Determining What Causes Droughts

In the last century, droughts have killed 11 million people and affected 2 billion more through crop failure and reduced drinking water. The U.S. has lost a total of $195 billion to related economic recovery.

The most well-known drought occurred in the 1930s. Due to overpopulation and poor soil conservation, much of the Southwest in the U.S. became nothing but plowed fields.

When the drought dried out the dirt, the wind picked it up and whipped it into a colossal dust devil that darkened the sun. The severe conditions forced 400,000 people to relocate out of harm’s way. This period became known as the Dust Bowl, or the Dirty Thirties.

Decades of study have lent scientists some insight into what causes droughts, such as disrupted weather patterns and our own human impact.

First, droughts commonly occur when disrupted weather patterns significantly alter water cycles. This year’s El Niño will disrupt storm patterns by increasing ocean temperatures, causing droughts in Australia, Indonesia and northeastern parts of South America.

Wind patterns sometimes block much-needed precipitation from certain areas for a time. Some experts speculate that global warming is the cause of many recent droughts.

The effects of a drought can impact areas that are a good distance away from the drought itself. If the mouth of a river doesn’t receive sufficient moisture from rain or melting snow, communities that reside downstream will suffer from the lack of water.

This is especially crucial in developing countries that still rely on rivers and streams for their water supply.

Secondly, humans can play a large part in drought development. Deforestation inhibits the soil’s ability to retain moisture. Trees pull water into the ground and anchor the soil, preventing soil erosion.

Dam construction, while a good method for retaining water, restricts the flow of water to downstream areas, which can severely impact vegetation, wildlife and people if not closely monitored.

As was the case with the Dust Bowl, mistreatment of crop soil can lead to desertification, in which soil becomes too compacted to absorb water and takes on an arid quality.

Though scientists are still conducting research on what causes droughts, they have developed several techniques that will reduce drought risk. Improved meteorology technology predicts approaching droughts, giving communities time to prepare.

Economically developed countries prevent and fight droughts by cutting back on water usage, replacing lawns with drought-friendly turf and installing water-saving toilets.

Farmers in any country can combat drought by rotating crops, allowing the soil to rest and reabsorb water. Emergency water kits, which are staples of almost any emergency aid organization, provide relief to drought-ridden areas as they wait for the next rainfall.

Sarah Prellwitz

Sources: UNL, National Geographic, BBC, LOC, Water
Photo: Pixabay