Environmental Impacts of Food Production

Food production has a large environmental impact in several ways

What are the environmental impacts of food and agriculture?

The visualization here shows a summary of some of the main global impacts:

• Food production accounts for over a quarter (26%) of global greenhouse gas emissions.¹
  
• Half of the world’s habitable land is used for agriculture. Habitable land is the land that is ice- and desert-free.
  
• 70% of global freshwater withdrawals are used for agriculture².
  
• 78% of global ocean and freshwater eutrophication is caused by agriculture.³ Eutrophication is the pollution of waterways with nutrient-rich water.
  
• 94% of non-human mammal biomass is livestock. This means livestock outweigh wild mammals by a factor of 15-to-1.⁴
  
• 71% of bird biomass is poultry livestock. This means poultry livestock outweigh wild birds by a factor of more than 3-to-1.⁵
  

Tackling what we eat, and how we produce our food, plays a key role in tackling climate change, reducing water stress and pollution, restoring lands back to forests or grasslands, and protecting the world’s wildlife.

Half of the world’s habitable land is used for agriculture

Around half of the world’s habitable land is used for agriculture. Habitable land is land that is ice- and desert-free. This is what the visualization shows.

Agricultural land is the sum of pasture used for livestock grazing, and cropland used for direct human consumption and animal feed.

Agriculture is, therefore, the world’s largest land user, taking up more area than forests, or wild grasslands.

Three-quarters of this agricultural land is used for livestock, which is pasture plus cropland used for the production of animal feed. The other quarter is for crops for human consumption. This large land use for livestock gives the world just 18% of global calories, and 37% of its protein.

Half of the world’s habitable land is used for agriculture

Food is responsible for one-quarter of the world’s emissions

Food systems are responsible for around one-quarter (26%) of global greenhouse gas emissions.⁸

This includes emissions from land use change, on-farm production, processing, transport, packaging, and retail.

We can break these food system emissions down into four broad categories:

30% of food emissions come directly from livestock and fisheries. Ruminant livestock – mainly cattle – for example, produce methane through their digestive processes. Manure and pasture management, pasture management also fall into this category.

1% comes from wild fisheries, most of which is fuel consumption from fishing vessels. 

Crop production accounts for around a quarter of food emissions. This includes crops for human consumption and animal feed.

Land use accounts for 24% of food emissions. Twice as many emissions result from land use for livestock (16%) as for crops for human consumption (8%).

Finally, supply chains account for 18% of food emissions. This includes food processing, distribution, transport, packaging, and retail.

When we include emissions from the production of non-food agricultural products – such as textiles, biofuels, and industrial crops, agricultural and food system emissions are responsible for closer to one-third of global greenhouse gas emissions.⁹

Food production is responsible for one-quarter of the world’s greenhouse gas emissions

How much of global greenhouse gas emissions come from food?

Emissions from food alone would take us past 1.5°C or 2°C this century

One-quarter to one-third of global greenhouse gas emissions come from our food systems. The rest comes from energy.

While energy and industry make a bigger contribution than food, we must tackle both food and energy systems to address climate change.

Michael Clark and colleagues modeled the amount of greenhouse gas emissions that would be emitted from food systems this century across a range of scenarios. 

In a business-as-usual scenario, the authors expect the world to emit around 1356 billion tonnes of CO_2-we by 2100.

As the visualization shows, this would take us well beyond the carbon budget for 1.5°C – we would emit two to three times more than this budget. And it would consume almost all of our budget for 2°C.

Ignoring food emissions is simply not an option if we want to get close to our international climate targets.

Even if we stopped burning fossil fuels tomorrow – an impossibility – we would still go well beyond our 1.5°C target, and nearly miss our 2°C target.

Emissions from food alone could use up all of our budget for 1.5°C or 2°C – but we have a range of opportunities to avoid this

What we eat matters much more than how far it has traveled

‘Eat local’ is a common recommendation to reduce the carbon footprint of your diet. But, it’s often a misguided one.

Transport tends to be a small part of a food’s carbon footprint. Globally, transport accounts for just 5% of food system emissions. Most of food’s emissions come from land use change and emissions from their production on the farm.

Since transport emissions are typically small, and the differences between different foods are large, what types of food we eat matter much more than how far it has traveled. Locally-produced beef will have a much larger footprint than peas, regardless of whether it’s shipped across continents or not.

The visualization shows this.

Producing a kilogram of beef, for example, emits 60 kilograms of greenhouse gasses (CO₂-equivalents). The production of a kilogram of peas, shown at the bottom of the chart, emits just 1 kilogram of greenhouse gasses. Whether the beef or peas are produced locally will have little impact on the difference between these two foods.

The reason that transport accounts for such a small share of emissions is that most internationally traded food travels by boat, not by plane. Very little food is air-freighted; it accounts for only 0.16% of food miles.¹² For the few products which are transported by air, the emissions can be very high: flying emits 50 times more CO₂eq than boat per tonne kilometer.

Unlike aviation, shipping is a very carbon-efficient way to transport goods. So, even shipping food over long distances by boat emits only small amounts of carbon. A classic example of traded food is avocados. Shipping one kilogram of avocados from Mexico to the United Kingdom would generate 0.21kg CO₂eq in transport emissions.¹³This is only around 8% of avocados’ total footprint. 

Even when shipped at great distances, its emissions are much less than locally-produced animal products.

You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local

Meat and dairy foods tend to have a higher carbon footprint

When we compare the carbon footprint of different types of foods, a clear hierarchy emerges.

Meat and dairy products tend to emit more greenhouse gasses than plant-based foods. This holds true whether we compare on the basis of mass (per kilogram), per kilocalorie, or per gram of protein, as shown in the chart.

Within meat and dairy products, there is also a consistent pattern: larger animals tend to be less efficient and have a higher footprint. Beef typically has the largest emissions; followed by lamb; pork; chicken; then eggs and fish.

You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local

There are also large differences in the carbon footprint of the same foods

The most effective way to reduce greenhouse gas emissions from the food system is to change what we eat. 

Adopting a more plant-based diet by reducing our consumption of carbon-intensive foods such as meat and dairy – especially beef and lamb – is an effective way for consumers to reduce their carbon footprint.

But there are also opportunities to reduce emissions by optimizing for more carbon-efficient practices and locations to produce foods. For some foods – in particular, beef, lamb, and dairy – there are large differences in emissions depending on how and where they’re produced. This is shown in the chart.

Producing 100 grams of protein from beef emits 25 kilograms of carbon dioxide-equivalents (CO₂eq), on average. But this ranges from 9 kilograms to 105 kilograms of CO₂eq – a ten-fold difference.

Optimizing production in places where these foods are produced with a smaller footprint could be another effective way of reducing global emissions.

Less meat is nearly always better than sustainable meat, to reduce your carbon footprint