Drought is an extended period of less-than-normal precipitation in a specific region. This reduced water supply leads to a variety of negative social impacts including food insecurity and conflict over scarce resources, as well as environmental degradation like soil erosion and wildfires.
The causes of drought are complex and involve a combination of meteorological and human factors. For example, changes in global atmospheric circulation can cause it to not rain in a particular region for weeks or even years. This can be due to things like winds that carry continental rather than oceanic air masses, ridges of high pressure over the area that block low-pressure systems that would normally bring rainfall, or slowing down in oscillations in ocean surface temperature variability that lead to local weather patterns.
In agriculture, drought can reduce crop production and lead to food insecurity for people and livestock. It can also lower the quality of crops, causing them to shrivel and die. It can also increase the cost of food in stores and lead to decreased incomes for farmers and ranchers. It can also have significant economic and political impacts as water levels in rivers and lakes decline, affecting communities that rely on them for recreation or as their primary source of drinking water.
In addition, drought can cause many adverse human health outcomes, such as nutrient deficiencies and increased risk of disease. It can also contribute to conflicts over water usage and exacerbate existing social problems like poverty and hunger. It can also lead to migration away from regions impacted by drought as people search for better living conditions and more food and water sources.