Laura Peterson
Laura Peterson
Professors and students at Luther College and Lafayette College are investigating southern hemisphere climate change over the last six million years to better understand key linkages and feedbacks within Earth’s climate system.

The project is funded through a $135,235 grant from the National Science Foundation awarded in June 2013 to Laura Peterson, Luther College assistant professor of environmental studies and chemistry, and a similarly funded grant awarded to collaborator Kira Lawrence, associate professor of geology at Lafayette College. The research will continue through 2016.

Peterson and Lawrence co-wrote the proposal, “Southern Hemisphere Processes and Global Climate Change: The Evolution of Miocene to Present Surface Ocean Conditions in the South Pacific and South Atlantic,” that earned them the grant.

The overall aim of the project is to create records of sea surface temperature change over the past six million years in order to assess symmetries in northern and southern hemisphere climate evolution during critical periods of climatic change. The sea surface temperature records are produced by making geochemical analyses of ocean sediment retrieved from the seafloor.

This spring Peterson’s students, Jamison Ash, Robbie Helgason, Devon Hovey and Travis Houle, are working on processing samples for stable isotopic analysis. The students are isolating microfossils of two particular species from the sediment core from the southwest Pacific Ocean in order to construct a record of past climate change from this part of the Southern Hemisphere.

Over the summer Hovey and Houle will be joined by fellow Luther student Katherine Huska to continue the research by generating and analyzing sea surface temperature data derived from the same sediment core. The sea surface temperature data will be produced entirely in Peterson’s lab at Luther, using analytical instruments acquired by Peterson with previous NSF funding.

The southern hemisphere, whose climate history has been largely unexplored, is known to play a critical role in important climate and oceanic processes related to carbon cycling and global heat distribution.

The project will include a detailed investigation of climate dynamics during an interval in Earth’s history when global temperatures were several degrees warmer than they are today—but similar to projected temperatures by the end of this century if human-caused greenhouse gas emissions continue to rise.

“One big motivation for understanding past climates is that some intervals of the Earth’s past resemble climatic conditions we may encounter in the near future,” said Peterson. “By looking to the past, we can test our assumptions about how the climate system operates, and potentially uncover new information that we can’t directly observe in the present.”

The researchers will examine the symmetry of climate evolution between the northern and southern hemispheres and the evolving response of the climate system to cyclic changes in the position and orientation of the Earth in its orbit relative to the Sun.

Beyond the scientific questions addressed in this research, this project will also advance the early preparation of future Earth scientists who will have the skills to face both the scientific and societal challenges presented by climate change. “Undergraduate student researchers involved with this project are gaining hands-on experience in the nature and process of scientific research, direct training in the field of paleoclimatology, critical thinking skills related to scientific research and a deeper introduction to the systems-thinking skills that distinguish the Earth scientist’s approach to understanding the world,” said Peterson.

Peterson and Lawrence have planned outreach to local K-12 students and educators to further disseminate the results of this work as well as the broader contributions of paleoclimatic research and climate science.