This spring, I took a month-long road trip across a country that we - you, me and everyone we know - are killing. One day, not long into my journey, I travelled over tiny ridges and groaning bridges on the back of a motorbike to reach the remote village of Munshigonj. The surviving villagers - gaunt, creased people - were sitting by a stagnant pond. They told me, slowly, what we have done to them.
Ten years ago, the village began to die. First, many of the trees turned a strange brownish-yellow colour and rotted. Then the rice paddies stopped growing and festered in the water. Then the fish floated to the surface of the rivers, gasping. Then many of the animals began to die. Then many of the children began to die.
The waters flowing through Munshigonj - which had once been sweet and clear and teeming with life - had turned salty and dead.
Arita Rani, a 25-year-old, sat looking at the salt water, swaddled in a blue sari and her grief. "We couldn't drink the water from the river, because it was suddenly full of salt and made us sick," she said. "So I had to give my children water from this pond. I knew it was a bad idea. People wash in this pond. It's dirty. So we all got dysentery." She keeps staring at its surface. "I have had it for 10 years now. You feel weak all the time, and you have terrible stomach pains. You need to run to the toilet 10 times a day. My boy Shupria was seven and he had this for his whole life. He was so weak, and kept getting coughs and fevers. And then one morning..."
Her mother interrupted the trailing silence. "He died," she said. Now Arita's surviving three-year-old, Ashik, is sick, too. He is sprawled on his back on the floor. He keeps collapsing; his eyes are watery and distant. His distended stomach feels like a balloon pumped full of water. "Why did this happen?" Arita asked.
It is happening because of us. Every flight, every hamburger, every coal power plant, ends here, with this. Bangladesh is a flat, low-lying land made of silt, squeezed in between the melting mountains of the Himalayas and the rising seas of the Bay of Bengal. As the world warms, the sea is swelling - and wiping Bangladesh off the map.
Deep below the ground of Munshigonj and thousands of villages like it, salt water is swelling up. It is this process - called "saline inundation" - that killed their trees and their fields and contaminated their drinking water. Some farmers have shifted from growing rice to farming shrimp - but that employs less than a quarter of the people, and it makes them dependent on a fickle export market. The scientific evidence shows that unless we change now, this salt water will keep rising and rising, until everything here is ocean.
I decided to embark on this trip when, sitting in my air-conditioned flat in London, I noticed a strange and seemingly impossible detail in a scientific report. The International Panel on Climate Change (IPCC) - whose predictions have consistently turned out to be underestimates - said that Bangladesh is on course to lose 17 per cent of its land and 30 per cent of its food production by 2050. For America, this would be equivalent to California and New York State drowning, and the entire mid-West turning salty and barren.
Surely this couldn't be right? How could more than 20 million Bangladeshis be turned into refugees so suddenly and so silently? I dug deeper, hoping it would be disproved - and found that many climatologists think the IPCC is way too optimistic about Bangladesh. I turned to Professor James Hansen, the director of Nasa's Goddard Institute for Space Studies, whose climate calculations have proved to be more accurate than anybody else's. He believes the melting of the Greenland ice cap being picked up by his satellites today, now, suggests we are facing a 25-metre rise in sea levels this century - which would drown Bangladesh entirely. When I heard this, I knew I had to go, and see.
1. The edge of a cliff
The first thing that happens when you arrive in Dhaka is that you stop. And wait. And wait. And all you see around you are cars, and all you hear is screaming. Bangladesh's capital is in permanent shrieking gridlock, with miles of rickshaws and mobile heaps of rust. The traffic advances by inches and by howling. Each driver screams himself hoarse announc-ing - that was my lane! Stay there! Stop moving! Go back! Go forward! It is a good-natured shrieking: everybody knows that this is what you do in Dhaka. If you are lucky, you enter a slipstream of traffic that moves for a minute - until the jams back up and the screaming begins once more.
Around you, this megalopolis of 20 million people seems to be screaming itself conscious. People burn rubbish by the roadside, or loll in the rivers. Children with skin deformities that look like infected burns try to thrust maps or sweets into your hand. Rickshaw drivers with thighs of steel pedal furious-ly as whole families cling on and offer their own high-volume traffic commentary to the groaning driver, and the groaning city.
