Earth — David Brin

A microscopic black hole has accidentally fallen into the Earth's core, threatening to destroy the entire planet within two years. Some scientists are frantically searching for ways to prevent the disaster. But others argue that the only way to save the Earth is to let its human inhabitants become extinct: to let the evolutionary clock rewind and start all over again. Earth is an edge-of the-seat thriller, a kaleidoscopic novel peopled with extraordinary characters and challenging new visions of an incredibly real future: global computer networks that put limitless information at everyone's fingertips, an environment ravaged by the greenhouse effect, a quiet revolution by the politically powerful elderly.