Water is essential not only to survival but is also equally or even more important than nutrients in food production. Agriculture accounts for nearly 70% of the water consumption, with some estimates as high as 85% (Hanasaki et al., 2008a,b). Water scarcity will affect over 1.8 billion people by 2025 (WHO, 2007). This could have major impacts on health, particularly in rural areas, and thus also major impacts on farmer productivity. Althoug...

There is great potential to restore carbon in tropical agricultural soils through management practices that, in the right circumstances, can also increase productivity. Agroforestry can offer particularly large carbon gains, although it can increase water demand. Agricultural carbon sequestration policies will need to be tailored to particular circumstances to allow farmers to benefit.

Water overuse is damaging the environment in many major basins. High overuse tends to occur in regions heavily dependent on irrigated agriculture, such as the Indo-Gangetic Plain in south Asia, the North China Plain and the High Plains of North America, and in areas undergoing rapid urbanization and industrial development. An estimated 1.4 billion people now live in river basin areas that are ‘closed’ (in that water use exceeds minimum recharge l...

The bulk of water supply for Nairobi comes from Thika, Sasumua and Ruiru Dams, as well as the Kikuyu Springs. Over time water supply for the city has failed to meet demand. The current estimated water demand for Nairobi is 650 000 m3/day compared to the production of 482 940 m3/day (WRMA 2010). The difference between production and demand has been widening over time due to population growth, inadequacy of the carrying capacity of the distributio...