Reducing carbon emissions is a priority issue on the European Union's agenda, especially with the approval of the Paris Agreement at the summit held in the French capital in December 2015.
According to United Nations estimates, by 2050 two thirds of the world's population will reside in urban areas, with the consequent social and environmental challenges that this poses.
Sustainable development of sprawling urban areas poses a challenge in urban policy-making at the territorial, state and global levels.
Urban planning is one of the most powerful tools to mitigate the environmental impact of cities and reduce their contribution to global warming.
Traditionally, in the disciplines responsible for deciding the shape and distribution of the city, sustainability criteria and environmental consequences derived from the use of public services by its inhabitants were not included, despite the fact that these services are essential for the well-being of citizens and the economic development of the area.
A joint investigation of the Polytechnic University of Madrid and the University of Granada has now succeeded in creating a method to evaluate the influence of urban planning strategies on the carbon emissions associated with cities.
Researchers have included with an innovative approach the environmental impact of public networks and services, the design of which is a direct consequence of urban planning conditioning factors and which has traditionally been ignored in environmental impact assessment.
Among others, the water supply network, the waste collection system and the public lighting network have been considered.
The results obtained show the considerable contribution of these elements in the environmental impact of urban areas throughout their life cycle.
As the carbon emissions associated with the use of the city come from buildings and urban facilities and public services, the authors of the study have focused on the stage of use and operation of these elements and not on the construction stage, since it is their use which represents the greatest environmental impact.
Urban plans with sustainability criteria
In the model developed, the scientists first calculated the energy consumption associated with the operational phase of the building, considering the following end uses: air conditioning systems, lighting, domestic equipment, hot water and elevators.
For urban infrastructure, the energy consumption of public facilities (public lighting and water pressure system) and the fuel consumption of the municipal waste collection service were considered.
Finally, the consumption of resources was transformed into carbon emissions through the application of national conversion factors, being able to differentiate three levels of management in the calculation procedure: domestic, municipal and national.
This methodology will allow the design of urban plans and urban regeneration strategies under sustainability criteria.
The authors emphasize that it is necessary to further study the role of public services in the carbon footprint of cities for the development of more effective energy and environmental policies.
The findings of this study, which have been published in the journalEnergy and Buildings,They represent a contribution to the existing literature on the environmental impact associated with urban development and highlight the importance of adopting a multidisciplinary perspective in evaluation.
“This methodology is helpful in making decisions about strategies and policies related to urban development. Building sustainable and more livable cities is the responsibility of the agents involved in the formulation of new policies, but also of researchers, professionals in the sector and ultimately of all citizens ”, says Rosalía Pacheco-Torres, researcher at the ETS of Civil Engineering the Polytechnic University of Madrid and main author of the work.