Food & Climate: The impact of food on the environment
6 minute read
Updated on: 22 Jun 2020
What’s the problem with agriculture?
Humans eat a lot of food. To grow it all, we rely on a process called agriculture, or farming [ref]. Given its scale, it’s no surprise that agriculture is a major contributor to climate change.
So, where do these emissions come from?
Running a farm requires energy. Most of this energy comes from burning fossil fuels, which releases CO₂ into the atmosphere [ref].
Fertilisers and Pesticides
While fertilisers are extremely useful, their production alone is responsible for 1.2% of global greenhouse gas emissions [ref].
Not only that, most crops can only use around 50% of the fertiliser applied [ref]. Leftover fertilizer is often broken down by soil microbes into nitrous oxide (N₂O) [ref]: a greenhouse gas with a warming effect 300 times stronger than CO₂ [ref].
If fertiliser is swept into rivers and lakes, the nutrients inside it feed algae and plankton that reduce the amount of light and oxygen in the water [ref]. This suffocates fish and other aquatic species [ref].
Pesticides are another chemical used by farmers. These protect crops from diseases, weeds, and plant-eating insects [ref]. Without crop protection strategies like pesticides, crop losses could be as high as 80% [ref]!
However, like fertilisers, these chemicals require energy to produce [ref]. They are also toxic to many other forms of wildlife [ref], including pollinators that help crop plants reproduce [ref1,ref2], and microbes that keep soils healthy and fertile [ref].
Agriculture is the biggest emitter of the greenhouse gases nitrous oxide (N₂O) and methane (CH₄), accounting for 80% and 45% of the man-made emissions of these gases respectively [ref].
Deforestation and Soil Degradation
Nearly a quarter of emissions from food production are released when land is cleared for agriculture [ref].
The crops that replace trees store less carbon and are not as good at holding the soil together [ref]. This makes the soil unstable and results in its degradation, leading to landslides and dust storms [ref1,ref2,ref3].
While water makes up 71% of the Earth’s surface [ref], only 3% of this is freshwater, the water we use to drink, wash, and water crops [ref1,ref2,ref3]. About two thirds of freshwater is locked away in ice, meaning only 1% of global water is accessible for direct use by humans [ref1,ref2,ref3].
Let’s look at this in more detail [ref]:
By 2050, the global population is set to reach 9.7 billion [ref], and food production will have to increase by between 50 - 100% to feed our growing population [ref1,ref2,ref3,ref4]. But how can we achieve this when agriculture is already putting such a strain on our resources and our planet?
What is sustainable agriculture?
Let’s recap quickly. Today, agriculture:
- Releases around 21% of global greenhouse gas emissions [ref1,ref2]
- Uses lots of energy [ref1,ref2,ref3]
- Damages surrounding ecosystems [ref1,ref2]
- Takes up 50% of Earth’s habitable land [ref]
- Degrades soils, which releases CO₂ and makes it harder for plants to grow [ref1,ref2,ref3]
- Accounts for 70% of global water use [ref1,ref2,ref3]
If agriculture was made more sustainable, food could be produced on the same land indefinitely, without depleting resources [ref1,ref2,ref3]. Sustainable farming is also less vulnerable to environmental change, which will be essential if we are to continue to feed ourselves in the face of climate change [ref1,ref2].
In the next chapters, we will look at what farmers and consumers can do to make food production more sustainable.