Modeling Is Believing

Graduate students huddled in the middle of a classroom in the Tang Center are in the midst of a passionate negotiation when Professor John Sterman yells, “Time’s up! Give me a number!” Getting no reply, he begins plugging figures into a laptop.

Sterman, Jay W. Forrester Professor of Management and director of the System Dynamics Group, is manipulating a new model for climate change. Input the amount of carbon dioxide emitted by every nation, in billions of tons per year, and the model lays out such environmental impacts as changes in sea level and global surface temperature for the years 2010 through 2100. Sterman had divided the class into three blocs–developed, developing, and less developed nations–and given them five minutes (after a few minutes of discussion within their blocs) to negotiate an agreement on greenhouse-gas emissions. They played hardball, and the five-minute limit expired without an agreement. So Sterman has to resort to figures reflecting “business as usual.”

The emissions negotiation exercise is part of the Sustainable Business Lab (S-Lab) curriculum, offered at the Sloan School of Management through a new program called the Initiative for Sustainable Business and Society. Launched in spring 2007, the initiative aims to teach students how businesses, government organizations, and nonprofits can foster ecologically and economically sustainable practices and policies. S-Lab, which is taught by four MIT faculty members, combines computer simulations, role playing, and case studies.

“With climate change, the effects are abstract and distant–one can’t feel the sea level rising,” says Sterman. “So we have created a simulated environment in which students can get immediate feedback on their decisions.” The students’ first bit of feedback, then, is that time is running out.

Now Sterman, at his laptop, uses the model he developed with the Sustainability Institute of Hartland, VT, and Ventana Systems, a software firm in Harvard, MA, to show the class what will happen to sea levels and temperatures by 2050 if carbon dioxide emissions remain on their current course. “It’s one thing to hear that sea level is going to rise,” says Adam Siegel, a first-year student at Sloan. “But to actually see that and other implications of our decisions on the environment–we knew we had to come back to the table more willing to commit to change.”

Students enter the second round of negotiations with more determination, but they’re still reluctant to reduce their own emissions, preferring instead to press other nations to do so. Although an agreement is reached, when the numbers are fed into the model, the results are still alarming: sea levels rise to heights that will put less developed coastal nations underwater by 2100. After a third round of negotiations, students finally reach an agreement that reduces carbon dioxide emissions enough to stabilize the concentration of the gas in the atmosphere at 450 parts per million. (The current concentration is 385 parts per million.)

“Even though it is chaotic and it is confusing, I would much rather run an interactive simulation like that than conduct a lecture or case study discussion,” says Sterman. “It is just much better for everyone.”