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Photograph by Ira Block
Inuit Johnny Issaluk holds a recent photo of a South Carolina swamp. That’s what his home, near the Arctic Circle on Baffin Island, would have looked like 56 million years ago, when summer water temperatures at the North Pole hit 74°F.
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Photograph by Ira Block
When the Ocean Went Dark
Paleoceanographer James Zachos holds a replica of a sediment core that shows an abrupt change in the Atlantic Ocean 56 million years ago, at the onset of the Paleocene-Eocene Thermal Maximum (PETM). White plankton shells vanished from the seafloor mud, shifting its color from white to red. As planet-warming CO2 surged into the atmosphere, Zachos says, it also seeped into the seas, acidifying the water and dissolving the shells. -
Photograph by Ira Block
Interlude with Dwarfs
Holes in fossil leaves like this one indicate that insects in the Bighorn Basin got more abundant and voracious as CO2 and temperatures rose during the PETM. Some mammals adapted by temporarily shrinking. Horses had shinbones the size of chicken drumsticks. The lesson, says Philip Gingerich: When it needs to be, "evolution is fast." One of the earliest complete horse skeletons, from a few million years later in the Eocene, is similar but 50 percent larger. -
Photograph by Ira Block
Interlude With Dwarfs
During the PETM, some mammals adapted by temporarily shrinking. Horses had shinbones the size of chicken drumsticks. The lesson, says Philip Gingerich: When it needs to be, "evolution is fast." One of the earliest complete horse skeletons (above) from a few million years later in the Eocene, is similar but 50 percent larger. -
Photograph by Ira Block
Today in the arid Bighorn, rust red bands of oxidized soil mark the sudden warming that occurred there 56 million years ago—which dried up the swamps that had been home to reptiles similar to the Okefenokee alligator pictured here.
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Photograph by Jason Hawkes
The source of the carbon surge 56 million years ago is uncertain, but it was natural. Today’s surge, which may prove much faster, is human made. Oceans and forests absorb atmospheric CO2 but can’t keep up with emissions from stacks like this one (at center) at a coal-fired power plant in England—the country where the industrial revolution began.
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Photograph by Ira Block
Using a technology that might forestall a warmer epoch, test tanks at an American Electric Power plant in West Virginia captured a fraction of the plant’s CO2. But until the government sets limits on emissions, the company has shelved the costly project.
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