We may be seven billion specks on the surface of Earth, but when you're in Bangladesh, it sometimes feels as if half the human race were crammed into a space the size of Louisiana. Dhaka, its capital, is so crowded that every park and footpath has been colonized by the homeless. To stroll here in the mists of early morning is to navigate an obstacle course of makeshift beds and sleeping children. Later the city's steamy roads and alleyways clog with the chaos of some 15 million people, most of them stuck in traffic. Amid this clatter and hubbub moves a small army of Bengali beggars, vegetable sellers, popcorn vendors, rickshaw drivers, and trinket salesmen, all surging through the city like particles in a flash flood. The countryside beyond is a vast watery floodplain with intermittent stretches of land that are lush, green, flat as a parking lot—and wall-to-wall with human beings. In places you might expect to find solitude, there is none. There are no lonesome highways in Bangladesh.
We should not be surprised. Bangladesh is, after all, one of the most densely populated nations on Earth. It has more people than geographically massive Russia. It is a place where one person, in a nation of 164 million, is mathematically incapable of being truly alone. That takes some getting used to.
So imagine Bangladesh in the year 2050, when its population will likely have zoomed to 220 million, and a good chunk of its current landmass could be permanently underwater. That scenario is based on two converging projections: population growth that, despite a sharp decline in fertility, will continue to produce millions more Bangladeshis in the coming decades, and a possible multifoot rise in sea level by 2100 as a result of climate change. Such a scenario could mean that 10 to 30 million people along the southern coast would be displaced, forcing Bangladeshis to crowd even closer together or else flee the country as climate refugees—a group predicted to swell to some 250 million worldwide by the middle of the century, many from poor, low-lying countries.
"Globally, we're talking about the largest mass migration in human history," says Maj. Gen. Muniruzzaman, a charismatic retired army officer who presides over the Bangladesh Institute of Peace and Security Studies in Dhaka. "By 2050 millions of displaced people will overwhelm not just our limited land and resources but our government, our institutions, and our borders." Muniruzzaman cites a recent war game run by the National Defense University in Washington, D.C., which forecast the geopolitical chaos that such a mass migration of Bangladeshis might cause in South Asia. In that exercise millions of refugees fled to neighboring India, leading to disease, religious conflict, chronic shortages of food and fresh water, and heightened tensions between the nuclear-armed adversaries India and Pakistan.
Such a catastrophe, even imaginary, fits right in with Bangladesh's crisis-driven story line, which, since the country's independence in 1971, has included war, famine, disease, killer cyclones, massive floods, military coups, political assassinations, and pitiable rates of poverty and deprivation—a list of woes that inspired some to label it an international basket case. Yet if despair is in order, plenty of people in Bangladesh didn't read the script. In fact, many here are pitching another ending altogether, one in which the hardships of their past give rise to a powerful hope.
For all its troubles, Bangladesh is a place where adapting to a changing climate actually seems possible, and where every low-tech adaptation imaginable is now being tried. Supported by governments of the industrialized countries—whose greenhouse emissions are largely responsible for the climate change that is causing seas to rise—and implemented by a long list of international nongovernmental organizations (NGOs), these innovations are gaining credence, thanks to the one commodity that Bangladesh has in profusion: human resilience. Before this century is over, the world, rather than pitying Bangladesh, may wind up learning from her example.
More than a third of the world's people live within 62 miles of a shoreline. Over the coming decades, as sea levels rise, climate change experts predict that many of the world's largest cities, including Miami and New York, will be increasingly vulnerable to coastal flooding. A recent study of 136 port cities found that those with the largest threatened populations will be in developing countries, especially those in Asia. Worldwide, the two cities that will have the greatest proportional increase in people exposed to climate extremes by 2070 are both in Bangladesh: Dhaka and Chittagong, with Khulna close behind. Though some parts of the delta region may keep pace with rising sea levels, thanks to river sediment that builds up coastal land, other areas will likely be submerged.
But Bangladeshis don't have to wait decades for a preview of a future transformed by rising seas. From their vantage point on the Bay of Bengal, they are already facing what it's like to live in an overpopulated and climate-changed world. They've watched sea levels rise, salinity infect their coastal aquifers, river flooding become more destructive, and cyclones batter their coast with increasing intensity—all changes associated with disruptions in the global climate.
On May 25, 2009, the people of Munshiganj, a village of 35,000 on the southwest coast, got a glimpse of what to expect from a multifoot rise in sea level. That morning a cyclone, called Aila, was lurking offshore, and its 70-mile-an-hour winds sent a storm surge racing silently toward shore, where the villagers, unsuspecting, were busy tending their rice fields and repairing their nets.
Shortly after ten o'clock Nasir Uddin, a 40-year-old fisherman, noticed that the tidal river next to the village was rising "much faster than normal" toward high tide. He looked back just in time to see a wall of brown water start pouring over one of the six-foot earthen dikes that protect the village—its last line of defense against the sea.
Within seconds water was surging through his house, sucking away the mud walls and everything else. His three young daughters jumped onto the kitchen table, screaming as cold salt water swirled around their ankles, then up to their knees. "I was sure we were dead," he told me months later, standing in shin-deep mud next to a pond full of stagnant green water the color of antifreeze. "But Allah had other plans."
As if by a miracle, an empty fishing boat swept past, and Uddin grabbed it and hoisted his daughters inside. A few minutes later the boat capsized, but the family managed to hang on as it was tossed by waves. The water finally subsided, leaving hundreds of people dead along the southwest coast and thousands homeless. Uddin and most of his neighbors in Munshiganj decided to hunker down and rebuild, but thousands of others set out to start a new life in inland cities such as Khulna and Dhaka.