Bill McKibben on Earth Day at 50
Bill McKibben writes: On the fiftieth anniversary of the first Earth Day, let’s think for a moment about the Earth—backdrop for our busy and dramatic life, but also a planet. One can observe it dispassionately, through scientific instruments, as if it were any other planet. And here’s how it looks, these past five decades: The white ice at the northern pole, one of the most obvious features on the planet, has shrunk dramatically: at least half the summer sea…