By Tamara Dietrich
1:01 PM EDT, July 17, 2013
For years, scientists couldn’t understand how Earth 3 or 4 billion years ago was roughly as warm as now, while the sun was still much dimmer – called the “faint young sun paradox.” Now they think they’ve figured it out: greenhouse gases.
National Geographic has just published a piece on a 3-D supercomputer simulation that takes a slew of new factors into account -- clouds, winds, ice, etc. -- when figuring out why ancient Earth wasn't an ice cube.
What they found, magazine authors Christine Dell’Amore and Robert Kunzig say, was fresh support for an old theory that high concentrations of carbon dioxide and methane kept the planet from freezing back when there were no or few clouds, little or no oxygen, no plants, lots of volcanoes and undersized continents.
The climate scientists who authored the study are Eric Wolf and Brian Toon of the University of Colorado at Boulder.
The methane would also likely have painted the sky a faint pink, so forget the big blue marble hanging in space that we all know and love.
It would be another billion or so years before the planet evolved enough to undergo its first global ice age.
For more, go to National Geographic.
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