Bangladesh: Life on the edge

For centuries, the farmers of Bangladesh's sandy chars have eked out an existence at the mercy of South Asia's great rivers. But as temperatures rise, time is running out for them

Life on the watery margins of Bangladesh is the poor man's Las Vegas. You can start with nothing and, if the heavens smile on you, within a couple of years you can be the master of what looks like a prosperous little farm, in one of the most wildly fertile corners of the planet. Then weeks later you can lose the whole lot to the floods.

The risks and the rewards of life on the delta's fissiparous edges have been of this order for centuries. But with global warming the odds are steadily worsening. More than 600,000 people live on these margins, and their lives are getting more precarious every year. With changing climate, the flooding grows ever more extreme and unpredictable, the rivers even wilder. At the same time a general rise in the ocean's level threatens the viability of the entire watery way of life: fresh water goes brackish, threatening drinking water and water for the crops and livestock. The line between survival and destruction grows ever finer.

Every year the waters of South Asia's great rivers, the Ganges and the Brahmaputra (known locally as the Padma and the Jamuna), come thundering down into Bangladesh from India and Tibet, bearing millions of tons of silt. At any point in their progress, whether slow, stately and corpse-encrusted at Benares or roaring like an express train through Assam, these vast rivers inspire awe. They feed and fertilise a subcontinent, and by the time they reach the last stage of their journey to the Bay of Bengal they are rampant and rampaging and the land is no match for them. They toy with it, tear it this way and that, carve new courses every year, create islands in the rivers one year, destroy them the next or 10 years later or even 20. A river that is a single mighty course one year, within a couple more can turn into a watery braid, dotted with islands.

And Bangladesh's poorest farmers grow fat or thin, prosperous or desperate, according to the rivers' whims. If you are a poor Bengali peasant and you have nothing at all and a family to feed, the chars are the place to head: sandy riverine islands or peninsulas created by the rivers' caprice. For the peasants without land, these sandy knobs are land without people, fresh-minted, claimed by no landlord or government, free of gates and fences, there for the taking.

What grows on sand? Not much, but sand can be shovelled into boats and sold to the construction industry in Dhaka. Or the sand can be mixed with the fertilising silt from the Himalayas: within months catkin grass begins to bed into it, providing thatch for the roofs of new huts, fences (fashioned from the stems) fodder for cattle, shelter for the huts of the betel nut farmers. When it is dry you can burn it for fuel. When the char floods you pile the grass into high mounds where the cattle can take refuge from the water.

Then the catgrass decomposes and draws in more silt and the wondrous fertility of the delta works its magic, and on the land that was water emerge banana palms, bamboo, jackfruit, guava, mango. In the West we hear nothing from Bangladesh but dire news of the country's poverty and misery. Then you pay the place a visit and once out of the toxic hell of Dhaka it's the garden of Eden, a riot of fecundity. On land that never existed before, and that cost nothing, and on which no title deeds existed nor ever will. It's the Big Rock Candy Mountain, South Asia style.

But then there is the price to pay. Because it's easy come and easy go. You live by the water and die by it too. There is absolutely no knowing how long a char can keep its head above the water. So there are crops, quick and easy trees, flimsy huts. But no pukka houses, no roads, no schools, no infrastructure at all. It's life on the edge. You might be there, reaping the catgrass, plucking the mangos for years. Or next week your life and the lives of your family could be in dire jeopardy – as the roaring river changes its mind. Then scrambling into the flimsy boats to find a new-made char elsewhere and start all over again.

The people of the chars are the most vulnerable of all in a country that is one of the most at risk as the climate heats up. The Intercontinental Panel on Climate Change indicates that a one metre rise in sea level "could displace nearly 15 million people" from their homes in Bangladesh – more than twice as many as in the whole of India; 30,000 square kilometres of land could disappear permanently. The char-dweller's poker game is steadily changing into Russian roulette.