What we eat - and what our livestock eat - has a big influence on global emissions
There is no agreed estimate for the contribution of the global food system to overall emissions - largely because there are different ways of counting (for example, some look at the agricultural system while others look at the food system more broadly). Additionally, emissions are highly distributed and practices vary dramatically, even within countries.
The food system increases global carbon emissions in many ways including through: transport; packaging and processing; retail; waste; production (emissions from nitrogen-based fertilisers and other agricultural inputs as well as the production of feedstocks for livestock and methane released from rice paddies); and deforestation - i.e. elimination of potential carbon sinks.
Making a difference in the area requires behaviour change on the part of consumers, including:
- eating less meat and dairy
- reducing food waste (also important for retailers and processors)
- avoiding air-freighted foods
Changing the way we produce food is also critical.
- We urgently need to rethink agricultural practices to maximise soil carbon sequestration (see the section on biological storage), most likely paying farmers to provide this service;
- It has been estimated that a large-scale switch to producing proteins through fermentation - i.e. in the lab rater than through traditional agriculture - (link: https://www.rethinkx.com/food-and-agriculture text: could reduce net greenhouse gas emissions from the food sector by 45% by 2030. This is partly due to grater efficiency of production and partly due to the fact that vast tracts of land would be freed up for afforestation or other carbon negative activities.
Another promising area of research is around the diets of animals raised for human food. Cows, expel methane, a powerful greenhouse gas, in large quantities: a single dairy cow can generate three tons of CO2 equivalent every year which is why methane emissions from cows account for 60% of the carbon footprint of dairy products. It has been shown that adding small amounts of seaweed or algae to cattle feed can make a big difference here, possibly by up to 80%, although there are challenges associated with cultivating and distributing the required amount of seaweed.