Drought is a slow moving phenomenon that impacts the economy on many different time scales. It’s also difficult to define because it affects regions differently.
There are a variety of definitions for drought, some are physically derived, such as lake or groundwater levels, which are easy to measure and set thresholds for. Others are index-derived such as agricultural or economic factors that rely on the availability of water to support activities. Still others may consider ecological and social implications such as stunted vegetation growth or the loss of flora and fauna.
The economic impact of drought can be dramatic, especially in areas where there is high dependency on agriculture. For example, the recent drought in the Midwest U.S. has wiped out more than $15 billion in crops. Farmers are losing their livelihoods, and federal assistance programs are helping some. However, a longer and more widespread drought could mean American consumers pay higher prices for food or must rely on imported goods.
Drought can also have serious health impacts. Indirectly, the lack of water can lead to an increase in infectious diseases such as E coli and Salmonella, because foods are often contaminated with dirty water. Additionally, the dry conditions can cause wildfires, which burn remaining trees and create air pollution that aggravates chronic lung conditions.
There are a variety of things that can cause drought, including climate change, intensive farming and population spikes, changes in ocean temperatures (like the El Nino and La Nina climate patterns) and water demand upstream in rivers and lakes used for irrigation. But there are also things people can do to reduce the risk of drought, such as planting more drought-resistant crops and planning ahead for future weather emergencies.