A seal swims by icebergs off the British Antarctic Survey's Rothera base in this Jan. 23, 2009 file photo. (Alister Doyle/Reuters)

Left unchecked, the extra water dumped into the oceans could push average global sea level six inches higher by 2050, the report finds. That would mark the ice sheets — defined as expanses of deep, long-term ice larger than 20,000 square miles — as the largest contributors to sea level rise, outstripping melting from Earth’s other frozen reservoirs, namely mountain glaciers.

Six inches of water may not seem much — that’s just barely nipping over your heels — but for some low-lying countries, such as the Republic of Maldives and Bangladesh, the loss of coastline could be devastating.