The Environmental Impacts of Droughts

As summer approaches, headlines about worrisome drought conditions usually dominate the news. All across the world, ecosystems from California to Kazakhstan have dealt with droughts of varying lengths and intensity. You probably already know that a drought means there is not enough water in a given area, but what causes a drought? And how do ecologists determine when an area is suffering from a drought? And can you actually prevent a drought? What Is A Drought? According to the National Weather Service  (NWS), a drought is a deficiency in precipitation over an extended period. It also occurs more regularly than you might think. Actually, almost every ecosystem experiences some period of drought as part of its natural climate pattern. The duration of the drought is what sets it apart.   Types of Droughts The NWS defines four distinct types of drought that vary depending upon their cause and duration: meteorological drought, agricultural drought, hydrological drought, and socioeconomic drought. Heres a closer look at each type. Meteorological Drought: This type of drought is defined by a lack of precipitation over a period of time.  Agricultural Drought:  This is the type of drought that occurs when factors -- such as lack of rainfall, soil water deficits, and reduced groundwater levels -- combine to produce conditions that do not allow an adequate water supply for crops.  Hydrological Drought:  When lake or stream levels decline and the groundwater table is diminished due to a lack of rainfall, an area may be in a hydrological drought.Socioeconomic Drought: Socioeconomic drought occurs when the demand for an economic good exceeds an ecosystems water-related means of sustaining or producing it. Causes Of Drought Drought can be caused by meteorological conditions such as a lack of rainfall or excess of heat. They can also be caused by human factors such as increased water demand or poor water management. On a wider scale, drought conditions are often thought to be the result of climate change that causes higher temperatures and unpredictable weather patterns. Effects of Drought At its most basic level, drought conditions make it difficult to grow crops and sustain livestock. But the effects of drought are actually much more far-reaching and complex, as they affect the health, economy and stability of an area over time. Droughts can lead to famine, wildfires, habitat damage, malnutrition, mass migration (for both people and animals,) disease, social unrest, and even war. The High Cost of Droughts According to the National Climatic Data Center, droughts are among the most costly of all weather events. There were 114 droughts recorded in the United States through 2011 that have resulted in losses in excess of $800 billion. The two worst droughts in the U.S.  were the 1930s Dust Bowl drought and the 1950s drought, each one lasted for more than five years affected large areas of the nation. How to Prevent a Drought Try as we might, we cannot control the weather. Thus we cannot prevent droughts that are caused strictly by a lack of rainfall or abundance of heat. But we can manage our water resources to better handle these conditions so that a drought does not occur during short dry spells. Ecologists can also use various tools to predict and assess droughts around the world. In the U.S., the U.S. Drought Monitor provides a day-by-day visual of the drought conditions around the country. The U.S. Seasonal Drought Overlook  predicts drought trends that may occur based on statistical and actual weather forecasts. Another program, the Drought Impact Reporter, collects data from the media and other weather observers about the impact of drought in a given area. Using the information from these tools, ecologists can predict when and where a drought might occur, assess the damages caused by a drought, and help an area recovery more quickly after a drought occurs. In that sense, they are really more predictable than preventable.