Long ago, in our past, our ancestors decided to settle around the most fertile strips of land and start family-centred communities. They chose climates and soils that favoured the growth of plants or animals and preferred the proximity of freshwater resources.
Nowadays, our preferred areas of inhabitance are somewhat different. Our current cities don't typically offer fertile soils, naturally clean water resources or clean air. However, they provide transportation services and access to these resources brought from elsewhere, such as via pipes, freight or other means.
Still, all urban and non-urban centres depend on agriculture. The environmental impact of agriculture has been significant, and we must analyse it and try to make it as sustainable as possible for generations to come.
What do we mean by the environmental impact of agriculture?
Agriculture refers to plant cultivation, animal rearing, and any afferent activities. It has been a natural result of human habitation for centuries, and many animals have adapted to living on farmlands. Agriculture is practised differently globally, depending on environmental conditions and available species.
The point of agriculture is to produce food, clothing and other products which enhance people's quality of life.
This hasn't been possible everywhere, and years of drought or insufficient agricultural produce have often stirred human conflicts.
COVID-19 has recently disrupted some countries' food and economic systems, and the 2022 war in Ukraine has triggered food crises around the world.
Food and Agriculture Organisation's (FAO) food price index shows an +137.5% increase in oil prices and a +69.5% increase in cereal prices worldwide, compared to 2016 averages.1
In the context of climate change, dictated by rising temperatures of both air and seawater and changing precipitation patterns, sustainable farming methods become essential.
Positive effects of agriculture on the environment
Agriculture is vital to the global food supply, but it also significantly impacts the environment. On the positive side, agriculture provides a major source of employment and contributes to economic growth. It also helps to conserve natural resources by using less land to produce more food.
Sustainable or regenerative agriculture can be quite different from industrial-scale or intensive agriculture.
Agriculture can help to:
Permaculture, also known as permanent crop culture, is the development of agricultural ecosystems intended to be sustainable and self-sufficient.
Negative effects of agriculture on the environment
On the negative side, agriculture can lead to soil erosion and water pollution. It can also contribute to climate change by releasing greenhouse gases into the atmosphere.
Agriculture is a driving force for deforestation globally, but especially in the following countries:
95% of all reported deforestation worldwide in 2019 occurred in the tropics.2
Deforestation occurs at the minute especially in South-American rainforests due to the changing political and economic views, and in the African rainforests due to ongoing conflict and war zones.
Subsistence clears and uses rainforest land slightly differently than commercial agriculture.
Native Americans had used subsistence agriculture for hundreds of years. It involved using a plot of land modified for the plantation of bananas, maize, or animal rearing until it started to lose fertility, typically within two years.
Such plots were left to recover between 50 and 100 years before the native inhabitants reoccupied them. This is believed to have contributed to the enhancement of the rainforest biodiversity.
Commercial agriculture clears land more intensively and over larger areas. The soils in those regions may be enriched chemically to allow crops to grow for longer. This means that tropical soils, which are already poorer in nutrients than temperate soils, may take longer to regenerate.
When abandoned, it is difficult for the forest to overtake them, as those plots of land may not be enclosed by rainforest patches anymore.
Similar trends exist around the world! Rotational grazing & cropland are one of the best techniques to prevent significant soil quality loss and erosion.
Oil palm plantations in Indonesia cause more deforestation and biodiversity loss in Indonesia than cattle rearing. Soy plantations cause the most plant agriculture-related deforestation in South America.
Some of the other negative effects of agriculture on the environment include:
'Mono-crops' is the practice of planting the same type of crop.
Earthworms and mycorrhizae help biodiversity and enhance crop growth but can go locally extinct through the use/overuse of pesticides or chemical fertilisers.
Mycorrhizae is a fungus that helps plants obtain nutrients through roots, and grow better.
Pesticide use:
Pesticides have been pivotal in preventing monocultures from being consumed by pests and preventing widespread famine. However, they are known to decrease the number of invertebrates, weed seeds, and microbiota, which otherwise feed a significant amount of the bird and mammalian population that inhabits flatlands. Intensive agriculture is the leading cause of bird population decline around the world.
- Genetic contamination:
It can happen naturally, through cross-pollination or hybridisation, or caused by human activities, such as genetically modified (GM) crops. GM crops have an advantage over their wild counterparts when specific conditions are provided, but they may not necessarily be more resilient in all given natural scenarios. The result is usually a loss of genetic diversity.
Impact of agriculture on biodiversity
Certain types of agriculture can promote biodiversity, while others impede the growth of anything else but the intended crop(s). Let's look at some examples of how agriculture impacts biodiversity.
Rotational agriculture in Transylvania, Romania
Opwall's 2021 case study of Romanian agricultural practices5 has identified several sustainable farming practices. Some of these characteristics include:
Sheep and cattle are allowed to graze together on unfenced terrain.
