The recent United Nations Climate Summit put agriculture’s greenhouse emissions estimate at around 50 percent of global emissions when land use changes, deforestation, and food processing, packaging, and distribution are taken into account. Without those things, emissions from the agricultural production fields alone is estimated to be about 14 percent.
This above graphic breaks down the emissions which stem from the different categories involved in the global food production system contributing to climate change.
A United Nations Council on Trade and Development paper helps sort out the emissions numbers (below):
There are an enormous number of complexities involved in understanding agriculture’s role in greenhouse emissions. Each region and each farmer’s method varies widely, so we must attempt to make generalizations. Agriculture is the number one global land use-changer, water user, and destroyer of biodiversity.
An article in today’s WSJ contains one idea about how agriculture needs to change to reduce emissions:
Agronomist and coordinator at Grain, Henk Hobbelink, says the solution to reducing agriculture emissions lies in small farming and decentralized food systems.
“The more localized emissions of small farmers barely contribute to the overall agriculture emissions because they use very little chemical fertilizer, a main source of emissions, and produce more for local markets, so they don’t contribute as much to the transport emissions,” he said. Fresh foods also don’t create as much emissions from processing, freezing, packaging and storing in supermarkets.
The underlying factor driving all of this is population, of course. You cannot separate the issues of population from greenhouse emissions, although government policies (such as biofuels mandates) and our economic systems built upon growth (while ignoring environmental costs) also play large roles — as do our dietary choices.