Changing the diet of wealthy people saves enormous CO2 emissions

If we changed global consumption habits and focused more on plants and less on meat, we could reduce global emissions by almost 20%, a new study shows.

Crucially, this reduction could be driven by changes in the diets of the world’s richest people. Indeed, changing the diets of top earners would release enough emissions to offset the rising emissions of the world’s poorest, who would then be more in line with global recommendations for a more balanced diet.

The study, published in Nature Climate Changediffers from other studies that only look at the impact of diet at the country level: This study takes into account that there can be large income differences within countries, which can lead to very different eating habits.

The researchers first examined the life-cycle emissions of 140 food items and looked at how consumption of these products was distributed across 139 countries or regions of the world – a sample that covered 95% of the world’s population. They linked this data with information on income and spending patterns for each country, which helped shed light on the link between diet and income.

Next, they looked at what would happen if we shifted global consumption to meet the requirements of the EAT-Lancet Planetary Health Diet, which favors plant-based foods over animal-based foods to meet human health requirements while remaining within the planet’s ecological limits.

Broadly speaking, the analysis found that the higher a population’s income and expenditure, the larger its emissions footprint. These higher emissions across the dataset were generally due to increased consumption of red meat and dairy products, but also cereals such as rice and wheat: these foods contributed 29%, 19% and 21% of global emissions, respectively.

Higher-income countries tend to have higher overall emissions because meat and dairy are more affordable for all citizens due to lower income inequality in these countries. In contrast, in lower-income regions, there is a larger discrepancy between wealthy consumers who can afford ample dairy and meat, while poorer citizens can only afford small amounts of these foods or none at all.

While the wealthy groups in these countries may be smaller, their impacts can still be significant. The researchers cite sub-Saharan Africa as an example, a vast region usually considered low-income, where the highest-spending 10 percent of the population alone account for 40 percent of regional emissions from the meat sector, 39 percent from the poultry sector and 35 percent from the dairy sector.

This suggests that income and purchasing power, together with country-level contributions, provide a more useful perspective to look at emissions from food.

This was confirmed when the researchers applied the EAT-Lancet diet. A global shift to more plant-based foods would lead to a huge reduction in dietary emissions of almost two gigatons of carbon dioxide equivalent, the researchers found. That’s a 17% decrease compared to 2019 levels.

They also showed that most of the greenhouse gas emissions could be reduced by changing the purchasing behavior of wealthy consumer groups in high and upper middle income countries. At the same time, poorer groups in most countries would see an increase in greenhouse gas emissions as their eating habits would inevitably change and they would consume more food, possibly even more meat, to bring their diets into line with the nutritional requirements of the EAT-Lancet diet.

What’s particularly interesting is that the researchers calculated that 32.4 percent of global food emissions could be saved if the highest-earning, “over-consuming” populations – who make up 56.9 percent of the world’s population – changed their diets. That’s more than enough to offset the 15.4 percent more needed to bring poorer populations up to the recommended global diet.

Undoubtedly, a dietary change on this global scale would be difficult to achieve: it would require an 81 percent reduction in the global supply of red meat and a 50 percent reduction in cereal consumption, while the supply of pulses and nuts would have to increase by 438 percent and that of fruit and vegetables by 28 percent.

But this study identifies purchasing power as a key lever to achieve this goal. The researchers say there could be promise in influencing the habits of affluent consumers through eco-labeling, carbon taxes on dairy and meat, and expanding the availability of vegetarian alternatives.

Challenging the appetites of the world’s rich “would help deliver significant health and climate benefits,” they say.

Hubacek et al. “Reducing the impacts of climate change on the global food system through dietary changes.” Nature Climate Change. 2024.