The world could face a global food crisis in the next 50 years, said experts at a recent UN-backed conference in Iceland on sustainable development. Their calculus is simple: In the coming half century, there will be more people on the planet, but rapid land degradation will make it difficult to produce commensurate increases in food. Warmer temperatures and more frequent floods, caused by climate change, will diminish soil fertility in many parts of the world—particularly in developing countries. As 800 million people are already at risk for hunger today, population growth alone is likely increase global food insecurity.

The expansion of biofuels could potentially exacerbate food shortages. A major UN report on biofuels warns that as more fields are devoted to producing corn, palm oil, sugar cane, and other agricultural products for use as biofuels, the amount of food that is produced for human consumption could decrease.

Climate change’s effects on marine ecosystems could also contribute to a food crisis. Changes in water temperature and salinity can damage coral reefs, which scientists estimate support between one-quarter and one-third of all marine life. In addition, a recent study published in Nature shows that phytoplankton—single-celled ocean plants that form the base of the marine food chain—are growing more slowly as the water at Earth’s mid and low latitudes becomes warmer. As the supply of phytoplankton becomes limited, fish have less food to eat, and at the end of the chain, human beings suffer from a scarcity of fish—a particularly dire situation in communities where fish is a primary source of food.

According to scientists at the Iceland forum, competition over scarce resources could lead to conflict. Studies on the relationship between environmental degradation and conflict indicate that such conflicts are likely to be intrastate and of low intensity. Scientists suggesting that food scarcity could trigger classic interstate wars, such as James Lovelock, who predicts that China and Russia will clash to exploit Siberia’s new fertile soils, are in the minority.

Yet policymakers should not be indifferent to food scarcity in developing countries merely because it is not likely to cause global-scale conflicts. Indeed, if the developing world faces more famines and malnutrition in the coming years, pressure on Western governments will be high to intervene.