On a cold summer day like this, I'm doing a bit of winter reminiscing. The snowy landscapes seem so far away but before we know it, it will be time for a winter whiteout again. Winter is coming anyone?
During the last 2 billion years the Earth's climate has alternated between a frigid "Ice House", like today's world, and a steaming "Hot House", like the world of the dinosaurs. This chart shows how global climate has changed through time.