To this day, nearly a quarter-century after he left, Loknath Das is afraid to return to the village where he was born.
The reason he gives is one heard throughout this corner of India, where Himalayan peaks give way to fertile flood plains: Immigrants from Bangladesh are taking over.
It is a visceral fear in India's Northeast, where people say they feel under siege – their culture, politics, and security threatened by a tide of Bangladeshis who are here illegally. "On the surface there is peace," says Mr. Das, who says he was forced out of his village through intimidation and murders by immigrants. "But this migration is a tragedy for us."
For now, there is relative calm. But security analysts worry that unrest could flare up again because of a new threat: global warming. As negotiators gather in Bali, Indonesia, this week to begin work on an agreement to fight climate change worldwide, concern is mounting that altered weather patterns will stoke conflict in various parts of the globe.
And this area of South Asia sits atop most experts' watch lists.
Bangladesh is not only one of the countries most vulnerable to climate change, it is also chronically unstable. It is in the midst of a political crisis and showing signs of nascent Islamist fundamentalism. The effects of global warming could amplify the forces of instability, experts say.
That remains an extreme view. The clearest threat, most agree, is a mass migration that sparks renewed conflict in the Indian Northeast – an independent-minded area of mountains and jungles fiercely proud of its distinct heritage and already fretted by a dozen insurgencies.
"It is the No. 1 conflict zone for climate change," says Peter Schwartz, chairman of the Monitor Group, a research firm in San Francisco that recently released a study on the security risks presented by climate change.
That field of study is relatively new, but analysts are beginning to lay the map of forecasted climate change over the map of political weakness to see where changes in weather could lead to volatility. No one argues that climate change alone will lead to war. But analysts suggest that it could be a pivotal factor that tips vulnerable regions toward conflicts.
"Climate change is a threat multiplier," says Geoff Dabelko, director of the Environmental Change and Security Program at the Woodrow Wilson Institute in Washington. "It's not that it creates a whole new set of problems, it's that it will make things that are already a problem worse."
For that reason, few expect climate change to throw Europe or North America into chaos. Both have the political stability and economic resources to cope. Areas that lack these advantages – such as sub-Saharan Africa, Latin America, and South Asia – are most at risk, experts say.
History suggests that climate can help breed political instability. One recent study charted climate changes, wars, and several other variables back to the 1400s. It found that significantly cooler periods were characterized by large-scale crop loss, starvation, and conflict.
Stronger storms predicted
"There was certainly a discernible effect," says Peter Brecke, an associate professor at the Georgia Institute of Technology in Atlanta and coauthor of the study, published in Proceedings of the National Academy of Sciences.
Earth today is warming, not cooling. But "the model is such that if you apply it with warmer climate, you should see similar effects," Professor Brecke says.
The scenario for Bangladesh requires little imagination:
•It is a frequent target of severe weather. During the worst floods, one-third of the country can be submerged. Last month's cyclone Sidr was an example of the kind of storms many scientists say will become more frequent in the future. Aid groups say the death toll in Bangladesh from Sidr could reach 10,000.
•Most of Bangladesh is flat and coastal, meaning that a sea-level rise of only three feet could consume 10 percent of the country, experts say.
•Bangladesh is the delta for several major river systems. They are fed by runoff from the Himalayan Mountains and provide the country with its fresh water. As Himalayan glaciers warm and melt, the rivers are expected to flood more in the short term. Later, as the glaciers disappear, they will become drier, which could lead to fresh water shortages.
"This is a very precarious piece of geography," says Adil Najam, one of the lead authors of the last two reports from the UN-sponsored Intergovernmental Panel on Climate Change. "What we are talking about is an intensification of this to levels taking it even more out of control."
Even now, many Bangladeshis cannot cope. Last month, Selim Hossain Howladar's home vanished, swept away by the 150-m.p.h. winds of cyclone Sidr. "I have seen so many cyclones in my lifetime, but I have never seen anything that could flatten entire villages like it has done this time," says Mr. Howladar, a fisherman from the village of coastal village of Sarankhola.
Where Howladar's house used to be is now just a clearing. The trawler he bought last year with a loan was torn to pieces by the storm. "I don't even have a fishing net," he says. "What can I do but move to the city?"
In the north of the country, the story is the same. Three years ago, 25 Hindu families lived in the border village of Itapota. Now only one remains. Floods have driven off the rest, who are looking for work across the border in India.
"When you have nothing left to lose, does it matter where you live?" asks Haripada, patriarch of the last remaining Hindu family in his village. "You live where you think you might find work and earn some money."
Evidence suggests that current migration is mostly toward the capital, Dhaka, but people from border districts are increasingly going to India for seasonal employment.
"Bangladesh is so densely populated," says Ainun Nishat, head of the World Conservation Union office in Bangladesh, "as climate-change impacts cause food shortages and lack of employment, desperation will drive people far afield to seek out a means of survival."
The population shifts could exacerbate security issues beyond Bangladesh's borders.
