A drought is a period of drier-than-normal conditions.A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy. Drought is a recurring feature of the climate in most parts of the world, becoming more extreme and less predictable due to climate change, which dendrochronological studies date back to 1900. Environmental effects include the drying of wetlands, more and larger wildfires, loss of biodiversity. Prolonged droughts have caused mass migrations and humanitarian crisis. According to National Integrated Drought Information System, a multi-agency partnership, drought is generally defined as “a deficiency of precipitation over an extended period of time (usually a season or more), resulting in a water shortage”. The National Weather Service office of the NOAA defines drought as "a deficiency of moisture that results in adverse impacts on people, animals, or vegetation over a sizeable area".

圖片編號： 298309213
拍攝者： Natureheart