Climate models predict that the Arctic will become an additional 7 to 12 degrees Fahrenheit warmer during the next century. If that happens, scientists expect at least half the Arctic sea ice to melt by the year 2100, significantly raising sea levels across the world.

A new computer model built by a joint UK/Finnish team shows the relationship between sea temperature and sea level over the last 2,000 years. According to a report by the BBC:

“For the past 2,000 years, the [global average] sea level was very stable, it only varied by about 20cm,” said Svetlana Jevrejeva from the Proudman Oceanographic Laboratory (POL), near Liverpool, UK.

“But by the end of the century, we predict it will rise by between 0.8m and 1.5m. The rapid rise in the coming years is associated with the rapid melting of ice sheets.”

For polar bears, the melting ice sheets are a particularly dire threat. Polar bears rely on the ice to hunt seals, their main food source, and also to rest between hunts out on the ice. But what happens when the ice vanishes?

Melting ice isn’t strictly a polar bear problem at the north pole. Down at the bottom of the world, rising sea temperatures threaten the Antarctic ecosystem too. In 2002, a massive ice shelf the size of Delaware broke off from the Larsen B peninsula, a collapse that scientists say was of a scale unprecedented in the last 12,000 years. If the trend continues, significant Antarctic ice melting could result in a disastrous rise in sea levels. Read about climate change in the Antarctic, then watch “Penguins of the Antarctic” this Sunday, April 27th at 8pm.

For more information about polar bears, visit Nature online and read about how polar bears evolved form grizzlies, and discover the striking intelligence of these massive carnivores.