Food Sector Could Achieve Net Negative Emissions by 2050

State-of-the-art agricultural technology and largescale changes to the global food system could help the sector achieve net negative greenhouse gas (GHG) emissions – where the emission sinks exceed the production of emissions – by the year 2050, according to a new analysis published in PLOS Climate.

Currently, the food system is thought to be responsible for up to one-third of total GHG emissions globally. But with changes to consumer purchasing habits, novel animal feeds and the rollout of new management practices, experts say the sector could become one of the most powerful measures to tackle climate change.

Changes to the food system could have a significant impact on global emissions

As the global population continues to expand, this places new pressure on the food sector to grow, process and distribute increasing amounts of produce to feed billions of hungry new mouths. But as the food and agriculture market swells, so too will its carbon footprint.

The food and agriculture sector is already one of the largest contributors to GHG emissions, with food production requiring the use of large amounts of land and high volumes of chemical fertilizer. But food waste and the specific types of crops or animals that are cultivated can also have an impact.

“The largest sources of emission from agriculture include methane from livestock, rice fields and manure nitrous oxide from fertilizer and CO₂ from land use conversion for croplands and rangelands,” said Professor Benjamin Houlton, dean of the College of Agriculture and Life Sciences at Cornell University, speaking to Technology Networks.

“When all emissions from the food system are added together, including food loss and waste and land use/land cover change, this sector contributes between 18–30% of global GHG emissions. As the world’s human population expands to 9–10 billion people by 2050, each of these sources will increase with rising food demands unless substantial change is implemented.”

To examine just how much impact consumer choices and changes to the food system might have on future global emissions, Houlton, together with Maya Almaraz, an associate research scholar at Princeton University, led a research team in the creation of an array of model scenarios describing how the food industry might function under different conditions.

Structural changes key to making progress on emissions

The analysis looked at the impact of selected agricultural technologies that have peer-reviewed literature suggesting they could have emissions mitigation potential, as well as different scenarios relating to food waste reduction and dietary choices. Each scenario was computed assuming either a 25, 50, 75 or 100% global adoption rate, in order to explore a range of climate change mitigation response strengths.

The new models showed that a complete commitment to transforming the food system – including the adoption of new agroforestry practices, hydrogen-powered fertilizer production and more sustainable fishing practices – has the potential to reduce the sector’s emissions below net zero, to 33 gigatons of net negative emissions per annum.

“Reducing and in fact reversing emissions is possible for each of these sources, including through the deployment of new technologies and management practices,” said Houlton. “Some of the biggest gains include agroforestry, reducing methane emissions from livestock with new feed additives, and carbon sequestration in the soil through organic and rock dust amendments.”

Dietary choices can help support the transition past net zero

In order to achieve net zero emissions targets, and even move past this into net negatives, global-scale changes in agricultural technology and food chain management will be key. But consumer choices can also have a significant, albeit much smaller, impact on GHG emissions.

The model suggests that if the whole world were to adopt a “flexitarian” diet – where a person is primarily vegetarian but will occasionally eat meat or fish – this could result in reductions of around 8.2 billion metric tons of GHGs every year.

“Knowing where and how the food you choose to eat is grown is critical information for consumers; yet information on practices, particularly those that reduce emissions and create net negative emissions, is not easily accessible,” Houlton said. “Even within plant-based diets, emissions can vary widely.”

“Animal-sourced foods carry on average a higher carbon footprint because of direct emissions of methane, land use effects and the crops that are used to feed livestock. However, animal-integrated systems that consider principals of circularity – recycling manure and reducing direct emissions – can substantially lower the carbon footprint of animal-sourced foods,” he continued. “This is why it’s critical to focus as much on what you eat as where it comes from and the practices that farmers are using to produce food.”

Reference: Almaraz M, Houlton BZ, Clark M, et al. Model-based scenarios for achieving net negative emissions in the food system. Benkeblia N, ed. PLOS Clim. 2023;2(9):e0000181. doi: 10.1371/journal.pclm.0000181

Benjamin Houlton was speaking to Alexander Beadle, Science Writer for Technology Networks.