Can’t Stop Won’t Stop – Transportation Planning in the Middle of a Climate Crisis

This post is about the current state of the climate crisis and what the implications are for transportation planners (and planners more generally). I start by reflecting on a simple graph that describes four possible futures depending on what actions we take (or fail to take) to address global warming. I then discuss recent research on the increased warming caused by reduced particulate pollution from ocean transport, and how further reductions in air pollution could accelerate global warming in the near-term (i.e. 10-20 years). The remainder of the post discusses how planners can respond to these dire predictions in a way that minimizes harm and maximizes our capacity to adapt to climate change. I conclude with a summary of the key points (which also functions as the TLDR).  

Humankind is now at the point in time on the above graph where three of the four lines diverge. Since we are not currently rolling out Carbon Dioxide Removal (CDR) or Solar Radiation Management (SRM) at anywhere near the scale required to bend the curve, we should expect warming to increase roughly within the widening space between the lines representing mitigation and business as usual (BAU). This means we need to expect and plan for the effects of climate change to worsen significantly. This is true even if SRM is rolled out at a global scale, because it will be at least another 10 years after rolling it out before we can be certain how effective SRM will be and what changes it will cause in regional weather patterns.  

In the face of these increasingly frightening climate risks, many transportation planners will be expected to advocate for transportation systems that promise to reduce CO2 emissions. However, planners have a responsibility to clearly communicate that reducing CO2 emissions alone will do nothing to ameliorate the impacts of climate change in the near-term. Even worse, it is possible that by reducing air pollution overall, the net effect in the near-term will be an acceleration of warming. Recent research by a group including James Hansen adds weight to the “global dimming” hypothesis that a significant amount of greenhouse gas (GHG) warming has been masked by the cooling effect of air pollution. The following graph gives a sense of how significant this global dimming may be:

James Hansen’s conclusion based on these results is that, “The 1.5-degree limit is deader than a doornail. And the 2-degree limit can be rescued only with the help of purposeful actions to affect Earth’s energy balance” (Chilukurki, 2023). This is not a universally held view among climate scientists and some have characterized Hansen’s comments as alarmist or irresponsible. Since most of us are not climate scientists, a disagreement among the experts provides only one clear piece of actionable information, which is to apply the precautionary principle to the full range of expert predictions. In other words, we should plan for the worst-case predictions rather than gamble on the hope that the best-case predictions turn out to be right. Considering our failure over the last 25 years to reduce GHG emissions and the now constant breaking of climate-related records, taking a pessimistic and precautionary stance towards transportation planning is reasonable. 

It will often be difficult for planners to be honest with clients/employers about the scale of the changes that are necessary to prepare for increasing risk and uncertainty. Planners in the unenviable position of having to deliver unpalatable messages will need backing from their peers and colleagues in the planning field. To create and maintain ethical professional standards and to provide each other with meaningful solidarity, planners should participate in formal and informal professional networks. It is important to ensure these networks stay focused on serving the populations who will live with the results of planning decisions, rather than being influenced by powerful short-term political and/or profit motives.  

Planners will also need to be honest with each other about what will and won’t work to mitigate the risk to the populations they serve. There are many wonderful visions for a more sustainable world that may have been a viable response to climate change if we had fully implemented them 20+ years ago. Unfortunately, we are now in a position of needing to prioritize mitigation of harm first. For example, seeking to implement a Netherlands-style transportation network which is more dependent on people exerting themselves and/or waiting outside will be increasingly less viable as more regions experience longer periods of dangerous heat and other extreme weather. This is especially true in countries with poor social safety nets, where the greatest burdens will fall on the most vulnerable. The well-off might use active and/or public forms of transportation as long as the weather is comfortable but will retain the option of using private cars when the weather is bad.  

Image from https://www.epa.gov/heatislands/climate-change-and-heat-islands

For regions where extreme heat will get worse, planners can advocate for choices that will reduce the urban heat island effect. There are many ways to do this, including increasing tree cover/green space, using permeable paving materials, painting roofs white, etc. (heat.gov). However, the need to keep people safe will sometimes increase outdoor heat. For example, transportation planners should advocate that every form of public transit has powerful air conditioning to make the transportation system a refuge from heat rather than a contributor to heat stress. Unfortunately, this will dump more heat and humidity into the outdoor environment at precisely the times when it is already hot outside. Transportation planners need to work with emergency planners to establish predetermined trigger points when public transport services will be modified or shut down in response to extreme heat. Wet-bulb events are of particular concern, because once wet-bulb temperatures reach 90F or more, it is dangerous for anyone to be outside for long, even if you are sitting in the shade, well-hydrated, and have a fan blowing on you (Cusick, 2023). In a wet-bulb event, shutting down the public transport system would likely save more lives than trying to keep it running, because people would not be trying to walk to and wait at transit stops. Transportation workers and resources could instead be used to facilitate essential services and emergency responses, for example being dedicated to moving people to emergency cooling centers if there is a localized loss of power/air conditioning. 

