Columbia Scientist co-leads Expedition through Iceberg Alley

June 24, 2019

Co-chief scientist Maureen Raymo of Columbia University’s Lamont-Doherty Earth Observatory led a crew of 120, including 30 scientists, along Expedition 382 on the scientific research ship JOIDES Resolution through what is known as “Iceberg Alley” in the Scotia Sea, just north of the Antarctic Peninsula and southeast of continental Chile.

The two-month cruise, co-led with climatologist Michael Weber of the University of Bonn, launched and returned to dock in Punta Arenas in the extreme south of Chile. From March 20 to May 20, 2019, the expedition participants sought to better understand the history of the Antarctic ice sheets over the past 10 million years, focusing on the late Pliocene period about 3 million years ago, when carbon dioxide levels were similar to today’s levels of some 400 parts per million, sea levels were high and temperatures were close to that expected by the end of this century.

The difference between the Pliocene and the current period is that the former’s high level of CO2 occurred naturally, while today’s high levels are caused by human activity. Regardless, the effects of today’s global warming could be catastrophic - at 5.4 million square miles, the Antarctic ice sheet is the greatest mass of fresh water on earth. If it were to completely melt, the result would be a 70-meter increase in global sea levels, wiping out coastal settlements and some nations altogether.

Knowing how fast this may happen would allow for the Earth’s inhabitants to prepare accordingly. In order to understand this, the Expedition 382 cruise drilled 600-meter sediment cores from the seabed at several sites. The idea is to study the debris unloaded by melting icebergs over millions of years. Studying the rocks and sediment, the scientists can figure out where they came from and when they were dropped. This gives them a picture as to how much ice was discharged and when, providing a roadmap to the changing climate and giving clues as to what expect in the future.

After having returned to terra firma in Chile, expedition members are continuing to study the core samples and will reconvene in two years to present the results of their individual research into the rates and causes of climate change before human activity-driven acceleration.

Expedition 382 – with scientists hailing from India, Japan, Korea, the Netherlands, Germany, Spain, Switzerland, Brazil, China, Germany, Australia, the United Kingdom and the US - preceded the Expedition 383, a 2-month scientific cruise that from May 25-July 25 is exploring the history of the Earth’s climate system in the Southern Ocean.