Sea water likely to flood a fourth of Bangladesh by 2050: study

A new research released globally on Tuesday said that a fourth of Bangladesh could face coastal floods by 2050 because of climate change-induced sea-level rise.

Coastal flooding would occur every year if walls and levees were not built to hold back the water and half the predicted area would remain permanently under water.

The predictions have been made by the research conducted by New Jersey-based Climate Central, a non-profit science and news organisation.

Massive displacements are feared in the aftermath of the sea-level rise with large numbers of people migrating to cities eventually striking the political stability off-balance according to the study launched in Princeton.

These are conservative predictions based on the assumption that carbon emission would be cut rapidly over the next three decades while ice caps and glaciers would continue to melt at the present rate, said the research.

A country-wise graphic presentation in the research  shows that by 2050 half of Bangladesh’s north-eastern region, nearly half of the central region, almost the entire south-western region and parts of Chattogram would get regularly flooded by sea water.

The sea-water inundation in Dhaka would be widespread with Karwan Bazar, Tejgaon, Mohakhali, Badda, Adabor, Mohammadpur, Gabtoli and Savar being the worst-hit, shows the graphic presentation.

The Khulna division would be worst hit with almost the entire division except for its Chuadanga district getting regularly inundated by sea water.

‘The Sunderbans would be the worst-hit area,’ said Saleem, who has been engaged in the work of Intergovernmental Panel on Climate Change.

Bangladesh sits on a deltaic plain where sedimentation is still high, though the rate of it is falling rapidly because of withdrawal of river water in the upstream.

The rising level of sea would not have been a problem had the natural system not been intervened.

The research warned that if carbon emission cuts remained moderate or continued to grow and Antarctic ice caps became unstable the implications would be far more serious.

‘These assessments show the potential of climate change to reshape cities, economies, coastlines, and entire global regions within our lifetimes,’ said Dr Scott Kulp, a senior scientist at the Climate Central and lead author of the study in a press release.

‘As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defenses can protect them,’ he said.

According to the research, the sea level rose by up to seven inches over the last century because of anthropogenic climate change and it could rise up to two feet this century.

The research is significant in the sense that it gives far greater indications of threats than previously thought from sea-level rise induced by climate change.

For instance, the study found about 237 million people in six Asian countries – China, Bangladesh, India, Vietnam, Indonesia and Thailand – living in places that without protection could face annual coastal flooding by 2050, quadrupling previous estimates based on older elevation data.

The research was based on a new digital elevation model developed to minimise errors in the older model.

Actual terrain elevation data is still unavailable for many parts of the world but the new model took care of the errors in which treetops or other high-rising infrastructures were mistaken for terrain elevation in the previous estimate.

‘With substantial, updated information the research shows to us that the threats we are facing from climate change are far more serious,’ said Bangladeshi climate scientist Saleemul Huq.

‘We need to look at these [climate change threats] much more seriously,’ said Saleem, director, the International Centre for Climate Change and Development.

By 2100, depending on emission scenarios and ice cap and glacier stability, land now home to 56 million to 70 million people would face annual coastal flooding, according to the study, about a five-fold increase in potential losses predicted in previous estimates.  

Another conservative estimate of the study is that land now occupied by about 18 million people would be permanently under sea water by 2050.

And by 2100 permanent inundation would affect land currently home to 30 million people.

Saleem noted that the deltaic process came to a halt in the Khulna division and was falling rapidly in the central region as well.

Chattogram and Cox’s Bazar, however, has retained the deltaic process where the rising sea level would be less of a problem, he said.

‘We have a very complex problem at our hand to deal with,’ said Saleem.

Water resource management expert Ainun Nishat said that Bangladesh was well prepared to deal with the problem of sea level rise with its strong network of 15-feet high polders.

‘As many as 139 polders are defending the entire coastline,’ said Ainun Nishat.  

A number of districts like Faridpur, Shariatpur, Madaripur and Gopalganj and islands and shoals like Nijhum Dwip and Bhashan Char, however, are at risk of coastal flooding due to lack of protection, he said.

‘Severe storm with surges leaping higher than the polders could prove disastrous anywhere in the country,’ said Ainun Nishat.

Coastal protection by polders faced scathing criticism from green activists over the years.

They said that polders built blocking natural water flows interfered with the deltaic process from the 1980s.

Researches showed that land elevation in polder-protected areas fell far below compared to areas outside protection where sedimentation regularly increased land elevation. 

Researches said that elevated coastline could compound impacts of rising sea level.

Green activists argued that breaches in polders or powerful storms could mean disaster of catastrophic proportions with vast areas getting inundated by sea water which would be impossible to be pumped out.

‘Polders are not only hampering land formation in this active delta but also creating ground for catastrophic disasters,’ said Bangladesh Paribesh Andolan joint secretary Sharif Jamil.

The Climate Central research said that analysis revealed a developed global coastline three times more exposed to extreme coastal water levels than previously thought.Globally, by 2050 the sea-level rise will push average annual coastal floods higher than land now home to some 300 million people, according to the research conducted on 135 countries in the world.

News Courtesy: www.newagebd.net