A drought is a stage during which farmers are urgently waiting for rain because the soils run dry. The rivers have low water levels, and the vegetation turns its colour from green to yellow during the growing season. Droughts emerge slowly over time and can differ in severity depending on duration of dryness, response of the vegetation to dry conditions, or amount of water stored in rivers and water reservoirs or in the soil.
With climate change, droughts will become more frequent and more severe. We need to plan proactively by looking at how much water is needed and what kinds of water resources are available under different drought conditions. We need to better understand which communities and which agricultural lands are at risk to droughts, and why, and then identify measures for prevention and build capacity locally. Drought risk reduction measures include introducing more drought-resistant crops or livestock in at-risk regions, and establishing fodder banks and water reservoirs during periods of no drought.
Droughts can trigger a vicious circle wherein human well-being, the economy, and the environment spiral downwards fast. Without sufficient water for agricultural production, farmers lose their harvest and livelihoods, the population is exposed to higher food prices, and the most vulnerable face food insecurity. The need for more agricultural land to produce enough food under drought conditions can lead to deforestation, thus reducing the capacity of the environment to store water. If there is not enough water for personal hygiene, people get sick; if there is not enough safe drinking water, conflicts may arise.
The years 2017 and 2018 saw several exceptional water crises around the globe. Cape Town (South Africa) was counting down to Day Zero, the day when water taps would run dry in the city. The east coast of Australia recorded less than a fifth of its typical rainfall per season. The US drought monitor detected the highest level of drought severity in some central states. Farmers in Germany applied for government aid to overcome their financial losses due to lost harvests in the dry and hot summer. No single reason that can explain all these drought events; each has its own narrative. South Africa, for example, is experiencing the late impacts of an exceptional drought in the years 2015/2016 that was mainly triggered by the strongest recorded El Niño year (when warm surface temperature in the tropical Pacific Ocean brought warm and dry winds to Africa). In Cape Town, water levels in the reservoirs were continually decreasing due to high demand of the growing population combined with water losses due to leakages in the supply system and relatively dry weather conditions.
Those parts of the world that do not take preventive actions and to which drought will come as a surprise will be affected most. Countries and regions most at risk typically share the following characteristics: regions with a large share of degraded land, where the livelihoods of people depend on agriculture, where irrigation schemes cannot help to overcome lack of rain, and where resources and capacities are inadequate to cope with a drought. However, there are many different scenarios on how different parts of the world will be affected by droughts, ranging from the high-tech industrialised agricultural or energy sectors which can experience large-scale economic losses to small-scale farmers who fully depend on the farm income.
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This is an edited/slightly condensed version of 5 Facts on Drought which was published on the UNU-EHS website.