CAMBRIDGE – Around the world, demand for fresh water doubles every 20 years, owing to increasing population and affluence. Yet pollution, climate change, and seawater intrusion are diminishing supplies of fresh water at similar rates. So, is a global fresh water crisis looming?
Fortunately, the situation appears to be less alarming. This is not to deny that the supply of fresh water is getting tight. Left unattended, major disruptions for human society could occur.
Many argue that water is different from resources such as oil, because there are often no substitutes for water in most uses (particularly growing food). Moreover, water is an essentially fixed resource, albeit one that renews itself every year.
There are prodigious quantities of water on the globe, but most of it is salty ocean water and brackish groundwater. There are huge resources of fresh water, but most is in ice sheets and glaciers, with only a small percentage readily available where and when we need it. The supply of water is also highly variable across regions and within countries, with floods and droughts occurring at irregular times.