Re: Bangladesh Coastline Rising
Can Crumbling Himalayas Protect Bangladesh From Rising Seas? - NYT
By Andrew C. Revkin
Scientists in Bangladesh have been reappraising forecasts of eventual inundation of sprawling, crowded delta regions as seas rise in a warming world. According to several reports, a fresh satellite analysis shows that new lands formed by sediment carried from the crumbling Himalayas are adding to Bangladesh's land area — at least for now.
As wire stories circulated overnight, I sent out some queries to sea-level experts and will report back on how this battle between new sediment and rising seas will play out.
Sea level is not uniform globally. Juneau, Alaska, is rising, for instance. The land there is rebounding, freed of the weight of ice-age glaciers. When I visited Juneau last year, biologists told me that a fight is brewing over whether protected coastal wetlands should no longer be protected once they are dry. (Coastal property owners say the new land is theirs.)
The fate of Bangladesh's lowlands will be determined by a mix of changes in the height of the Indian Ocean, subsidence of deltas as aquifers are drained and newly deposited sediments compress, and the addition of all that Himalayan soil.
In checking out the news from Bangladesh, I noticed that the Dutch have been advising Bangladeshis to do as the Dutch do — use engineering to work with the flow of sediment and accelerate the accretion of new lands. A recent article in The New Nation — "Can Bangladesh Trap Silt?" — is worth a look. All of this serves as a useful reminder that humans are not some static element in the climate puzzle, but a dynamic, responsive and innovative one — at least once a human community gets a strong signal that action is needed.
When I wrote with James Kanter last year about the report from the Intergovernmental Panel on Climate Change on impacts from global warming, I made sure we noted how the consequences for humans change significantly when adaptation is taken into account (boldface added):
Without such adaptations, it said, a rise of 3 to 5 degrees Fahrenheit over the next century could lead to the inundation of coasts and islands inhabited by hundreds of millions of people. But if steady investments are made in seawalls and other coastal protections, vulnerability could be sharply reduced.
Bangladesh has already proved to be one of the world's most resilient countries in the face of flood threats, as Secretary General Ban Ki-moon pointed out here. It sounds as if the country is getting geared up to find ways to exploit the eroding Himalayas as a way to counter the erosion of its coasts.
Adaptation can buy time and cut losses in the short run. But in the end, many experts note that unabated greenhouse-gas emissions essentially mean there will be no new normal climate or coastline to adapt to — in Bangladesh or anywhere else.
--- On Wed, 7/30/08, Isha Khan <bd_mailer@...> wrote:
From: Isha Khan <bd_mailer@...>
Subject: Re: Bangladesh Coastline Rising
To: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, zoglul@..., email@example.com, rehman.mohammad@..., firstname.lastname@example.org, mahmudurart@..., rivercrossinternational@..., email@example.com
Date: Wednesday, July 30, 2008, 5:43 AM
Bangladesh landmass 'is growing'By Mark Dummett
BBC News, Dhaka
Bangladeshis are used to frequent flooding
New research shows Bangladesh may not be as vulnerable to rising sea levels caused by climate change as previously feared, scientists in Dhaka say.
They say satellite images show the country's landmass is actually growing because of sediment dumped by rivers. A report by UN scientists has projected that rising sea levels will inundate 17% of Bangladesh by 2050, making about 30 million people homeless. One its authors said he saw little in the new research to change his mind.
Satellite images of Bangladesh over the past 32 years show that the country is growing annually by about 20 square kilometres (12.5 square miles), said Maminul Haque Sarker of the Dhaka-based Centre for Environment and Geographic Information Services.
This was due, he said, to the billion tonnes of sediment that the Ganges, the Brahmaputra and 200 other rivers bring from the Himalayas each year before crossing Bangladesh. Only about a third of this sediment, he said, makes it into the Bay of Bengal. Much of the rest is dumped in Bangladesh's vast delta, attaching itself to river banks, or even creating new islands. Mr Sarkar said that in the next 50 years this could add up to the country gaining 1,000 square kilometres.
But others maintain that Bangladesh is going to lose land over that period. Dr Atiq Rahman, a lead author of the UN Intergovernmental Panel on Climate Change report, told the BBC that there was little in the new research to make him think that their projection needed revising. He said that many people living along the coast had observed that sea levels where higher now than in their grandparents' day. "The rate at which sediment is deposited and new land is created is much slower than the rate at which climate change and sea level rises are taking place," he said.
So while some new land may be created in parts of the country, elsewhere a much larger amount of land will disappear, he said. In any case, the new land will take decades to become useful, and so compensate for fertile farmland that was flooded. Dr Rahman said that what is needed now is a village-by-village survey of coastal Bangladesh.
--- On Fri, 7/25/08, Isha Khan <bd_mailer@...> wrote:
From: Isha Khan <bd_mailer@...>
Subject: Bangladesh Coastline Rising
To: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, zoglul@..., email@example.com, rehman.mohammad@..., firstname.lastname@example.org, mahmudurart@..., rivercrossinternational@...
Date: Friday, July 25, 2008, 9:36 PM
Bangladesh Coastline Rising