To what percent are humans responsible for extreme hurricanes? What does statistics tell us?

By Indraneel Kasmalkar, PhD Candidate in Computational & Mathematical Engineering (ICME)

... climate change likely increased Harvey’s seven-day rainfall by at least 19 percent ... climate change roughly tripled the odds of a Harvey-type storm.

These are bites from a National Geographic article [1] that highlights the impact of global climate change on Hurricane Harvey, the category 4 storm that wreaked havoc on the coast of Texas in late August 2017. The article cites a couple of papers that conducted these analyses. But how were those researchers able to get quantitive results in the first place? How can we confidently attribute the effects of anthropogenic climate change, a complex global phenomenon, to a specific storm? I would like to dive into one of the papers: "Attributable Human-Induced Changes in the Likelihood and Magnitude of the Observed Extreme Precipitation during Hurricane Harvey" by Mark Risser and Michael Wehner of Lawrence Berkeley National Laboratory [2].

A robust study of the impacts of anthropogenic climate change would require a physics-driven global climate model that could simulate the winds, the oceans, the CO2 emissions, the clouds, not to mention the coast and the terrain. With our current supercomputers we are not able to do these global simulations at high resolution in a reasonable amount of time, and our low resolution results are not accurate enough.

Instead, Risser and Wehner used the approach of extreme value statistics. At its core, this method looks at data concerning the occurrence of extreme events, say earthquakes, and then tries to fit a special curve through it so that we can estimate how likely it is for a large earthquake to occur. There are some concerns about using this approach: statistics generally works well for estimating average values but it is much harder to capture the extremes, partly because they are so rare and spread out, and especially in the case of predicting extreme events that have never occurred before. In fact, Stuart Coles, who developed the statistical model that Risser and Wehner used in their study, writes in his book [3]:

It is easy to be cynical about this strategy, arguing that extrapolation of models to unseen levels requires a leap of faith, even if the models have an underlying asymptotic rationale. There is no simple defense against this criticism, except to say that applications demand extrapolation, and that it is better to use techniques that have a rationale of some sort.

If we accept the premise of extreme value statistics, the next step is to acquire a data set on which this model can be applied. Risser and Wehner decided to use daily weather station measurement data in the Houston, Texas area, obtained from the Global Historical Climatology Network (GHCN). They had to clean up some of the data and choose a subset of stations to streamline the data set. But the biggest caveat is that there is no data prior to 1950. Is seventy years of weather station data enough to identify the contribution of human-induced climate change to a specific storm in Houston? Ideally I would have liked to see data from the start of the industrial revolution to truly capture the effects of CO2 emissions on global climate. But since our historical weather records do not go so far back in time, we are restricted to the 1950-2017 data set.

Now that we have a model and a data set, we need something to isolate the effects of human activity and natural activity. After all, Harvey's extreme devastation could simply be the result of the forces of nature alone. What could we use to separate the human and natural components? Risser and Wehner addressed this issue by using 1. CO2 levels, and 2. El Niño wind and sea temperature data. In particular, they took a time series data set of seasonally averaged global CO2 levels, and annually averaged values of the El Niño Southern Ocean Index (ENSO). The idea is that CO2 levels are a proxy for human activity, while the ENSO would capture natural variations in the climate. And this is an idea where skepticism would be very healthy. Can El Niño measurements truly capture all the natural variation in global climate? Is this approach good enough to account for all the complex non-linear ways in which CO2 levels can affect ocean temperatures, which in turn affect precipitation? But collecting enough data to be able to capture human and natural activities is hard. The proxies that Risser and Wehner have used are simple and straightforward, and that makes this analysis easy and transparent. My overall opinion is that there is a good theoretical idea here, but the numbers that come out from this study should not be taken literally unless there are a multitude of other studies that use similar approaches on varied data sets to yield the same results.

Nevertheless, if we agree to use CO2 levels and ENSO values, then we can use standard statistical procedures such as regression to isolate the contribution of one data series on another. In this case, we would end up with something akin to rainfall estimates for Houston, Texas along with two dials: The CO2 levels and the ENSO values. We could then dial the CO2 level up or down to see how estimates for extreme rainfall would vary.

With the ability to statistically isolate the effects of CO2, Risser and Wehner simply compared the model with 2017 CO2 levels to that with 1950 CO2 levels. For example, you can look at the model and figure out the probability of getting as extreme an event as Hurricane Harvey. If you keep this probability value fixed, but dial down to CO2 levels of 1950 you then get a storm with smaller rainfall values. How small? Roughly 19%. This is where the number in the original articles comes from: "... climate change likely increased Harvey’s seven-day rainfall by at least 19 percent."

To summarize, there are a lot of assumptions and modeling choices that go into this study which merit caution: Extreme value statistics is something to be used carefully at all times. Furthermore, weather data from 1950-2017 may not be enough to make strong statements about climate change. And isolating human and natural activities with CO2 levels and El Niño values may be too narrow of an approach.

It must be said that these statistical approaches have good, simple and transparent ideas. But in the end there is immense complexity in the global climate system. And we must acknowledge that this complexity may significantly obscure the meaning of the results that we get from statistical approaches.


[1] National Geographic. 2017. Climate Change likely super-sized Hurricane Harvey.