I wanted to wade through all this chaos to find Bangladesh's climate scientists, who are toiling in the crannies of the city to figure out what - if anything - can be saved.
Dr Atiq Rahman's office in downtown Dhaka is a nest of scientific reports and books that, at every question, he dives into to reel off figures. He is a tidy, grey-moustached man who speaks English very fast, as if he is running out of time.
"It is clear from all the data we are gathering here in Bangladesh that the IPCC predictions were much too conservative," he said. He should know: he is one of the IPCC's leading members, and the UN has given him an award for his unusually prescient predictions. His work is used as one of the standard textbooks across the world, including at Oxford and Harvard. "We are facing a catastrophe in this country. We are talking about an absolutely massive displacement of human beings."
He handed me shafts of scientific studies as he explained: "This is the ground zero of global warming." He listed the effects. The seas are rising, so land is being claimed from the outside. (The largest island in the country, Bhola, has lost half its land in the past decade.) The rivers are super-charged, becoming wider and wider, so land is being claimed from within. (Erosion is up by 40 per cent). Cyclones are becoming more intense and more violent (2007 was the worst year on record for intense hurricanes here). And salt water is rendering the land barren. (The rate of saline inundation has trebled in the past 20 years.) "There is no question," Dr Rahman said, "that this is being caused primarily by human action. This is way outside natural variation. If you really want people in the West to understand the effect they are having here, it's simple. From now on, we need to have a system where for every 10,000 tons of carbon you emit, you have to take a Bangladeshi family to live with you. It is your responsibility." In the past, he has called it "climatic genocide".
The worst-case scenario, Dr Rahman said, is if one of the world's land-based ice-sheets breaks up. "Then we lose 70 to 80 per cent of our land, including Dhaka. It's a different world, and we're not on it. The evidence from Jim Hansen shows this is becoming more likely - and it can happen quickly and irreversibly. My best understanding of the evidence is that this will probably happen towards the end of the lifetime of babies born today."
I walked out in the ceaseless churning noise of Dhaka. Everywhere I looked, people were building and making and living: my eyes skimmed up higher and higher and find more and more activity. A team of workers were building a house; behind and above them, children were sewing mattresses on a roof; behind and above them, more men were building taller buildings. This is the most cramped country on earth: 150 million people living in an area the size of Iowa. Could all this life really be continuing on the crumbling edge of a cliff?
2. 'It is like the Bay is angry'
I was hurtling through the darkness at 120mph with my new driver, Shambrat. He was red-eyed from chewing pan, a leaf-stimulant that makes you buzz, and I could see nothing except the tiny pools of light cast by the car. They showed we were on narrow roads, darting between rice paddies and emptied shack-towns, in the midnight silence. I kept trying to put on my seatbelt, but every time Shambrat would cry, "You no need seatbelt! I good driver!" and burst into hysterical giggles.
To see if the seas were really rising, I had circled a random low-lying island on the map called Moheshkhali and asked Shambrat to get me there. It turned out the only route was to go to Coxs Bazar - Bangladesh's Blackpool - and then take a small wooden rowing boat that has a huge chugging engine attached to the front. I clambered in alongside three old men, a small herd of goats, and some chickens. The boat was operated by a 10-year-old child, whose job is to point the boat in the right direction, start the engine, and then begin using a small jug to frantically scoop out the water that starts to leak in. After an hour of the deafening ack-ack of the engine, we arrived at the muddy coast of Moheshkhali.
There was a makeshift wooden pier, where men were waiting with large sacks of salt. As we climbed up on to the fragile boards, people helped the old men lift up the animals. There were men mooching around the pier, waiting for a delivery. They looked bemused by my arrival. I asked them if the sea levels were rising here. Rezaul Karim Chowdry, a 34-year-old who looked like he is in his fifties, said plainly: "Of course. In the past 30 years, two-thirds of this island has gone under the water. I had to abandon my house. The land has gone into the sea." Immediately all the other men start to recount their stories. They have lost their houses, their land, and family members to the advance.
