February 18, 2015

The Core of the Arctic

Polar exploration yields clues to climate change
Julie Brigham-Grette at Lake El’gygytgyn

A hundred kilometers north of the Arctic Circle, beyond the reach of any roads, lies a 3.6-million-year-old crater lake that holds a key to understanding our planet’s climate history—and perhaps adapting to its future.

Lake El’gygytgyn [Yupik for “the lake that never thaws,” nicknamed “Lake E”] is an 18-kilometer-wide lake formed when a large asteroid crashed to Earth in northeastern Siberia. The lake has yielded one of the most complete and longest sediment records ever found in the entire terrestrial Arctic.

Professor of Geosciences Julie Brigham-Grette, an expert in climate evolution, glacial geology, and sea-level history, leads the International Lake El’gygytgyn Drilling Project—an effort which involved contracting ice truckers and helicopter pilots, and getting a drill rig onto the frozen surface of the lake to take samples.

Because glaciers never covered Lake E from the moment its crater was formed, nothing blocked its collection of sediment, so the core taken from the lake’s bottom furnishes a continuous record of the last 3.6 million years: fossils that tell about changing water temperatures, and pollen and tree detritus that reveal a dark, forested Arctic, when the summertime climate was probably 10 to 14 degrees Celsius warmer than it is today.

The next stage for researchers is determining why and how the Arctic climate system evolved from a warm, forested ecosystem into one dominated by ice, and extrapolating from that what our climate future might look like.

“Geologists are like Time Lords,” Brigham-Grette says. “We can go backward and forward in time.”

As the Earth’s atmosphere warms, the prospect of a modern ice-free Arctic raises issues of concern such as increased shipping traffic, which can pose a threat to already vulnerable ecosystems.

Brigham-Grette was recently named chair of the U.S. National Academy of Sciences Polar Research Board, which connects the U.S. polar research community to international planning activities regarding the Arctic and Antarctic. Her committee advises federal agencies, and spends summers in the field on the Svalbard archipelago co-leading undergraduate teams researching tidewater glaciers. With climate change inevitable, and the tree line marching northward yet again, she emphasizes that the role of humans is now to be adaptable.

“It’s coming. Our destiny is set,” says Brigham-Grette. “Now we have to be problem-solvers. Students should see an opportunity in how they can help improve things.”