400 ppm – Pliocene Levels of CO2

An instrument near the summit of Mauna Loa in Hawaii has recorded a long-awaited climate milestone: the amount of carbon dioxide in the atmosphere there has exceeded 400 parts per million ppm for the first time in 55 years of measurement—and probably more than 3 million years of Earth history.

via Climate Milestone: Earth’s CO2 Level Nears 400 ppm.

Its been at least 800,000 years since it was this high. This has serious, and scary, implications for the people, plants, and animals on earth.  We are already seeing shifting agricultural zones, pests, and flora.

How will changing climate zones impact food production, and the pests that go with them?  Will we be able to produce enough food?  Will the changing climate be drier where we need it to be wetter?  Will we be creative enough to cope with 9 billion people dependent on a steady food supply?

If anything, those numbers understate how different the Pliocene climate was. The tropical sea surface was about as warm as it is now, says Alexey Fedorov of Yale University, but the temperature gradient between the tropics and the poles—which drives the jet streams in the mid-latitudes—was much smaller. The east-west gradient across the Pacific Ocean—which drives the El Niño-La Niña oscillation—was almost nonexistent. In effect, the ocean was locked in a permanent El Niño. Global weather patterns would have been completely different in the Pliocene.

What was it like when camels roamed Ellsmere Island?

Beavers and camels on Ellesmere Island, instead of glaciers, might not be so bad.  But there was a lot less ice in general in the Pliocene. That means there was a lot more water in the ocean, which means sea level was a lot higher—how high exactly, no one knows.

“The estimates have been all over the map,” Raymo says. They’ve ranged from 10 meters (33 feet) to 40 meters (131 feet) higher than today. But even the conservative estimate, were it to recur today, would mean flooding land inhabited by a quarter of the U.S. population.

Where will these people go?  And more importantly, who will pay for it?  And that’s just the US.  Rising seas will impact cities all over the world.  What sort of global trade will take place if the ports are flooded?

What questions do you have about climate change?

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