The Climate Case for Eating Your Leftovers

By Kristen Moree

As a city dweller, it can sometimes feel difficult for me to find powerful, palpable connections to climate change and mitigation strategies. I find myself feeling disconnected from the farming practices happening outside of the Denver-metro area where I reside and I have trouble picturing polar bears on melting Arctic ice. Both of these places are hundreds to thousands of miles away from me at any given moment, resulting in a substantial disconnect between my decisions and their impact on the planet. I see this mindset pervading cities at large – a frighteningly narrow lens of perceived influence. This is frightening because 80% of the U.S. population currently lives in cities – that is roughly 260 million people in the U.S. (or 6 billion people globally) that are living with an environmental impact blind spot.

For a long time, I thought the best strategy I could promote on a personal level to find this connection was through my diet (switching to electric energy for the entire US transportation system seemed too large of a scale to take on alone). I stopped eating meat ten years ago after learning that with the onset of developing economies’ populations entering higher-income brackets and meat-heavy diets, the demand for meat was outpacing its sustainable supply. I concluded that eating neither grass-fed nor grain-fed beef was ethical from a climate and land-use perspective.

  By boycotting meat - I was merely removing my vote from the capitalistic food system.

By boycotting meat - I was merely removing my vote from the capitalistic food system.

But after recently discovering regenerative agriculture and holistic grazing practices, I soon realized that boycotting the entire meat industry wasn’t actively helping change our food production processes, and in turn not having as great an impact on climate change as I’d thought. Yes, I wasn’t supporting industrial farming systems, but I also wasn’t promoting holistic systems either – the ones that are slowly moving the needle in our livestock production industry towards sustainability. I was merely removing my vote from the capitalistic food system. So I changed my eating habits again (“locally-sourced, sustainably-raised” is my new compass). But being so focused on the production side of the food spectrum in its relation to climate – how the food I’m eating is raised – I couldn’t help but wonder if I was still keeping myself from understanding my true carbon footprint.

  What farming practices can we adopt to minimize repetitive tilling, methane emissions, unnecessary chemical inputs and water use?

What farming practices can we adopt to minimize repetitive tilling, methane emissions, unnecessary chemical inputs and water use?

Feeding ourselves accounts for 20% of total global greenhouse gas (GHG) emissions, making agriculture one of the largest single industry contributors to climate change. The minor decisions we make in our eating habits each day compound into a force that is disrupting the entire global ecosystem. Society largely associates food and agriculture with just the production processes of our food system, the myriad inputs and energy resources that go into growing and raising it. And for good reason – 95% of our food comes from outside of cities.

But as a result, much of our knowledge of food’s relation to climate change has focused only on this agricultural production side of the equation: How can we better support local family farmers? What farming practices can we adopt to minimize repetitive tilling, methane emissions, unnecessary chemical inputs and water use? How can organic farms and ranches compete with the industrial livestock industry? These are important questions, but they’d be more important if 80% of our population were farmers living in rural areas. Instead, we should be expanding our narrative to include what cities can do to alter our current agricultural system.

  A study released in early 2018 found that emissions from the production of food that is eventually wasted (i.e. never reaching a table for possible consumption) accounts for 14% of food food sector emissions.

A study released in early 2018 found that emissions from the production of food that is eventually wasted (i.e. never reaching a table for possible consumption) accounts for 14% of food food sector emissions.

We can begin focusing on the impact that cities actually have on our food system by extending our definition of the agriculture industry to include the demand side of food production – that is, the role of urban consumers, retailers, and municipalities in affecting climate change via the entire food life cycle, from production to distribution to consumption to waste.

Studies that are centered on cities’ roles in mitigating food-related emissions are discovering mounting evidence of the impact of urban food consumption on climate health, in terms of municipal waste management practices, retail supply chains, and consumer demand patterns. When considering the entire life cycle of food systems, we find that feeding ourselves actually accounts for closer to 30% of global GHG emissions, as opposed to agriculture’s 20%. In fact, cities account for two thirds of total GHG emissions associated with the food sector – not the rural farming communities that are producing the food. Therefore, it’s no surprise to find that urban areas have huge potential for reducing emissions by implementing simple policies and strategies that address their populations’ eating habits and their food waste.

