FROM THE FIELD
You Asked

You Asked: How Can I Find Out the Carbon Footprints of Different Foods?

by |April 24, 2019

Got a burning question about climate change? “You Asked” is a series where Earth Institute experts tackle reader questions on science and sustainability. To submit a question, drop a comment below, message us on Instagram, or email us here.

Today we’re answering a few questions together. These come via our Earth Month Q&A on Instagram:

Grass fed cows. Photo: Phebe Pierson

What impact does stopping animal product usage and consumption have on an individual’s ecological/carbon/environmental footprint?

There are huge differences between the types of meats consumed and ghg footprint: what is the best source for determining those?

Relatedly, what is the best source for understanding the footprints of processed foods? i.e. edamame vs. tofu.

Answer provided by Phebe Pierson

For this answer I rounded up work done by Earth Institute scientists and others over the past few years.

HoldtheBeef.org is based on a great study that came out in 2016 by grad students at the Columbia School of International and Public Relations and co-advised by Maureen Raymo of the Lamont-Doherty Earth Observatory. The study focuses on the high impact that beef has—a much higher impact even than other meats.

An infographic from HoldtheBeef.org compares the relative impacts of different types of protein.

The site has infographics that show the impacts of different meats, dairy, eggs, and veggies (left). It also has a thorough write-up of the research behind the graphics and links to other sources that discuss these topics.

There’s also a great article on our blog about Raymo’s work on what a sustainable beef industry might look like, where more cows are grass-fed on pastures rather than factory-farmed.

As for the question about soybeans, at first glance it seems like unprocessed soybeans easily would have a much lower footprint than tofu, right? The extra effort to turn soy into tofu requires energy, so that logic follows. Actually, processing soybeans into tofu for human consumption takes a little energy but it’s far from a big issue in the conversation about agriculture and processed foods and their environmental impacts. The main concern when it comes to soy and tofu is actually still meat-based.

This is because it turns out the bulk of the soybean industry is geared towards growing soybeans for animal feed. Seventy percent of global soy production is fed to livestock! Tofu, edamame (for humans), soy sauce, and soy milk are only a small fraction of the total soybean industry.

BBC News created this greenhouse gas calculator for food using research by Oxford University scientists.

Soybeans grown for animal feed are an issue for a couple reasons. First off, livestock—especially cows—eat a LOT, which is part of why meat has a high carbon footprint in the first place. Lots of soy plantations are needed to feed the volume of livestock that our meat-heavy diets demand, which means that tons of land, fertilizer, water, and other resources are being poured into producing soybeans. Secondly, it turns out that soy plantations are responsible for widespread deforestation in many countries (like the rainforests in Brazil). Deforestation bumps up the carbon footprint of any product astronomically, because the trees that get cut down release carbon into the atmosphere instead of storing it for a long time.

Another great source I came across: BBC News created a greenhouse gas calculator for food and some very clear infographics, based off a study out of Oxford University.

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I entered “tofu 1-2 times a week” into the calculator, above are the results.

This chart from BBC News shows that the way a food was farmed, processed, or sourced can have a huge impact on the emissions it causes. A particularly noteworthy example is the difference between chocolate farmed on deforested rainforest land versus chocolate that’s sustainably farmed.

This last graph shows the impacts of beef in different geographical areas. As you can see, Latin America’s beef is highest in greenhouse gas emissions (because of aforementioned deforestation). Cows on deforested land are not only consuming food and water, and emitting methane, they are also causing depletion of carbon storage in the form of trees.

Hope these sources help to answer your questions!

Phebe Pierson is communications coordinator at the Earth Institute and a former GrowNYC Greenmarkets employee. 

Help fund climate research by Earth Institute experts here. The more we know, the better we can protect our planet.

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