What would happen if all the ice in the world melted?

Sea level would rise about 70 meters (230 feet) vertically and put large parts of the world underwater. For example Florida, the Netherlands and most of England would disappear. Only the tops of New York City’s skyscrapers would be visible. For this to happen the entire Antarctica ice cap would have to melt. Fortunately, the average temperature in most of Antarctica is around -37 °C (-35 °F) and shows no indication of rising above freezing any time soon. So the complete melt down scenario isn’t likely to happen.

The Greenland Ice Sheet on the other hand is melting. After the Antarctic Ice Sheet, it’s the second largest ice body in the world. A study shows that between 2003 and 2008 the Greenland Ice Sheet lost and average of 195 cubic kilometers of ice per year. That’s enough to cause an annual rise in global sea level of only a half a millimeter a year (5 cm over one century). What is troubling is that the rate of ice loss in the last couple years has increased dramatically. If you compare the first two years of the study to the last two there has been a 70% increase. Scientist don’t have enough data yet to determine if this increasing trend will continue.

What if the Greenland Ice Sheet were to completely melt? Sea level would rise by more than 7 m (23 ft) placing most coastal areas and large coastal cities like London and Los Angeles under water.