Agriculture, Livestock, and Climate Change
Climate scientists observed last week that the world crossed an important milestone. For the first time in 3 million years, the concentration of CO2 in the atmosphere exceeded 400 parts per million. The last time we were at this point, the world looked very different. It was the Pliocene Epoch, and global temperatures were 2 to 3 degrees Celsius warmer. Alligators and tapirs lived on islands off the coast of Greenland, and much of the world was covered by grasslands that looked a lot like the modern African savanna.
I’ve previously discussed the impact that climate change will likely have on the world’s agriculture in general and on California’s wine industry in particular.
But, as Laura Reynolds notes at Nourishing the Planet, agriculture will not just be affected by climate change; it is also an important contributor. Reynolds observes that,
In 2010, global greenhouse gas emissions from the agricultural sector totaled 4.7 billion tons of carbon dioxide (CO₂) equivalent, up 13 percent over 1990. Agriculture is the third largest contributor to global emissions by sector, following the burning of fossil fuels for power and heat, and transportation. In 2010, emissions from electricity and heat production reached 12.5 billion tons, and emissions from transport totaled 6.7 billion tons… According to the United Nations Food and Agriculture Organization, methane accounts for just under half of total agricultural emissions, nitrous oxide for 36 percent, and carbon dioxide for some 14 percent. The largest source of methane emissions is enteric fermentation, or the digestion of organic materials by livestock, predominantly beef cattle. This is also the largest source of agricultural emissions overall, contributing 37 percent of the total.
Livestock thus accounts for a large portion of global greenhouse gas emissions, and cattle are a particularly large contributor. India, home to an estimated 485 million head of cattle, goat, buffalo, and sheep, is the world’s second largest contributor of methane gas—behind only China.
But reducing greenhouse gas emissions from livestock has been a challenge. The Indian government (in a move widely supported by a diverse array of developing countries) called for a differentiation between “survival” and “lifestyle” emissions in climate change negotiations, concluding that there should be a difference between the treatment of an Indian family with a single cow and the millions of cows in massive, industrial slaughterhouses, even if they emit the same amount of methane in total.
It’s certainly a complicated picture. Both are emitting methane and contributing to climate change, but on a per capita basis,
India’s emissions fall well behind those of the United States and other developed countries. But collectively, all contribute to climate change. Efforts to address agricultural-related greenhouse gas emissions have been stalled for more than a year. And while Reynolds and the staff at the Worldwatch Institute have developed an interesting plan to promote climate-friendly food production, broader structural changes appear to be further off.