- Mar 3, 2006
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What Earth was like last time CO2 levels were so crazily high
"We’re on our way to the Pliocene." - April 18, 2023The last time CO2 levels were as high as today, ocean waters drowned the lands where metropolises like Houston, Miami, and New York City now exist.
It’s a time called the Pliocene or mid-Pliocene, some 3 million years ago,(opens in a new tab) when sea levels were around 30 feet higher(opens in a new tab) (but possibly much more and giant camels dwelled in a forested high Arctic. The Pliocene was a significantly warmer world, likely at some 5 degrees Fahrenheit (around 3 degrees Celsius) warmer than pre-Industrial temperatures of the late 1800s. Much of the Arctic, which today is largely clad in ice, had melted. Heat-trapping carbon dioxide levels, a major temperature lever, hovered around 400 parts per million, or ppm. Today, these levels are similar but relentlessly rising, at over 420 ppm.
Humanity is currently on track to warm Earth to Pliocene-like temperatures by century’s end — unless nations ambitiously slash carbon emissions in the coming decades. Sea levels, of course, won’t instantly rise by tens of feet: Miles-thick ice sheets take many centuries to thousands of years to melt. But, critically, humanity is already setting the stage for a relatively quick return to Pliocene climes, or climes at least significantly warmer than now. It’s happening fast. When CO2 naturally increases in the atmosphere, pockets of ancient air preserved in ice show this CO2 rise happens gradually, over thousands of years. But today, carbon dioxide levels are skyrocketing as humans burn long-buried fossil fuels.
"CO2 in the atmosphere has gone up 100 ppm in my lifetime," said Kathleen Benison, a geologist at West Virginia University who researches past climates. “That’s incredibly fast geologically."
What Earth was like last time CO2 levels were so crazily high
"We’re on our way to the Pliocene."
mashable.com
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