A woman stood where her house was before Cyclone Aila destroyed it in 2009. Scientists expect rising sea levels to submerge 17 percent of Bangladesh's land and displace 18 million people in the next 40 years. Photo: Kadir van Lohuizen / The New York Times

By Gardiner Harris
28 March 2014 DAKOPE, Bangladesh (The New York Times) – When a powerful storm destroyed her riverside home in 2009, Jahanara Khatun lost more than the modest roof over her head. In the aftermath, her husband died and she became so destitute that she sold her son and daughter into bonded servitude. And she may lose yet more. Ms. Khatun now lives in a bamboo shack that sits below sea level about 50 yards from a sagging berm. She spends her days collecting cow dung for fuel and struggling to grow vegetables in soil poisoned by salt water. Climate scientists predict that this area will be inundated as sea levels rise and storm surges increase, and a cyclone or another disaster could easily wipe away her rebuilt life. But Ms. Khatun is trying to hold out at least for a while — one of millions living on borrowed time in this vast landscape of river islands, bamboo huts, heartbreaking choices and impossible hopes.As the world’s top scientists meet in Yokohama, Japan, this week, at the top of the agenda is the prediction that global sea levels could rise as much as three feet by 2100. Higher seas and warmer weather will cause profound changes. Climate scientists have concluded that widespread burning of fossil fuels is releasing heat-trapping gases that are warming the planet. While this will produce a host of effects, the most worrisome may be the melting of much of the earth’s ice, which is likely to raise sea levels and flood coastal regions. Such a rise will be uneven because of gravitational effects and human intervention, so predicting its outcome in any one place is difficult. But island nations like the Maldives, Kiribati and Fiji may lose much of their land area, and millions of Bangladeshis will be displaced. “There are a lot of places in the world at risk from rising sea levels, but Bangladesh is at the top of everybody’s list,” said Rafael Reuveny, a professor in the School of Public and Environmental Affairs at Indiana University at Bloomington. “And the world is not ready to cope with the problems.” The effects of climate change have led to a growing sense of outrage in developing nations, many of which have contributed little to the pollution that is linked to rising temperatures and sea levels but will suffer the most from the consequences. At a climate conference in Warsaw in November, there was an emotional outpouring from countries that face existential threats, among them Bangladesh, which produces just 0.3 percent of the emissions driving climate change. Some leaders have demanded that rich countries compensate poor countries for polluting the atmosphere. A few have even said that developed countries should open their borders to climate migrants. “It’s a matter of global justice,” said Atiq Rahman, executive director of the Bangladesh Center for Advanced Studies and the nation’s leading climate scientist. “These migrants should have the right to move to the countries from which all these greenhouse gases are coming. Millions should be able to go to the United States.” River deltas around the globe are particularly vulnerable to the effects of rising seas, and wealthier cities like London, Venice and New Orleans also face uncertain futures. But it is the poorest countries with the biggest populations that will be hit hardest, and none more so than Bangladesh, one of the most densely populated nations in the world. In this delta, made up of 230 major rivers and streams, 160 million people live in a place one-fifth the size of France and as flat as chapati, the bread served at almost every meal. Though Bangladesh has contributed little to industrial air pollution, other kinds of environmental degradation have left it especially vulnerable. Bangladesh relies almost entirely on groundwater for drinking supplies because the rivers are so polluted. The resultant pumping causes the land to settle. So as sea levels are rising, Bangladesh’s cities are sinking, increasing the risks of flooding. Poorly constructed sea walls compound the problem. The country’s climate scientists and politicians have come to agree that by 2050, rising sea levels will inundate some 17 percent of the land and displace about 18 million people, Dr. Rahman said. Bangladeshis have already started to move away from the lowest-lying villages in the river deltas of the Bay of Bengal, scientists in Bangladesh say. People move for many reasons, and urbanization is increasing across South Asia, but rising tides are a big factor. Dr. Rahman’s research group has made a rough estimate from small surveys that as many as 1.5 million of the five million slum inhabitants in Dhaka, the capital, moved from villages near the Bay of Bengal. The slums that greet them in Dhaka are also built on low-lying land, making them almost as vulnerable to being inundated as the land villagers left behind. Ms. Khatun and her neighbors have lived through deadly cyclones — a synonym here for hurricane — and have seen the salty rivers chew through villages and poison fields. Rising seas are increasingly intruding into rivers, turning fresh water brackish. Even routine flooding then leaves behind salt deposits that can render land barren. Making matters worse, much of what the Bangladeshi government is doing to stave off the coming deluge — raising levees, dredging canals, pumping water — deepens the threat of inundation in the long term, said John Pethick, a former professor of coastal science at Newcastle University in England who has spent much of his retirement studying Bangladesh’s predicament. Rich nations are not the only ones to blame, he said. In an analysis of decades of tidal records published in October, Dr. Pethick found that high tides in Bangladesh were rising 10 times faster than the global average. He predicted that seas in Bangladesh could rise as much as 13 feet by 2100, four times the global average. In an area where land is often a thin brown line between sky and river — nearly a quarter of Bangladesh is less than seven feet above sea level — such an increase would have dire consequences, Dr. Pethick said. “The reaction among Bangladeshi government officials has been to tell me that I must be wrong,” he said. “That’s completely understandable, but it also means they have no hope of preparing themselves.” Dr. Rahman said that he did not disagree with Mr. Pethick’s findings, but that no estimate was definitive. Other scientists have predicted more modest rises. For example, Robert E. Kopp, an associate director of the Rutgers Energy Institute at Rutgers University, said that data from nearby Kolkata, India, suggested that seas in the region could rise five to six feet by 2100. “There is no doubt that preparations within Bangladesh have been utterly inadequate, but any such preparations are bound to fail because the problem is far too big for any single government,” said Tariq A. Karim, Bangladesh’s ambassador to India. “We need a regional and, better yet, a global solution. And if we don’t get one soon, the Bangladeshi people will soon become the world’s problem, because we will not be able to keep them.” Mr. Karim estimated that as many as 50 million Bangladeshis would flee the country by 2050 if sea levels rose as expected. [more]

Facing Rising Seas, Bangladesh Confronts the Consequences of Climate Change