Flooded houses south of Dhaka, Bangladesh
Covered by a vast network of 300 waterways, including the Ganges, Brahmaputra, and Meghna Rivers, which descend the slopes of the Himalayas to the Bay of Bengal, Bangladesh is a delta plain that is subject to seasonal monsoons. In 1970s, two-thirds of the country remained under water for several months following the worst floods of the century that claimed half million deaths. Bangladesh suffers monsoon floods almost every year. The worst floods in 15 years swept the country in 2004, killing more than 1,000 people and making millions homeless. A rising sea level, possibly caused by global warming, will only aggravate the difficulties of this country, and may lead to permanent flooding of a considerable portion of its rice fields. Before 2020, 20 million people might have to leave their country because of flooding.