A quarter of farmland is highly degraded, according to the first report into the state of the world's land resources

The threat posed to crop production by plant pests and diseases is one the key factors that could lead to "a perfect storm" that threatens to destabilise global food security.

Already, the biological threat accounts for about a 40% loss in global production and the problem is forecast to get worse, scientists warn.

BBC News has asked Dr Matthew Cock, chief scientist for Cabi, a UK-based agri-environment research organisation, to compile a list of the worst plant pests threatening crops around the world.

Droughts and rising sea levels could reverse efforts to improve living conditions of world's poorest people, report warns

Unchecked environmental destruction will halt – or even reverse – the huge improvements seen in the living conditions of the world's poorest people in recent decades, a major new UN report warned on Wednesday.

LONDON, Oct 17 (Reuters) - The Earth's natural resources like food, water and forests are being depleted at an alarming speed, causing hunger, conflict, social unrest and species extinction, experts at a climate and health conference in London warned on Monday.

Increased hunger due to food yield changes will lead to malnutrition; water scarcity will deteriorate hygiene; pollution will weaken immune systems; and displacement and social disorder due to conflicts over water and land will increase the spread of infectious diseases, they said.

Trying to tap into the best thinking about the future of global agriculture, as I have tried to do in my work as a reporter, can be an exercise in frustration. Many groups and many bright people go at the problem, but not many of them go at it in a holistic way.