ABOUT seven years ago, Gaur Mondol noticed he couldn't grow as much rice on his land as salty water seeped in from the Passur River, which stretches from his home in Bangladesh's interior all the way to the Indian Ocean.
Now the rice paddies are completely inundated, leaving the land barren. To find work, he must walk for miles each day to other villages. His annual income has fallen by half to 36,000 taka ($569). He makes about $5 a day if he's lucky, and most of that goes to buy food for his family of four.
"I'm always worried that my house will be washed away someday," Mondol said from his home in Mongla sub-district, pointing to a riverside tamarind tree with water swirling around its exposed roots. "My family is constantly under threat as the river creeps in."
Rising sea levels are one of the biggest threats to the $185 billion economy over the next half a century, with farmers like Mondol already facing the consequences. Bangladesh, which needs to grow at 8 per cent pace to pull people out of poverty, stands to lose about 2 per cent of gross domestic product each year by 2050, according to the Asian Development Bank.
"The sea-level rise and extreme climate events are the two ways that salinity intrudes into the freshwater system," Mahfuzuddin Ahmed, an adviser in the ADB's regional and sustainable development department, said by phone from Manila. "The implication for food security is quite big."
Bangladesh is one of the world's most densely populated countries, with half the US population crammed into an area the size of New York state. About 50 per cent of its citizens are directly dependent on agriculture for their livelihoods, a quarter live in the coastal zone, and 21 per cent of these lands are affected by an excess of salinity.
The proportion of arable land has fallen 7.3 per cent between 2000-2010, faster than South Asia's 2 per cent decline, with geography playing a large role.
Bangladesh is nestled at a point where tidal waves from the Indian Ocean flow into the Bay of Bengal. While these create the Sundarbans mangroves, home to the endangered Bengal tiger, winds and currents cause saline water to mix with upstream rivers.
Global weather changes worsen this. Bangladesh's average peak-summer temperature in May has climbed to 28.1 degrees Celsius (83 Fahrenheit) in 1990-2009 from 26.9 in 1900-1930, and could rise to 31.5 degrees in 2080-2099, World Bank data show. Average June rainfall has dropped to 467.1 millimetres from 517.5mm in that time.
Bangladesh leads 32 countries facing extreme risks from climate change, amplifying the possibility of civil unrest, according to a study by British researcher Maplecroft published on October 29. The Intergovernmental Panel on Climate Change estimates production of staples such as rice, wheat and maize could fall as much as 59 per cent over 35 years in these nations.
"It's a disaster - both natural and man-made," said Noor Alam Sheikh, the local coordinator of Bangladesh Poribesh Andolon that campaigns for environmental protection. Families that can't grow crops are turning to shrimp farming, which makes salinity permanent as it involves creation of enclosures that block the outflow of salty water, he said.
Bangladesh spends $1.2 billion a year, or about 7 per cent of its annual budget, to adapt to climate change, with three-quarters paid by the government and the rest by international donors, according to the United Nations.
This will need to rise to $7 billion by 2050, the World Bank predicts, with disproportionate demands falling on the poorest Bangladeshis. The average European citizen emits as much carbon in 11 days as the average Bangladeshi in an entire year, according to UN data.
"Bangladesh will never exceed the average per capita emission of the developing world," Prime Minister Sheikh Hasina said on September 23 at the UN General Assembly in New York. "The large emitting countries should reciprocate our voluntary commitments."
Most of the 6000 kilometres of embankments built to keep out the sea have been damaged due to poor maintenance, said Mahabub Hossain, an economist at non-government organization BRAC. In Mondol's Mongla, devastated by two cyclones since 2007, more than 100,000 people are left without easy access to water for drinking and farming.
Gita Halder, 55, is another of them. She walks about 6km and crosses a turbulent river to fill pots and jugs for her family of six. If she can't make it to the pond, she'll have to spend 20 taka to buy 30 litres of unfiltered fresh water from local suppliers.
After salinity ruined their farmland, her nephew used 14 acres for fish farming, mainly shrimp. The family earns about 200,000 taka a year from this and their water bill runs into 2000 taka. That's over and above the trudge to the pond and the 1000L of water they harvest in a black plastic tank during the June-September monsoon.
"There are many poor people who toil to make ends meet and can't afford to spend half the day only for water," Halder said on November 15, seven years to the day that cyclone Sidr made landfall. "But what can they do? Water is life."