So what if we're able to use the planet's own record-keeping to fill in those important blanks?

This is the bold approach taken in a new study from Oregon State University (OSU) and University of St Andrews scientists, who, working with the US National Science Foundation, have unlocked a 50,000-year timeline of atmospheric carbon dioxide – thanks to tiny bubbles trapped in Antarctic ice, frozen in time miles below the Earth's surface.

"Studying the past teaches us how today is different," said Kathleen Wendt, an assistant professor at OSU and the study's lead author. "The rate of CO2 change today really is unprecedented."