Arguments over which type of farming will best meet growing food demands are ignoring the most critical factor - water availability - say analysts from the International Water Management Institute (IWMI). Agriculture currently uses 70 per cent of the freshwater available for human use and, according to the IWMI, unless there is a huge leap in water-use efficiency on farms worldwide, a 70 or 100 per cent increase in food production will require roughly twice the amount of water in use today.