Entire cities are at risk of being submerged under rising sea levels over the next 30 years, putting hundred of millions of people at risk of losing their homes, according to a new study.
A new digital elevation model known as CoastalDEM indicates that as many as 630 million people around the world live on land that lies below projected annual flood levels for 2100.
The figures, published in the Nature Communications journal, also show that some 340 million people will be living on land that falls below the levels of average annual coastal land by 2050 - up from the previous NASA estimate of 250 million.
People at risk of annual floods live in major cities including Bangladesh, Jakarta and Thailand - with the threat of being entirely submerged making the areas at risk of being uninhabitable.
Other cities across Asian countries are vulnerable - such as Shanghai, Tianjin and Hong Kong - while the Vietnamese capital Hanoi and the entire southern tip of the country could be flooded, according to the projections.
Nineteen other countries, including Brazil and the UK - where London is predicted to be affected - could also see land being lost beneath the waves.
Read more from Yahoo News UK:
Benjamin Strauss, co-author of the study and CEO of Climate Central, said: "The results indicate that, yes, a great deal more people are on vulnerable land than we thought.”
He added that the affected regions need to take immediate action to avoid the impending "economic and humanitarian catastrophe”.
The study adds: ”Recent work has suggested that, even in the US, sea-level rise this century may induce large-scale migration away from unprotected coastlines, redistributing population density across the country and putting great pressure on inland areas.”
Climate Central researchers claim that previous predictions of sea levels rising by as much as three metres are too conservative.
The melting of Greenland’s ice sheets has resulted in over 275 gigatons being lost on average per year between 2006 and 2015, according to a UN report on climate change.
It is believed that rising sea levels contribute to warmer temperatures across the globe, resulting in a lack of food and running the risk of severe health crises.