One of the fundamental concepts in environmental studies pertains to the earth’s “carrying capacity”—the number of people our planet can sustainably support. But this figure turns out to be incalculable unless you start with some basic assumptions about the style in which most people will live: will we eat cheeseburgers and drive Cadillacs, eat chicken and drive Priuses, or eat rice and beans while peddling bicycles?
At least since the 2006 publication of Livestock’s Long Shadow, it’s been abundantly clear that current levels of red meat consumption may be unsustainable, and that maintaining a world population of anything like six billion people could well require steep reductions in beef and pork production.
And now a new study, published in the prestigious Proceedings of the National Academy of Sciences, has just come out that paints a grim picture of what may happen in just the next forty years. A Reuters article summarizes its findings:
Monday’s paper used coarse estimates to argue that, on current trends, livestock farming on its own—disregarding all other human activity—would push the world near danger levels for climate change and habitat destruction by mid-century.
The study notes:
…a profound disconnect between the anticipated scale of potential environmental impacts associated with projected livestock production levels and even the most optimistic mitigation strategies…
The authors look at how much mitigation would need to occur to stay out of trouble:
…if the livestock sector is to grow as forecasted but maintain its current proportional share of contributions to these issue areas and human activities are to be constrained to respect the proposed sustainability boundary conditions, it will be necessary to reduce greenhouse gas emissions per unit livestock protein produced to roughly 13% of year 2000 levels, biomass appropriation to 25%, and reactive nitrogen mobilization to 14%.
An 87% reduction in methane production for each pound of beef or gallon of milk? It simply can’t be done. So the only way to avoid big problems is to dramatically cut per capita consumption of red meat and dairy products.
The trouble is, the world lacks the governmental or economic mechanisms to reign in livestock production. Given the degree to which animal agribusinesses has coopted its regulators, it’s hard to imagine that major governments will clamp down on livestock production. Likewise, this is a problem that can’t be solved through market forces: there’s no way to price red meat and dairy products in a way that accounts for all the future environmental damage these foods will create.
The thing that worries me most is that it appears that the question about whether big trouble is headed our way isn’t even a close call—that back-of-the-envelope calculations of what’s likely to occur over the next forty years put us well beyond any reasonable margin of safety. There needs to be some way to put livestock interests on the hook for the environmental damage they’re unleashing, but sadly I’ve yet to see any possible way to make that happen. (Via Starkman.) Links: Reuters coverage; abstract.