The world is heading for a three-feet rise in sea level and NASA has warned it is too late to prevent it.
Sea levels have risen about three inches since 1992 due to warmer temperatures and the burning of fossil fuels, but a further three feet would put millions of lives at risk.
According to NASA, more than one-third of the human population – nearly 2.4bn people – lives within 100 km (60 miles) of an oceanic coast and low-lying capitals such as Dhaka in Bangladesh, with a population of 14 million people, could see rivers flooding within the next 20 years, leaving parts of the city submerged.
New Orleans, still recovering from Hurricane Katrina, may also be at risk, with NASA’s words raising concerns that flood-proofing projects may have underestimated the sea-level rise.
The United Nations’ Intergovernmental Panel on Climate Change predicted two years ago that sea levels would rise between one and three feet by 2100 but Steve Nerem, lead researcher on NASA’s Sea Level Change Team, says the world will probably see the rise being at the higher end of that.
He said: “It’s pretty certain we are locked into at least three feet of sea-level rise, and probably more, but we don’t know whether it will happen within a century or somewhat longer.”
The findings are based on satellite data looking at sea levels, heat stored in oceans and the amount of water being added by melting ice sheets in the Arctic and Antarctica.
Some scientists, for example, already believe that the Arctic could be ice-free during the summer within 15 years, with massive effects for people living there who rely on the ice, along with the animals that depend on it.
The warmer temperatures are to blame for at least a third of the world’s sea level rise and oceans absorb most of that heat.
Mr Nerem says: “When heat goes under the ocean, it expands just like mercury in a thermometer. That expansion means more mass for the ocean and a higher sea level overall.”