Exploring Past and Future Climate Change Using EdGCM

In a twist on Charles Lyell, past climate change may be a key to anticipating what life will be like in a future warmer world. Such an approach requires a combination of data- and model-based study for analyzing climate change that is ideally suited to the geoscience classroom. We have developed a modular exercise, using EdGCM (Educational Global Climate Model), that allows students to learn about climate while also gaining hands-on experience with computer climate modeling, one of the most important techniques society has for examining an uncertain future.

Students are first guided through a comparison of the mid-Pliocene warm interval and the Last Glacial Maximum to the present climate, thus establishing a framework for understanding of the range of recent natural climate variability. Instructors can also explore paleoclimate reconstruction issues, such the robustness of paleoproxy data used for pCO2 estimates for use in boundary conditions. This module can also be used as a launching point for discussions on the strengths and limitations of climate models in general.

Students then analyze the results of two future climate simulations involving two "styles" of global warming: an instantaneous doubled CO2 experiment (the classic simulation for testing model sensitivity), as well as a gradual increase in CO2 through the year 2100. This module focuses on understanding how the magnitude of projected future climate change differs from the amplitude of natural variability they previously investigated via paleoclimate analysis, and on the demonstration that anthropogenic forcing is indeed a key factor in current climate change. This module can also be used to explore the inertia inherent in the climate system, which is relevant to any discussion of mitigation and/or adaptation to future warming.