ABSTRACT
Groundtruth Points ........................................................................... 210 7.6 Next Steps ..................................................................................................... 212 References .............................................................................................................. 214
The global population has more than doubled in the past five decades, from 3 billion in 1959 to 6.6 billion in 2007 [1]. It is estimated that by 2025, one-third of the world’s population will face severe water shortages (see Ref. [2] and references therein), and to meet increased demands, the world’s water supply will need to increase by an additional 22% from 1995 use levels [3]. Considering that irrigation consumes about 60% of the world’s diverted freshwater resources [4], competition for water between irrigation, and municipal and industrial uses will only increase.
