Could Humans Go Extinct?

To see the apocalypse firsthand, start at McKittrick Creek in Texas and hike up switchbacks, through juniper trees, along the Permian Reef trail. About 1,200 feet up are huge blocks of limestone formed from the discarded shells of an impressive variety of sea creatures—rice-like foraminifera, elaborate brachiopods that filtered seawater for bits of dead flesh, hundreds of varieties of snails....