Water-energy-carbon nexus among different functional areas of campus: Pattern, flow, and efficiency

Water, energy, and carbon, integral to human activities on Earth, directly influence ecosystems and social development through interactions and utilization efficiency. Campuses, as special societal communities, boast diverse functional areas and dense populations with substantial water-energy consumption and carbon emissions. Taking campus as special case allows effective exploration of water-energy-carbon (WEC) nexus at the micro-community scale, which can promote sustainable development on a wider scale. This study calculated the WEC footprints of a campus to reveal the underlying patterns and flows among different functional areas. The efficiency of WEC utilization was evaluated and key areas of the campus suitable for carbon reduction were identified. Results indicated that the water, energy, and carbon footprints of the campus in 2021 were 2.7925 million t, 582.8 thousand GJ, and 56,315.77 t, respectively. The WEC system exhibited intricate nexuses, and the correlations increased annually with direct nexuses proving stronger. The correlations for the WEC, energy-carbon, and energy-water systems were 0.7462, 0.9227, and 0.6436, respectively. Residential areas exhibited higher totals/intensities and the lower utilization efficiency of WEC. The findings provide a new perspective for optimizing regional human-environment systems with multielement nexuses that could transform campuses into efficient, water-saving, energy-conserving, low-carbon communities adapted to and supporting mitigation of the effects of climate change.