By 2100, the oceans could rise by 5 feet, according to a new scientific study

Previously, scientists had estimated that climate change would lead to glacier melts and sea levels rising by a few centimeters at century's end. Now, a new international study offers a more dramatic picture of our changing coastlines.

Climate change has transformed the face of the Earth for billions of years. At one time, Antarctica was a tropical paradise. And for much of the planet's history there was almost no land at all, and life made its home in a vast, planet-wrapping sea. Now we're seeing the first signs that the planet might be headed back to a more watery version of Earth.

A new scientific study is being circulated among government leaders by an international team from the Arctic Monitoring and Assessment Program (AMAP). The group of scientists found that glaciers are melting much faster than expected, and as a result there is less shiny, white ice to reflect the sunlight back into space. This means the oceans absorb more heat than ever, leading to more melting, and . . . you get the idea. World leaders will be debating the report in Copenhagen this week, during a conference on climate change.

According to AP, which has seen the report:

Drawing on improved research techniques and recent scientific papers, the AMAP report updates forecasts made by the U.N.'s expert panel on climate change in its last major assessment in 2007.

The melting of Arctic glaciers and ice caps, including Greenland's massive ice sheet, is projected to help raise global sea levels by 35 to 63 inches (90 to 160 centimeters) by 2100, AMAP said, although it noted that estimate was highly uncertain.

That's up from the 2007 projection of 7 to 23 inches (19 to 59 centimeters) by the U.N. panel. The U.N. group had left out the possible acceleration of melting in Greenland and Antarctica, saying research on that hadn't advanced sufficiently by the mid-2000s. The U.N. estimate was based largely on the expansion of ocean waters from warming and the runoff from melting land glaciers elsewhere in the world.

Now the AMAP assessment finds that Greenland was losing ice in the 2004-2009 period four times faster than in 1995-2000.

In addition, the cover of sea ice on the Arctic Ocean is shrinking faster than projected by the U.N. panel, threatening the long-term survival of polar bears and other ice-dependent species. Summer ice coverage has been at or near record lows every year since 2001, said AMAP, predicting the ocean will be almost ice-free in the summer in 30 to 40 years.

An independent study by American geologists confirms these findings, and suggests that sea levels could rise by as much as 13 inches by 2050.

Sea level rise will hit different areas of the world unevenly. Florida may be submerged, while other areas could be largely unaffected. Even cities that remain above the water line could still suffer tremendous economic damage. New York City's subways would flood, for example, costing the city enormous amounts of money to repair.

Read more via AP

Illustration via Terradreams