The interwoven future of climate and agriculture

The world’s gaze has fallen on Egypt's Sharm El-Sheikh for COP27. And there’s a lot to talk about. Since COP26 last year, we’ve seen flooding in Pakistan that has affected at least 33 million people, devastating tropical storms and flooding across East Africa and a year of record temperatures worldwide. 

The international conference comes a month after the United Nations warned that there's "no credible pathway to 1.5°C in place." Without additional action, current policies will lead to warming of 2.8°C by 2100. A continuation of the level of climate change mitigation implied by current climate pledges¹ lowers these projections to about 2.6°C (range 1.9°C – 3.1°C).

To put those temperature rises into context, 1.8°C (read: below the lower threshold of the current best-case scenario) exposes half the world’s population to life-threatening effects of climate change.

As the UK itself seesaws between climate leader and pariah, it is hard to determine where COP27 lies on humanity’s fated road to Damascus.  

However, so far ambitious international climate pledges made at COP events have failed to address one of the most neglected sources of greenhouse gases (GHG) – agriculture. 

The precipitous growth of agricultural production has underpinned the development of a global food system that not only is a major driver of climate change, but also increasingly vulnerable to it. 

The food system is currently responsible for about a third of total greenhouse gas emissions (or 18 GtCO₂e per year) and more than half of those emissions can be attributed to livestock production. Moreover, total GHG emissions from agriculture are likely to increase by about 30 - 40% by 2050. If diets continue along this current trajectory, the livestock sector alone will use up around half of our total 1.5°C-consistent carbon budget by 2030. This trend in global diet has been driven by three key factors:

• increasing demand based on population;
• income growth; and
• dietary change.

The global trade of crop and animal-sourced food has increased by around five times between 1961 and 2013. Over this period, the global food availability has increased such that we have moved from a global food deficit to a food surplus situation. During the same period, GHG emissions associated with agricultural production have almost doubled.

Despite the increase in the supply and availability of food, 821 million people are currently undernourished, 151 million children under five are stunted, 613 million women and girls aged 15 to 49 suffer from iron deficiency, and two billion adults are overweight or obese. It is an unequal system that is increasingly under pressure from stressors such as population and income growth, demand for animal-sourced products and climate change.  
 

What if people ate less meat? 

GHG mitigation potential of different diets
The IPCC examined the estimated impact on GHG emissions of the world’s population adopting a variety of diets

^{Source: IPCC}

The mitigation potential of changing diets is not only evidently high, but so far largely overlooked by current international policies and pledges. The graph above illustrates the total mitigation potential of changing diets by 2050 according to a range of scenarios. The total mitigation potential of dietary changes is estimated to be as high as 8 GtCO₂e per year by 2050 – this is the same as the emissions avoided through the global use of nuclear power in 2018, or 20 times the total UK emissions in 2019.

There are myriad co-benefits of reducing global meat consumption. For instance, the implication of our dietary choice has severe consequences for land. If every country were to adopt the UK’s 2011 average diet and meat consumption, 95% of global habitable land area would be needed for agriculture – up from 50% of land currently used. For the average USA diet, 178% of global land would be needed!  In this way, shifting diets towards more plant-based diets would reduce the demand for cropland that then aids measures to reduce deforestation. 

Clearly, transforming food systems is not only important for addressing climate change, but also essential for ensuring a fairer system and food security for all.

The chart below illustrates the likely food system emissions trajectory versus the mitigation potential of several required transformations to help agriculture meet the goals set out in the Paris Agreement. 
 

Food systems emissions trajectory and mitigation potentials 
 

^{Source: United Nations Environment Programme}

The policy implications are clear: 

• Food systems illustrate that there is enormous potential to reduce emissions far beyond current mitigation pledges, and to get on an emissions pathway aligned with the Paris Agreement temperature goal, they will have to be rapidly transformed. 
• Required transformations include changing diets, protecting natural ecosystems, improving food production and decarbonising the food chain.

Now, aside from general principles such as cutting meat and dairy consumption, the biggest hurdles policymakers face are:

• How is the global agricultural model re-worked to feed a growing population? The mitigation potentials of different measures discussed in this blog are subject to considerable uncertainty. For example, decarbonising the supply chain relies on technologies that have yet to be proven to work at scale like carbon capture and storage.
• What are the likely synergies and trade-offs between low-GHG emissions diets, food security and climate change?

Ultimately, the feasibility of how to create economically viable transitions to more sustainable and healthy diets that also respect food security is a question that future research will need to address.  

Over to you COP27…

¹ _{Intended nationally determined contributions: Intended NDCs are submissions from countries describing the national actions that they intend to take to reach the Paris Agreement’s long-term temperature goal of limiting warming to well below 2°C.}

Estimated global warming implications over the course of the 21st Century under different scenarios and with 66% likelihood.

^{Source: United Nations}

Investment Analyst Will Da Silva contributed to this blog