University of Maine Students Experience the Global Carbon Cycle and Climate Change with STELLA®
Global Environmental Change is a 200-level course designed primarily for sophomore Earth Science majors at the University of Maine, Orono. It’s not surprising though that the course attracts freshmen, seniors, and juniors from anthropology, marine science, history, biology and other departments across the university. The course focuses on the carbon cycle and its relationship to climate change; and climate change affects us all.
Five years ago, Karl Kreutz, PhD, who is on the faculty of the School of Earth and Climate Sciences and conducts research through the Climate Change Institute, was grappling with the challenge of teaching his diverse students about the global carbon cycle and climate change. “I could show them ice core samples from my own climate change research, I could take them into the lab and show them how we can use the cores to measure particles and time, but the carbon cycle is a hard thing to explain. I wanted to give them a deeper understanding.”
Like so many natural cycles, the carbon cycle requires us to see the earth as a huge system. Carbon is a building block of life on earth. It’s in our soil, our water, our food, and us. Carbon is released into the atmosphere from a number of reservoirs – the ocean, the atmosphere, soil, etc. – via a number of fluxes - plant respiration, decomposition, and human emissions (most predominantly the burning of fossil fuels). The higher the carbon dioxide concentration in the earth’s atmosphere, the warmer the earth’s climate. The cycle’s changes are felt over the long term. (Kreutz’s research considers climate change over thousands and hundreds of thousands of years.)
Five years ago, Kreutz was introduced to STELLA, Systems Thinking software from isee systems. He realized that building models of the carbon cycle would give students a fuller appreciation of the carbon cycle than they’d get by looking at ice core samples, visiting his lab to see how particulate measurements were made and taking notes during classroom lectures. “I knew that if students could really get their hands on the carbon cycle, they would be able to feel it,” says Kreutz.
Now, Kreutz starts his class with its very diverse set of students by saying, “We know that carbon dioxide has an important relationship to climate change and sea level but to really understand that we’ll use models.” Before they use STELLA, Kreutz has them use spreadsheets to look at concentrations of CO2 in the atmosphere over time. After that, they use STELLA to build simple models to understand the role of reservoirs (where does water come from, where does it go) and critical feedback loops. After that, they build carbon cycle models.
Modeling is as new to Kreutz’s students as the carbon cycle but that’s not an impediment. “Students come to class interested in the content,” says Kreutz. “They aren’t worried about modeling or learning Systems Thinking. That’s just part of the course. Learning Systems Thinking and modeling is like learning anything else, some students take to it and others need some hand holding. The really strong students often go on to use it for other projects, courses, and their own undergraduate or graduate school research.”
Models are especially useful for helping students understand the role of humans in the global carbon cycle. “Our first model looks at the cycle between the atmosphere, land plants and the ocean,” says Kreutz. “When we add humans and fossil fuel burning, students see their immediate impact. They understand that the only way to explain the last 100 years of carbon concentration is the burning of fossil fuels.”
Students are also able to appreciate the long-term nature of the carbon cycle and understand that earth science processes have always regulated the concentration of carbon dioxide in the atmosphere. “Students are impressed to learn that CO2 concentrations have been higher in the past,” says Kreutz. “Sixty million years ago, they were much higher. Students can think of an earth with palm trees at the North Pole. The models really make the point that no matter what time period they look at, students will see the relationship between the earth’s temperature and carbon dioxide concentration.”
With some modeling under their belts, students are ready to tackle questions like “What do you think CO2 concentrations and temperatures will be in the year 2100?” “Even their simple models allow students to predict the future,” says Kreutz. “By applying climate sensitivity and experimenting with reservoirs and fluxes they can see how climate will change if we keep burning fossil fuels at current rates, what will happen if we switched to solar power, or how things would change if we burned only natural gas. Building models and seeing those changes is so much more powerful than just talking about it.”
Other professors in the School of Earth and Climate Sciences are also getting interested in STELLA as a way to model the systems central to their work. “A professor of Marine Sciences has built a model to simulate carbon dioxide concentrations in the ocean,” says Kreutz. “He talks to the class about that work. We’re starting to have a lot of teaching and research collaboration. As more of us get interested in the pedagogical implications of Systems Thinking and modeling, we’re becoming more of a community.”
Kreutz is currently working with several students who are using STELLA in their Senior Honors Thesis work. “One student is modeling the movement of isotopes in the atmosphere and another is researching the impact of volcanic activity on climate.” But Kreutz doesn’t plan to let his students out-model him. He says, “Systems Thinking and STELLA are creeping into my research too.”
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