In the USA, government health, weather, and emergency agencies are working together to create tools like www.heat.gov to help people get a handle on the hotter world we are making. Planners can use these tools to better predict what extremes are likely to increase in frequency and intensity for the regions where they work. They can also use these tools to set trigger points to help the transportation system plan and adapt to extreme weather.  

Conclusion/TLDR

Planners should apply the precautionary principle and develop their plans based on the more pessimistic predictions by climate scientists. This is more true when there is disagreement among climate scientists, since disagreement signals uncertainty in the field. The logic of defaulting to the most pessimistic predictions will also be true if we begin large-scale CDR and SRM, because it will take time until uncertainty is resolved regarding the impacts on the climate and regional weather patterns.  

It will be challenging for planners to advocate for large changes to transportation infrastructure and policies, especially when citing increased uncertainty about climate science as the reason to make those changes. Planners can be aided in meeting this challenge by purposefully building professional standards and solidarity that supports individual planners in holding the line. Planners themselves need to let go of the wonderful possibilities for how we could have addressed climate change, but for which it is now too late. Instead, planners in many regions will need to prioritize mitigating climate risks in order to save lives and protect critical systems and infrastructure. 

Sustainable Urban Mobility: Rethinking land use and zoning to take back the cities from cars

Sustainable mobility is a topic of concern in the current world. The over dependency on automobiles in every city has become so severe that we have created for ourselves, numerous challenges. This phenomenon of making cars the primary modes of transportation in North America has not been contributed by only one factor. Multiple driving forces that played their part in influencing car-oriented development. One of the major influences is land use and zoning regulations.

The dominance of car-centric development in the landscape of American societies is an undesirable outcome of the decades of flawed and restrictive land use planning practices. The North American planning process has always been following segregation and exclusionary zoning practices that separates different social classes in different part of a city. In a study conducted by (Stepanik, 2020) on suburbanization growth in Calgary, Canada, the author argued that the city followed the typical American path of segregated land use and zoning practice. The author also discussed that the land use and transportation decision in 1950s were focused on physical and technological aspects of planning, centered on cars and single-family housing, without thinking about social and environmental impacts of the decision. Cars have always been a sentiment for people in this region. Especially, in the post-World War II period, car ownership had a deep influence in shaping the North American Society that reflected individualism, freedom, and solitude⁶.

Zoning regulations that initially introduced in the early 20^th century have inadvertently promoted segregation by separating residential, commercial, and industrial districts, on top of that, by creating different types of residential zones. The idea of living a quality life in the urban outskirts, coupled with the strong sense of individualism helped the automobile industry to expand. The planning practices in the 1940s led to a significant expansion of suburbanization⁶, which is one of the major reasons for urban sprawl. In the mid-20th century, the decentralization of urban areas caused a significant increase in suburban population that rose from 19.5% in 1940 to 30.7% by 1960⁷.  The typical suburban characteristics such as low population density, larger distance from the downtown and limited availability of buses or trains reduced the demand for public transits⁴.

Since people started moving to these suburb areas, they started using public transit less and less. As a result, the public transit industry declined, and the automobile industry boomed over the years. People who live in the suburbs are inclined towards automobiles because cars offer greater flexibility and freedom, besides most suburban communities don’t have good access to public transportation. Even if anyone wants to use public transit, they aren’t provided with a lot of choices. Even if someone doesn’t live in a distant suburban community, it is noticeable that almost all the single-family residential zones within the city boundaries are planned further away from commercial zones. People living in these areas are bound to use their cars for fulfilling daily necessities. In addition, zoning policies like minimum parking requirements for commercial development have led to inefficient land use pattern and encouraged more and more cars in the city centers.

“This is true particularly when zoned, separated land-use exists in conjunction with laws that mandate large numbers of parking spaces for each business and wide multi-lane roadway. Such requirements make it virtually impossible for pedestrians to comfortably navigate the area”¹

The exclusionary zoning practices that legislate minimum square footage, minimum lot size, limits on the number of household members, restrictions on land and structural usage, all favoring the development of single-family residential zones created an enabling environment for urban sprawl. This has led to the depletion of open lands, promoted the dependency on the automobile, exacerbated air pollution, fuel consumption and caused declination in physical activities².