They agreed to show me their vanishing island. We clambered into a tuc-tuc - a motorbike with a carriage on the back - and set off across the island, riding along narrow ridges between cordoned-off areas of sand and salt. The men explained that this is salt-farming: the salt left behind by the tide is gathered and sold. "It is one of the last forms of farming that we can still do here," Rezaul said. As we passed through the forest, he told me to be careful: "Since we started to lose all our land, gangs are fighting for the territory that is left. They are very violent. A woman was shot in the crossfire yesterday. They will not like an outsider appearing from nowhere."
We pulled up outside a vast concrete structure on stilts. This, the men explained, is the cyclone shelter built by the Japanese years ago. We climbed to the top, and looked out towards the ocean. "Do you see the top of a tree, sticking out there?" Rezaul said, pointing into the far distance. I couldn't see anything, but then, eventually, I spotted a tiny jutting brown-green tip. "That is where my house was." When did you leave it? "In 2002. The ocean is coming very fast now. We think all this" - he waved his hand back over the island - "will be gone in 15 years."
Outside the rusty house next door, an ancient-looking man with a long grey beard was sitting cross-legged. I approached him, and he rose slowly. His name was Abdul Zabar; he didn't know his age, but guessed he is 80. "I was born here," he said. "There" - and he points out to the sea. "The island began to be swallowed in the 1960s, and it started going really quickly in 1991. I have lost my land, so I can't grow anything... I only live because one of my sons got a job in Saudi Arabia and sends money back to us. I am very frightened, but what can I do? I can only trust in God." The sea stops just in front of his home. What will you do, I asked, if it comes closer? "We will have nowhere to go to."
I was taken to the island's dam. It is a long stretch of hardened clay and concrete and mud. "This used to be enough," a man called Abul Kashin said, "but then the sea got so high that it came over the dam." They have tried to pile lumps of concrete on top, but they are simply washed away. "My family have left the island," he continued, "They were so sad to go. This is my homeland. If we had to leave here to go to some other place, it would be the worst day of my life."
Twenty years ago, there were 30,000 people on this island. There are 18,000 now - and most think they will be the last inhabitants.
On the beach, there were large wooden fishing boats lying unused. Abu Bashir, a lined, thin 28-year-old, pointed to his boat and said, "Fishing is almost impossible now. The waves are much bigger than they used to be. It used to be fine to go out in a normal [hand-rowed] boat. That is how my father and my grandfather and my ancestors lived.
"Now that is impossible. You need a [motor-driven] boat, and even that is thrown about by the waves so much. It's like the bay is angry."
The other fishermen burst in. "When there is a cyclone warning, we cannot go out fishing for 10 days. That is a lot of business lost. There used to be two or three warnings a year. Last year, there were 12. The sea is so violent. We are going hungry."
Yet the islanders insisted on offering me a feast of rice and fish and eggs. I was ushered into the council leader's house - a rusty shack near the sea - and the men sat around, urging me to tell the world what is happening. "If people know what is happening to us, they will help," they said. The women remained in the back room; when I glimpsed them and tried to thank them for the food, they giggled and vanished. I asked if the men had heard of global warming, and they looked puzzled. "No," they said. We stared out at the ocean and ate, as the sun slowly set on the island.
3. No hiding place
Through the morning mist, I peered out of the car window at the cratered landscape. Trees jutted out at surreal angles from the ground. One lay upside down with its roots sticking upwards towards the sky, looking like a sketch for a Dali painting. Shambrat had spat out his pan and was driving slowly now. "There are holes in the ground," he said, squinting with concentration. "From the cyclone. You fall in..." He made a splattering sound.
It was here, in the south of Bangladesh, that on 15 November last year, Cyclone Sidr arrived. It formed in the warmed Bay of Bengal and ripped across the land, taking more than 3,000 people with it. Like Americans talking about 9/11, everybody in Bangladesh knows where they were when Sidr struck. For miles, the upturned and smashed-out houses are intermixed with tents made from blue plastic sheeting. These stretches of plastic were handed out by the charities in the weeks after Sidr, and many families are still living in them now.
