Fixing food’s big climate problem

by Jonathan Foley, Ph.D.
An image of the sun with forks and knives as sun rays. Two people are farming in the foreground.

It surprises many people to learn that the food we eat, the farms that grow it, and the landscapes we’ve cleared all contribute to climate change. And contribute in a big way.

Unfortunately, policymakers, business leaders, investors, and philanthropists often overlook this critical aspect of climate change. Moving forward, we must carefully weigh the food system’s impact on climate and develop a robust portfolio of solutions to address it.

But this is a tricky topic, filled with confusion, misinformation, and greenwashing. To avoid these pitfalls on the path to a sustainable food system, policymakers and climate advocates must move forward with clarity, staying grounded with scientific facts.

Food is BIG

The most salient fact about the world’s food system is that it’s almost unimaginably big. 

In fact, nothing else we do rivals the sheer geographic size of the global food system. We use around 16 million square kilometers of land – comparable to the entire South American continent – to grow crops. And we use roughly 34 million square kilometers of land – about the size of Africa – to graze animals, primarily cattle. Together, croplands and grazing lands cover ~38% of the Earth’s land surface. To put this in perspective, all of the world’s cities and suburbs cover less than 1% of Earth’s land.

...the food system dominates our planet. And animals dominate our food system.

Most of this land is used for animal agriculture. Combining the land used for grazing with the land used to grow animal feed, we find animal agriculture uses around 29% of Earth’s land. All other agriculture – for plant-based food, biofuels, and other uses – comprises the remaining 9%. 

In short, the food system dominates our planet. And animals dominate our food system.

The environmental impacts of the food system are enormous. The food system’s giant footprint makes it the largest driver of habitat and biodiversity loss on Earth. Nothing else comes close. The food system is also by far the biggest user of water on Earth, siphoning off around 70% of the world’s water withdrawals. (This figure climbs to an astonishing ~85% if you consider “consumptive” use, where water withdrawals are not returned to the same watershed.) It is also the most pronounced water polluter worldwide, mainly due to fertilizer runoff that has more than doubled the flows of nitrogen and phosphorus through the Earth’s watersheds and ecosystems. This has led to heavily polluted rivers, lakes, and coastal ecosystems across the planet.

Food Has a Huge Climate Problem

Beyond its massive impacts on land, water, and ecosystems worldwide, the food system also contributes to climate change. While most people typically focus on fossil fuels as the primary driver of climate change – which is true – we must also evaluate the substantial role of farming, land clearing, and the rest of the food system.

According to the IPCC and other sources, direct emissions from food, agriculture, and land use release around 22% of the world’s greenhouse gases. That’s roughly equivalent to the emissions from the electricity or industry sector – yet food-related emissions still get far less attention from policymakers, investors, philanthropists, and activists.

A chart showing global greenhouse gas emissions by sector

If we consider the larger food system – including emissions associated with food waste rotting in landfills plus emissions from cooking, refrigerating, processing, transporting, and packaging food – the total emissions from the food system rise to ~34%. That makes food the single largest emitting economic sector – larger than power generation, industry, transportation, or buildings.

Unfortunately, food-related emissions are still rising globally, even in countries like the United States, which is making tremendous progress in reducing emissions across other high-polluting sectors.

Map showing global trends in food sector greenhouse gas emissions

Where Do Food Emissions Come From?

To cut emissions from the food system, we must first understand where they come from. Focusing on the direct emissions from food, agriculture, and land use, we find that they come from four primary sources.

A chart showing sources of food-related greenhouse gas emissions

The largest, by far, is deforestation. Roughly 11% of the world’s emissions come from forest clearing, mostly associated with expanding agricultural land for cattle grazing, soybean production (mainly for animal feed), palm oil, and other commodities. To put these emissions in perspective, they exceed those from the entire United States, which contributes around 10.5% of global emissions.

The second largest source comes from ruminant livestock, which belch methane as part of their digestive process, at ~5% of global emissions. Despite misinformation and greenwashing campaigns trying to distract us from this fact, ruminant animals (including beef cattle, dairy cows, sheep, and goats) are the largest source of methane in the atmosphere. While native ruminants, such as bison and oxen, have existed for millennia, the massive number of livestock on Earth today – an astonishing 3.7 billion cattle, sheep, and goats – and the tremendous increase in their per-animal emissions (from breeding, feeding, and raising animals to maximize growth) has led to a huge increase in ruminant methane emissions.

The third largest source is industrial farming practices, at around 3%. These are largely due to fertilizer overuse, which leads to nitrous oxide emissions from the soil, and poor soil management, which leads to carbon dioxide emissions from degrading soil organic matter. While these farming practices might boost yields in the short term, they come at the cost of greenhouse gas emissions, water pollution, and soil loss. This is unstainable by any measure.

When it comes to addressing the food system’s role in driving climate change, the first goal is to cut primary emissions as quickly as possible.

