Decreasing water levels in the river Po are putting Italian agricultural production at risk, according to a new study by environmental protection agency APAT. Water levels in the 675 km-long river have fallen by 20-25 per cent in the last 30 years due to global warming, which is responsible for increased evaporation from the river as well as for farmers needing to siphon off more water for crops. Rainfall in the Po valley has decreased by 15-20 per cent since 1987. APAT said there is a danger that the river will stop short of its mouth around the Ferrara area, which would result in salt water from the Adriatic sweeping up the valley. According to farmers