There have always been cyclones in Bangladesh, and there always will be - but global warming is making them much more violent. Back in Dhaka, the climatologist Ahsan Uddin Ahmed explained that cyclones use heat as a fuel: "The sea surface temperatures in the Bay of Bengal have been rising steadily for the past 40 years - and so, exactly as you would expect, the intensity of cyclones has risen too. They're up by 39 per cent on average." Again I circled a cyclone-struck island at random and headed for the dot.
The hour-long journey on a wooden rowing boat from the mainland to Charkashem Island passed in a dense mist that made it feel like crossing the River Styx. The spectral outline of other boats could sometimes be glimpsed, before they disappeared suddenly. One moment an old woman and a goat appeared and stared at me, then they were gone.
The island was a tiny dot of mud and lush, upturned greenery. It had no pier, so when the rowing boat bumped up against the sand I had to wade through the water.
I looked out over the silent island, and saw some familiar blue sheeting in the distance. As I trudged towards it, I saw some gaunt teenagers half-heartedly kicking a deflated football. From the sheeting, a man and woman stared, astonished.
"I was in my fields over there," Hanif Mridha said. "I saw the wind start, it was about eight at night, and I saw everything being blown around. I went and hid under an iron sheet, but that was blown away by the wind. The water came swelling up all of a sudden and was crashing all around me. I grabbed one of my children and ran to the forest" - he pointed to the cluster of trees at the heart of the island - "and climbed the tallest one I could reach. I went as high as I could but still the water kept rising and I thought - this is it, I'm going to drown. I'm dying, my children are dying, my wife is dying. I could see everything was under water and people were screaming everywhere. I held there for four hours with my son."
When the water washed away and he came down, everything was gone: his house, his crops, his animals, his possessions. A few days later, an aid agency arrived with some rice and some plastic sheeting to sleep under. Nobody has come since.
His wife, Begum Mridha, took over the story. Their children are terrified of the sea now, and have nightmares every night. They eat once a day, if they're lucky. "We are so hungry," she said. The new home they have built is made from twigs and the plastic sheet. Underneath it, they sleep with their eight children and Begum Mridha's mother. The children lay lethargically there, staring blankly into space over their distended bellies.
Begum Mridha cooks on a lantern. They eat once a day - if that. "It's so cold at night we can't sleep," she said. "The children all have diarrhoea and they are losing weight. It will take us more than two years to save up and get back what we had."
If cyclones hit this area more often, what would happen to you? Hanif looked down. He opened his mouth, but no words came.
4. Bangladesh's Noah
In the middle of Bangladesh, in the middle of my road trip, I tracked down Abul Hasanat Mohammed Rezwan. He was sitting under a parasol by the banks of a river, scribbling frenetically into his notebook.
"The catastrophe in Bangladesh has begun," he said. "The warnings [by the IPCC] are unfolding much faster than anyone anticipated." Until a few years ago, Rezwan was an architect, designing buildings for rich people - "but I thought, is this what I want to do while my country drowns? Create buildings that will be under water soon anyway?"
He considered dedicating his life to building schools and hospitals, "but then I realised they would be under water soon as well. I was hopeless. But then I thought of boats!"
He has turned himself into Bangladesh's Noah, urging his people to move on to boats as the Great Flood comes. Rezwan built a charity - Shidhulai Swanirvar Sangstha, which means self-reliance - that is building the only schools and hospitals and homes that can last now: ones that float.
We clambered on to his first school-boat, which is moored in Singra. In this area there is no electricity, no sewage system, and no state. The residents live the short lives of pre-modern people. But now, suddenly, they have a fleet of these boats, stocked with medicines and lined with books on everything from Shakespeare to accountancy to climatology. Nestling between them, there are six internet terminals with broadband access.
The boat began to float down the Curnai River, gathering scores of beaming kids as it went. Fatima Jahan, an unveiled 18-year-old girl dressed in bright red, arrived to go online. She was desperate to know the cricket scores. At every muddy village-stop, the boat inhaled more children, and I talked to the mothers who were beating their washing dry by the river. "I never went to school, and I never saw a doctor in my life. Now my children can do both!" a thin woman with a shimmering heart-shaped nose stud called Nurjahan Rupbhan told me. But when I asked about the changes in the climate, her forehead crumpled into long frown-lines.
