CO2 may have saved Earth from freezing over early in the planet's history.From the press release:
A new analysis of ancient rocks from the eastern shore of Hudson Bay in northern Quebec, Canada now provides shows that CO2 Earth's atmosphere could have sustained surface temperatures above freezing before 3.75 billion years ago.
Previous studies had shown liquid water existed at Earth's surface even though the weak sun should have been unable to warm the planet above freezing conditions. But high concentrations of CO2 or methane could have warmed the planet, according to the research team.
Nicole Cates and Stephen Mojzsis survey a landscape of ancient rocks in Hudson Bay. Image CU-Boulder
