How to overcome water scarcity & achieve food security?

We are already surviving with around 1,700-1,800 cubic metres per year. We are soon going to be in a situation where there will be wars for water. Much of the prosperity in the last two decades is because of groundwater exploitation. As our demand for water has increased drastically over the years, per capita water availability has taken a beating. Change in food habits is also responsible for exploitation of this resource as more water is required to produce the kind of food we prefer nowadays.