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What is drought?
Drought is a natural event that can occur nearly anywhere on earth, and is also one of the most common and severe of natural disasters. It occurs when there is less rainfall than average over an extended period of time. Droughts can have a substantial impact on the ecosystem and agriculture of the affected region. The severity of the drought depends upon the degree of moisture deficiency, the duration, different geographical features and human factors such as the demand for water that can exacerbate the impact that drought has on a region. In most world regions the economic damages caused by droughts are greater than those caused by any other events such as earthquakes and volcanic eruptions. World-wide population growth has intensified the demand on water resources and increased the vulnerability to drought. Drought is usually looked at in three perspectives- meteorological, agricultural and hydrological. A drought in terms of meteorology takes into account deficincies in measured precipitation. Each year the measurements are compared to what is determined as a "normal" amount of precipitation, and drought is determined from there. Agricultural drought is brought about when there is insufficient moisture for average crop or range production. This condition can arise, even during times of average precipitation, due to soil conditions or agricultural techniques. For hydrologists droughts are monitored by checking stream flow and lake, reservoir, and aquifer water levels, as well as precipitation as it contributes to the water levels. It is important that we are aware of drought as Australia is expected to experience more severe and frequent droughts in the future due to natural and human impacts.