Most future increases in global demand for food are expected to arise by 2050. By that time, demand could increase by 2.5 to 3.0 times the present level. Given present knowledge about agricultural production, prospective global supplies of land, water, plant genetic, and climate resources will be insufficient to meet future demand at acceptable economic and environmental costs. Nor will extending natural resource supplies by increased conservation of these resources suffice. The only hope of sustainably meeting future food needs is through investment to expand knowledge of agricultural production and its environmental consequences.