Illuminating carbon’s climate effects
Harvard scientists are helping to paint the fullest picture yet of how a handful of factors, particularly a worldwide increase in atmospheric carbon dioxide, combined to end the last ice age 10,000-20,000 years ago. As described in a paper published April 5 in Nature, researchers compiled ice and sedimentary core samples collected from dozens of locations around the world, and found evidence that while changes in the planet’s orbit may have touched off a warming trend, increases in CO2 played a far more important role in pushing it out of the ice age. “Orbital changes are the pacemaker. They’re the trigger, but they don’t get you too far,” lead author Jeremy Shakun, a visiting postdoctoral fellow in earth and planetary sciences, said. “Our study shows that CO2 was a much more important factor, and was really driving worldwide warming during the last deglaciation.” Though scientists have known for many years, based on studies...