I thought back to what the scientists told me in Dhaka. Bangladesh is a country with 230 rivers running through it like veins. They irrigate the land and give it its incredible fertility - but now the rivers are becoming supercharged. More water is coming down from the melting Himalayan glaciers, and more salt water is pushing up from the rising oceans. These two forces meet here in the heart of Bangladesh and make the rivers churn up - eroding the river banks with amazing speed. The water is getting wider, leaving the people to survive on ever-more narrow strips of land.
Nurjahan took me up to a crumbling river edge, where tree roots jutted out naked. "My house was here," she said. "It fell into the water. So now my house is here -" she motioned to a small clay hut behind us - "but now we realise this is going to fall in too. The river gets wider day by day."
But even this, Nurjahan said, is not the worst problem. The annual floods have become far more extreme, too. "Until about 10 years ago, the floods came every year and the water would stay for 15 days, and it helped to wet the land. Now the water stays for four months. Four months! It is too long. That doesn't wet the fields, it destroys them. We cannot plan for anything."
When the floods came last year, Nurjahan had no choice but to stay here. She lived with her children waist-deep in the cold brown water - for four months. "It was really hard to cook, or go to the toilet. We all got dysentery. It was miserable." Then she seemed to chastise herself. "But we survived! We are tough, don't you think?"
We sat by the river-bank, our feet dangling down towards the river. I asked if she agrees with Rezwan that her only option soon will be to move on to a boat. He is launching the first models this summer: floating homes with trays of earth where families can grow food. "Yes," she said, "We will be boat-people."
I clambered back on to one of the 42 school-boats in this area. Young children were in the front chanting the alphabet, and teenagers at the back were browsing through the books. I asked a 16-year-old boy called Mohammed Palosh Ali what he was reading about, and he said, "Global warming." I felt a small jolt. He was the first person to spontaneously raise global warming with me. Can you tell me what that is? "The climate is being changed by carbon dioxide," he said. "This is a gas that traps heat. So if there is more of it, then the ice in the north of the world melts and our seas rise here."
I asked if he had seen this warming in his own life. "Of course! The floods in 1998 and 2002 were worse than anything in my grandfather's life. We couldn't get any drinking water, so the dirty water I drank made me very sick. The shit from the toilet pits had risen up and was floating in the water, but we still had to drink it. We put tablets in it but it was still disgusting. What else could we do?"
Mohammed, do you know who is responsible for this global warming? He shakes his head. That answer lies a few pages further into the book. Soon he, and everybody else on this boat, will know it is me - and you.
5. The warming jihad
What happens to a country's mind as it drowns? Professor Philip Jenkins of Pennsylvania State University believes he can glimpse the answer: "The connection between climate change and religious violence is not tenuous," he says. "In fact, there's a historical indicator of how it could unfold: the Little Ice Age."
Between the ninth and 13th centuries, the northern hemisphere went through a natural phase of global warming. The harvests lasted longer - so there were more crops, and more leisure. Universities and the arts began to flower. But then in the late 13th century, the Little Ice Age struck. Crop production fell, and pack ice formed in the oceans, wrecking trade routes. People began to starve.
"In this climate of death and horror, people cast about for scapegoats, even before the Black Death struck," he says. Tolerance withered with the climate shocks: the Church declared witchcraft a heresy; the Jews began to be expelled from Britain. There was, he says, "a very close correlation between the cooling and a region-wide heightening of violent intolerance."
This time, there will be no need for imaginary scapegoats. The people responsible are on every TV screen, revving up their engines. Will jihadism swell with the rising seas? Bangladesh's religion seems to be low-key and local. In the countryside, Muslims - who make up 95 per cent of the nation - still worship Hindu saints and mix in a few Buddhist ideas, too. In the Arab world, people bring up God in almost every sentence. In Bangladesh, nobody does.
