As if scaling the highest mountain on Earth wasn’t hard enough, global warming and pollution are making the trek even tougher, according to new research presented at the American Geophysical Union meeting in May. Since the first climbers reached the summit of Mount Everest in 1953, over an eighth of the mountain’s glacial ice has melted, creating a rockier—and more dangerous—terrain. Worse, some of the melted water has pooled into glacial lakes that are unstable and threaten to spill over, endangering both climbers and residents of Himalayan villages. While more scientists have begun studying this dire situation, it’s best to play it safe(r) and book your Mount Everest climb now, before things get even worse.