Previous scientific estimates have dated the dawn of Man back to no more than a few hundred thousand years ago. But new evidence suggests that people started screwing up the environment hundreds of thousands of years earlier.

Scientists are looking back to a time when "greenhouse gases" were not the problem they are today, and it is giving them a clearer picture of how people are making it worse.

A team of European researchers analyzed tiny air bubbles preserved in Antarctic ice for millennia and determined there is more carbon dioxide in the atmosphere now than at any point during the last 650,000 years.