A Water Abundance Revolution
Water covers 71% of
the Earth's surface, and is vital for all known forms of life. On Earth,
it is found mostly in oceans and other large water bodies, with 1.6% of
water below ground in aquifers and 0.001% in the air as vapor, clouds
(formed of solid and liquid water particles suspended in air), and
precipitation. Oceans hold 97% of surface water, glaciers and polar ice
caps 2.4%, and other land surface water such as rivers, lakes and ponds
0.6%. A very small amount of the Earth's water is contained within
biological bodies and manufactured products.
Water security and climate change
Climate change will affect the water security of developing countries. Freshwater is a scarce resource. Only 2.5 per cent of the 1.4 billion km3
of water on Earth is freshwater fit for human consumption, and most of
this is inaccessible — nearly 70 per cent is locked up in glaciers, snow
and ice. Our greatest source of freshwater is the 8 million km3 of groundwater, with only 0.3 per cent of freshwater (105,000 km3) being found in rivers, streams and lakes.
Discussions about
freshwater availability increasingly focus on water security, which
refers to people's access to enough safe and affordable water to satisfy
their needs for household use, food production and livelihoods.
Water insecurity can
arise from physical scarcity, resulting either from climatic or
geographical factors, or from unsustainable consumption or over exploitation. It can also have economic origins, with poor
infrastructure or capacity preventing access to the water resources
available, or occur where pollution or natural contamination renders
water resources inaccessible.
Water insecurity and
scarcity already affect large parts of the developing world. The past
century has seen a sixfold increase in global water demand. Nearly three
billion people (about 40 per cent of the global population) live in
areas where demand outstrips supply.
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