Due to technical development and sharp population increase, the global groundwater balance has been negative since at least 1900. Groundwater abstraction between 1965-2010 tripled to 986 km3. As a consequence, resources like the Australian Artesian Basin were depleted. Groundwater must be seen as resource in transition. In general, its level fell due to pumping and the sealing of large surfaces, causing them to become impervious to infiltrating water. Groundwater deterioration occurred due to excess pumping, resulting in salinisation. Groundwater contamination occurred because of leaking toxic liquid waste at nuclear repositories; leaking unconfined, tailings containing residual heavy metals, sulphuric acid, and cyanide; dispersed PCBs; industrial waste dumped in abandoned mine workings; injection of residual salt brines and liquid radioactive waste underground; and excess utilisation of artificial fertilisers and manure in industrial agriculture, resulting in elevated NO3 - -concentrations in groundwater wells. Example: Widespread decreasing groundwater availability and quality, as well as groundwater level fall, in China due to overuse for domestic, agricultural, and industrial demand. Groundwater protection measures improved the situation locally. In general, climate change-induced water scarcity can only be temporarily compensated by technology.
Keywords: Aquifer, Brine injection, Contaminant transport, Contamination, Groundwater abstraction, Groundwater protection, Pollution, Quality standards, Reactive nitrogen, Resource depletion, Salinisation, Transitional resource.