The nitrogen footprint for an Australian university: Institutional change for corporate sustainability

Reactive nitrogen (Nr; all species of nitrogen other than N2 gas) is a major cause of air and water pollution, with worldwide costs of billions in human health and ecosystem damages. The nitrogen (N) footprint, which quantifies the anthropogenic release of Nr from the production and consumption of both food and energy, has been used as an indicator of sustainability at individual and national levels. Here, we present the first institutional N footprint in Australia - the N footprint for The University of Melbourne (UoM) in 2015, and projections to 2020 under four scenario families. The total N footprint of UoM in 2015 was 139 tonnes N; food production (36.7%), utilities (32.4%), and transport (28.1%) were the major contributors while food consumption and fertilizer usage made up the remaining 2.8%. Under a businessasusual scenario, the N footprint of UoM would grow by 13% to 157 tonnes N in 2020 due to increase in student and staff population and infrastructure development. However, UoM has the potential to reduce its N footprint by 59% relative to the 2015 baseline if it implements changes to food purchases and energy use by 2020. The mitigation strategies with the largest potential reduction should be prioritized, including shifting purchased electricity fuel sources to wind or solar (26% reduction) and reducing air travel emissions (25% reduction). We demonstrate the potential of the N footprint as a tool for an institution to assess and monitor the sustainability of its operations and governance. Universities are leading the way in sustainable development, and the calculation of N footprint for UoM is the starting point for future work on sustainable institutional Nr management in Australia.