What do lakes, fisheries, coral reefs, moods, kayaks, social media posts, the spread of disease, and the Earth’s energy balance all have in common? Tipping points: when a system changes abruptly from one alternative steady state to another. How can mathematical modeling help support decision making in the face of these alternative possibilities? What makes for resilience? What causes change?
On April 19, 2018, mathematician Dr. Mary Lou Zeeman (Bowdoin College) answered your questions about these exciting and accessible dynamics, which can inform your own choices and those of our global society. She was joined by environmental scientist Dr. Ross Lieblappen (Vermont Technical College). Read more below to learn about the Q&A, and you’ll also find a list of resources recommended by both scientists!
Dr. Zeeman is a professor of mathematics at Bowdoin College in Maine. She is also the co-director of the Mathematics and Climate Research Network, and on the executive council of the Computational Sustainability Network, working with other researchers to build understanding of how mathematics can help us make decisions for sustainability and resilience in the face of a changing planet.
Dr. Lieblappen is an assistant professor at Vermont Technical College who teaches physics and environmental biology. Ross is a specialist in polar research, especially what we can learn from the microstructure of snow and ice. Here’s a photo of him sharing ice core samples with visitors to the 2017 National Math Festival!
Online Q&A Highlights
Tipping points apply across many different kinds of systems. Not only coral reefs, ponds, and other natural environments, but your mood, social media, and many other phenomena are all subject to the choices we make. You can find a short video from Dr. Zeeman’s talk at the National Math Festival last year if you want an example of some tipping points!
Q: What do the ice cores have to do with the mathematics you research?
Answer (Dr. Lieblappen): Ice cores are a fascinating material with many different research questions they can help answer. Different types of ice cores can help answer different questions. The first distinction to make is whether the ice is glacial ice (meaning it is from a glacier/ice sheet and over land) or sea ice (frozen ocean). Glacial ice cores from Antarctica or Greenland can help us answer questions about the climate of Earth hundreds of thousands of years ago. The Antarctica Ice sheet has places where the ice is 2 miles thick and about 800,000 years old. Sea ice does not get much thicker than 10 feet and is usually only 1-10 years old. Thus, the scientific questions it can help answer are generally more geared to recent climate.
My personal research is primarily on sea ice cores. I am interested in understanding the structure of the ice. Sea ice has a complex network of salt water (brine) channels that remain liquid even at very cold temperatures. These channels provide a pathway for chemical compounds such as salts to travel between the ocean and the atmosphere, where they can play a role in atmospheric chemistry.
Answer (Dr. Zeeman): Good question! Check out the graph of Earth’s global temperature history over the last 800,000 years here. It shows temperature and CO2, and their really tightly linked behavior. The data to build those graphs came from the ice cores. Math modeling of climate processes is then used to help understand which processes could be responsible for the observations we see, and how the processes interact with each other.