Definition & Causes
A drought is a period of time when an area or region experiences below-normal precipitation. The lack of adequate precipitation, either rain or snow, can cause reduced soil moisture or groundwater, diminished stream flow, crop damage, and a general water shortage. Droughts are the second-most costly weather events after hurricanes.
Unlike with sudden weather events such as hurricanes, tornadoes, and thunderstorms, it is often difficult to pinpoint when a drought has started or when it has ended. The initial effects of a drought may be difficult to identify right away, so it may take weeks or months to determine that a drought has started. The end of a drought is hard to identify for the same reason. A drought may last for weeks, months, or even years. Sometimes, drought conditions can exist for a decade or more in a region. The longer a drought lasts, the greater the harmful effects it has on people.
Droughts affect people in a several ways. Access to clean drinking water is essential for all life, and sources of water may dwindle during a drought. Without the presence of water, people must bring in enough water from elsewhere to survive. Water is also needed for crops to grow. When not enough precipitation falls to naturally water crops, they must be watered by irrigation. Irrigation is possible only when there is enough water in nearby rivers, lakes, or streams, or from groundwater. During a drought, these water sources are diminished and may even dry up, preventing crops from being irrigated and causing them to die off.
Here are the 5 natural and human causes of drought:
1) Land and water temperatures cause drought.
As overall temperatures increase more water evaporates and severe weather conditions increase. Landscapes and crops need more water to survive and overall the demand for water increases. This is why it is so important to consider changes when discussing water savings. You might be using more water or less water depending on weather conditions.
2) Air circulation and weather patterns also cause drought.
Key events like La Nina help contribute to drought in areas. All the water we ever had we have today and it is stored in the air or on land. Weather patterns move the water in the air around. This is constantly changing.
3) Soil moisture levels also contribute to drought.
When soil moisture is depleted there is less evaporation of water to create clouds. Surface temperatures rise, more water is needed and less is available which contributes to a more severe drought.
4) Drought can also be a supply and demand of water issue.
When a region is growing rapidly the demand for water can exceed the supply. When weather conditions, temperatures or air patterns push a region toward a drought the demand for water by people can offset or worsen the situation depending on how the region reacts. Excessive irrigation is an excellent of people contributing to a drought.
5) If the timing of water doesn’t match the agricultural season you may have too much water when you don’t need it and too little when you do need it.
Proper storage and collection of water is key to counter balancing this cycle and clearly in the scope of human management.
Severe droughts also impact the migration of people. As countries continue to protect their natural resources people will move to water. The amount and timing of the movement can contribute to water issues not previously felt before.
Example for droughts