As seen in the Toronto Star, cities on the east and west coasts of North America will face even greater flooding if a massive Antarctic sheet melts completely.

A new report, recently published in the journal Science, finds the current estimate of global sea rise is inaccurate because it doesn’t consider three geophysical factors if the West Antarctic ice sheet melts.

The paper states that the average estimate of a five-metre sea level rise should actually go up to seven metres. The seemingly small difference could submerge much of southern Florida, San Francisco, New York and Washington, D.C., while inundating parts of New Brunswick, Nova Scotia, P.E.I. and British Columbia with water.