How to Decarbonize Mid-sized Cities: A Perspective on Ann Arbor's Carbon Neutrality Goal

By Zachary Berquist

How do you decarbonize a city? By definition, the city would need to remove more carbon than it produces from its three sources: (1) electricity generation, (2) heating/cooling, and (3) mobility (or transportation).

The first two are quite straightforward. For electricity generation, cities can procure electricity from renewable sources by partnering with local electricity suppliers, purchasing renewable energy credits, mandating rooftop solar cell installation, and facilitating the purchase of renewable energy plants. Cities around the world have demonstrated success with this process (table below). As for heating/cooling, renewables can be used for them as well. Electric heaters powered by renewable electricity can easily and efficiently replace natural gas or coal powered furnaces. Air conditioning can quite simply be powered by renewables as well. However, there are also passive methods (i.e. requiring no electricity) to meet demands. Solar heaters can be used to supplement electric furnaces and help drive down the cooling demands in the summer. Green roofs (rooftop gardens), white roofs (reflective paints), and radiative cooling can passively reduce cooling demand. Lastly, smart windows can reduce the cooling and heating demands through improved insulation and temperature-dependent transparency.

On the other hand, mobility is more difficult for cities to decarbonize – and more so for mid-sized cities. Large cities like New York, Madrid, Philadelphia, Tokyo, etc. have existing infrastructure for electric-powered public transportation methods like trolleys and subways. Furthermore, these cities have the financial resources to afford massive boring projects to expand their systems. It does not make much sense, however, for mid-sized cities to implement subways – the upfront capital is not practical for the relatively small system a mid-sized city’s needs.

So what can cities like Ann Arbor do? Ultimately, the city must make opportunity cost of using a carbon-intensive method of travel must be more expensive (financially, socially, and mentally) than a carbon-neutral one.

First off, the personal automobile MUST be phased out as it is the single biggest contributor to emissions in cities. While electric vehicles can be used to eliminate emissions, that puts more stress on electricity generation, and it poses an unfair problem to lower income families. Not all residents can afford an electric vehicle by 2030. Going back to the opportunity cost, driving should be made more difficult while other mobility options are made easier. For example, in San Sebastian, Spain, roads are no longer 3 lanes for cars. One lane has been repurposed to a bus-only lane and the other is a two-way bicycle lane – resulting in only 1 lane for cars. Moreover, entire sections of the city are pedestrian only. This increases foot traffic for local businesses and makes walking safer and faster. In other cities in Spain as well as cities across Sweden, certain types of vehicles (or vehicles entirely) have been banned in city centers allowing only buses, scooters, bikes, and pedestrians. These initiatives not only reduce the demand of cars, but also improve every other form of mobility. Buses move faster and are more effective when they have their own lanes and there are less cars on the road. Civilians are more likely to bike when the city builds the infrastructure to make biking safer and faster. Lastly, 40-60% of public spaces in cities is dedicated to cars! Repurposing roads is one way to reduce this number, but the other method is to remove car parking in town. The parking lots and garages can be converted to affordable housing, parks, or businesses. If civilians have nowhere to park, they will resort to other means of mobility. Additionally, the price of parking ought to increase significantly to once again incentivize walking, biking or public transport.

Secondly, public transportation must be improved. The number one complaint for public transportation is that it is inefficient. Removing car lanes and parking lots and increasing the costs of parking without improving public infrastructure will result in public unrest and failed attempts to decarbonize. Although the opportunity cost needs to be more expensive for cars, the cost of mobility ought to remain the same – just reorganized. Public transportation in the end should be as convenient as driving is now. Though bus lanes seem appealing to improve public transportation, they are difficult to decarbonize. Either expensive biofuels are needed, or they need to be electrified. Two possible alternatives are street cars and gondolas (yep, those things that are suspended in the air). In fact, street cars were immensely popular in the US earlier in the 20th century, but a lack of investment in public transportation rendered them inferior to the car. A renewed investment can make them highly appealing. Street cars are promising for a few reasons: they are powered by electricity, can be unmanned, move quickly and efficiently, and require less maintenance than buses. Placing multiple streetcars on each track and having dedicated lanes can ensure frequent opportunities to board and easy transfers. As for gondolas, Medellin, Colombia built gondolas for its city as a unique form of public transportation which came with a few positive (some unexpected) side effects. First, gondolas, like subways, do not consume space on the roads like street cars do – leaving more space for bike lanes, scooter parking, etc. Unlike subways, though, gondolas do not require expensive capital costs like boring. Additionally, gondolas improve public safety. The most effective form of public security is the public eye. As civilians traverse over of the city, streets all over town are constantly watched, deterring criminals. In fact, Medellin wen from literally the most crime infested city in the world (i.e. Pablo Escobar) to receiving the Lee Kuan Yew City Prize in 2016 (for being a world leader in economic development and sustainable transportation) due to its investment in public transportation.

One argument against these initiatives is that it will increase the cost of using cars too much, and that it will be an inequitable transition. Is it fair to charge students even more to own a vehicle? Citizens may first oppose the removal of parking lots, increased rates to park, and reduced car lanes. However, owning a personal automobile is a privilege. It is expensive to own a personal vehicle in the US, which is why lower income residents are the main users of the current public transportation system. The average vehicle costs well over $200 per month when accounting for just insurance, gas, registration, and maintenance. But the monthly cost of using Ann Arbor’s current public transportation system is only $30! Incentivizing public transportation will significantly reduce the mobility costs for many residents. More so, investing in public transportation will make cheaper residential options further from downtown more appealing, driving down housing costs for those who need to commute into the city. I personally bought a car because it is too difficult to get around Ann Arbor without one! Investing in public transportation is not a cost to residents; it is a savings.

The main ideas presented here to decarbonize mobility are to invest in public transportation, incentivize walking and biking, and disincentivize cars. These ideas not only reduce carbon emissions but have also been proven to decongest traffic, improve air quality and public health, establish equitable transport, create jobs, and increase city GDP. These ideas are not bold. They are proven solutions to improving a city.

They do, however, require public support which could be difficult in a midwestern town like Ann Arbor. How would the citizens of Ann Arbor respond if cars were banned between State Street and Main Street? Would they utilize the increased biking infrastructure? (In the winter??) Would they really use the a streetcar system? How would these ideas change transportation to north campus? Med campus? Would visitors and commuters use them? Stripping the personal car from Americans is… un-American. Right here in Michigan Henry Ford made the personal car a commodity item. In the US, 97% of working households have a car. Essentially forcing residents to ditch their cars is a MAJOR change… is any town in America ready for it?

These questions have no answers. But if the city of Ann Arbor is serious about being carbon neutral by 2030, we will soon find out.

Zachary Berquist

Main Source:
Ren21 report on cities (

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