Global Cities Fighting the Greenhouse Effect

A comparative analysis by Croci, Melandri and Molteni looks at policies in large cities to cut climate-changing greenhouse gases. They find cities tend to be more carbon-effective and energy-efficient than the nation-states in which they are embedded, but this does not hold for cities in emerging economies, where transportation is the single largest carbon emitter

Municipal governments of global cities seek to tackle emissions coming from private transportation and residential energy use, as these are the two largest sources of greenhouse gases, according to the findings of the comparative study contained in the paper co-authored by Edoardo Croci, Sabrina Melandri and Tania Molteni, researchers at the Bocconi Institute for Energy and Environmental Economics (IEFE).

In the paper titled A Comparative Analysis of Global City Policies in Climate Change Mitigation: London, New York, Milan, Mexico City and Bangkok (IEFE Working Paper Series, n. 32) the three authors look at local emission inventories and mitigation plans. The five cities where chosen for being global centers of finance, media, commerce and having roughly consistent data sets concerning emissions. The lack of standardized methodologies and indicators requires a concerted research effort, which is one of the paper’s recommendations. For instance, local emissions accounting can vary depending on whether emissions “embodied” in the goods and services consumed by urban-dwellers are accounted for.

Generally speaking, cities in the industrialized world exhibit lower per capita emissions of greenhouse gases than their respective host countries, thanks to better energy efficiency. The same does not hold for cities in developing countries. Furthermore, while in London, Milan and New York, it’s buildings being the main cause of emissions, in Mexico City and Bangkok it’s transportation.

Policies in London, Milan and New York are coherent with this, since they emphasize higher efficiency in individual energy consumption, promote higher efficiency in new construction, a larger role for renewable energy, combined heat-electricity generation, and pressuring the energy providers to achieve higher efficiency in power generation and lesser carbon intensity per kilowatt-hour supplied.

A far as global cities in developing countries are concerned, the authors note that: “Bangkok and Mexico City share an emissive context and mitigation strategies strongly influenced by transportation. Their climate strategies identify the most relevant mitigation potential within the transport sector and strongly rely on public transport provision.”

All the five cities considered have thus defined strategies that are coherent with their local emission contexts, as their mitigation measures concern sectors identified as most relevant in determining urban emissions.

Croci, Melandri and Molteni conclude by saying that: “As local mitigation policies and city planning instruments for climate change keep spreading worldwide, a wider range of case studies will be gradually available for comparison.”