The world as we know it would end if all the ice on Earth melted. A large portion of North America and Europe, however, would vanish entirely.

The whole ice melt may cause a global sea level increase of nearly 70 meters. Complete thawing of the ice, however, would call for a planet that is far hotter than the one we now inhabit.

This means that the thermal expansion of water, or the fact that hot water occupies more space than cold water, might add another 30 meters to the total height of the structure (bringing the total height to 70 meters).

A rise of 70 meters in sea level would have a profound effect on the global landscape; if it happened overnight, it might affect as much as half of the world’s population, and the other half would be forced to accommodate an additional 3.5 billion homeless people.

Three huge ice sheets constitute 99 percent of the world’s ice; Greenland’s ice sheet contributes roughly seven meters to sea level rise, West Antarctica contributes about eight meters, and East Antarctica contributes about 55 meters.

Although global sea levels would rise if all three ice caps disappeared, the increase would not be uniform.

Greenland’s melting ice flows into the South Pacific, while Antarctica’s causes sea levels to rise around Europe and North America because of the mass pull from the ice caps changing the Earth’s gravitational field.

The United Nations’ climate panel predicts that a temperature increase of between one and four degrees Celsius over pre-industrial levels will melt all of Greenland’s ice sheet in under a millennium.