind of journalistic pieces as this one is a direct consequence of your and your colleague’s authorship of sketchy, ambivalent publications which follows uncritically the line of the FAO-reports “Livestock’s Long Shadow” and “Tackling Climate Change Through Livestock”.
The Economist cites correctly the essence of your paper when telling the readers that you argue that “the answer is intensive livestock farming, which is more efficient and environmentally friendlier than small scale, traditional pastoralism of the sort beloved by many greens”.
As you might know, I am by no means a romantic “green”. However, your arguments in favor of intensification and the depreciating comments in your paper on pastoral systems in the developing world can only be understood when quite a number of facts are overlooked, which every critical scientist ought to be aware of, but unfortunately your consortium of authors does not seem to be:
1) The claim that livestock is a driver of climate change and causes global warming relies on many unconfirmed and even improbable assumptions, ignores essential empiric realities, and depends on a number of grave methodological deficiencies as outlined here:http://www.pastoralismjournal.com/content/4/1/1 . Taking the GHG-emissions from pastoral systems as what they are, significantly overstated and almost irrelevant to the global GHG-budgets, these systems appear suddenly much friendlier to the planet than you, The Economist, and unfortunately also the FAO make them appear.
2) Up to half of the terrestrial surface, marginal for cropping though holding a growth of useful herbage rich in fiber, billions of tons of harvest residues (also rich in fiber), and lots of by-products from the food processing industry are best transferred by ruminants into valuable food for humans. Approaches to improve food conversion efficiency are often limited in extensive grazing systems. Wherever improvements are feasible, they are welcome, of course! However, in the absence of rewarding alternative land use options to generate income and food, it does not make sense to discredit pasture based production systems because of “low” food conversion efficiency, when comparing it directly with factory farming.
3) Livestock is also blamed for using ineffectively huge amounts of water. However, in the semi-arid Chaco, for example, a big part of the beef industry (including abattoirs) relies entirely and sustainably on locally harvested rainwater, which would not be available anyway at other places for other uses at a reasonable price. And in many humid regions water availability is not a problem. So again, this widely used argument is not justified. Let the economy decide what to use the available water for and not narrow-chested logic, ethically stained with meaningless arguments!
It is a pity that CSIRO, after decades of outstanding research carried out in its former Tropical Crops and Pasture Division, moved over to trendy issues based on poor theory, damaging to global food security.
Owner of a cattle station in Paraguay
Fellow of the Tropical Grassland Society of Australia
JC comments: Feeding a planet with rapidly increasing population while minimizing environmental degradation is a big challenge. Several years ago I read the book Omnivore’s Dilemma, which analyzes different food chains: industrial, pastoral, personal. John Foley writes extensively on this overall issue, a recent article worth reading is Changing the Global Food Narrative.