Ice sheets in Greenland and Antarctica are now melting six times faster than they were in the 1990s due to rising temperatures, according to a new report.

From 1992 to 2017, the two landmasses lost over 6 trillion tonnes of ice, pushing sea levels up by almost 18 millimetres.

Co-leader of the study, Professor Andrew Shepherd, from the University of Leeds, said: "Three-quarters of the ice loss is because the waters around Greenland and Antarctica are too warm. It's not really hot. It's only half a degrees centigrade above freezing but it's enough to cause the glaciers to destabilise and to pour more ice into the sea."

Scientists say the melt rate follows the “worst-case scenario” model and without a substantial cut to carbon emissions, it could put around 400 Million people at risk of annual coastal flooding over the next 80 years.

"Those models have been too conservative as they've been outstripped in the past 20 to 30 years so instead of 50 cm of sea-level rise we should expect another 15 or 20 cm. That will force people to built higher flood defences of bringing forward by several decades the defence plans they are already making," said Shepherd.

"We are also in the middle of a climate emergency which is going to affect younger people and we could do something to stop that as well so let's hope governments will put money on the table to solve this problem for future generations."