UN warning over future of crop growing
29 November 2011 Last updated at 03:30 GMT
The world may not be able to properly feed itself by 2050 - that is the stark warning from a UN report which suggests a quarter of the world's land surface is now severely degraded and may not be able to grow enough crops for a rising population.
The report blames a combination of climate change and poor farming practices.
Bill Hayton reports.