Old deciduous forests surround grazing and agricultural hillside fields.
Hay and clover fields are allowed to grow wildflowers and wild herbs. Cutting is also done later in the season.
Agriculture is practised with little heavy machinery.
Avoidance of pesticides and reliance on natural predators.
Maltese aquifers
Agricultural irrigation represents the most significant factor of aquifer depletion in Malta.
Malta is an island surrounded by saltwater and subject to low precipitation and high annual temperatures.
Unregulated practices in agriculture, such as the use of nitrite and nitrate fertilisers, have led to the pollution of underground water reserves (aquifers). The result is that most of the water on the island is obtained from saltwater filtration, which is innovative, but also expensive.
Environmental impact of agriculture examples
Many historical and present examples can effectively illustrate the environmental impacts of agriculture.
The Aral Sea
The Aral Sea was once the fourth-largest inland sea in the world. However, it has been rapidly shrinking since the 1960s due to excessive irrigation from nearby agriculture. Specifically, agricultural development re-routed the river tributaries to fields, meaning that the sea, already subject to high temperatures, was left without enough incoming water volume.
Evapotranspiration is a process whereby water is evaporated from the surface of the earth and transpired from plants.
Evapotranspiration is a major component of the water cycle and plays a significant role in determining the climate of an area.
Once the sea's water table shrunk to unsustainable levels, the evapotranspiration rate became the leading cause of its shrinking. This is because the Aral Sea occupies a hot and arid part of the world.
This has resulted in the loss of habitat for local wildlife, and the increased salinity of the water has made it toxic to many fish. The Aral Sea is now less than 10% of its original size, and its ecosystem is on the brink of collapse.6
The Attica region of Greece
Timber-cutting and grazing, especially goat and sheep grazing, started to affect the landscape of Greece from 2400 years ago.
Four centuries before Christ, Plato described Attica (the region around Athens), saying: “What now remains compared with what then existed is like the skeleton of a sick man, all the fat and soft earth having wasted away, and only the bare framework of the land being left.”7
Agriculture and climate change
Deforestation creates desertification, which leads to a lack of food, water and species displacement. Agriculture also causes water pollution from pesticides and fertilizers, soil erosion, and greenhouse gas emissions from livestock and heavy machinery.
The Intergovernmental Panel on Climate Change (IPCC) releases state-of-the-art reports on climate change. Let us look below at three of the most critical greenhouse gases emitted from agriculture.
Chemicals | Global warming potential (Measured over 20 years, according to IPCC's Sixth Assessment Report) | Effects |
Nitrogen oxides (NOx) | 273 | Released into the air, waterways and soils through fertilizer application, manure management and crop burning. Causes eutrophication (algal overgrowth). Contributes to the formation of smog and acid rain. Contributes to ozone depletion. Can cause respiratory problems.
|
Carbon dioxide (CO2) | 1 | Released from tilling and deforestation, fossil fuel combustion for vehicles and tools (tractors, chainsaws, etc.), and crop burning. |
Methane (CH4) | 80.8 | Comes from livestock (cattle, sheep, etc.), manure management, and rice agriculture. |
The Global Warming Potential (GWP) is a gas's capacity to absorb heat. The reference point in measuring these gases is CO2, which is represented by the value 1.
While it is true that agriculture can lead to habitat loss and the decline of some species, it can also provide new opportunities for other species to thrive. Human communities worldwide will perhaps reach a point where they produce enough food sustainably and have overcome agricultural diseases and environmental limitations—sharing our resources with other species and allowing co-existence to promote sustainability and biodiversity.
Environmental Impact of Agriculture - Key takeaways
Agriculture is disrupted by environmental 'fickleness', war, and other natural or artificial factors worldwide.
Agriculture impacts the environment through pesticide and fertilizer use, air pollution, deforestation, etc.
Agriculture puts significant pressure on freshwater and forest resources, especially in the tropics.
Agriculture can also positively impact the environment, helping reduce air pollution and providing a resource-rich habitat to certain wild species.
The Aral Sea is an extreme example of the effects of unsustainable agriculture. An entire landlocked sea evaporated because of them!
References
- Dea Bankova et al., The war in Ukraine is fuelling a global food crisis, 2022.
- Global Forest Watch, Commodity-driven deforestation’, 2019.
- Food and Agriculture Organization, Water for Sustainable Food and Agriculture, 2017.
- Annette McGivney, 'Like sending bees to war': the deadly truth behind your almond milk obsession, 2020.
- Sophia Wood, How does Transylvania’s agriculture promote biodiversity?, 2021
- Shamseer Mambra, Aral Sea Disaster: Why One of the Biggest Inland Seas Dried Up?, 2022.
- Ecosystem Services Partnership, Environmental Pollution in Greece, 2022.
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