As the world temperatures continue to rise, climate scientists are increasingly concerned about one of the largest caches of freshwater on the planet – Antarctica. According to a report from the Washington Post, their fears may be completely justified. A new study has revealed that there are enough fossil fuels remaining on planet to melt every last ice molecule on the Antarctic ice sheet.

The study found that it would likely take up to 10,000 years for the Antarctic ice sheet to melt completely, which is miles thick in some areas. The consequences could be dire, however; when all the ice on Antarctica is gone, the sea level may rise as high as 200 feet.

Ken Caldeira, a scientist at Stanford’s Carnegie Institute of Science says that he first heard the question asked in the late 1970s, but was never able to fully examine how much fossil fuels it would take to melt Antarctica. Over time, climate models developed enough to make a legitimate estimate. The ice and climate models used in the study have become the standard for modeling changes in ice cover over time.

Caldeira estimates that it would take about 500 years to use up the Earth’s remaining reserves of fossil fuels. The CO2 and other greenhouse gases produced these sources would linger in the atmosphere for millennia, however, slowly melting ice caps and causing the sea level to rise.

Warming oceans would be responsible for the majority of the melting, and not the temperature increases from the atmosphere. Caldeira says it may take thousands of years to completely destroy the ice cap, but he urges officials to act swiftly. As alternative energy sources continue to develop, it’s just a matter of how quickly they can be adopted by nations before we can say for sure how much time the Antarctic ice sheet has left.