As Allan Savory explained in his breakthrough Ted Talk, “Desertification is a fancy word for land that is turning to desert.” The idea is a simple one. In climates with little or variable rainfall, known as dryland ecosystems, desertification takes place when climatic variations and/or unsustainable land management practices result in a decline in biological productivity in those ecosystems.
Among the human contributions to desertification are: deforestation, poorly managed livestock grazing, chemically-supported industrial agriculture, unsustainable water management (including inappropriate agricultural irrigation resulting in soil salinization), and the heat island effect from sprawling cities in arid and semi-arid environments.
So, we know what desertification is, but if drylands are already dry by definition, why is desertification such a problem? As lands become less productive, they also become less resilient in the face of inevitable natural disasters. Before desertification, when heavy rains would come to drylands, soil containing more organic matter could absorb substantially more water, sustaining plant and animal life during drier periods. In the face of desertification, however, these formerly life-sustaining heavy rains can’t infiltrate the soil. This typically results in flooding and further soil erosion, as well as reduced water quality and sedimentation in waterways.
Likewise, before desertification, times of drought would not hit drylands as hard as they do now because the root systems of grasses and other vegetation would minimize erosion. Now, however, when these areas do have droughts, the earth is already so bare and eroded that there is nothing to stop the immense dust storms that caused the 1934 Dust Bowl or recent haboob episodes in Arizona, in other parts of the Southwest, and even in the Northwest’s Columbia Basin.
Fortunately, there are solutions to the desertification crisis. Through both water harvesting practices and holistic management, individuals and communities can restore balance to the fragile and essential drylands ecosystems. See the next entry in this series, Reversing desertification through stormwater management, to learn how.