By Felix Creutzig
Citizens of Europe enjoy high accessibility to energy-efficient modes of transportation, such as public transit, and often can cycle safely in cities. Still, CO2 emissions in urban transport measure about two tonnes per capita each year even in well-designed cities such as Barcelona, Freiburg, Malmö, and Sofia. For ambitious mitigation these numbers need to be cut considerably. But automobile-centered structure of the periphery makes decarbonizing a daunting task. In a new study in Environmental Research Letters (ERL) I, along with colleagues, investigated possible options for reducing the CO2 emissions in urban transport of the four cities mentioned above.
A first look suggests that European fuel efficiency regulation already contribute their relevant bit. In BAU scenarios with relatively low additional demand (demography; trend in transport policies) more efficient cars due to suggested 2020 regulation will lower GHG emissions about 40% until 2040. But the ERL study focused most on urban transport policies. These were clustered into three classes: “Pull” policies that attracted citizens into more efficient modes, such as tram-ways, bus rapid transit, and bicycles; “Push” measures that made the use of CO2 and energy intensive modes less attractive, e.g. reduced and more expensive parking space; and “Land-use” policies that enable the use of public transit and cycling by increasing accessibility on short-to-medium distances.
The study reveals that the combination of pull, push and land-use measures reduces CO2 emissions by an additional 40-70%, measured from the technology BAU scenario, and brings per capita emissions down to around 0.6t annually. The pull scenario brings only a small contribution, as many commuters prefer to stay in their cars. However, if push measures are added on the pull measures, a significant modal shift is expected: Car driving becomes more expensive, and additional space for walking, cycling and busses makes those modes even more attractive. Land-use measures such as densification and the prohibition of big boxes outside the city proper contributes a few more percentages to decarbonizing. This is particularly so in Malmö, a city that is in now in commuter distance to Copenhagen and is expected to grow considerably in population size. New medium-dense and transit-oriented development would make a huge difference here.
Crucially, the study demonstrates huge benefits in public health, and transport efficiency, accompanying such a decarbonizing strategy. Fuel spending would be reduced by billions of Euros annually, keeping more of spent income within city regions. Congestion would be reduced, enabling faster traffic for taxis and a down-scaled car fleet. At the same time, more cycling and walking would decrease coronary and other diseases, and cleaner air would improve well-being and reduce asthma incidents.
The ERL paper highlights that decarbonization might be beneficial on a societal level, changing the debate of climate change mitigation from costs to benefits. It would be interesting to integrate such perspectives into conventional cost-focused studies of climate change mitigation.