Climate Benefits of Changing Diet
An Environmental Article from


Humane Research Council (HRC)
March 2015

Dietary changes could therefore not only create substantial benefits for human health and global land use, but can also play an important role in future climate change mitigation policies.

Authors: Elke Stehfest. Lex Bouwman, Detlef P. van Vuuren, Michel G. J. den Elzen, Bas Eickhout, Pavel Kabat

Short Description:

In the wake of the UN's groundbreaking publication of Livestock's Long Shadow in 2006, scientists have sought to better understand the role that factory farming plays in climate change. This study uses computer models to explore the potential impact of different dietary transitions, from simply reducing red meat consumption to becoming vegan, and analyzed how each might effect carbon cycles, land use, and more. The results provide concrete data to show how individual food choices can have a global impact on animals and the environment.


In 2006, the UN published Livestock's Long Shadow, a paper that established the scale of factory farming across the globe, and outlined the huge detrimental impact it's having on the environment. Three years after its publication, researchers used modelling techniques to try to better understand how changing people's dietary habits could positively effect this dire situation. The study examined different aspects of dietary impact. The researchers found out how changes in diet could effect greenhouse gas emissions, land use and other environmental outcomes. Using a model called "IMAGE 2.4" they "compared four alternative dietary variants," including "(a) complete substitution of meat from ruminants (NoRM), (b) complete substitution of all meat (NoM), (c) complete substitution of all animal products (meat, dairy products and eggs) (NoAP) and finally (d) partial substitution of meat based on a healthy diet variant (HealthyDiet, HDiet)."

The experimental approach showed positive results: "changes in dietary patterns can be an effective means to decrease greenhouse gas emissions, in addition to more conventional strategies such as changes in the energy system, reforestation and the reduction of non-CO2 gases by add-on abatement technology," noted the authors. They also stated that "in addition to reductions in CH4 and N2O, the shift to low-meat diets induces a reduction in agricultural area, and subsequently leads to land availability for other purposes such as energy crops or nature reserves. The regrowth of vegetation on these abandoned areas leads to a substantial, though transient, uptake of CO2." These two conclusions alone shows powerful evidence that positive dietary choices taken up by many individuals can effect massive change.

Like any good researchers, they are up front about the limitations of their work. In the case of this study, the modelling was done without paying attention to the world of economics whatsoever. "We have ignored possible socio-economic implications such as the effect of health changes on GDP and population numbers. We have not analyzed the agro-economic consequences of the dietary changes and its implications; such consequences might not only involve transition costs, but also impacts on land prices," the authors say. Looking forward to the future, they note that "consumption of animal products including ruminant meat in developing countries is increasing rapidly at the moment. Possibly, these trends can still be influenced towards meat preferences which are beneficial to both health and climate, before they turn into hard-to-change traditions." This is a crucial point for animal advocates, and continues to be of the utmost relevance today.

Original Abstract:

Climate change mitigation policies tend to focus on the energy sector, while the livestock sector receives surprisingly little attention, despite the fact that it ac- counts for 18% of the greenhouse gas emissions and for 80% of total anthropogenic land use. From a dietary perspective, new insights in the adverse health effects of beef and pork have lead to a revision of meat consumption recommendations. Here, we explored the potential impact of dietary changes on achieving ambitious climate stabilization levels. By using an integrated assessment model, we found a global food transition to less meat, or even a complete switch to plant-based protein food to have a dramatic effect on land use. Up to 2,700 Mha of pasture and 100 Mha of cropland could be abandoned, resulting in a large carbon uptake from regrowing vegetation. Additionally, methane and nitrous oxide emission would be reduced substantially. A global transition to a low meat-diet as recommended for health reasons would reduce the mitigation costs to achieve a 450 ppm CO2-eq. stabilisation target by about 50% in 2050 compared to the reference case. Dietary changes could therefore not only create substantial benefits for human health and global land use, but can also play an important role in future climate change mitigation policies.

Read Climate Benefits of Changing Diet - PDF.

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