Much as increasing levels of carbon dioxide in the atmosphere create a greenhouse effect that warms the Earth, new research that explores CO2 levels from 30 million-plus years ago found that lower levels of the gas helped the formation of the polar ice caps.
CO2 was on the low side during the Eocene-Oligocene (say that five times fast) climatic transition period and allowed the planet to chill enough for ice to form at the polar extremes.
It turns out the clues rested in the East African village of Stakishari in Tanzania. There scientists were able to precisely date the time where rocks of the period were formed. Those rocks, in turn, give a look at levels of various gases in the atmosphere so long ago.
The period marked the biggest change in the planets climate since the extinction of dinosaurs 65 million years ago.