But then, as we returned to Dhaka, I was having a casual conversation with Shambrat. He had been driving all night - at his insistence - and by this point he was wired after chewing fistfuls of pan, and singing along at the top of his voice to the Eighties power ballads. I mentioned Osama bin Laden in passing, and he said, "Bin Laden - great man! He fight for Islam!" Then, without looking at me, he went back to singing: "It must have been love, but it's over now...."
I wondered how many Bangladeshis felt this way. The Chandni Chowk Bazaar - one of the city's main markets - was overcast the afternoon I decided to canvass opinions on Bin Laden. I approached a 24-year-old flower-seller called Mohammed Ashid, and as I inhaled the rich sweet scent of roses, he said: "I like him because he is a Muslim and I am a Muslim." Would you like Bin Laden to be in charge of Bangladesh? "Yes, of course," he said. And what would President Bin Laden do? "I have no idea," he shrugged. What would you want him to do? He furrowed his brow. "If Osama came to power he would make women cover up. Women are too free here." But what if women don't want to cover up? "They are Muslims. It's not up to them."
A very smartly dressed man called Shadul Ahmed was strolling down the street to his office, where he is in charge of advertising. "I like him," he said. "Bin Laden works for the Muslims." He conceded 9/11 "was bad because many innocents died," but added: "Osama didn't do it. The Americans did it. They are guilty."
As dozens of people paused from their shopping to talk, a pattern emerged: the men tend to like him, and the women don't. "I hate Bin Laden," one smartly dressed woman said, declining to give her name. "He is a fanatic. Bangladeshis do not like this." As the praise for Bin Laden was offered, I saw a boy go past on a rickshaw, stroking a girl's uncovered hair gently, sensuously. This is not the Arab world.
The only unpleasant moment came when I approached three women selling cigarettes by the side of the road. They were in their early thirties, wearing white hijabs and puffing away. Akli Mouna said, "I like him. He is a faithful Muslim." She said "it would be very nice" if he was president of Bangladesh. Really? Would you be happy if you were forced to wear a burqa, and only rarely allowed out of your house? She jabbed a finger at my chest. "Yes! It would be fine if Osama was president and told us to wear the burqa." But Akli - you aren't wearing a burqa now. "It's good to wear the burqa!" she yelled. Her teeth, I saw, were brown and rotting. "We are only here because we are poor! We should be kept in the house!"
I wanted to track down some Bangladeshi jihadis for myself, so I called the journalist Abu Sufian. He is a news reporter for BanglaVision, one of the main news channels, who made his name penetrating the thickets of the Islamist underground. He told me to meet him at the top of the BanglaVision skyscraper. As the city shrieked below us, he explained: "In the late 1980s, a group of mujahideen [holy warriors] who had been fighting the Soviets in Afghanistan came back to launch an Islamic revolution here in Bangladesh. They tried to mount an armed revolt in the north and kill the former Prime Minister. But it didn't come to much."
Islamic fundamentalism is hobbled in Bangladesh, because it is still associated for most people with Paki-stan - the country Bangladesh fought a bloody war of independence to escape from.
But Sufian says a new generation of Islamists is emerging with no memory of that war. "For example, I met a 21-year-old who had fought in Kashmir, whose father was a rickshaw driver. He said it was his holy duty to establish an Islamic state here through violence. Most were teenagers. All the jihadis I met hated democracy. They said it was the rule of man. According to them, only the rule of God is acceptable."
He said it would be almost impossible to track them down - they are in prison or hiding - but my best bet was to head for the Al-Amin Jami mosque in the north-west of Dhaka. "They are fundamentalist Wahhabis, and very dangerous," he said. Yet when I arrived, just before 6pm prayers, it was a bright building in one of the nicer parts of town. Men in white caps and white robes were streaming in. An ice-cream stall sat outside. I approached a fiftysomething man in flowing robes and designer shoes. He glared at me. I explained I was a journalist, and ask if it would it be possible to look inside the mosque? "No. Under no circumstances. At all."
