New Delhi, March 28: China, India and Bangladesh are among five countries that account for more than half the global population living in low-lying coastal zones vulnerable to sea-level rise and storms, says a new study.
Using population distribution and human settlement patterns for the first time to estimate areas threatened by climate change, the study has shown that 268 million people in these three countries live within 10 metres of sea level.
In all, 634 million people live in such low-lying areas around the world — from urban coastal areas in the eastern US to the delta regions of Bangladesh to the rapidly growing east coast of China.
Over 80 million people in Indonesia and Vietnam also live in zones that, scientists believe, could face sea-level rise or tropical storms associated with climate change.
“What comes out strongly is that more than half of the population in low-lying coastal areas are in these five Asian countries,” said Gordon McGranahan, director, human settlements group, at the International Institute of Environment and Development in London, and a co-author of the study published in the April issue of the journal Environment and Urbanization.
“These are fast-growing and fast-urbanising areas, and many of their coastal cities already have large low-income populations settled on their flood plains,” McGranahan told The Telegraph.
India has 63 million people living in low-lying coastal areas, while the number for Bangladesh is 62 million. China, whose export-driven economic growth has led a coastward movement of people, has 148 million in low-lying coastal zones.
The reason for low-income groups to settle on the flood plains is precisely because of the flood risk — it makes the land inexpensive and undeveloped by commercial developers, McGranahan said. Although the low-lying coastal areas make up only 2 per cent of the world’s land area, about 10 per cent of the global population lives there.
The Intergovernmental Panel on Climate Change had in its assessment report released earlier this year said that sea-level rise may range from 18 cm to half-a-metre over the next few decades.
“Even as the seaward risks associated with climate change are increasing, the areas most at risk are experiencing particularly high population growth,” the study said.
It cited Bangladesh where, although flooding is already a problem, the rural population in the low-elevation coastal zones is growing at “an even faster rate than the country’s urban average”.
Although China has also witnessed coastward population movements, “the risks of climate change are clearly far more threatening and intractable for Bangladesh than for China,” McGranahan and his colleagues from US institutions said.
The paper has said adaptation to the risk of climate change would require a combination of regulations and economic incentives to redirect new settlements to better-protected locations and investments in infrastructure.