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Modern agriculture accounts for 86% of the world’s water consumption. However, in regions where crops and livestock are actually cultivated, the rate of consumption often outstrips what local water sources can provide.
Empirical data suggest that it’s possible to use around only 30% of an area’s total annual renewable water resource (TARWAR) before acute water stress problems set in. According to projections modeled in our recent report, Malthus Returns, the total amount of water withdrawn for agricultural purposes is set to rise to 4,923 km3 by 2050 if all current agricultural practices are retained. In the regions where people live and grow food, the aggregate total annual renewable water resource (TARWAR) is 8,128 km3.
Translation: In 2050, agriculture’s demand for water could represent nearly twice what can be reasonably withdrawn in the areas where people live and grow food.
The solution, it would seem, requires 100% adoption of available technologies, such as those shown above. Although that would help bring agricultural water use closer to sustainable rates, it’s more feasible to project adoption rates of 25%. The results of such a scenario are sobering.
At a 25% adoption rate, these technologies will help reduce water consumption to 27% of TARWAR, which still brings agricultural water consumption uncomfortably close to the limits of sustainability. Figure in reservoir evaporation, and agricultural water withdrawals jump above sustainability to 36% of TARWAR.
Biofuels make the situation even worse. Included into the above water wedge analysis, biofuels push total agricultural water needs to 37% of TARWAR when reservoir evaporation is factored in.
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