Water: See Climate change. | Irrigation.

Significance70% of the Earth’s surface is covered by water. ‘The sea it represents is salty, accounting for 97.5% of all the water on Earth. A further 1.75% is frozen, at the poles, in glaciers or in permafrost. So the world has to rely on just 0.75% of the planet’s available water, almost all of which is subterranean groundwater, though it is from the 0.3% on the surface that it draws 59% of its needs. Just nine countries account for 60% of all available fresh water supplies,’ (The Economist, Special Report on Water, March 2nd 2019, p.5).