Food

Globally, 85% of oyster beds had basically disappeared by early 2011, making oyster beds potentially the most severely impacted marine habitat in the world.

As global population increases and people become wealthier, agricultural production will need to likewise increase, but food systems may become more stressed because of competition for water.

The 2010 Global Hunger Index (GHI) showed some improvement over the 1990 GHI, falling by almost one-quarter.  Nonetheless, the index for hunger in the world remains at a level characterised as

700m or so extra people may move to cities by mid-century and may double or triple demand for health services, transport, energy, housing, sanitation, food and water.

Biofortification may help make staple foods - which provide millions of poor people with calories but which do not always contain enough of the micronutrients required for good health - more nutritious.

The UN has warned that commercial fishing could be destroyed globally within 50 years.