By Michael Replogle, ITDP

More than $100 trillion in cumulative public and private spending, and 1,700 megatons of annual carbon dioxide (CO₂)—a 40 percent reduction of urban passenger transport emissions—could be eliminated by 2050 if the world expands public transportation, walking and cycling in cities, according to a new study, A Global High Shift Scenario, by Lew Fulton and myself, published by the University of California, Davis, and the Institute for Transportation and Development Policy (ITDP). This would give a major boost to the public transport mobility of the poorest half of the world’s population, expanding access to opportunities for work, education, and health services.

We are releasing the report at the United Nations in New York on September 17^th, in advance of the September 23^rd United Nations Secretary-General’s Climate Summit, where many nations and corporations will announce voluntary commitments to reduce greenhouse gas emissions, including new efforts focused on sustainable transportation, including a pledge by the world’s public transportation operators to double the share of trips by public transportation by 2025.

Transportation, driven by rapid growth in car use, has been the fastest growing source of CO₂ in the world. Many transportation system indicators have been moving in the wrong direction in the developing world, with increasing air pollution, road crash deaths, and congestion, time and money wasted in inefficient mobility.

The overly energy focused climate policy framework of the past quarter century has led much of the world until now to overlook highly affordable strategies to slow and reduce global warming pollution by giving people clean public transportation and safe walking and cycling opportunities. This new study begins to sketch a roadmap for a brighter future.

Transportation in urban areas accounted for about 2,300 megatons of CO₂ in 2010, almost one quarter of carbon emissions from all parts of the transportation sector. Absent changes in investments and policy, rapid urbanization—especially in fast developing countries like China and India—will cause these emissions to nearly double by 2050.

But what if more countries were to adopt national transport financing programs and policies like those of Mexico or Colombia, which have helped dozens of their cities to begin developing high quality Bus Rapid Transit or rail systems? What if more cities were to adopt investment programs like China’s aimed at rapidly expanding public transport and public bike infrastructure? Or to learn from best practices in countries like France and Germany that have fostered high quality mass transit and promoted safe walking and cycling networks? What if projected growth in personal mobility in the developing world were accomodated with only half the forecast growth in light duty motor vehicle use?

Our new study calculates CO₂ emissions in 2050 under two scenarios, a business-as-usual scenario and a “High Shift” scenario where governments significantly increase urban rail and clean bus transport, especially Bus Rapid Transit (BRT), and ensure safe walking and bicycling. By accommodating forecast growth in personal mobilty in developing countries through these modes, less needs to be spent on road construction, parking garages and other things that encourage car ownership and use. Under this High Shift, not only would CO₂ emissions plummet, but the net financial impact of this shift would be a one-fifth savings in cumulative construction, operating, vehicle and fuel-related costs over the next 35 years. The cost of building more sustainble transport infrastructure would rise sharply in percentage terms, but overall infrastructure costs would drop by roughly 40 percent overall.

Personal mobility grows with income worldwide, but is accommodated in a variety of ways. If the availability of rapid transit (and basic bus services) is low, more growth in mobility will be handled by people buying and using cars or motorized 2-wheelers. If public transport services are more widely available and of higher quality, with safe and attractive conditions for walking and cycling, fewer people will buy and use motor vehicles. Adapting the International Energy Agency (IEA) Mobility Model (MoMo), we estimated these effects across 33 countries and regions covering the world.

The biggest difference between business-as-usual and the High Shift scenario is the quantity and quality of public rapid transport services. We defined a Rapid Transit per Resident (RTR) indicator as the number of kilometers of metro, light rail, urban commuter rail, and Bus Rapid Transit lines per million urban residents. In the 34 generally affluent, developed, democratic market economies that make up the Organization for Economic Development and Cooperation (OECD), we calculated an RTR today of 60, compared to 9 in the remainder of the world. Under a business-as-usual baseline case, we forecast the RTR would remain flat out to 2050, while under a High Shift scenario, this would grow by 50 percent (to 90) in the OECD and triple (to 30) in the rest of the world.

While our study has not focused on further actions to boost motor vehicle fuel economy, it takes into account existing policies that, in the IEA Baseline scenario, improve average new car fuel economy by 32 percent in the OECD countries and 23 percent in the rest of the world. The High Shift scenario increases this to 36 percent and 27 percent respectively, due to improved in-use driving conditions and a slight shift to smaller vehicles.  However, the Global Fuel Economy Initiative calls for much more: a 50 percent reduction in fuel use per kilometre for light-duty vehicles worldwide by 2030.  Achieving the GEFI 2030 goal could reduce 700 to 1,400 megatons of CO2 annually beyond the 1,700 reduction possible from a High Shift scenario.  Taken together, achieving this fuel economy goal with better public transport, walking and cycling could cut annual urban passenger transport CO2 emissions in 2050 by 55 percent from what they might otherwise be in 2050 and 10 percent below 2010 levels.

For our study, we asked the International Council on Clean Transportation (ICCT) to use their Roadmap model to evaluate how these scenarios might affect air pollution emissions and related health impacts, with and without enhanced emission control strategies. They found future growth in vehicle activity could produce a four-fold increase in associated early deaths from traffic related air pollution by 2050, even with a global shift to mass transit. But 1.4 million early deaths could be avoided annually by 2050 if national leaders commit to a global policy roadmap that requires the strongest vehicle pollution controls and ultralow-sulfur fuels.Cleaner buses alone would account for 20 percent of these benefits.

Our report is the first study to examine how major changes in transport investments worldwide would affect not only urban passenger transport emissions but also the mobility of different income groups. Today and out to 2050, lower income groups will have limited access to cars in most countries under almost any scenario. Under business-as-usual, everyone will suffer more congestion, but the poor will suffer more by being robbed of access due to declining bus speeds and shrinking space for safe walking and cycling. But under the High Shift scenario, mass transit access is projected to more than triple for the lowest income quintile (i.e., the lowest income 20 percent of the population) and more than double for the second lowest quintile. Notably, the overall mobility evens out between income groups, providing those more impoverished with better access to employment and services that can improve their family livelihoods.

In 2015, the United Nations will adopt new Sustainable Development Goals (SDGs) to guide global development initiatives over the next 15 years, as the Millenium Development Goals have done for the past 14 years. The UN will also adopt a new climate policy framework. While it is urgent that we make rapid progress to cut global warming emissions, this will happen only if climate policy is built on a foundation of inclusive social and economic development.  The SDGs recommended to the UN General Assembly in recent weeks include good targets for sustainable transport that should be strengthened further in coming months.

Effectively limiting global warming emissions will require effective policies to reduce transportation emissions. That will take a focus on both passenger and freight transportation, especially considering how transportation shapes the sustainability of cities. To support inclusive urban social and economic development, climate change policy and related development financing, capacity building, and technology transfer initiatives will need to ensure support for countries, cities, and the private sector to adopt, implement, and mainstream High Shift transport approaches, as well as improved fuel economy and vehicle emission controls.