Switching to a planet-friendly diet could slash global emissions by 17%

By Priyanjana Pramanik, MSc.Reviewed by Benedette Cuffari, M.Sc.Aug 21 2024

In a recent study published in Nature Climate Change, researchers investigate the global distribution of dietary greenhouse gas (GHG) emissions across 139 countries using household expenditure data. The predict that adopting the EAT-Lancet planetary health diet could reduce global dietary emissions by 17%, with a significant proportion of this reduction coming from decreased red meat consumption.

Study: Reducing climate change impacts from the global food system through diet shifts. Image Credit: SunCity / Shutterstock.com

How do food choices affect climate change?

Food choices significantly impact both human health and the environment. High food consumption, particularly of animal-based products, is a major source of GHG emissions and has been linked to obesity and several non-communicable diseases.

Despite efficiency improvements in food production, GHG emissions continue to rise, thereby exacerbating climate change. Meanwhile, over 800 million people are estimated to face hunger, with many unable to afford a healthy diet.

Previous research has highlighted the potential of healthier diets, like the planetary health diet developed by the EAT-Lancet Commission, to reduce GHG emissions and improve health outcomes. However, additional research is needed to clarify how various demographic groups will be affected by these dietary shifts.

About the study

In the current study, researchers analyzed GHG emissions from diets across 139 countries in 2019. Data on 140 food products were used to estimate carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (NO_x) emissions generated throughout the supply chain from farming to consumption.

Emissions for each food product consumed in each country were initially calculated, following which this data was linked with household expenditure information to determine how emissions varied among different income groups. The potential effects of adopting the planetary health diet on emission levels were subsequently modeled.

Data were obtained from various global sources that monitor food production and trade, as well as household expenditure surveys. All study findings were adjusted for certain factors like food waste at the household level to more accurately resemble true dietary intake and its impact on GHG emissions.

Study findings

In 2019, global dietary emissions were equivalent to 11.4 gigatons of CO₂, with China and India the largest contributors.

Emissions varied widely across countries, with Bolivia having the highest per capita emissions, whereas Haiti and Yemen had the lowest. Animal-based products, particularly red meat and dairy, significantly contributed to emissions, despite providing fewer calories than plant-based foods.

Regionally, emissions from animal-based products were highest in Australia, the United States, and East Asia, whereas plant-based emissions were prominent in Southeast Asia and sub-Saharan Africa.

Wealthier populations generally had higher dietary emissions, particularly from animal-based foods. In contrast, poorer populations relied more on staple foods like grains and tubers, which contributed to lower emissions.

The researchers also examined the impact of adopting the planetary health diet, which could reduce global emissions by 17%, with the most significant reductions identified following reduced red meat consumption. However, emissions could increase in low-income countries as their diets become more diverse.

Conclusions

The study findings highlight the unequal distribution of dietary emissions and the potential benefits of more sustainable diets. Although transitioning to the EAT-Lancet planetary health diet could reduce global dietary emissions by 17%, these changes require region-specific policies to be effective.

Low-income countries face challenges in adopting healthier diets due to the high cost and low availability of nutritious foods. To address these issues, improving agricultural efficiency, increasing the availability of affordable, nutrient-rich foods, and implementing policies that support vulnerable populations will be imperative.

Global diet shifts would necessitate substantial changes in food production, which could impact agricultural markets. Thus, careful policy planning is crucial to mitigate any potential negative effects on food prices and producers.

Notable limitations of the current study include its reliance on regional data for food waste and consumption patterns, which may not accurately represent national variations. Additionally, food prices and consumption patterns were assumed to be consistent across income groups, which may not reflect reality. Key populous countries are also missing from the data, which could also affect global estimates.

Future studies are needed to explore the effects of changing food supply sources, such as shifts in domestic production and imports, on GHG emissions. Additional research should also assess how diet shifts might impact household incomes, particularly in regions reliant on food production. The incorporation of price elasticity models would also allow researchers to evaluate the long-term feasibility and economic consequences of adopting more sustainable diets.