The mystery of how Antarctica's ice sheet came to exist. Fossil evidence has shown a 2.5 Celsius (4.5 Fahrenheit) drop in the temperature of the ocean, which would have been significant enough to cause Antarctica to freeze. Now scientists are hoping they will also be able to use this information to predict whether global warming will cause it to thaw.

"New evidence could solve the puzzle of why Antarctica went into the deep freeze," the University of Cardiff said of a study by scientists in Wales and the United States and published in the Geological Society of America's journal Geology.

"Now we understand the system better," Caroline Lear, of Cardiff University and lead author of the study, told Reuters. "Some other records had suggested there was even a warming at that time, which was really confusing."

Just to add some perspective, the potential outcome of Antarctica fully melting would be a 190-foot rise in world sea levels, however a small melt could still be disastrous for coastal cities such as New York.

Hit the jump for a more in-depth (read: scientific) explanation of why ocean cooling had such a major impact on Antarctica.

» Reuters Environment