Environmental Impact of Agriculture

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.

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.

Agriculture can help to:

• Reduce carbon dioxide (CO₂) levels in the atmosphere by storing carbon (C) in soils:

  • Crop and soil carbon sequestration are, for example, possible through permacultures and tall-growing plants such as bamboo.

• Improve air quality:

  • Plants "catch" and reduce dust levels.

• Provide habitat for wildlife:

  • Farmland hedgerows and their riparian (river, banks, etc.) areas tend to be quite biodiverse.

• Develop new technologies:

  • Ionising radiation is used to mutate DNA and enhance species of agricultural importance. This radiation is made by radiation-generating technology, such as electron accelerators.

• Lead scientific advancements:

  • The Haber-Bosch process was born from the need to fertilise agricultural fields. It revolutionised the industry, allowing our population to grow significantly. The Haber-Bosch process managed to produce ammonia (NH₃) from nitrogen (N) and hydrogen (H), and nowadays, it may also be used to enrich animal feed.

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:

• Brazil (South America)

• Indonesia (Asia)

• Malta and the United Kingdom (Europe)

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.

• 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.

Some of the other negative effects of agriculture on the environment include:

• Changes to the hydrological cycle:

  • Agriculture uses 70% of all freshwater our society taps into annually.³ Altered vegetation cover (with only a few species of agricultural plants) influences the quality and amount of water that seeps through the rocks back into basins and aquifers, usually negatively. Moreover, inefficient irrigation techniques can account for excessive water evaporation before it reaches the soil.

    Drip irrigation is more water-efficient than sprinklers!

• Soil quality loss:

  • Soil loses quality through compaction by trampling and through the use of heavy machinery. Moreover, mono-crops reduce overall soil nutrients and biodiversity and lead to further loss of soil fertility.

• 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.

• Domestic bee-dependent, leading to a decline in biodiversity:

  • Both wild and domestic bees need to be allowed to survive. Almond farms in California are mono-crops (monocultures) that need bee pollination, with the side effect that almond flower pollen and nectar cannot solely provide for the nutritional needs of honeybees. As a result, fifty million bees died in the winter of 2018-2019 alone.⁴

• 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.

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.

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.

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.

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.

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.