The fourth largest source, at roughly 2%, is methane from rice production. Rice is typically grown in flooded paddies, which create an anaerobic environment that releases methane from waterlogged soils. Innovations in rice production, which alternate wet and dry conditions, might dramatically lower these emissions without compromising production.

The remaining 1% or less of emissions from food, agriculture, and land use include those from manure and biomass burning to clear crop residues.

The Most Important Solutions Cut Emissions

When it comes to addressing the food system’s role in driving climate change, the first goal is to cut primary emissions as quickly as possible. This means curbing the direct emissions from deforestation, ruminant livestock, industrial farming methods, and rice production. We must also cut emissions in the larger food system, including emissions associated with landfills, transportation, refrigeration, cooking, and food processing.

Below are four key focus areas to reduce food system emissions.

1. Improve Food System Efficiency

Addressing the incredible inefficiencies in our food system is the first and most important step in lowering related emissions.

The best place to start is curbing food loss and waste. A staggering 30-40% of the world’s food is never eaten due to excessive losses in food supply chains (between the farm and the market) and excessive food waste by consumers. With roughly one in three units of food lost or wasted, we have to grow about 50% more food than we actually eat. This inefficiency costs the world money and resources, exacerbates food insecurity, and causes environmental damage.

Since all of that food is lost or wasted, that means 30-40% of the world’s agricultural land, water use, chemical inputs, and greenhouse gas emissions are not necessary. Cutting food loss and waste – even a little – can dramatically improve the efficiency of the food system, curbing “upstream” emissions from when the food is produced and “downstream” emissions from when food dumped in municipal landfills releases methane into the atmosphere. 

Project Drawdown has found that reducing food loss and waste is one of the largest climate solutions across all sectors, not just in the food system. Plus, it could provide additional benefits to land, water, and biodiversity while also improving food availability and food security worldwide.

Another key place to focus for efficiency is diet, particularly in countries with high red meat and dairy consumption. Red meat (including beef and lamb) and dairy products are associated with extremely high greenhouse gas emissions, mainly due to their methane emissions and extensive land use. In fact, one pound of beef can produce nearly one hundred pounds of greenhouse gases, making it the most climate-polluting substance, pound for pound, that most people interact with on a regular basis. (For comparison, burning a pound of coal releases about two pounds of carbon dioxide. Beef production can release ~50 times more.)

Cutting back – even a little – on red meat and dairy products can have disproportionally large benefits for climate change. While an all-vegan diet is unlikely to become the norm anytime soon, small shifts toward a more plant-rich diet with fewer and smaller portions of less-polluting animal protein can provide huge benefits for climate, land, water, biodiversity, and human health.

A chart showing greenhouse gas emissions by food source

2. Protect Ecosystems

Since deforestation is the largest contributor to food-related emissions, protecting forests (and other vital ecosystems) is a top priority for climate action. Emerging evidence shows that the best way to do this includes (1) working with local and indigenous communities to help maintain their stewardship of forested lands; (2) cleaning up global supply chains so they no longer trade in deforestation-linked commodities, such as beef, soy, and palm oil; and (3) working to dramatically improve carbon markets, which have – so far – mostly failed in their promise to protect large areas of intact forest.

Preventing tropical deforestation and other ecosystem loss is one of the best, largest, and fastest solutions we have to address climate change. It is also a key solution to the world’s biodiversity crisis. We must dramatically accelerate work in this area, including massive increases in funding for effective forest protection efforts worldwide.

3. Improve Farming Methods 

Beyond making the food system more efficient and protecting forests, we must also find ways to reduce emissions from farming practices.

A key area to focus on is fertilizer management. There are large areas of fertilizer overuse – far above levels crops can actually use – across the United States, Western Europe, China, and India. This leads to massive nitrous oxide emissions from the soil that contribute to climate change and high levels of nitrate and phosphorus runoff that pollute rivers, lakes, and coastal oceans. Smarter policies and farming practices could dramatically reduce this pollution without affecting food production.

Soil management is another area to focus on for improved farming. Too many of the world’s croplands and rangelands are heavily exploited, leading to soil degradation, which breaks down organic matter and releases carbon dioxide into the atmosphere. Improving soil management is a critical climate solution that also benefits soil health, water quality, and food security.

Finally, reducing methane emissions from rice by changing water management and other practices will also be crucial. In terms of total calorie production, rice is the most important crop in the world and the bedrock of global food security. Addressing emissions from rice without compromising yields will be an essential goal.

4. Clean Up the Larger Food System

Beyond cutting direct emissions from deforestation, livestock, industrial farming methods, and rice, we must also find ways to reduce emissions from the broader food system. Methane emissions from landfills are particularly important, where food waste and organic matter drive much of the problem. We should also focus on clean cooking, which reduces black carbon emissions and forest loss. More efficient refrigeration – and using non-greenhouse gas refrigerants – alongside improved food transportation, packaging, and processing will also be critical areas to address.

