Philippine irrigation investment under climate change: Scenarios, economic returns, and impacts on food security

Three broad strategies in the agricultural water sector can be used to address the challenge posed by climate change: (1) increasing the supply of water for irrigation through investment in infrastructure; (2) conserving water and improving the efficiency of water use in existing systems; and (3) improving crop productivity per unit of water and land through integrated water management and agricultural research and policy efforts (Rosegrant, 2015). This paper analyzes in detail the first strategy for the Philippines, together with a brief comparison with the third strategy. The alternative irrigation investment scenarios also assess different regional allocation rules, expansion targets, and investment costs. Results show that on all the economic and food security outcomes, at the lower irrigation cost estimate of US$3,500/ha, irrigation development has a higher positive impact compared with investment in varietal and seed development and farm level technology. But at higher irrigation cost levels, the varietal and seed and farm level technologies can have higher rates of return, and it would be preferable to shift some of the investment to these other development strategies. If the costs of new irrigation can be kept relatively low, faster irrigation development would make a major contribution to agricultural development and food security in the Philippines. © 2018 by De La Salle University