Water security is the capacity of a population to ensure that they continue to have access to potable water. It is an increasing concern arising from population growth, drought, climate change, oscillation between El Nino and La Nina effects, urbanisation, salinity, upstream pollution, over-allocation of water licences by government agencies and over-utilisation of groundwater from artesian basins. Water security is rapidly declining in many parts of the world.According to the Pacific Institute, "While regional impacts will vary, global climate change will potentially alter agricultural productivity, freshwater availability and quality, access to vital minerals, coastal and island flooding, and more. Among the consequences of these impacts will be challenges to political relationships, realignment of energy markets and regional economies, and threats to security".It impacts regions, states and countries. Tensions exist between upstream and downstream users of water within individual jurisdictions.