Climate change is one of the greatest threats to human lives and livelihoods in coastal regions all over the world. It will significantly aggravate existing hazards such as flooding from cyclones and storm surges. Other climate-induced risks, including sea level rise, salinity intrusion, drought, and temperature and rainfall variations, are becoming serious threats to food, water, energy, and health security for humankind.

The coastal countries of the Indian Ocean region from East Africa to Southeast Asia are highly vulnerable to climate change. Many are especially endangered because of their geographic location and topography. Bangladesh and Vietnam, for example, are predicted to be among the most substantially affected countries in the world because of the large portion of their populations living in major river deltas exposed to sea level rise. In Bangladesh, the shallow and funnel-shaped Bay of Bengal intensifies cyclones and storm surges, increasing their impact on the country’s low-lying coastal plains. Tropical cyclones hit Bangladesh some 29 times in the second half of the last century, with one of the most devastating taking 138,000 lives in April 1991.

Additional factors—including excessive population growth, poverty, lack of awareness of climate risks, and unplanned urbanization—make the region all the more susceptible to climate-induced extreme events. Currently, about 20 percent of South Asia’s population lacks access to water services, and more than 27 percent are without adequate food. Climate change and climate variability threaten to push these figures even higher in a number of countries in the region. A 5-meter rise in sea level, for instance, would submerge 11 percent of the productive land of Bangladesh and displace over 30 million people. Even at lesser amounts of sea level rise, saline intrusion into both soil and freshwater could force millions of people from their homes in search of safe water for drinking and other uses.