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.

Climate change has been altering the world’s geography so rapidly that cartographers can hardly keep up. The prestigious Times Comprehensive Atlas of the World was last published in 2003, and in preparation for the release of the 12th edition this year, coastlines, lakes, forests, and cities have had to be redrawn.

The Aral Sea in Central Asia has shrunk by 75 percent in 40 years, while Lake Chad in Africa is only 5 percent of its 1963 size. Furthermore, during certain times of the year, the Rio Grande, Colorado, Yellow, and Tigris rivers fail to reach the sea.

The 12th edition of the atlas contains approximately 20,000 updates. Naturally, not all the updates are consequences of climate change: 3,500 are simply name changes, and not every geographic update is the result of climate change. Also, not all the geographic changes occurred during the last four years—some happened earlier, but are only now being noticed by mapmakers, who are becoming increasingly aware of climate change-related geographical changes.

Some changes were previously unknown because they were happening in isolated parts of the world. In India, for instance, official records list 102 islands in the Sunderbans, where the Ganges and Brahmaputra rivers empty into the Bay of Bengal. Those islands are inhabited by 1.8 million people. However, after a six-year study, scientists have been able to map only 100 islands, finding that the other two had been swallowed up by the sea, said Sugata Hazra, director of Calcutta’s School of Oceanography Studies at Jadavpur University. Scientists estimate that the submersion of the two islands rendered approximately 10,000 people homeless.

Rising sea levels—which threaten to submerge some 12 additional islands in the Sunderbans—are sometimes perceptible to the human eye. In Bangladesh, many islands disappear each year, forcing populations to migrate from island to island and to live in extremely precarious conditions. As Shahidul Mullah, who lives with his family on a small island in Bangladesh, told Spiegel Online, “When I moved here, we still had three fields in front of the house. Now there are only two. I’m afraid the water will take another piece away from me this year.”