Global sea levels could rise more than two meters by the end of this century if emissions continue unchecked, swamping major cities such as New York and Shanghai and displacing up to 187 million people, a new study warns. The study, says sea levels may rise much faster than previously estimated due to the accelerating melting of ice sheets in both Greenland and Antarctica. Lead author Jonathan Bamber is a Professor of Physical Geography at the University of Bristol in the UK.