Which dietary changes are critical to reduce our environmental burden?

Two internationally influential publications in 2018 provided specific insights into how current food choices impact on our environmental footprint and what dietary shifts are needed to reduce the burden. The first publication by Poore & Nemecek has become the global go to dataset for the environmental footprint of specific foods whilst the Springmann publication’s key findings are used to set sustainable dietary recommendations globally.

Reducing food’s environmental impacts through producers and consumers – Poore & Nemecek

Poore et al. (1) gathered a wealth of information from a wide range of food producers across the globe on their practices and the associated environmental impacts. Data was collated from 38,700 farms in 119 countries to provide detailed environmental impact of 40 commonly consumed foods which account for approximately 90% of global protein and calorie intake.

Environmental indicators examined included land use, freshwater use, greenhouse gases emissions (GHGe), acidifying and eutrophying (fertilizer use) emissions.

Key findings

The database provides the detailed environmental impact of the 40 food products by global region and as a global average. The study identified significant variations in values which were highly influenced by country of origin, importation, transport and farming practices.

Meat, aquaculture, eggs and dairy use approximately 83% of the world’s farmland and contribute to 58% of all dietary environmental emissions, despite providing just 37% of our protein and 18% of our calories. Even the lowest environmental impact animal products can markedly exceed that of vegetable substitutes.

While the authors suggest introducing mitigation strategies to producers with particularly high environmental impacts, they note that there are limits as to how far producers can go to reduce their contribution.

The authors calculated that by excluding animal products and introducing plant-based protein food sources, land use would reduce by 76%, GHGe by 49%, acidification by 50%, eutrophication by 49% and scarcity-weighted freshwater withdrawal by 19% compared to a 2010 reference year.

Conclusion

The authors conclude, that shifts towards more healthy plant-based dietary patterns with significant reductions in meat and dairy, are critical if we are to bring about the reduction in environmental emissions needed to mitigate climate change and irreversible environmental damage.

Options for keeping the food system within environmental limits – Springmann et al.

The study published in the journal Nature, strongly indicates that switching to a more plant-based diet is a critical step towards feeding 10 billion people sustainably by 2050.(2) The study was conducted by the EAT Lancet Commission scientists and formed the basis for their 2019 internationally ground-breaking publication - Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems (3) – which is now the gold standard for setting sustainable dietary guidelines.

The Springmann lead study was the first to quantify how food production and consumption affects five of the nine planetary boundaries (4), a term which describes a safe operating system beyond which Earth’s vital systems could become unstable.

The five planetary boundaries and related environmental indicators

Key findings

Without concerted action (i.e. business as usual) the environmental impacts of our food system could increase 50 to 90% by 2050 as a result of a growing population and a rise in consumption of Western style diets. These levels are beyond the capacity of the boundaries for planetary stability.

This was followed by an analysis of various dietary adaptations and their ability to reduce environmental burden. Three specific food system adaptations were identified as most impactful:

• Adopting a more plant-based, flexitarian diet that reduces meat and dairy intake in line with global dietary guidelines

• Cutting food loss and waste in half

• Improvements in farming practices

The researchers estimated that switching to a healthier, more plant-based diet could:

• More than half current food related GHGe

• Reduce the use of fertiliser, cropland and freshwater by 6 to 22%

Recommendations to achieve this include aligning national dietary guidelines with the current evidence on what constitutes a healthy and environmentally sustainable diet.

Since this publication, the EAT-Lancet commission has published multiple papers including their international guidance on the optimum Planetary Health Diet.

Find out more about the EAT Lancet