Food Security Under Climate Change

Some of the most profound and direct impacts of climate change over the next few decades will be on agricultural and food systems. On page 607 of this issue, Lobell et al. (1) show that increasing temperatures and declining precipitation over semiarid regions are likely to reduce yields for corn, wheat, rice, and other primary crops in the next two decades. These changes could have a substantial impact on global food security.

Since the 1990s, rising commodity prices and declining per capita cultivated area have led to decreases in food production, eroding food security in many communities (2). Many regions that lack food security rely on local agricultural production to meet their food needs. Primarily tropical and subtropical, these regions are substantially affected by both global climate variations and global commodity price fluctuations. Warming in the Indian Ocean (3) and an increasingly "El Nino-like" climate (4) could reduce main-season precipitation across parts of the Americas, Africa, and Asia (see the figure).

In food-insecure regions, many farmers both consume their product and sell it in local markets. This exposes farmers to climate variations, because when they produce less their income goes down while their costs go up to maintain basic consumption. Large-scale hunger can ensue, even when there is sufficient food in the market that has been imported from elsewhere.

Prioritizing Climate Change Adaptation Needs for Food Security in 2030

Investments aimed at improving agricultural adaptation to climate change inevitably favor some crops and regions over others. An analysis of climate risks for crops in 12 food-insecure regions was conducted to identify adaptation priorities, based on statistical crop models and climate projections for 2030 from 20 general circulation models. Results indicate South Asia and Southern Africa as two regions that, without sufficient adaptation measures, will likely suffer negative impacts on several crops that are important to large food-insecure human populations. We also find that uncertainties vary widely by crop, and therefore priorities will depend on the risk attitudes of investment institutions.

¹ Food Security and Environment Program, Woods Institute for the Environment and the Freeman Spogli Institute for International Studies, Stanford University, Stanford, CA 94305, USA.
² Lawrence Livermore National Laboratory (LLNL), Livermore, CA 94550, USA.
³ National Center for Atmospheric Research, Boulder, CO 80305, USA.
⁴ Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA.

For more see: http://www.sciencemag.org/cgi/content/full/319/5863/607