Please note that as with other resource problems like soil, there is a
demographic trap that limits the effectiveness of relying only on conservation
and technological strategies. We can substantially conserve existing supplies
and increase efficiency, but, given the nature of the hydrological cycle, we
cannot expand the total supply much. In view of the relatively fixed human
and agricultural needs for water use, how will we manage water sufficiency
during the next decades, when human population undoubtedly will pass the
six billion mark and the need for water increases as affluence spreads?