Potential for sustainable use of trees in hot arid regions: A case study of Emirati neighborhoods in Abu Dhabi

This paper explores the future of landscapes in arid, coastal regions based on 4 water-energy regimes, using a case study of villa neighborhoods in Abu Dhabi, United Arab Emirates. It examines the potential for the planting of 15 selected tree species for carbon storage under various water-energy regimes to create carbon neutral (or negative) villa neighborhoods. Recent improvements to solar photovoltaic and reverse-osmosis desalination technology have lowered the carbon emissions for water production by over 99% relative to current gas-powered multi-stage flash desalination (0.08 kg CO2/m(3) vs.12.8 kg CO2/m(3)). This allows trees planted in hot, desert climates to utilize treated ocean water while net sequestering between 1.7 and 38.2 kg C/tree/yr depending on species. When planted in existing neighborhood open spaces, we find that net carbon storage rates from trees are significant (15-800%) relative to operational emissions rates for building energy (cooling, lighting, equipment) when households are supplied from 100% renewable energy sources. Thus, as technology advances, landscape design strategies in the region could evolve to maximize planting to sequester carbon while also creating more comfortable outdoor spaces that enhance the livability of neighborhoods. This study provides a first step in identifying the potential for landscape architectural design to employ a tree-based, neighborhood scale, carbon storage strategy in arid regions such as those in the Arabian Peninsula. As nations move towards a carbon-neutral future, it is imperative to develop innovative solutions that address urban sustainability, especially in resource-challenged and extreme climate regions where new urban development is planned.