Ethiopian livestock-keeper and her children (photo credit: ILRI/Apollo Habtamu).

Livestock production may have a bigger impact on the planet than anything else. A new study from the International Livestock Research Institute (ILRI) shows how the effects vary from country to country — and points the way toward a more sustainable future.

Below, Time Magazine‘s senior environmental journalist Bryan Walsh reports (well) on a big new livestock study from ILRI.

‘You may think you live on a planet, but really you live on a gigantic farm, one occasionally broken up by cities, forests and the oceans. Some 40% of the world’s land surface is used for the purposes of keeping all 7 billion of us fed — albeit some of us, of course, more than others. And the vast majority of that land — about 30% of the word’s total ice-free surface — is used not to raise grains, fruits and vegetables that are directly fed to human beings, but to support the chickens, pigs and cattle that we eventually eat.

Livestock production — which includes meat, milk and eggs — contributes 40% of global agricultural gross domestic product, provides income for more than 1.3 billion people and uses one-third of the world’s fresh water. There may be no other single human activity that has a bigger impact on the planet than the raising of livestock. But as a new study out today in the journal Proceedings of the National Academy of Sciences (PNAS) shows, there is tremendous variation in how we raise livestock around the world — and major differences in what that means for the earth and for us.

‘Researchers from the International Livestock Research Institute in Kenya, the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia and the International Institute for Applied Systems Analysis (IIASA) in Austria produced a comprehensive assessment of the livestock industry around the world, in developed nations where factory farming is common and in developing nations where livestock are more likely to graze on grasslands.

‘They dug up some striking statistics that underscore just how much meat production varies from region to region.

‘Each year the livestock sector globally produces 586 million tons of milk, 124 million tons of poultry, 91 million tons of pork, 59 million tons of cattle and buffalo meat, and 11 million tons of meat from sheep and goats. That 285 million tons of meat altogether — or about 36 kg (80 lb.) per person, if it were all divided evenly. It’s not — Americans eat 122 kg (270 lb.) of meat a year on average, while Bangladeshis eat 1.8 kg (4 lb). . . .

‘1.3 billion tons of grain are consumed by farm animals each year — and nearly all of it is fed to livestock, mostly pork and poultry, in the developed world and in China and Latin America. All of the livestock in sub-Saharan Africa eat just 50 million tons of grain a year, otherwise subsisting on grasses and on crop residue.

‘The poor feed quality in impoverished regions like sub-Saharan Africa means that a cow there may consume as much as 10 times more feed — mostly grasses — to produce a kilogram of protein than a cow raised in richer regions. That lack of efficiency also means that cattle in countries like Ethiopia and Somalia account for as much as 1,000 kg of carbon for every kg of protein they produce — in the form of methane from manure as well as from the reduced carbon absorption that results when forests are converted to pastureland. That’s 10 times higher than the amount of carbon released per kg of protein in many parts of the U.S. and Europe, where livestock production is much more intensive. . . .

The upside of inefficient livestock production in the developing world is that there is a lot of room to improve, given the right kind of help — which is exactly what the authors of the PNAS paper are hoping for.

‘“Our data can allow us to see more clearly where we can work with livestock keepers to improve animal diets so they can produce more protein with better feed while simultaneously reducing emissions”, said Petr Havlik, a research scholar at IIASA and a co-author of the study. What we need is “sustainable intensification” — efficiency but pursued in a measured way. . . .

Above all else, the study underscores that while meat production will need to change in the future, so will meat consumption. . . .

What’s clear is that American levels of meat consumption can’t be sustainably adopted by the rest of the world, even if livestock management becomes more efficient globally.

“Demand management has to be part of the solution as well,” says Herrero. For the environment — and for our hearts and waistlines too.’

Read the whole Bryan Walsh article in Time Magazine: New study shows the major environmental impact of meat production, 16 Dec 2013.

Read an article in ILRI’s News Blog about this publication: As livestock eat, so they emit: Highly variable diets drive highly variable climate change ‘hoofprints’–BIG new study, 16 Dec 2013.

Read the full paper in the Proceedings of the National Academy of Sciences: Biomass use, production, feed efficiencies and greenhouse gas emissions from global livestock systems, by Mario Herrero (ILRI), Petr Havlík (ILRI and IIASA), Hugo Valin (IIASA), An Notenbaert (ILRI), Mariana Rufino (ILRI), Philip Thornton (ILRI), Michael Blümmel (ILRI), Franz Weiss (IIASA), Delia Grace (ILRI) and Michael Obersteiner (IIASA), in a Special Feature on Livestock and Global Change, early online edition of 16 Dec 2013.

119 pages of supporting online information, including 50 maps, is available at PNAS here.

Read the introduction to this Special Feature on Livestock and Global Change: Livestock and global change: Emerging issues for sustainable food systems, by Mario Herrero and Philip Thornton, in the early online edition of 16 Dec 2013.