IMPROVED CLIMATE LITERACY FOR UNDERGRADUATES VIA HANDS-ON INVESTIGATION OF CARBON CYCLE PROCESSES

One of the best ways to understand climate change is through first-hand experience with processes that comprise the global carbon cycle. In a semester-length field program located on Hawaii Island undergraduate students pursue two types of C-cycle projects. Working from a biogeochemical perspective students analyze carbon fluxes from natural systems. Working within the context of environmental sustainability, students quantify the anthropogenic carbon footprint of the field program. Finally, we work with local partner organizations to both eliminate and offset the program’s CO₂ footprint.

Biogeochemistry: Students analyze biosphere-atmosphere exchange of CO₂ by measuring soil gas efflux. Samples are acquired along a climate gradient that spans arid to wet tropical forest environments. Soil gas fluxes are a proxy for ecosystem NPP. Efflux data and soil carbon distributions are used to model the production and diffusion of CO₂ from the soil, and to calculate the soil pCO₂ as a function of depth. The chemical weathering flux is estimated by measuring alkalinity in stream waters, and calculating the hydrologic flux of alkalinity to the oceans. USGS data are used to estimate the degassing flux from Kilauea volcano. These data can be expressed on an areal basis to compare the magnitudes of these fluxes on the island. The project combines measurements and models to improve understanding of important carbon fluxes and their relative magnitudes.

Sustainability: Students examine anthropogenic CO₂ fluxes on an individual, small-group, and island-wide basis. Each individual calculates a CO₂ footprint derived from air travel and meals. These two inputs are combined with the field program’s ground travel, electric and gas usage, and waste. These six components are tallied on a daily/weekly basis and summed to give the CO₂ footprint of the program as a whole. Using data available for Hawaii Island, the program is placed in the context of island-wide anthropogenic CO₂ emissions. Program emissions that cannot be eliminated are offset by the students themselves, in partnership with island-based conservation organizations. The combined approach of measuring both natural and anthropogenic CO₂ fluxes gives students first-hand experience with the vastly different rates and scales of C-cycle processes that drive climate change.