Using Carbon and Nitrogen Footprints to Advance UHM Sustainability

Abstract

Human activities have greatly altered the planet’s nitrogen and carbon cycles. Combustion of fossil fuels and land use changes that reduce ecosystem carbon stocks have increased atmospheric carbon dioxide concentrations, resulting in climate change. The invention of chemical fixation of inert dinitrogen (N2) has increased all other forms of reactive nitrogen in the environment. While essential to life, excessive reactive nitrogen cascades through the land, air, and water and contributes to multiple consequences for environmental and human health. Many universities and colleges have sustainability goals aimed at reducing their contribution to carbon and nitrogen pollution. However, making informed decisions on which actions to take is a challenge and evaluating the impact of those actions remains a challenge for institutional sustainability. We conducted the first nitrogen and carbon footprint assessment for the University of Hawai‘i at Mānoa (UHM) to quantify the amount of reactive nitrogen and carbon dioxide released into the environment as a result of its activities. Purchased electricity and food were the largest contributors of UHM’s nitrogen footprint, and purchased electricity and commuting transportation contributed most to the carbon footprint. We calculated scenarios within each sector to project the impact of potential actions on UHM’s carbon and nitrogen footprint, and we identified opportunities to refine data collection and analysis for future footprint assessments. This research provides a comprehensive baseline of UHM’s carbon and nitrogen footprint, which can be used to support and guide the university’s sustainability goals.