We need to talk about food when we talk about climate

Michael Clark

If we were to immediately stop all greenhouse gas (GHG) emissions from fossil fuel combustion but continue to eat the way we do, would we meet the climate targets that aim to avoid global temperature increases of 1.5C and 2C?

In a paper published today in Science, we investigated these questions by forecasting how food systems might change from 2020 to 2100. We linked these forecasts to estimates of the greenhouse gas emissions per unit of food produced to forecast greenhouse gas emissions from food systems.


Discussions on how to meet the 1.5C and 2C climate targets rightfully focus on emissions from fossil fuels. The idea of not reducing emissions from fossil fuel combustion is frightening, and would likely mean that we would miss the 1.5C target within 15 years and the 2C target before 2050.


Yet our work reveals that emissions from food systems alone would result in a world with more than 1.5C of warming by 2065, and 2C shortly after 2100. That is, even if emissions from fossil fuel combustion were to be immediately stopped, we would likely miss the 1.5C climate target within decades and the 2C climate target within a century.


Fortunately, there are multiple strategies to reduce greenhouse gas emissions from food systems. Transitions to healthier and primarily plant-based diets, reductions in food loss and waste, sustainable increases in crop yields, and increases in efficiency of food production will likely all be needed. If fossil fuel emissions were immediately stopped, implementing any one of these strategies could be used to meet the 2C target, but all would be needed to meet the 1.5C target.


Figure 1. Emissions in different food system strategies. Bar height indicates cumulative GHG emissions from 2020 to 2100, while dashed lines indicate how many GHGs we can emit before we miss the 1.5C or the 2C temperature targets. Bars that exceed the dashed lines indicate that the food system strategy will not meet a climate target. Business-as-usual indicates food systems continue to change along recent trajectories. Plant-rich diets indicates that diets transition to contain a larger proportion of plant-based food. Healthy calories indicate that caloric consumption shifts to healthier quantities. High yields indicate that crop yields sustainable increase at faster than historic rates. Half waste indicates that food loss and waste reduces by 50% by 2050. High efficiency indicates that the GHG emissions per unit of food produced reduces by 40% by 2050. 50% all and 100% indicate that all of the other strategies are implemented to 50% or 100% of their potential, respectively. From Clark et al, 2020, Science.

Unfortunately, food systems are not the only source of climate change, and it is a bit absurd to assume that greenhouse gas emissions from fossil fuels will be immediately halted. This means there is a clear tradeoff between emissions from food systems and from other sectors if we aim to meet climate targets: more emissions from food systems allow for fewer emissions from other sectors, while more emissions from other sectors allow for fewer emissions from food systems.


Meeting the climate targets when accounting for greenhouse gas emissions from both food and non-food activities will be difficult, and will require concerted and rapid action across all sectors of the economy. Policy-makers, businesses, non-governmental organisations, and individuals all have a role to play, for instance by incentivising more sustainable behaviours through policy implementation (e.g. mandating food labelling), increasing availability of climate outreach and education (e.g. agricultural outreach programs aiming to improve practices of food producers), and shifting behaviour to choosing climate-friendly foods when they are available (e.g. reducing intake of meat and increasing intake of plants).


This is all to say: when it comes to climate targets, fossil fuels matter, but so does what we eat and how we produce it.


John Lynch, has analysed the work here, for The Conversation.

About the author

Michael Clark is a food system researcher at the University of Oxford. His research focuses on understanding the impact that diets have on environmental sustainability and on human health, how these impacts might change in the future, and how these impacts might be reduced.