Uncovering Climate’s Past: How Sediment Cores Reveal Our Future
Bailey Nash stood on the shores of Narsaq, Greenland, surveying the stark expansive Arctic landscape. This remote environment may hold a crucial key in the journey of deciphering the Earth’s climatic past. Nash, a third-year Ph.D. student at Northwestern University, is part of a team of climate scientists focused on extracting and analyzing sediment cores—cylindrical samples of lake bed deposits that serve as time capsules, preserving thousands of years of climate history.
Iceberg visible from shore in Narsaq, Greenland. Image by Adrian Boliston.
These sediment cores, carefully retrieved from lakes in Greenland and the Midwest, hold invaluable data. Each layer of sediment represents a different period, capturing evidence of how climate conditions have changed over the past 20,000 years. By studying these layers, the team hopes to uncover patterns that could inform our understanding of current climate change and guide future responses.
The research process is meticulous. Once the cores are brought back to Northwestern’s Quaternary Sediment Laboratory, Nash and her colleagues begin the detailed work of analysis. Nash focuses on cellulose, a biopolymer found in plant material that has been preserved in the sediment. Using mass spectrometry, she examines the isotopic composition of cellulose, which can reveal critical information about past climate conditions, such as temperature variations and changes in lake levels.
Examples of sediment cores. Image by Hannes Grobe.
These findings are particularly relevant for the Arctic, where climate shifts have historically led to significant environmental changes. Understanding whether lake levels rose or fell during previous warm periods is critical for predicting how current and future warming might impact water availability for Arctic communities. The implications of this research extend to real-world challenges faced by Indigenous communities who rely on these lakes for their water supply.
While Nash’s research centers on Arctic lakes, her colleague Aidan Burdick is investigating sediment cores from lakes in the Midwest. His work sheds light on how human activities, particularly since European settlement, have altered the region’s hydroclimate. For instance, Burdick has observed a marked increase in sediment deposition over the past 200 years in lakes like Crystal Lake, Illinois—an indicator of the profound impact of agriculture and urbanization on the environment. Understanding these changes is essential for improving water resource management and planning in the Midwest.
However, the research’s impact goes beyond scientific insights; it also involves a significant ethical dimension. The Northwestern team is acutely aware that their work takes place on Indigenous lands, particularly in Greenland. They recognize the importance of working respectfully and collaboratively with Indigenous communities, who have lived in balance with and reverence for these environments for millennia. Meaningful engagement with these communities serves to enrich the research process itself as Indigenous knowledge, passed down through generations, provides invaluable context and understanding of the local environment that can enhance scientific inquiry.
Nash and her colleagues approach their work with a commitment to ethical practices, ensuring that their research does not disrupt or disregard the needs and values of the communities they engage with. Building trust and mutual respect is a central tenet of their approach. This involves open communication, transparency about the goals of their research, and a willingness to listen to and incorporate the perspectives of Indigenous peoples, fostering a collaborative relationship that benefits all.
The shore near Narsaq, Greenland. Image by Melissa Cherry Villumsen.
The work of Nash, Burdick, and their team underscores the importance of studying Earth’s climate history. As they continue to analyze the sediment cores, they are piecing together a complex puzzle that could provide crucial guidance for our future. The data they uncover may hold the key to understanding how we can better prepare for the challenges posed by climate change, making their research an essential contribution to the global effort to safeguard our planet.
In Narsaq, as the team carefully collects another sediment core, they are reminded that the stories locked within these layers of Earth are not just relics of the past—they are essential clues that could help shape the future. This work, grounded in scientific rigor and the wisdom held by Indigenous communities, is a vital step toward understanding and addressing the climate challenges that lie ahead.
Additional Reading
Greenland’s glacier retreat rate has doubled over past two decades – Northwestern University