These practices have not only shaped our cities, but also adversely affected our way of life by leading to environmental degradation, economic inefficiency, and social inequity. Car-centric development patterns marred the environment by burning fossil fuels, increasing heat and particulate matters in the air, ultimately contributing to increase global warming. Today, the environmental effects of car usage are evident as people around the world are now suffering from excessive heat or extreme cold weather, natural disasters like flood, draught, wildfire etc.⁵ Besides, traffic congestion – another effect of excessive car usage, causes a significant loss of time, reduces labor productivity, thus incurs loss in economy.

The social effects of automobile dependency are quite harmful, but often overlooked in zoning and transportation planning. The social activist, Hackett, argued that urban designs and transportation planning favors the middle-class suburb communities and disregards the lower income residents with development initiatives centered around automobiles³. For instance, in the city I live in, all the grocery stores are in a distant location from my neighborhood. The closest one is more than 15 minutes’ walk and has no direct public transit system. People in my neighborhood must commute through multiple routes and spend almost 40-45 minutes in public transit to buy basic needs. This is a result of conventional zoning practices which created accessibility barriers for people with lower incomes and for those who don’t use a car. This is one of many examples of social inequity that exists in every city resulting from accessibility barriers to education, employment and other amenities and facilities.

Today, as we confront these challenges, it is crucial to look back on the past mistakes and reassess the zoning policies to set a new course for people-centric, climate friendly and sustainable urban transportation system. Addressing these challenges needs a collective effort from various government bodies to reimagine the land use and zoning regulations. Instead of stretching out the car-oriented development patterns, policymakers should prioritize compact and walkable cities with form-based zoning, diverse housing options and comprehensive transportation system. Cities should adopt flexible zoning policy and allow mixed use development, prioritize investment for public transit, incorporate pedestrian-friendly policies and innovative road designs to discourage car usage. With flexibility in zoning, cities can incentivize affordable housing and prioritize transit-oriented development to minimize automobile dependency and promote social and economic diversity.

A holistic approach from state and local governments, therefore, essential to reform the land use and zoning ordinances. The federal government also plays a crucial role along with state and local authorities in this process. Federal funding mechanisms should prioritize transportation projects that promote active transportation such as walking, biking etc., transit-oriented development, smart urban designs.

In 2024 National Planning Conference, I attended a session called “Washington’s Role in Advancing Housing & Zoning Reform” where the speakers Vincent Reina and Chad Maisel talked about how federal grants are being used in housing and zoning reform. One federal action that stood out to me is prioritization of those infrastructural development programs in federal grants that promote density and include housing factors in their plans. This idea can also be used in advancing sustainable transportation planning. The federal government can discourage urban sprawl by prioritizing development projects that incorporate some elements of sustainable transportation, affordable housing initiatives, compact and mixed-use development, and environmental standards etc.

Finally, to achieve the vision of smart, equitable and sustainable urban transportation, it is imperative to ensure public engagement in the transformative shifts of zoning and transportation planning. Community input and collaboration from diverse stakeholders are essential to understand the local context and address the unique challenges that each community faces. It is also important to enlighten the residents about the negative impacts of automobile usage and the positive sides of public transit, walking and biking etc. By making the planning process more inclusive and adaptive, we can reduce car-oriented development and foster livable and sustainable human-centric communities.

References

1. Batchis, W. (2010). Enabling Urban Sprawl: Revisiting the Supreme Court’s Seminal Zoning Decision Euclid v. Ambler in the 21″ Century. Virginia Journal of Social Policy & the Law, 371, 380-381.
2. Batchis, W. (2012). Suburbanization and constitutional interpretation:exclusionary zoning and the supreme court legacy of enabling sprawl. Stanford Journal of Civil Rights & Civil Liberties, 8(1), 1-44.
3. editorial, G. (2012). Social impacts and equity issues in transport: an introduction. Journal of Transport Geography, 21, 1-3. doi:10.1016/j.jtrangeo.2012.01.032
4. Gordon, P., & Richardson, H. W. (1997). Are Compact Cities a Desirable Planning Goal? Journal of the American Planning Association, 63(1), 95-106. doi:10.1080/01944369708975727
5. Scientists, U. o. (2023, September 15). Cars, Trucks, Buses and Air Pollution. Retrieved from Union of Concerned Scientists: https://www.ucsusa.org/resources/cars-trucks-buses-and-air-pollution
6. Stepanik, L. (2020). Follow the Suburban Roads: How Car-Centric Values Shaped the City of Calgary’s Urban Landscape and its Sustainable Future. University of British Columbia.
7. Yawp), U. H. (2024). The Rise of Suburbs. Retrieved from US History II (American Yawp): https://courses.lumenlearning.com/suny-ushistory2ay/chapter/the-rise-of-suburbs-2/#:~:text=The%20country’s%20suburban%20share%20of,an%20astonishing%20rate%20of%20126.1%25.