For now, Bangladesh's Islamists are largely confined to a narrow band of remote hills in the extreme southeast. But if global warming creates more "dead land" – abandoned because it has been made infertile by sea-level rise, it could "create space for [terrorists] to operate," says Peter Ogden of the Center for American Progress, who cowrote a study titled "The Security Implications of Climate Change."
More stress for a stressed nation
That would be an unwelcome development for a country frequently under duress. In its 36 years of independence, Bangladesh has had 14 governments – four of which were replaced by military coups. The current government is again under military stewardship, with civilian leaders being rounded up on corruption charges.
"This is an added stress on a country that doesn't necessarily have the capacity" to deal with it, Mr. Ogden says.
More certainly any increase in migration will increase competition for land, water, and jobs. In India, the border district of Dhubri is already being pushed to its limits. Many of the environmental trends that stress Bangladesh are present here, too. For instance, Dhubri is losing huge swaths of land each year to the wandering course of the Brahmaputra River.
Like many in Bangladesh, Ramzan Ali has lost his livelihood because of it. He squats on an embankment of silt above what used to be his farmland. Today it is under water. Of the four acres he once had, he now has less than one, and that is fallow because of siltation. The family's only income comes from his son, who works in a mill in Dhubri town.
Squeezed by erosion and the arrival of Bangladeshi migrants, other families have had to move upriver permanently – where, ironically, they, too, are seen by the people there as Bangladeshis. According to recent voting records, 99 percent of the residents in the area nearest the Bangladeshi border are migrants.
"Our land is shrinking," says Abdul Hamid Sheikh, standing in a shallow skiff that ferries locals to the river island of Bhasani Char. "If this migration continues, it will affect us, too."
Experts expect the effects to intensify as global warming intensifies, with more Bangladeshis being forced into India.
The fear is that this fate awaits every state in the Northeast. In the wake of the turmoil of Bangladeshi independence in 1971, one state, Tripura, saw its indigenous people consigned to a minority by Bangladeshi refugees. In India, virtually every state has its own lineage of kings, literary heritage, and language. Migration threatens to extinguish local cultures. This has made the people of the Northeast fierce guardians of their cultural identity.
On one hand, it has given rise to numerous anti-Indian, pro-independence insurgencies. On the other, it has created a climate of paranoia about Bangladesh, a country of 150 million people packed into an area roughly the size of Iowa.
For this reason, the debate about Bangladeshi migration here is often based not on fact or reasoned analysis, but "on conjecture and perception," says R.N. Mathur, director-general of police in Assam, the state at the heart of the Northeast – and the migration debate. "The issue is mainly political."
Politicians stoke local fears
And politicians have used it, stoking local fears and heightening tensions.
"This [migration] is a design," says Prafulla Mahanta, a member of the state assembly of Assam and one of the leaders of Assam's antimigrant protests during the 1980s. "Their aim is to convert Assam into an Islamic state."
Police official Mr. Mathur has not seen evidence of this. The Bangladesh border has been a corridor for small numbers of terrorists to enter India, security officials say – a primary reason for the construction of a 2,100-mile fence. But migration and security "are separate issues," he says.
Militants have not found haven among migrant communities, he adds: "They are not using areas of Assam as a base of terror operations."
The depth of the distrust is compounded by the almost total isolation of the two communities from each other. Sitting on his porch amid the primary colors of Dhing's British-era bungalows, D.N. Hazarika says that he does not know what to make of the "many new faces."
"The newspapers are always telling us that they are coming with weapons in their hands, and the government always says that they are up to something," says the former high school principal with equal measures of consternation and confusion. "But I cannot give you any proof."
"We do not know where they come from," he adds. "What is their ambition?"
The divide is not the traditional Indian divide: Hindus versus Muslims. Like Mr. Hazarika, few in Assam draw any distinction between the Hindus and Muslims who have been here for generations. The concern surrounds Muslims who are more Bengali in custom and speech – and who, it is feared, will usurp the Assamese, either by migration or higher birthrates.
At this point, the potential for global warming to add to the trend has not reached the streets. "I have not come across views on this subject at all," says Mathur, the police official.
Memories of killings
But the past offers a window into what happened the last time the Assamese felt in danger of being overwhelmed by Bangladeshis. In 1983, at the height of a six-year antimigrant campaign of protests and strikes, a band of Assamese killed some 3,000 Muslims believed to be Bangladeshi migrants.
For Loknath Das and other former residents of the riverside village of Sutargaon, though, 1983 brings back different memories. It was the year that they say migrants killed Chandra Kanta Das as he walked back to his home alone. Within two years, all the original villagers had fled.
Tonu Ram Das, another displaced resident, points out landmarks in the village: the pond where he fished as a boy; the place where his house stood – now two shacks by a stand of bamboo; his family's farmland, where he harvested rice and jute. At last, he stands gingerly on a small causeway. This is the place where Chandra Kanta Das was murdered, he says.
"I hardly come here anymore," he says. "It is painful because I remember my childhood."
Loknath Das is even more cautious. Seated under the shade of a simul tree, he says: "We don't dare to venture into their village after nightfall."