Our June 7th blog on how to feed 10 billion people sustainably by 2050 examined the first part of a “Five Course Menu” designed to meet the challenge. The menu is part of a report called, “Creating a Sustainable Food Future”, by the World Resources Institute wri.org that offers ways to reform our global food system to address the climate crisis, slow down global warming, and feed the world’s rapidly growing population a more sustainable diet. If implemented, the menu can reduce agricultural emissions by 70%.
While all the courses offer appealing options, this blog will stampede to dessert (who doesn’t like dessert?) and examine the last item on the menu — how to reduce GHG emissions from agricultural production.
Animal agriculture has a global carbon footprint of 14.5% according to the UN FAO, larger than the emissions footprint of the entire global transportation sector. And the total footprint of agriculture is at least 25% of global emissions. Reducing these emissions is a huge lever to help close the three sustainability gaps identified in the report: the Food Gap; the Land Gap; and the GHG Mitigation Gap (see our June 7th blog). These measure the distance from where we are today to where we need to be by 2050 for a sustainable food future.
The problem is that, on our current trajectory, global meat consumption is expected to rise significantly over the next 30 years. The report shows how what we eat now and how it is produced is not sustainable.
Agriculture sector GHG emissions are produced primarily by livestock farming, nitrogen fertilizers, rice cultivation and energy use. The chart below shows the predicted growth of GHG emissions from each major part of the production cycle but it does not include emissions from “land use changes” that include deforestation and the destruction of biodiversity from agricultural expansion.
Cattle, sheep and goats (ruminant livestock) produced about half of agriculture’s GHG emissions in 2010 and the biggest contributor was enteric fermentation (see our March 17th blog “Why Cows Belches Matter”), which is a significant source of methane, a powerful GHG. So, measures that can reduce the production of methane will have a significant effect on the reduction of emissions. Tests in New Zealand of chemical feed additives that inhibit microbial methane have reduced emissions by up to 30%. The report recommends that governments encourage these technologies and farmers be given financial incentives to use them.
Manure represents 21% of agricultural GHG emissions and offers another opportunity that is ripe for emissions reduction. For example, livestock in the US produce 108 million pounds of manure every hour!
Better management of manure waste systems can deliver GHG reductions and “health, water and pollution benefits”. Technology already in use at some US pig farms can reduce almost all forms of pollution. The report recommends regulating and supporting farmers to adopt emissions reductions technologies and for better monitoring of water and air pollution from leaking manure systems.
Other recommendations to reduce agriculture emissions include better fertilizer management, improved carbon sequestration in soils and shifting farm production methods away from fossil fuels to more efficient renewable energy sources. Nitrous oxide, a very powerful GHG, is produced when nitrogen fertilizers are applied to crop land and pastures, but only half is absorbed by crops. There are natural grasses and chemical additives that can reduce the production of nitrous oxide and cut emissions as a result.
Taken together, all of the measures recommended in the Five Course Menu create a pathway to a sustainable food system. The chart below shows the cumulative impact of emissions reductions across all parts of the food production system.
Source: World Resources Institute
However, the reality is that systemic change takes time and the climate crisis is already upon us. The good news is that there’s something each of us can do right away. The UK government’s climate watchdog: “Committee on Climate Change”, says people can reduce their diet-related emissions by 35% by moving from a high- to a low-meat diet. That would make the kind of wholesale change needed to ensure a sustainable food future happen a lot faster!
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