A study released in early 2018 found that emissions from the production of food that is eventually wasted (i.e. never reaching a table for possible consumption) accounts for 14% of total food sector emissions. It cited this production-side food waste as the second highest source of emissions within the food and agriculture industry, second to decarbonising the electric grid. But the picture isn’t that cut and dry. The emissions from solid waste disposal – i.e. throwing away food that you purchased from the supermarket, or what’s leftover on your plate at a restaurant – accounts for an additional 12% of emissions. Already, we’re at 26% of food sector emissions directly due to food that doesn’t ever get consumed– it is grown, processed, distributed, processed again, purchased, transported, refrigerated, cooked, prepared, and then thrown away, only to stay in a landfill for 20+ years (and this is on the short end of the spectrum – it can take a head of lettuce 25 years to decompose in a landfill). This wasted, decomposing food then goes on to release methane into the atmosphere, joining the excess CO2 already emitted from it’s energy-intensive transport to the landfill, without providing any value along the way. If food waste were a country, it would be the third largest producer of GHG emissions, preceded only by the U.S. and China.

  Distribution and transportation (including the entire cold chain and the energy that goes into that food storage during transport) accounts for 6% of food sector emissions.

Distribution and transportation (including the entire cold chain and the energy that goes into that food storage during transport) accounts for 6% of food sector emissions.

Many of us imagine healthy, robust urban food systems as flourishing backyard vegetable gardens and bustling local farmers markets. “Eat Local” has taken over our bumper sticker real estate. And yes, supporting local growers, suppliers, distributors and food service providers is important, but we are disproportionately outweighing the significance of distribution and transportation on food-related GHG emissions at the expense of addressing other critical components of the entire life cycle of food from seed to plate to landfill.

If you were to ask me a few months ago what the most significant contributing factor to climate change was within the food system, I’d have replied transportation – the GHGs emitted from the transport of food from the farm to my pantry. However, distribution and transportation (including the entire cold chain and the energy that goes into that food storage during transport), accounts for only 6% of food sector emissions – significant in its own right, but meager next to our 26% in direct waste-related emissions.

This 26% only measures the emissions that are directly quantifiable from food waste. In reality, food waste is actually far more potent from an emissions standpoint when you start to account for the indirect impact it has on other aspects of the food system, making its reduction that much more impactful. Why is food waste so critical? Because a reduction in food waste reduces demand-related emissions upstream (excess food production), demand-related emissions downstream (food waste going into landfills), and the emissions at every step of the value chain along the way. It impacts every single stage of the life cycle of every piece of food that enters our system, whether it lands on a plate or in the trash.

So what can cities – and their residents – do to start mitigating climate change associated with local food systems? Here are 3 strategies for local governments to start reducing emissions now:

  1. Reduce Food Waste (i.e. buy less food): Cities can develop campaigns that encourage residents to purchase only what they need, support retailers and food service players with systems to track food storage and food waste, implement carbon-intensive food product taxes, offer low-carbon food incentives, and invest in clean cold-storage technologies to prevent food from spoiling that is purchased;

  2. Improve Food Waste Diversion & Reduce Post-Consumer Food Waste (i.e. throw away less food): Offer and incentivize residential and retail composting programs, develop systems for compost to reach and be used by farmers as alternatives to chemical / fertilizer inputs, incentivize and support recycling programs to reduce food packaging waste;

  3. Improve Waste Management Practices (i.e. handle thrown-out food more efficiently): Invest in anaerobic digesters to breakdown biosolids with decreased methane emissions.

If cities implemented each of these strategies, the reduction in emissions could be staggering: a 50% reduction in consumer and retailer food waste alone could result in an 11% reduction in total food system emissions (and if that reduction targeted waste from meat products, the results are even better). This is equivalent to reducing natural gas consumption by 25%. To provide additional context, if we took on a similarly-sized urban agriculture strategy and converted 50% of our cities’ vacant lots to urban farms, we’d only offset 1% of total food-related emissions. Add in the use of anaerobic digesters for just 50% of biosolid waste, along with supplementary composting and recycling programs, and total food-related emissions could be reduced by an additional 7%. Combined, these strategies total an 18% reduction in total food system emissions. Within the framework of the food sector, this reduction in emissions from avoided food waste is equivalent to decarbonising the electric grid (see graphic below).

Food Waste Diagram 2.jpg

The gains don’t stop there. If we implemented these food distribution and consumption practices in cities now, by 2050 we could reduce overall global GHG emissions by 14%. That’s a 14% total reduction across industries as a whole, not just within the food and agriculture sector.

So while Meatless Mondays may be one necessary ingredient in the collective suite of agricultural solutions to climate change (4% to be exact), it seems that it isn’t so much what’s on our plates to begin with that matters, but what’s left over.