Often when we think of pollution and climate change, we picture gas-guzzling cars or power plants spewing fumes into the atmosphere. Rarely, however, do we think of the food we eat. But according to two different sources, if we really want to get serious about climate change, food is exactly where we should start.
Differing estimates, same conclusion In 2012, the CGIAR Research Program on Climate Change, Agriculture and Food Security released a report stating greenhouse gas emissions (GHG) from the global food system accounted for about 28% of all GHG emissions. Of that chunk, deforestation and direct emissions from farms made up the largest percentage.
Breakdown of agricultural emissions
More recently, the United Nations Conference on Trade and Development came out with its own estimates, which showed an even greater effect from food, accounting for roughly half of all global GHG emissions -- with deforestation and transportation creating the most pollution.
Instead of focusing on the rather large differences between these two estimates, I think it's far more productive to simply acknowledge that the global-food-production system plays an enormous role in climate change -- and that it's also an important player in reversing the negative effects of climate change.
Emissions directly from farms If we do the math, both studies estimate that pollution coming directly from agricultural production accounts for about 13% of all GHGs. The two biggest contributors to this subgroup are:
Nitrous oxide emanating from the soil as a result of increased usage of fertilizers.
Enteric fermentation resulting when livestock consume food and excrete methane gas.