At first glance, Ben Tre is a paradise. Water buffaloes nose around verdant rice paddies; labourers in conical hats cut an iconic silhouette against the dipping sun.

When the waters rise, however, it’s another story. “The weather definitely has changed,” says 78-year-old Nguyen Van Trinh. “Even after the rain, the weather seems stuffy. I don’t know exactly why... only science can explain. Before, it was rainy or sunny at the right time. Now it rains for several days and the soil cannot dry.”

A circus of curious grandchildren mills around Van Trinh’s home. His daughter cuts grapefruit; his wife cossets their great-grandchild in a hammock. Outside, white-washed ancestral graves stand amongst coconut trees and mucky irrigation channels. “About five months ago, a storm blew off my roof,” he tells me. More recently, inclement weather knocked out the TV and other electrical devices. His family appears resigned, but mystified.

Vietnam’s Mekong Delta is one of the most beautiful corners of South East Asia. Tourists are increasingly drawn to its rice paddies, floating markets and lush, undulating greenery. But this idyll is increasingly threatened by a combination of science and human behaviour and most that live and work here simply do not understand. “I’ve heard of the term ‘climate change’,” says 26-year-old Nguyen Thi Ut, whom I encounter squatting by a paddy, cutting weeds from the water near the Nguyen homestead on Ben Tre. “But I hope the change will be in a positive way.”

In fact, climate change kills some 160,000 people every year, according to the World Health Organisation (WHO) - both directly due to flooding, draughts and higher temperatures, and indirectly as a result of related malaria, diarrhoea and malnutrition. Its effect on developing countries is disproportionate.

A recent EPA report signalled that Irish temperatures are warming at twice the rate of the rest of the world, but in Vietnam, according to the Ministry of Natural Resources and the Environment, natural disasters claimed 7,760 human lives and caused total losses of $2.5 billion between 1996 and 2002.

Floods and storms endanger livelihoods. Beyond that, they impact on health, education, infrastructure and food security. In the Mekong Delta, a poorly-educated population with an average annual income of $638 is ill-equipped to cope. “When the water rises it comes up to your knees,” illustrates Tran Thi Dieu, 29, who lives with her family in a stilted shack near the busy town of Cao Lanh. “You have to raise the beds, sleep in hammocks and build bridges between houses.”

As we speak, a woman next door washes her hair in the river. Nearby, a boy pees off a bridge. Further upstream, an open rubbish tip broaches the roadside. Tourists might be appalled to witness these things in such close proximity. In the Mekong Delta, it’s day to day life.

Awareness is beginning to grow, however, as Nguyen Huu Thien, a conservationist linked with the World Conservation Union, explains. After the American War, he says, “the whole nation was hungry, so the mentality was food, food, food... nobody talked about conservation.” The Delta was largely forested until the 19th century, I learn.

But the awesome Mekong River, stretching 4,500km from the Tibetan Plateau to multiple mouths in South Vietnam, would not remain untapped for long. French colonists were the first to plug in, siphoning off canals to irrigate and fertilise a rich agricultural catchment area.

During the Vietnam War, the Viet Cong added to their infrastructure, albeit on a far larger scale. Frequent bursts of bombs, napalm and other defoliants choked biodiversity in the region. Afterwards, when food production hit almost industrial levels, areas like the Plain of Reeds were subsumed by a patchwork quilt of canals, roads and rice paddies.

In economic terms, the post-war policy was a success. The Mekong Delta today produces almost half of Vietnam’s rice; indeed, it is one of Asia’s great rice bowls. But come September and October, human interference is repaid in spades. Water can increase 60-fold, according to the WHO. “It looks like Bangladesh,” Huu Thien says. Once, he adds, monsoons were considered a blessing. They flushed salt and acidity from the soil, rinsed it with fertile silt. Now canals invite more and more water into the countryside. “People used to call it the water season. Now they call it the flood season.”

Huu Thien describes natural wetlands around the Mekong as “hearts” – regulators whose pumping has been disrupted by hand of man. Canals stop the water spilling into them in low season, barring replenishment of the soil, preventing soakage. Come floods, they act like highways. There is simply not enough conservation “at the larger scale,” he says.

At Can Tho, a staging post for many tourist trips into the Delta, the city’s floating market is a major attraction. On the caramel coloured water, tiny boats sell to small boats, and small boats to big boats – limes, yams, onions, carrots, pumpkins. It’s wet when we visit - the traders wear ponchos and traditional conical hats. Raindrops carve little craters into the water, and traders describe the adverse effects of floods. In bad weeks, they say, fewer customers appear, there is less produce to sell, and danger increases.

“In the last five or six years there have been more storms and rain,” says Trinh Thi Diep, 59, vending breakfast noodles from her sampan. “I don’t know why. It’s God. The government has taken steps to prevent and protect against the flooding, but they can’t do anything against God’s will.”

“The weather in recent years seems to have no rules,” Nguyen Van Hung, Vice Director of Tram Chim National Park, tells me at his office in Dong Thap. Disaster Preparedness projects are underway, but the magnitude of the problem seems overwhelming. “It is unstable.”

“Two months ago, a strong wind blew the outer roof down,” adds Tran Thi Bay, 55, operating a boat-making business in the village of Long Thanh. “It has been different from other years. There has been more wind and rain, especially at night. I don’t know why.”

Hers is a familiar refrain. The concrete and wooden stilts on which Ms Tran’s business, and many neighbouring shacks, perch are slimy and rotten. The village has been freshly flushed with rain, and it looks like even moderately serious weather would cause collapse. “Climate Change does affect people’s lives,” says Phan Van Ut, Chief of Administration at the Department of Fisheries in nearby Ca Mau, sitting beneath a portrait of ‘Uncle Ho’ (Chi Minh).

“People in the Mekong Delta have no way to avoid floods, so they have to adapt and live with them.” People accept that the Vietnamese need to broaden their awareness about climate change, address their own responsibility to cut pollution, stem deforestation and control the heady curve of industrialisation and urbanisation underway in a rapidly developing country, he says.

But despite their own faults in making a monster of the Mekong, they can do little about glacial melting at the river’s Himalayan source. They can do little about deforestation and urbanisation upstream in Cambodia - alone estimated to have tripled peak flows in 30 years.

Global warming, habitat destruction, rising sea levels – Western consumers and industry are responsible for flooding in South East Asia too, when the strange fruits of our carbon emissions come thundering into the corner of Vietnam that can least afford it. In 2000 alone, some 480 people in the Mekong Delta lost their lives to the wet season.

“For things out of control, such as melting ice caps and the greenhouse effect, international organisations should encourage all countries to do something about it,” Van Ut sighs. “All countries should be united in fighting these problems.”

(This story was funded by the Simon Cumbers Media Challenge Fund.)