A group of the world’s top ecologists have issued a stark warning about the snowballing crisis caused by climate change, population growth, and unchecked development. Their assessment is grim, but big-picture societal changes on a global scale can still avert a disastrous future. Within the lifetime of anyone born at the start of the Baby Boom, the human population has tripled. Has this resulted in a human endeavor three times better — or one-third as capable of surviving? In the 1960s, humans took about three-quarters of what the planet could regenerate annually. By 2016 this rose to 170 percent, meaning that the planet cannot keep up with human demand, and we are running the world down.