Using trees to slash energy costs in our cities

Using trees to slash energy costs in our cities

Trees can lower the temperatures in cities between 2°C and 8°C. Planting trees near a building may allow to reduce air-conditioning use by 30% and reduce heating energy use by a further 20 - 50%. According to experts recently meeting at the United Nations Habitat III Conference in Quito, Ecuador, the ideal city should have at least the 40% of its surface covered by trees. One large tree can absorb 150kg of carbon dioxide a year, as well as filter some of the airborne pollutants, including fine particulates.  

This may be of great interest for cities in the MENA region. The recent drought that began in 1998 in the eastern Mediterranean is probably the worst drought of the past nine centuries, and the  future effects of climate change are likely  to further exacerbate the situation in the region over the coming decades. When the New York City park department measured the economic impact of its trees, the benefits added up to $120m a year, almost five times the city’s $22m annual parks department expenditure. Some of the key benefits included $28m worth of energy savings, $5m worth of air quality improvements and $36m of costs avoided in mitigating storm water flooding. The journalist Amy Fleming, writing on the Guardian mused “it’s hard to put a price on how an avenue of plane trees can muffle the roar of a main road, although trees do on average increase the value of property by 20%. Perhaps money does grow on them after all…”

Approaches to urbanism need a radical re-imagination to improve urban living to transition towards sustainability. The New Urban Agenda (NUA), adopted at the Habitat III Conference, is an inclusive, action-oriented, and concise document intended to guide the next twenty years of sustainable and transformative urban development worldwide. It offers a vision of pluralistic, sustainable, and disaster resilient societies that foster green economic growth. 

Further resources

Quito Implementation Plan

Leading Integrated Research for Agenda 2030 in Africa

The State of African Cities