Desertification: Definition, Causes, and Impacts

Desertification is a growing problem in our world, due to a mix of climate change and poor land  management. In this article we will define desertification, its causes, its impacts, and what can be done  to stop it.

For such a transition to be considered desertification, the land must: 

• Undergo land degradation – land’s loss of current or future productive capabilities.
• Be dryland – land in an arid, semi-arid, or dry sub-humid climate.  

In dry climates, soil moisture tends to correlate with short-term rainfall patterns – the wetter the soil,  the higher likelihood of rain the next day. So, a wet season is likelier to be wetter if there are more plants in a dryland to hold the moisture. But if over time more and more plants die from desertification, it can be challenging to stop the cycle. 

Desertification is a serious environmental concern. It has significant consequences for both ecosystems and human populations.  

Dryland makes up about 46% of all the land on earth, an area home to 3 billion people. There are six  countries that have 99% or more of their land classified as dryland. 

Desertification is a global problem - 17 countries, which are home to nearly 2 billion people, have highly  stressed aquifers. That means water, food, and land for a quarter of the world’s population is at serious  risk.

If desertification and climate change are not taken seriously, it is likely that millions of people will choose to leave their homes for areas with more consistent access to food and water.

Desertification is caused by a multitude factors that often compound each other. Variations in the climate play a part in the phenomenon, as do human activities. 

Urbanization and improper agriculture and land management practices drive factors that cause  desertification, including: 

• Deforestation 
• Forest fires 
• Pesticide use 
• Excessive irrigation 
• Overgrazing 

Drylands, by definition, get little rain. Therefore, the groundwater supply of drylands is typically a fragile  resource. As droughts intensify, lengthen, and become more common with climate change, the aquifers holding the groundwater will shrink year by year, even when they are refilled by rains. 

Climate change intensifying droughts

Since the early 1900s, global drought has been steadily increasing due to greenhouse gas emissions by  humans. 

The addition of more greenhouse gases to our atmosphere has been steadily warming our planet and  contributing to climate change. Warmer temperatures make more water evaporate from earth’s  surface. This means plants have a harder time holding on to moisture and staying hydrated in arid areas. 

During each year from 2000 until 2020, about 20% to 70% of the U.S. land area experienced anywhere  from abnormally dry (going into drought) conditions to exceptional drought (widespread crop and  pasture loss). 

In fact, the Southwestern United States and Northwestern Mexico are in the midst of a 22-year-long  megadrought. That makes it the worst drought in that area in over 1,200 years, despite the common  nature of megadroughts there from 800 to 1600.

Poor land management 

When drought-affected areas are well managed, the land can rebound when rain inevitably comes. 

But drylands that are poorly managed during drought have a much harder time recovering to pre drought stability. Heavy use of groundwater for irrigation, drinking water, putting out forest fires, or  urbanization needs can limit the water available for plants to rely on during drought.  

Two other big factors of poor land management are overgrazing of cattle and excessive use of  pesticides. These common practices contribute to desertification by deteriorating soil health and  texture. 

Overpopulation can also lead to improper land management. It creates greater demands on the soil for food than it can sustainably give. Overuse can easily trigger erosion of quality soil, which will put more stress on nearby land to compensate for this loss. 

One of the main impacts of desertification is biodiversity loss. As dry land ecosystems get drier and more inhospitable, fewer plants and animals can adapt and survive.  

Forest fires and low soil quality, as we have discussed, are also common consequences of  desertification. An area becoming more arid makes it more fire friendly. And as soil deteriorates with  erosion, it cannot hold as much moisture, further adding to forest fire potential.  

Habitat loss is inevitable when an ecosystem is ravaged by forest fires, depleting soil, increased  temperatures and more sparce precipitation. Animals and plants are forced to migrate but finding new homes can be challenging – it depends on environmental conditions and competition for resources.

Impact on humans 

Of course, land becoming desert makes the area less hospitable to humans as well. 

The productivity of crops and livestock tends to go down due to desertification. Wildfires are more likely  to spark as drylands become drier, threatening humans themselves, their crops, and their livestock. 

When the rare rains eventually do come, poor soil conditions can lead to flooding and polluted water  sources, compounding water stress on communities. 

You may be wondering where desertification is happening or where it is likely to occur.  

As we know, desertification happens only in areas that are already particularly dry. While not all  drylands are near a desert, desertification is most likely to happen on the shoulder of the desert – where  precipitation is as or more sparce than on the dryland itself.

Desertification is creeping its way across California

The Golden State, as an agricultural capital of the U.S., is particularly thirsty for water. Unfortunately, a good chunk of California has experienced drought for much of the last decade.  

It’s fair to say that during this period, the land has not been managed very well - parts of the state’s  central valley have sunk as much as two feet each year due to excessive groundwater use.  

Los Angeles, Sacramento, and Fresno seem to be the areas most vulnerable to desertification. Besides  agriculture, the vulnerability is due to factors like drought, urbanization, and deforestation, which all  contribute to forest fire potential as well. 

Africa 

Two thirds of the continent of Africa is currently classified as either dryland or desert. That was not always the case – but with desertification increasing, transitionary land between desert and non-desert  has become less and less habitable.  

For example, the Sahel, a long band of dryland separating the Sahara Desert from the humid savannas to  the South, becomes more barren each year. Desertification happens there partly due to growing  populations’ greater demands on the land for sustenance. Also, the cattle commonly overeat the limited  supply of grass, leaving the soil exposed to erosion when rainfall comes. 

However, there is a movement to replant native Acacia trees to the region. They will help hold the topsoil in place and keep the Sahara from encroaching further. The trees have also been helping  communities of the Sahel economically, giving them more community support than just ecological.

Planting native trees in dryland areas is a great solution to keeping desertification at bay and reverse what has already happened. Flora native to drylands tend to be drought-resistant and can hold onto soil,  limiting erosion. And as trees do, they can help limit global warming by removing carbon from the  atmosphere. 

Another way to limit desertification is by protecting windy areas. We can do this by building a wind  fence or planting an ecological border, which will be key to limiting soil erosion.

Contact Greenly if your company needs help measuring and offsetting its carbon emissions. Greenly will give you expert analysis and advice every step of the way towards minimizing your impact on climate change.