More than 40 million people than expected will be affected by coastal flooding by 2100 a new study has revealed.
The study, published by the University of Leeds, shows that Greenland's ice sheet is melting at a much faster rate than originally predicted.
It shows that Greenland has lost 3.8 trillion tonnes of ice since 1992, pushing global sea levels up by 10.6 millimetres.
Previous studies predicted global sea levels would rise 60 centimetres by 2100, which would have put 360 million people at risk of annual coastal flooding.
Professor Shepherd said: 'As a rule of thumb, for every centimetre rise in global sea level another six million people are exposed to coastal flooding around the planet.
'On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to all sea level rise.
'These are not unlikely events or small impacts; they are happening and will be devastating for coastal communities.'