OK. I asked a few polite questions about Islam, and then asked what he thought of Osama bin Laden. "Osama bin Laden?" he said. Yes. He scowled. "I have never heard of him." Never? "Never." I turned to the man standing, expectantly, next to him. "He has not heard of Osama bin Laden, either," he said. What about September 11 - you know, when the towers in New York fell? "I have never heard of this event, either." Some teenage boys were about to go in, so I approached them. Behind my back, I can sense the Gucci-man making gestures. "Uh... sorry... I don't think anything about Bin Laden," one of them said, awkwardly.
I lingered as prayers took place inside, until a flow of men poured out so thick and fast that they couldn't be instructed not to speak. "Yes, we would like Osama to run Bangladesh, he is a good man," the first person told me. There were nods. "He fights for Islam!" shouted another.
The crowd says this mosque - like most fundamentalist mosques on earth - is funded by Saudi Arabia, with the money you and I pay at the petrol pump. As I looked up at its green minaret jutting into the sky, it occurs to me that our oil purchases are simultaneously drowning Bangladesh, and paying for the victims to be fundamentalised.
After half-an-hour of watching this conversation and fuming, the initially recalcitrant man strode forward. "Why do you want to know about Bin Laden? We are Muslims. You are Christian. We all believe in the same God!" he announced.
Actually, I said, I am not a Christian. There was a hushed pause. "You are... a Jew?" he said. The crowd looked horrified; but then the man forced a rictus smile and announced: "We all believe in one God! We are all children of Abraham! We are cousins!" No, I said. I am an atheist. Everyone looked genuinely puzzled; they do not have a bromide for this occasion. "Well... then..." he paused, scrambling for a statement... "You must convert to Islam! Read the Koran! It is beautiful!" Ah - so can I come into the mosque after all? "No. Never."
6. The obituarist?
In a small café in Dhaka, a cool breeze was blowing in through the window along with the endless traffic-screams. The 32-year-old novelist Tahmima Anam was inhaling the aroma of coffee and close to despair.
She made her name by writing a tender novel - A Golden Age - about the birth of her country, Bangladesh. When the British finally withdrew from this subcontinent in 1948, the land they left behind was partitioned. Two chunks were carved out of India and declared to be a Muslim republic - East Pakistan and West Pakistan. But apart from their religion, they had very little in common. The gentle people of East Pakistan chafed under the dictatorial fundamentalism imposed from distant Islamabad. When they were ordered to start speaking Urdu, it was enough. Her novel tells how in 1971, they decided to declare independence and become Bangladesh. The Pakistanis fought back with staggering violence, but in the end Bangladesh was freed.
Now Anam is realising that unless we change, fast, this fight will have been for the freedom of a drowning land - and her next novel may have to be its obituary.
Anam came to Bangladesh late. Her Dhaka-born parents travelled the world, so she grew up in a slew of international schools, but she always dreamed of coming home. Her passion for this land, this place, this delta, aches through her work. About one of her characters, she wrote: "He had a love for all things Bengali: the swimming mud of the delta; the translucent, bony river fish; the shocking green palette of the paddy and the open, aching blue of the sky over flat land."
"You can see what has started to happen," she says. The vision of the country drowning is becoming more real every day. Where could all these 150 million people go? India is already building a border fence to keep them out; I can't imagine the country's other neighbour - Burma - will offer much refuge. "We are the first to be affected, not the last," Anam says. "Everyone should take a good look at Bangladesh. This story will become your story. We are your future."
It is, she says, our responsibility to stop this slow-mo drowning - and there is still time to save most of the country. "What could any Bangladeshi government do? We have virtually no carbon emissions to cut." They currently stand at 0.3 per cent of the world's - less than the island of Manhattan. "It's up to you."
Anam is defiantly optimistic that this change can happen if enough of us work for it - but, like every scientist I spoke to, she knows that dealing with it simply by adaptation by Bangladeshis is impossible. The country has a military-approved dictatorship incapable of taking long-term decisions, and Dutch-style dams won't work anyway. "Any large-scale construction is very hard in this country, because it's all made of shifting silt. There's nothing to build on."
So if we carry on as we are, Bangladesh will enter its endgame. "All the people who strain at this country's seams will drown with it," Anam says, "or be blown away to distant shores - casualties and refugees by the millions." The headstone would read, Bangladesh, 1971-2071: born in blood, died in water.