The UN Food and Agriculture Organisation (FAO) estimates that farmers will have to produce 70% more food by 2050 to meet the needs of theworld's expected 9-billion-strong population. That amounts to 1bn tonnes more wheat, rice and other cereals and 200m more tonnes of beef and other livestock.
But as it is, most available farmland is already being farmed, and in ways that decrease its productivity through practices that lead to soil erosion and wasting of water.
This means that to meet the world's future food needs, a major "sustainable intensification" of agricultural productivity on existing farmland will be necessary, the FAO said in its report, State of the World's Land and Water Resources for Food and Agriculture.
...the UN report found that 25% of the world's farmland was now "highly degraded" with soil erosion, water degradation and biodiversity loss. Another 8% was moderately degraded, while 36% was stable or slightly degraded and 10% was ranked as "improving".
The rest of the Earth's surface is either bare or covered by inland water bodies.
...The report found that water around the world was becoming ever more scarce and salinated, while groundwater was becoming more polluted by agricultural runoff and other toxins.