Food and Environment

Alon Shepon

Weizmann Institute of Science, Israel

Prof. Ron Milo lab

environment livestock dietary preferences food security

fish future foods

• <1 billion undernourished and <2 billion overweight.

• Need to increase food production by 70% in coming decades (“food gap”).

• A 1/3 of all food produced is lost.

• Two way interaction between climate and food.

• Dietary changes is imperative to meet future food security and environmental goals.

The food crisis involves issues of food security and sustainability

Bajzelj et al (2014) Nat. Clim. Chan.

1. Linear system yet complex.

2. Inefficient segments.

3. Large processing. 4. Pasture is largest

land user. 5. About 1/3 of

cropland to feed. 6. Dairy and beef in

mixed farms; pork and poultry use concentrated feed

Herrero et al (2015) Annu. Rev. Environ. Resour.

Gordon et al (2017), Environ. Res. Lett.

Gordon et al (2017), Environ. Res. Lett.

Understanding the role of livestock

Livestock incur major environmental burdens

Ref: Livestock’s long shadow, Steinfeld et al, UN-FAO, 2006

• Dominate anthropogenic land use (habitat fragmentation & biodiversity loss) • Disruption of N, P biogeochemical cycles air pollution, soil acidification,

ecosystem alteration. • Key reason for tropical deforestation, eutrophication, soil erosion, and

antibiotic overuse. • Roughly 20% of global GHG emissions. • Estimated 20% of total global water use (1/3 of agriculture use).

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Steinfeld et al 2006 Livestock’s long shadow

US agriculture supports livestock production

Data from 2007 US Census. Map made by Bill Rankin 2009

Chicken or beef?

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• USDA use outdated data (often reflecting 1960s feeding practices).

• Aggregate level analyses (meat category) don’t capture individual food items.

• Updated and detailed LCA results vary by geography and agrotechnology difficult to get widely representative costs.

How the calculation was performed?

What is the environmental cost of each feed?

Environmental burden per calorie consumed

How much feed is consumed by each livestock?

15 Eshel et al (2015) J. Agri. Sci.

Ref: Eshel, Shepon, Makov & Milo, PNAS 2014

Beef requires about 10-fold more resources per calorie than other animal categories

Resource needed for a consumed Mcal (1000 kcals)

land water GHG Nr Animal derived

calories in mean US diet

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Diary and eggs are very similar to pork and poultry

Eshel G, Shepon A, Makov T and Milo R (2014) PNAS

Beef production dominates the USA overall livestock environmental burdens

Beef production dominates the USA overall livestock environmental burdens

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feed to food conversion ratio is a reflection of the environmental burdens

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3 2

concentrates

cultivated feed

beef pork poultry

protein

Shepon et al. Environ. Res. Lett., 2016

Eshel et al (2017) Nature Eco. & Evol.

Poore and Nemecek (2018) Science

Avoiding meat and dairy is ‘single biggest way’ to reduce your impact on Earth Gaurdian 31 May, 2018

Poore and Nemecek (2018) Science

“Producers have limits on how far they can reduce impacts. Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change.”

potential dietary shifts

Cassidy et al (2013) Environ. Res. Lett

o “..shifting the crop calories used for feed and other uses to direct human consumption could potentially feed an additional 4 billion people.”

o Main caveat:

feed cannot be consumed as food directly (not interchangeable!)

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food a

The dietary shift potential is the amount of additional people that can be fed on spared

land resulting from dietary shifts

food b whole diet

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Substitution of beef with poultry entails spared lands that can feed an additional 120-140 million people

beef poultry

Shepon et al (2016) Environ. Res. Lett. Eshel et al (2016) Environ. Sci. Technol

beef plants The dietary shift potential of a dietary transition from beef to a plant based diet is approx. 190 million people

plant-based replacement diets =350 million additional people> supply chain food waste.

Shepon et al (2018) PNAS

Roos et al, (2017) Glob. Environ. Change

• dietary shifts is a necessary strategy to meet targets to limit global warming to 2 degrees. Hedenus et al. Clim. Change 2014

• GHG emissions of mediterranean, pescetarian (vegetarian diet with fish) and vegetarian diets would be 30%, 45%, and 55% lower.

Tilman D and Clark M Nature 2014

• “plant-based diets…could reduce global mortality by 6–10% and food-related GHG emissions by 29–70%”

Springmann et al PNAS 2016

• “We……show that improved diets and decreases in food waste are essential to deliver emissions reductions, and to provide global food security in 2050.”

Bajzelj et al Nature Climate change 2014

• “…dietary shifts towards low-impact foods and increases in agricultural input use efficiency would offer larger environmental benefits than would switches from conventional agricultural systems to alternatives such as organic agriculture or grass-fed beef.”

Clark M and Tilman D Environ. Res. Lett 2017

Can global fisheries replace livestock production?

Myers et al, (2017) Ann. Rev. Pub. Heal.

A system level approach is needed to tackle future challenges

• Animal-based products incur a large disproportionate

environmental toll. • Dietary preferences can potentially reduce environmental costs or

feed millions of additional people with no additional resource usage.

• Supply (agriculture) and demand (diets) side changes are needed simultaneously.

• In developing countries livestock have a different role and foodprint.

• Executing de facto large scale dietary shifts will require further multi disciplinary research (e.g. behavioral economics) and targeted policy.