Urban sprawl responsible for 30% of all greenhouse gases

News - 26 November 2015

Urban sprawl accounts for a third of all greenhouse gas emissions, and curbing this urban sprawl could be key to slowing down climate change. These are the conclusions doctoral candidate Michael Mehaffy draws in his doctoral research. He has developed software that can predict how urban design will influence CO2 emissions.

Thesis defence Michael Mehaffy: Urban Form and Greenhouse Gas Emissions
30 November 2015 | 15:00
Location: Aula, TU Delft

Mehaffy’s research indicates that urban sprawl has a much more significant impact on the environment than previously thought. Low-density construction requires more infrastructure than in a compact city, which also means more roads and more kilometres travelled per resident. The doctoral candidate at the Faculty of Architecture and the Built Environment analysed various urban areas and concluded that urban sprawl is responsible for more than a third of global CO2 emissions. Dispersed construction not only leads to an unnecessary rise in energy and raw material usage, but also increased land usage and neighbourhood patterns of consumption. And these factors cannot be compensated for with the introduction of renewable energy sources or sustainable – electric – means of transport. ‘That’s why it’s essential that we radically revise the models and methods we use for urban design’, explains Mehaffy. ‘Business as usual is no longer an option, if we don’t change course, we’re heading for disaster’. 

The fact that changes in the field of urban planning progress slowly is no reason not to take action. Quite the contrary, argues Mehaffy – it’s precisely because change is slow that finding another form of urban planning should be given top priority. Certainly in parts of the world that are rapidly urbanising. Because even minor changes to urban design can have long-term effects, reaching far into centuries ahead. Compact cities with an effective blend of functions in which distances can be easily walked or covered using public transport have the potential to offer enormous environmental returns. In his thesis, ‘Urban Form and Greenhouse Gas Emissions: Findings, Strategies, Design Decision Support Technologies’, Mehaffy emphasises the importance of well-designed networks of public spaces as a precondition for efficient cities producing low emissions.  ‘Urban design influences how we move, interact and consume. My research offers insight into how this works as a system and how we can utilise it as part of conservation efforts’. 

Using his research findings, Mehaffy teamed up with a software engineer to develop a digital resource to aid the decision-making process for urban designs. The design tool assists in the evaluation of various urban design scenarios and in forecasting the emissions produced by various combinations of design elements. This brings feasible alternatives within reach that can help to identify and reduce emissions. The software is suitable for use by planning offices, urban planners, developers and other interested parties.

Mehaffy will present his research during the COP21 in Paris, working in collaboration with UN-Habitat, the Project for Public Spaces and the Ax:son Johnson Foundation. He will defend his thesis at 15:00 on Monday, 30 November. 

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