If the present rate of clear-cutting continues, all tropical forests may be gone before the end of the century, and with them possibly 50 percent of all species of life on Earth. No comparable biological catastrophe has occured on this planet since the time of the dinosaur extinctions 64 million years agio, when the impact of a massive asteroid blasted as many as half of all living species into oblivion.
— Chet Raymo, The Path