The world’s deserts are arid ecosystems that receive less than 25 centimeters (10 inches) of annual rainfall. Although daytime temperatures in some deserts are extremely hot, climbing as high as 130 degrees Fahrenheit, after nightfall, temperatures typically plummet—and some deserts are cold year-round. Ice-covered Antarctica is technically a desert.
We tend to think of the world’s deserts as arid, desolate wildernesses, with harsh conditions that make it nearly impossible for flora and fauna to survive. In reality, far from being empty and lifeless, most deserts are home to a plethora of plant and animal species. We humans have been living in deserts for thousands of years.
Indeed, deserts are home to around a billion people, or about one-sixth of the global population. Representing about one-fifth of the Earth’s land, deserts are found on every continent. Moreover, they are not all made of sand like the classic image of a desert that many people picture. Sand dunes cover just 10% of the world’s deserts. Some deserts are salt flats, others are mountainous, and some consist of dry expanses of rock.
The world’s deserts fall into five categories:
- Coastal deserts
- Subtropical deserts
- Interior deserts
- Rain Shadow deserts
- Polar deserts
The world’s largest desert is Antarctica, which spans more than 14 million square kilometers and ranks as the coldest desert on the planet. Largely composed of ice flats, temperatures in Antarctica can fall as low as -128 degrees Fahrenheit, with the ice that covers the area measuring up to 2.45 kilometers thick.
Farming in the Desert
People have been farming in deserts for thousands of years. Civilizations in arid regions thrived by developing irrigation systems to transport freshwater to crops. They also cultivated plants in depressions in the earth, where rainwater and runoff would collect, and built terraces to stabilize the soil and prevent erosion. Ancient Egypt, of course, was known as the breadbasket of the Roman Empire—Egyptian farmers grew wheat and other crops in the fertile soil along the Nile.
Today, deserts and arid regions are still important to agriculture. For example, despite receiving just three inches of rainfall per year, California’s Imperial Valley is one of the most productive farming regions in the state. Located in the Sonoran Desert, the Imperial Valley is irrigated by water from the Colorado River. A network spanning 16,000 miles of canals transports water from the river to farmers’ fields. The region has been farmed for a century, having established itself as a major supplier of winter vegetables in the United States, as well as a source of alfalfa, cotton, and grain. Much of the country’s sheep and lamb are produced in the Imperial Valley as well.
In Africa, Damaraland in Namibia has been renowned for goat farming for centuries, with some farmers also keeping chickens and cattle. Here, livestock is seen as a reflection of a family’s affluence, their accumulated wealth stored in the form of milk and meat. However, the uncertainties of the hot-dry and cold-dry seasons in this desert landscape present local farmers with significant challenges, forcing them to travel in search of edible vegetation for their herds to graze on.
Desert farming increases overall food productivity in desert regions, bolstering vulnerable food systems, strengthening value chains, and creating job opportunities and economic growth. It provides a vital income source for farmers, families, and communities. It can also deliver numerous ecological benefits, protecting and enriching the soil with microorganisms and organic matter. Desert agriculture also promotes the practice of intercropping, where trees and crops are planted together to create windbreaks and shade for better microclimate conditions.
The Sahara Forest Project
Situated in the Gulf of Aqaba on Jordan’s Red Sea coast, the Sahara Forest Project has created a farming success in one of the driest regions on the planet. Despite Jordan being one of the world’s most water-poor nations—the country is forced to import a staggering 98% of its food—the Sahara Forest Project is an inspiring example of how farming can adapt to the challenges of high temperatures and little water. Crops of peppers, cucumbers, and passionfruit are flourishing in greenhouses, thanks to ingenious use of technology.
The whole project is powered by sunlight and seawater—solar panels power a system that evaporates seawater, helping to keep the air inside greenhouses humid and cool, while simultaneously removing salt so the water can feed the crops. Surrounding the greenhouses, more salt-tolerant plant species have been planted to provide more cooling. Efforts are also underway to take the waste products from the operation and use it to make fertilizer to nourish the soil.
The project is an example of how desert agriculture hinges upon the creative, efficient use of water—and in this case, desalination is the key. So it is across much of the Middle East, which is home to about 60% of the world’s total desalination capacity. Desalination is also increasingly important in other arid countries like Australia and Morocco. Though the technology is undoubtedly a lifeline for water-stressed regions, there are challenges.
Desalination is expensive and energy-intense, though using renewable energy, as the Sahara Forest Project does, is one way to reduce the environmental impact. Desalination also creates a concentrated, salty brine as a byproduct. When discharged into the environment, this brine can harm coastal and sea ecosystems. Efforts to create more environmentally friendly, cost-effective desalination techniques are underway, however. Sustainable desalination would be a boon not only for farmers in the Middle East, but for agriculture in every arid and desert region around the world.