Clues to Climate Change in Earth's Past

By Bonnie Eissner

To understand what more carbon dioxide in the air means for our planet, Professor Stephen Pekar (GC/Queens, Earth and Environmental Sciences), a geologist, is looking back - way back to 60 million years ago.

In late July, he and 29 fellow scientists from around the world will embark on a nine-week ocean drilling voyage off the east coast of Australia — the International Ocean Discovery Program (IODP) Expedition 371. The goal is to drill about 3,000 feet below the ocean floor to reach sediment from the Paleogene Epoch - a few million years after the dinosaurs died off.

"We're going to be developing high-resolution climate records during time intervals when greenhouse gases were higher than today," Pekar says. "And as high as what we expect for this century."

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Looking at old sediment to predict the future is nothing new for Pekar. Previous expeditions have led him to the coast of Antarctica to understand the relationships between carbon dioxide, climate, and glacial ice in the earth's history.

"The size of the Antarctic ice sheet has fluctuated by up to 60 percent of its total volume in the past resulting in sea-level changes of well over 100 feet," he says. "While this took centuries to a millennium to occur, we only need a small percentage of that to cause a catastrophe of flooded cities that would result in hundreds of millions of refugees."

Pekar points out that for thousands of years leading up to the Industrial Revolution, atmospheric carbon dioxide was fairly constant — around 280 parts per million. Today, it's over 400 parts per million, and "we're heading for at least 500 parts per million, even if everyone gets on board," Pekar says. "And the Paris Agreement is not good enough."

Atmospheric carbon dioxide levels last reached 500 parts per million tens of millions of years ago. "So what humanity is going to do in a couple centuries, Mother Nature couldn't do in tens of millions of years."
 
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Pekar calls the IODP program "the most successful international scientific endeavor ever" - perhaps even more influential than the International Space Station. It started in the late 1960s as a U.S. mission to 'prove plate tectonics.' According to Pekar, it has since developed "the best climate records' of the last 100 million years.

"This is the closest you're going to get to being on the USS Enterprise with Captain Kirk," Pekar says, explaining that the scientists on board the ship share data and collaborate on research. "This is Spock data; this is the best of the best."

Beyond the research, Pekar sees an opportunity to broadcast the findings. He has reached out to partner organizations to plan Google hangouts, Webinars, and chats with teachers and students around the country. A videographer is joining the expedition, and Pekar and his colleagues will maintain a blog.

"The science of climate change is indisputable," Pekar says. "We scientists need to do a better job" of communicating that to the world.