As more people around the world begin to feel the effects of climate change, many are asking themselves how we will power the world moving forward. Studies show that the Antarctic ice sheet is extremely sensitive to temperature increases, and that burning all of the fossil fuels in the world would ensure a certain death for the ice surrounding the South Pole.

But just how much coal, oil and gas do we need to burn in order to change the climate in such a significant way? One study estimates that among the available fossil fuel reserves on Earth, there are over 10,000 gigatons of carbon that could potentially be released into the atmosphere. At the rate we currently burn fossil fuels, it would take roughly 500 years to burn through this reserve.

According to the U.S. Energy Information Administration, the world held an estimated 1,655.5 billion barrels of oil in reserves across the globe in 2014. This is actually up from a level of just 1,475.6 billion in 2011. There is currently more oil on the planet than is economically viable to extract in many places.

While we probably won’t see the end of oil anytime soon, climate scientists illustrate a valid point. Without making any changes to the way the world consumes energy, it would only take 500 years to eliminate one of the largest ice sheets on the planet. Climate change is a serious threat to life on Earth, and only by making changes now can we keep things from getting out of hand.