As we ponder the cause of our planet's warming, much comfort is taken from Earth's four hundred and fifty thousand year history of natural climatic variations. The Vostock Ice Core tells us what happened, but why it happened remains a mystery. The Climate Trap goes deeply into Earth's history, 10,000 times further back than the ice core, to determine why Earth suddenly heats up after it slowly freezes and what Earth's built-in freeze protection system will do when Earth is gently warmed.