Up to 216m threatened by rising sea levels: Study

Scientists have long warned that global warming could swallow hundreds of islands and large swathes of coastal areas by the end of the century. But a new study has identified just how many people - and where - could find their homes under water come 2100.

Some 147 million to 216 million people would find their homes below the sea or subject to chronic flooding by the end of the century, assuming that the emissions of greenhouse gases continue at the current rate, according to analysis by Climate Central, a news and scientific organisation.

Among the top 20 countries and territories with the greatest number of people exposed to the risk of flooding or submerged homes, 12 are located in Asia.

Over a quarter of Vietnam's population will risk seeing chronic floods or their homes submerged, while 12 per cent of Thais and 10 per cent of Japanese will face the same threat.

In terms of sheer numbers, China topped the chart with more than 50 million people exposed, followed by Vietnam, with more than 23 million considered vulnerable. India, Bangladesh, Myanmar, the Philippines and Indonesia are the other countries at risk.

In Singapore, between 0.9 per cent and 1.4 per cent of its population - or up to 72,000 people - would be affected, said Climate Central in response to queries from The Straits Times.

Dr Ben Strauss, a Climate Central director, said: "The degree of underestimation is likely to be greatest or at least higher than average in large, dense urban areas… So since Singapore's population is concentrated pretty much exclusively in such an area, I am confident that - unfortunately - the ultimate numbers will prove much higher."

The study was based on analysis of the most detailed sea-level data available, looking at how heat-trapping gases such as carbon dioxide would melt the ice caps and raise sea levels, while taking into account likely reductions in emissions in the future, as well as the sensitivity of sea levels to temperature changes.

Much of the greenhouse gas is released when fossil fuels are burned for energy, but the rapid loss of forests has also accelerated the process as it leaves fewer trees to absorb carbon dioxide.

Small island states like the Maldives are particularly vulnerable to being obliterated by rising sea levels.

Among the countries or territories with more than one million people, the Netherlands had the greatest percentage of population exposed to floods or submergence, but the study also noted that its extensive network of levees may protect its residents.

Residents of China - currently the biggest contributor to such gases - form the largest group of people who would have to contend with homes under water.

Climate Central warns that the figures in its report are probably understating the severity of the problem because of the likely imprecision of the data used. "If the overall error factors we calculated for the US apply globally, then 300 to 650 million people live on land that will be submerged or exposed to chronic flooding, by 2100, under current emission trends," it said on its website.

This article was first published on Sep 25, 2014.
Get a copy of The Straits Times or go to straitstimes.com for more stories.