Greenland is the biggest island in the world. If we put all the ice in Greenland into the ocean, the global sea level would rise by 6 metres, which would put the majority of the world’s coastal cities under water. With a temperature increase of 2°C by 2100, 130 million people would be affected by the rising ocean from the ice sheets in Greenland and Antarctica and the mountain glaciers. A 4°C climate warming would threaten between 470 million and 760 million people along the coasts. Megacities such as Shanghai, Tianjin, Dhaka, Kolkata, Mumbai, Hong Kong, Jakarta and Taizhou would be partly below sea level.
Recent estimates indicate the global risk in terms of population and assets exposed to coastal flooding up to 2070.
source: weforum.org