Next generation climate scientists prepare for the future by studying past North Atlantic iceberg melting

Yuxin Zhou looking at a sediment core, holding a metal spatula.
As a research fellow for Woods Hole Oceanographic Institution (WHOI), Zhou helped collect on sediment samples and sectioned portions of the core. (© Woods Hole Oceanographic Institution, T. Kleindinst)

By Grace Rodgers 
Medill Reports

In a race against climate change, Yuxin Zhou, 26, is among the next generation of climate scientists studying the Earth’s responses to rapidly rising temperatures, threatening life on the planet.

As a fifth-year Ph.D. student at Columbia University’s Lamont-Doherty Earth Observatory, studying how the Earth’s climate behaved in the past is the best way for Zhou to understand the pace and consequences of climate change today.

In a similar way, to understand Zhou’s pathway into climate science, it’s important to look back on his journey to the present.

After graduating high school in Nanjing, China, Zhou moved to the United States to study computer science at the University of Southern California. However, less than one year into the undergraduate program, he switched to geological sciences, inspired by his first earth science class.

“My deepest memory is my professor talking about his experience going into a submersible for research. He said it’s like looking down from an airplane onto New York City streets because it’s bustling with life,” Zhou said. “It was really that class that captured me and helped me become interested in earth science.”

Yuxin Zhou and Pablo Alasino working performing field work in Argentina.
While in Argentina as a University of Southern California undergraduate student, Zhou worked with professor Pablo Alasino (left) on geological mapping. (Yuxin Zhou/Columbia University)

While in undergrad, he also participated in multiple research opportunities in geochemistry, one of which was a summer fellowship at the Woods Hole Oceanographic Institution. He also gained publications in Nature Geoscience and Journal of Geophysical Research – Atmosphere.

From there, he moved cross-country to pursue a degree in earth and environmental sciences at Columbia University’s Lamont-Doherty Earth Observatory just outside of New York City.

“I just really wanted to continue to do the research, and earning a Ph.D. was the natural next step,” Zhou said.

As a current fifth-year Ph.D. student, Zhou’s research focuses on the factors destabilizing the circulation in the North Atlantic, spanning the past 150,000 years

Jerry McManus, a geochemistry professor and researcher at Lamont-Doherty, works closely with Zhou as his research advisor and has seen his growth as a young scientist in the field.

“He started his Ph.D. working on more recent climate issues, and then became interested in paleoclimate and in geochemistry. He’s gone up a learning curve and has done brilliantly,” said McManus. “I work with wonderful, bright junior people, and if I can stay out of their way and help them to do their great work, then that works out the best all-around.”

Yuxin Zhou standing at a podium presenting his research at the Goldschmidt geochemistry conference in Barcelona.
While at the Goldschmidt geochemistry conference in Barcelona, Zhou presented his research on the history of iceberg discharge in the western North Atlantic. (Athena Nghiem/Columbia University)

In early October, both Zhou and McManus presented their new research at the Comer Climate Conference, an annual summit where climate scientists from around the world gather to present emerging research.

Zhou’s presentation focused on his new method to track and measure the amount of freshwater released by melting icebergs following Heinrich events. Icebergs break off from glaciers into the ocean all the time, but Heinrich events are special in that a large number of icebergs do so in a short amount of time. These events can impact ocean circulation and in turn, weather temperatures, storms and rainfall across the globe.

Unlike existing research on iceberg melting in the North Atlantic, Zhou’s new method measures the amount of freshwater and the location of freshwater released. Much of his research is based on new and previously published measurements of sediment cores collected from ocean floors in the North Atlantic.

In measuring these sediment cores, Zhou can identify specific elements and isotopes within sections of the core that correlate to the amount of freshwater released by melting icebergs during a certain period of time. The correlations follow past ice ages and warm spells, which can help predict the pace of climate change today.

“I have the opportunity to use and apply cutting edge technologies to analyze the cores,” Zhou said. “It’s very inspiring to me because you’re not thinking about your own or your own generation’s scientific career, but 10s of years in the future.”

While at Lamont-Doherty, Zhou has worked alongside Celeste Pallone, a 2nd-year Ph.D. student.

“The biggest things I’ve learned from his work is both how he does lab work, but also how he organizes and prepares his data,” said Pallone. “I’ve learned what kind of statistical methods he uses to back up his claims, and just how to do good science.”

Yuxin Zhou standing at a booth with Jennifer Middleton presenting their research at the annual Lamont-Doherty Earth Observatory open house.
During the annual Lamont-Doherty Earth Observatory open house, Zhou worked with a team (right: Jennifer Middleton, a postdoc researcher) on an exhibition about iron availability in the ocean. (Yuxin Zhou/Columbia University)

In addition to earning his Ph.D., Zhou hopes to remain in academia, working with students in science. For the past two years, Zhou has volunteered for the nonprofit Girls Who Code, teaching high school girls how to create a website. He has also worked as the Graduate Student Committee chair at Lamont-Doherty Earth Observatory, advocating for student concerns to the department and pushing for student representation on hiring committees.

“Having an inclusive teaching environment and active learning experience is very important to me,” Zhou said. “We want to make sure that hiring has a certain voice on it, and hopefully, that will translate to more diversity, equity, and inclusion.”

Looking into the future, Zhou hopes to work with other climate scientists to help predict and mitigate the effects of climate change. Having comparisons between data observations and model simulations can be a very powerful tool to narrow down estimates on the freshwater fluxes and their impacts, Zhou said.

“What we’re seeing now is unprecedented. We do have some imperfect analogs of the current scenario in the past,” Zhou said. “But by better understanding those past events, we establish a baseline of what may happen in the future.”

See related: Breaking down clues to climate change from ocean floors to measure iceberg melting

Grace Rodgers is health, environment and science reporters at Medill. You can follow her on Twitter at @gracelizrodgers.