The global urban population has been steadily increasing ever since records began in the 1950s by the United Nations, and now represents 70% of the world population. Thus it is essential to develop metrics to measure the carbon footprint of cities, to monitor their changes in time and to understand the underlying drivers in order to help constrain the global growth in CO₂ emissions and tackle climate change. It is also essential to understand how climate change adaptation and mitigation measures interact with CO₂ emissions in cities.

Much work is underway to quantify the carbon footprint of cities. However, most of the ongoing work focuses on large cities, and relatively little is know about the carbon footprint of medium-size cities, how these compare to that of large cities, and how the carbon intensity of cities is changing with time. Medium-size cities represent a large part of the urban population: In the UK, 45 of the 66 listed cities are between 100 and 500 thousands habitants, representing nearly half of the urban population of the UK. Similarly in China, 242 of the 348 listed cities have a population between 1 and 5 million, representing 42% of the urban population in China.

This PhD project will develop an up-to-date understanding of the contribution of cities to global CO₂ emissions, and most importantly to their trends in the past 20 years. It will gather information from a wide range of sources, particularly national and international sources such as the Carbon Disclosure Project, and develop a methodology to estimate CO₂ emissions from a range of cities of different sizes. It will apply decomposition methods such as a modified Kaya identity to separate the contribution of various driving factors (including population density, wealth, temperature, etc) to the changes in cities' CO₂ emissions. Finally, the project will explore the interactions between emissions in cities and adaptation and mitigation policies using integrated assessment models. This project will be done in collaboration with colleagues from the Tyndall Centre for Climate Change Research and the Global Carbon Project, and will offer possibilities for extended visits to other universities.

This project is suitable for candidates with first degrees in mathematics, physics, engineering, computer sciences, and earth and environmental sciences. Enthusiastic candidates with interest in policy-relevant research and facility with computer-based analysis are encouraged to apply. The candidate will be trained in the analysis of complex information, in the use and development of models, and in the diffusion of knowledge to a wide audience. She/he will have opportunities to interact with an international group of experts and with policy makers in the climate change area.    

Dhakal, Shobhakar (2010). GHG emissions from urbanization and opportunities for urban carbon mitigation. Current Opinion in Environmental Sustainability, Volume 2, Issue 4, October 2010, Pages 277–283DOI: 10.1016/j.cosust.2010.05.007

Raupach, M.R., G. Marland, P. Ciais, C. Le Quéré, J.G. Canadell, G. Klepper and C.B. Field (2007). Global and regional drivers of accelerating CO₂ emissions. PNAS, 104, 10288-10293.

Dhakal, Shobhakar and Ram M. Shrestha eds. (2010) Carbon Emissions and Carbon Management in Cities. Energy Policy Journal Special Section, Volume 38, Issue 9, Pages 4753-5296 (September 2010).

Le Quéré, C., M.R. Raupach, J. G. Canadell, G. Marland, L. Bopp, P. Ciais, T.J. Conway, S.C. Doney, R. Feely, P. Foster, P. Friedlingstein, K. Gurney, R.A. Houghton, J.I. House, C. Huntingford, P. Levy, M.R. Lomas, J. Majkut, N. Metzl, J.P. Ometto, G.P. Peters, I.C. Prentice, J.T. Randerson, S. W. Running, J.L. Sarmiento, U. Schuster, S. Sitch, T. Takahashi, N. Viovy, G.R. van der Werf, F.I. Woodward. Trends in the sources and sinks of carbon dioxide. Nature Geosciences, 2, 831-836.