We must be extremely careful about relying on carbon removal as a climate solution.

After Cutting Emissions, Natural Carbon Removal

The most effective way to address climate change is to cut emissions at the source, period. No other approach is as effective, impactful, or permanent. However, land-based carbon removal – whether by trees, grasses, or soils – can be a viable complementary climate solution, as long as it never replaces cutting emissions. 

We must be extremely careful about relying on carbon removal as a climate solution. Why? First, it is incredibly small right now (far less than a tenth of a gigaton) and could take decades to implement and grow to any meaningful scale. Second, it is unlikely to ever approach the levels of net carbon removal suggested by some in the popular media, especially when accounting for soil carbon limits and livestock methane emissions. Third, trees and soils can never permanently sequester carbon, especially when just one future fire or farmer can disrupt the landscape and instantly release carbon back into the atmosphere.

Most of all, we must ensure that carbon removal isn’t used to greenwash the food industry, providing a bucolic PR fig leaf to a highly polluting sector. While stories of large-scale regenerative agriculture and tree planting sound great, they are unlikely to arrive as promised. And even if they do, they are still a poor substitute for cutting emissions today, which is always and unequivocally the better approach to address climate change.

We need to exercise extreme caution with land-based carbon removal, just like we must be careful about relying on technological carbon removal in the electricity and industry sectors. Nevertheless, it is worth counting carbon removal as a smaller, secondary, and complementary approach – while focusing much more attention on primary emissions cuts.

Here are the two most promising approaches to land-based carbon removal.

1. Rewilding Agricultural Lands

First, we can restore former agricultural land – such as those lands spared from production by curbing food waste and shifting to more efficient diets – back to natural ecosystems. Restoring agricultural lands to forests, savannas, grasslands, or coastal ecosystems would allow us to sequester carbon, restore natural habitats, and improve water quality on landscapes heavily impacted by agriculture. 

The rewilding of agricultural lands could be a big win for climate and nature. But it first requires shrinking the overall footprint of the food system by cutting food waste, shifting away from wasteful diets, and phasing out crop-based biofuels.

2. Regenerative Agriculture Practices

We can also implement regenerative agriculture practices on our working lands.  

Though it still lacks a consistent and rigorous definition, regenerative agriculture aims to return working lands to a healthier state by mimicking some of nature’s processes and building vegetation cover and soil carbon. Borrowing techniques from organic agriculture, permaculture, agroecology, conservation farming, and beyond, the burgeoning excitement around regenerative agriculture is palpable. It can offer tremendous benefits to soil health and water quality while also making farms more resilient to climate shocks.

Together, we can create a food system that nourishes the world today and far into the future.

However, as a climate solution, regenerative agriculture suffers from a lot of overhype and greenwashing. While regenerative grazing practices can help build soil carbon, there are limits to how much carbon can be stored in soil (especially since carbon accumulation slows down after a few years). Moreover, the finite – and likely smaller than suggested – amount of carbon that can be absorbed into the soil can be quickly overwhelmed by ongoing methane emissions from livestock. There are also concerns that regenerative grazing can take more land than conventional methods, which comes at an additional “opportunity cost” of carbon.

Overall, regenerative agricultural practices are a better way to farm – for soil health, water quality, and limited carbon removal – but they are not a silver bullet for addressing climate change. They pale compared to other solutions, especially curbing food waste and shifting diets. They are best used as complementary solutions, combined with and leveraging efforts to shift diets, reduce food waste, protect forests, and reduce fertilizer use.

Let’s Fix Our Food System

Project Drawdown has a rich portfolio of effective climate solutions – organized into six key pillars – in the food, agriculture, and land use space. We can cut emissions by building a more efficient food system, protecting ecosystems, moving to low-carbon farming techniques, and cleaning up the larger food system. Then, as a complementary set of solutions, we can remove some carbon through rewilding and regenerative agriculture.

A graphic showing six pillars of food-related climate action

There isn’t a single silver bullet solution that addresses climate change in the food system. Vegan diets won’t solve it alone. Neither will regenerative agriculture or improved fertilizers. Instead we must use a whole portfolio of solutions and deploy them in tandem. Taken together, these solutions can address the problem – but only if we do them all and do them quickly.

While the food system’s role in the climate crisis presents an enormous challenge, I also see it as an incredible opportunity. None of the solutions we need to take require new technology, trillions of dollars, or breaking the laws of physics. It’s all possible today.  We have a chance to build an entirely better food system. One that restores nature instead of destroying it and addresses climate change instead of accelerating it. Together, we can create a food system that nourishes the world today and far into the future. 

Jonathan Foley, PhD, (@GlobalEcoGuy) is a climate scientist and the Executive Director of Project Drawdown, the world’s leading resource for climate solutions. These views are his own.

This work was published under a Creative Commons CC BY-NC-ND 4.0 license. You are welcome to republish it following the license terms.