John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
It will be impossible to reach U.N. temperature targets without reducing our intake of certain foods, researchers say.
Serious about battling climate change? Then you might want to consider going vegetarian. That's because it's looking like world temperatures will continue to climb unless people stop chowing on so much meat and dairy, according to new research from Sweden.
The United Nations believes it's imperative to keep future warming from rising more than 2 degrees Celsius above pre-industrial levels. To meet that target, there will have to be a sharp decrease in greenhouse-gas emissions by the end of the century. Some of the reductions must come from the energy industry, and some must hail from the agricultural realm.
But with agriculture, it won't be enough to roll out "smarter" animal feeds and better methods of crop production, say scientists at the Chalmers University of Technology in Gothenburg. Rather, "reduced ruminant meat and dairy consumption will be indispensable for reaching the 2 °C target with a high probability, unless unprecedented advances in technology take place," they assert in a study in Climatic Change.
Here's the crux of their findings:
Emissions from agriculture threaten to keep increasing as global meat and dairy consumption increases. If agricultural emissions are not addressed, nitrous oxide from fields and methane from livestock may double by 2070. This alone would make meeting the climate target essentially impossible.
"We have shown that reducing meat and dairy consumption is key to bringing agricultural climate pollution down to safe levels," says Fredrik Hedenus, one of the study authors. "Broad dietary change can take a long time. We should already be thinking about how we can make our food more climate friendly."
Many in the agricultural industry are trying to cut emissions of nitrous oxide and methane (the latter being a mightily potent greenhouse gas). There's the general streamlining of processes to make meat and dairy production more efficient, for example. Then there are technical tweaks. One is occasionally draining the water from rice paddies, as microbes in flooded paddies generate a large amount of methane. Another is adding supplements to livestock feed to prevent the animals from belching so much. Gassy livestock is a serious atmospheric force; for instance, the fermentation taking place inside cows and sheep accounts for two-thirds of Australia's agricultural emissions.
The Swedish team thinks that if these improvements become widespread they will get us close to U.N. targets, but not quite there. They whipped up this graph to show how agricultural emissions are likely to change if conditions remain static (blue), if productivity and technical innovations are widely adopted (orange), and if technical measures are paired with a 75 percent reduction in meat-and-dairy eating across the globe. The gray line shows "how much total emissions must be reduced to meet the two degree target with large certainty," they say, and the "distance between the bars and the line shows the total possible magnitude of emissions from energy, transport, industry and deforestation":
But how do you stop an increasingly voracious planet from eating dairy and meat? It surely won't be enough to ask people to change their diets. One interesting possibility is tinkering with food economics. In a study published in December, scientists suggested reducing the global mass of 3.6 billion ruminants—which is 50 percent more than roamed the planet a half-century ago—by implementing some sort of tax-or-trade system. The Guardian explains:
The scientists' analysis, published in the journal Nature Climate Change, takes the contentious step of suggesting methane emissions be cut by pushing up the price of meat through a tax or emissions trading scheme.
"Influencing human behaviour is one of the most challenging aspects of any large-scale policy, and it is unlikely that a large-scale dietary change will happen voluntarily without incentives," they say. "Implementing a tax or emission trading scheme on livestock's greenhouse gas emissions could be an economically sound policy that would modify consumer prices and affect consumption patterns."