Environmental Impacts of Agricultural Modifications

Environmental Impacts of Agricultural Modifications

With the human population soaring out of control, agriculture must follow suit. But the innovations that boost crop yields carry ecological costs.


3 - 12


Biology, Ecology, Chemistry, Conservation


Rice Fields in Bali

More than half the planet's suitable land has been cultivated for crops, like these terraced rice fields in Bali, Indonesia.

Photograph by Cyril Ruoso/NaturePL
More than half the planet's suitable land has been cultivated for crops, like these terraced rice fields in Bali, Indonesia.
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Over the years, people have found ways to grow more and more food. Farming, or agriculture, has allowed the world's population to grow. In the last 100 years, the world's population has quadrupled.

More people means that we need more space to grow food. In 2016, farmers used millions of square kilometers. They used it to grow grains like wheat and rice.

In the coming years, feeding a growing population might become difficult. Earth is heating up. This type of climate change is called global warming. It causes all kinds of changes in long-term weather patterns. These changes, like rainfall and drought, may make farming more challenging.

Modern farming is also responsible for its own problems. Farmers often grow food in ways that are not sustainable. Farming sustainability means balancing human needs with the health of ecosystems. It also means that future generations can meet their needs too.

Sometimes, farmers are only able to grow food in ways that hurt ecosystems. There are three main ways that farming affects ecosystems: irrigation, animal grazing, and fertilizers.

Freshwater is stored in lakes, rivers, and underground. People use it for washing, drinking, and growing food. Farming accounts for 70 percent of the freshwater that we use.

A lot of freshwater is used for irrigation. This is the process of watering crops through pipes, canals, or sprinklers. It is needed to grow large amounts of food.

Irrigation has consequences for the environment. It can drain water out of rivers, lakes or underground. In these areas, the soil can become too salty. This harms plant growth. Irrigation can also flood land in some areas. This also harms plants.

Irrigation can even affect weather. The water sprayed on crops increases evaporation. When something evaporates, it turns from liquid to gas. Evaporation changes the air's temperature and moisture. This affects rainfall patterns.

Animal Grazing
A lot of farm land is used for cows and other animals. This is especially true in the western United States. More land is set aside for animal grazing than for anything else. Grazing is when animals eat grass in pastures.

Farm animals often release greenhouse gases. Greenhouse gases trap heat in Earth's atmosphere. This causes the planet to warm. One major greenhouse gas is methane. Cows and their manure release lots of methane. This gas traps heat and makes Earth warmer, causing climate change.

Sometimes, overgrazing happens on farms. Overgrazing is when too many animals graze on the same piece of land for too long. It harms plants. Their root systems can get very damaged. Some plants may be unable to grow back, and certain types of plants might die off.

Cows also often eat near streams. Overgrazing and cow waste can pollute water.

Modern farming depends on fertilizers, which are substances that farmers spread over crops or into dirt. They often contain nitrogen and phosphorus. These are nutrients that plants need to grow.

Fertilizers have allowed farmers to grow much more food. They have also increased nitrogen and phosphorus in the environment. About half the nitrogen in fertilizers escapes from crop fields. It finds its way into soil, air, and water.

Large amounts of nitrogen and phosphorus harm ecosystems. Ecosystems become loaded with too many nutrients. In lakes and the ocean, this causes algae to grow quickly. As algae decay, they use up the oxygen in the water. This leaves almost no oxygen for other plants and animals in the water. The areas with little oxygen are called "dead zones." Many animals die without oxygen.

Feeding a growing population in the future will be challenging. We might have to find more sustainable ways of farming.

Media Credits

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Tyson Brown, National Geographic Society
National Geographic Society
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Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Clint Parks
Last Updated

October 19, 2023

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