Of the nearly 1.4 billion km³ of water covering the earth, fresh water represents merely 2.6% or 36 million km³. About one third of this amount circulates reasonably quickly and is thus referred to as hydrological cycle.
This may sound like a huge quantity but compared to the 146 million m³ of water consumed annually by, for example, the population of a metropolis like the Austrian capital Vienna, and assuming a 100 m³ per capita consumption, this seemingly large amount is virtually insigni cant. The per capita consumption is nearly twice as high in the United States and Canada.
While private households consume only 10%, agriculture is responsible for the bulk of almost two thirds of the global fresh water consumption and industry accounts for the remainder. Both of the latter sectors show a clear increase in consumption. Based on this data we can easily extrapolate that we will consume the entire circulating rainwater and thus no longer feed the natural aquifer storage system.
Equally distributed access to fresh water, which is important for health, should have top priority for decision-makers.