" David Breashears is probably best known for his high-altitude cinematography—a world-class climber, he took the IMAX images for the classic film Everest. But one of his most important projects consists of still images like these. He took old pictures of the roof of the world—many from the 1921 Mallory expedition to Everest—and painstakingly found the same vantage points so he could recreate the shots eight decades later. Side by side, what the images showed was an almost unbelievable loss of ice—the scale of these mountains is so huge that it takes a moment to realize that, in the pictures of the Ronbuk Glacier, 400 vertical feet of ice (that’s taller than the Statue of Liberty) has disappeared. "

― Bill McKibben , The Global Warming Reader: A Century of Writing About Climate Change