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.”

Flooding causes massive damage each year in South Asia, but this destruction will not be diminished without more comprehensive disaster preparedness, says a new report by Oxfam International entitled Sink or Swim: Why Disaster Risk Reduction is central to surviving floods in South Asia. The report comes halfway through a monsoon season that has already harmed the livelihoods of 20 million people in Bangladesh, Nepal, and India, crumbling homes and schools, sweeping away crops, and crippling the region’s already-weak infrastructure.

Current flood control efforts are often ineffective and can even exacerbate the problem, says the report. For instance, poorly designed and broken culverts and embankments often flood roads and downstream areas. One embankment in Bihar, India caused a flood-prone area to expand from 2.5 to 6.9 million hectares over the course of fifty years.

In the report, Oxfam recommends that governments implement local emergency plans; avoid building additional dams and embankments; equip communities with preparedness capacities such as early warning systems and first-aid skills; provide community assets such as flood shelters, raised homesteads, and motorized boats; and mainstream disaster preparedness into government policy. Furthermore, the report urges donors to increase funding for disaster risk reduction, which is a strong long-term investment.

Governments and NGOs should also note that lower-income groups and women are more vulnerable to disasters—and tailor their programs accordingly. Poorly built houses are easily destroyed, the landless have reduced access to post-flood aid, and women struggle with malnutrition and disease in displacement camps. Reducing disaster risk—especially for the most vulnerable members of the population—is an important step in raising the standard of living in South Asian countries afflicted by flooding.