The world’s climate-stressed and pollution-degraded farming and agricultural system must shift quickly to sustainable practices to feed an additional 2 billion mouths expected by 2050, a new United Nations report finds.

Almost 10% of the 8 billion people on earth are already undernourished with 3 billion lacking healthy diets, and the land and water resources farmers rely on stressed to “a breaking point.” And by 2050 there will be 2 billion more mouths to feed, warns a new report from the United Nations Food and Agriculture Organization (FAO).

For now, farmers have been able to boost agricultural productivity by irrigating more land and applying heavier doses of fertilizer and pesticides. But the report says these practices are not sustainable: They have eroded and degraded soil while polluting and depleting water supplies and shrinking the world’s forests. The FAO report discusses some important climate change impacts, such as changing distribution of rainfall, the suitability of land for certain crops, the spread of insects and other pests, and shorter growing seasons in regions affected by more intense droughts. While not the sole source of obstacles facing global agriculture, the report makes clear that climate change is further stressing agricultural systems and amplifying global food production challenges.