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.

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 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 3 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, 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, Poland, in November, there was an emotional outpouring from countries that face existential threats, among them Bangladesh, which produces just 0.3 per cent 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 Centre 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 slightly bigger than the state of New York and as flat as chapati, the bread served at almost every meal.

A perilous position

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 per cent of the land and displace about 18 million people, Rahman said.

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, 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 7 feet above sea level - such an increase would have dire consequences, 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.”

Rahman said he did not disagree with Pethick’s findings, but 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 Calcutta, India, suggested that seas in the region could rise 5 to 6 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.” Karim estimated that as many as 50 million Bangladeshis would flee the country by 2050 if sea levels rose as expected.

The poverty of people like Khatun makes them particularly vulnerable to storms. When Cyclone Aila hit, Khatun was home with her husband, parents and four children.

A nearby berm collapsed, and their mud and bamboo hut washed away in minutes. Unable to save her belongings, Khatun put her youngest child on her back and, with her husband, fought through surging waters to a high road. Her parents were swept away.

In the village of Choto Jaliakhali, where Khatun lives, dozens of people said they could see that the river was rising. Several said they had been impoverished by erosion, which has cost many villagers their land.