Bangladesh is often held up as the 'ground zero' of climate change, with environmental experts predicting that rising sea levels could engulf much of the country of 150 million people within the next 50 years.

But a recent survey by a Bangladeshi research institute shows that the country's landmass has actually increased by more than 1,000 square km (386 square miles) since 1973, due to rivers dumping sediment as they meet the sea.

Bangladesh could also gain another 1,000 square km by 2050, according to scientists from the state-run Centre for Environment and Geographic Information Services (CEGIS) in Dhaka, Bangladesh's capital.

CEGIS, which is funded by the Dutch government, reached its conclusion after studying satellite images of the country dating back to 1973.

Maminul Haque Sarker, head of the department that conducted the research, told The Times that most of the new land was on the southern coast where the Ganges and Brahmaputra Rivers flow into the Bay of Bengal.

The rivers carry more than a billion tonnes of sediment every year as they cascade down from the Himalayas and across Bangladesh's densely populated lowlands, he said.

"They deposit a third of that in their estuaries – and the amount of sediment is increasing every year," he said.

"The satellite images show that Bangladesh's landmass has been growing by about 20 square kilometres annually in the last few years."

One of the most crowded countries on the planet, Bangladesh lies on a vast delta, mostly less than 10 metres above sea level, and suffers devastating floods, cyclones and tornadoes almost every year.

The United Nations' Inter-governmental Panel on Climate Change (IPCC) predicted last year that the country could lose 17 percent of its land by 2050 because of rising sea levels due to global warming.

The Nobel Peace Prize-winning body also predicted that 20 million Bangladeshis would become environmental refugees and the country would lose some 30 percent of its food production by 2050.

Professor James Hansen, Director of the US-based NASA Goddard Institute for Space Studies, goes even further, predicting a sea level rise of up to 25 metres by 2100, which would completely submerge Bangladesh.

Dr Sarker and other Bangladeshi experts agree that, if the sea rises by one metre, it would submerge 25-30 percent of Bangladesh, devastating the economy and displacing millions of people.

However, they believe that the IPCC forecasts do not take into account natural sedimentation and artificial land accretion from the construction of dams.

Mahfuzur Rahman, head of Bangladesh Water Development Board's Coastal Study and Survey Department, explained that dams built in the 1950s and 1960s, as well as natural sedimentation, had created hundreds of square miles of new land.

The government is also planning to build 19 cross-dams between islands that could increase Bangladesh's landmass by another 700 square kilometres, he said.

The new land would be planted with trees and remain as forest for five to ten years, but could be turned into farmland after that, he predicted.

"There will undoubtedly be a sea level rise in coming decades, but I can't agree that Bangladesh will be completely under water," he said.

"Every year we are losing some land and gaining some land, but gaining more than we are losing."

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