[2] Risser, M. D., & Wehner, M. F. (2017). Attributable human-induced changes in the likelihood and magnitude of the observed extreme precipitation during Hurricane Harvey. Geophysical Research Letters, 44.

[3] Coles, S. 2001. An Introduction to Statistical Modeling of Extreme Values. Springer-Verlag London Limited.

Feature image from Vox:

Saving Green: Environmental Sustainability and Affordability in Rental Developments

By Emmanuel Assa, B.S. CEE, Class of 2017

Two of the hottest topics in building design these days are environmental sustainability and affordability. This is especially true in places like the Bay Area in California, where affordable housing is a growing problem and environmental sustainability is a constant focus. However, the two are often placed in conflict - if it costs more to design and build a green building, how could it possibly be affordable? Green technology and materials can be expensive up front, but due to the lowering costs of technology, the consideration of life-cycle costs, and increased incentives for developers and homeowners, affordable environmental stewardship is more possible than ever.

A lot of the opposition to combining green development with low rental prices comes from the idea that creating green buildings is prohibitively expensive. While it’s true that green buildings can cost more up front, people often think that the additional costs are greater than in actuality. The World Business Council for Sustainable Development found that people believed that on average, green features added 17% to the cost of a building (Knox, 2015). In fact, the actual amount is more around a 2% increase in marginal cost (Knox, 2015). Another common complaint is the cost of hiring “green” designers or construction companies. As of right now, LEED-certified contractors or architects command a premium, and the difference in cost can be off-putting (Vamosi, 2011). Getting a building LEED-certified can also be costly, as LEED charges a varying amount for permitting that depends on the size of the building. For larger buildings, the cost of certification can even exceed $1 million (Vamosi, 2011). Though the amount is usually small in comparison to the entire project (a $400 million budget office building had a LEED certification fee of $1.08 million, or 0.27% of the total cost), it can still cause budget-sensitive developers to balk. And if they decide to go ahead with the project and certification, it often means an increase in the asking price of development units.

What makes this argument against green building flawed is the fact that it only considers up-front costs. The picture changes dramatically when you take into consideration life-cycle costs, which are made up of both upfront and continuous operating costs. Over the lifetime of a building, the operating costs actually outweigh its upfront costs. Green buildings perform far above average in terms of operating costs, because green buildings are designed to use less energy and water than normal, resulting in lower water and energy bills (Penny, 2012). This means that the owners of the building save more over time than they spend up front. For example, a major hotel project spent about $184,000 on energy efficiency improvements but saved about $58,000 a year - the improvements paid for themselves in a little over three years (USGBC, 2015). Consider this generalization: if energy costs in a building are $2 per square foot, making the building more energy efficient will add savings of about 30%, or $0.60 (Valhouli, 2008). Each year, a 100,000sq ft building would save $60,000, or a discounted net present value of $750,000 over its 20-year lifespan (Valhouli, 2008). All with a small upfront investment in the right technology. With life-cycle costs taken into account, the argument for green building becomes all the more convincing.

These “long-term” incentives are extremely important for low-income renters and homeowners. In affordable housing, whether public or private, renters are often asked to pay for utilities. If a building is made to be energy efficient, this means that the cost to those renters is greatly reduced, increasing the affordability of the housing (Schweitzer, 2016). Many cities with public housing projects are realizing this. In Ann Arbor, Michigan, “the local housing commission is completing floor-by-floor renovations in the five-story Baker Commons public housing facility with the goal of reducing energy use at least 20 percent” (Schweitzer, 2016). In Pittsburg, “affordable housing opened in February 2015 by the nonprofit ACTION-Housing Inc... provides homes for young adults phasing out of foster care and low-income designed to be capable of generating enough renewable energy to meet or exceed its annual energy demand” (Schweitzer, 2016). In both these cases, the aim is to make the developments more affordable for residents. With improved, cost-effective technology and retrofits, it’s possible to create housing developments that are even better suited to low-income inhabitants.

However, this altruistic streak very rarely applies to private housing developers. Though public entities and nonprofits are motivated by social good, it’s rare for private developers to feel the same. Not only that, but there’s often a sense of “split incentive” - why should developers pay for up-front improvements to the building if renters are the ones paying for utilities and reaping the savings (Valhouli, 2008)? In a nutshell, “investing in high-performance features can become a driver for returns for building owners by increasing tenant retention and reducing costs associated with lease churn” (Valhouli, 2008). Tenants understand the value of energy and water-efficient buildings, and will prefer them to rentals without. Tenants saving money on utilities will also be less likely to leave the rental in the long run, providing more reliable sources of income. Still, this doesn’t give an exact incentive for developers to specifically create low-income housing. That’s where policy comes in. One of the most prominent incentives for affordable housing is the Low-Income Housing Tax Credit (LIHTC), which reduce the amount of tax the developer has to pay in exchange for the creation and upkeep of low-income rental units (ACTION, 2016). The LIHTC makes developing affordable housing attractive to for-profit developers, which would be hard-pressed to make housing affordable in regular market conditions. What makes the LIHTC more sustainable is the fact that it gives additional consideration to developments that also adhere to green development standards. For example, an Uptown Lofts development in Pennsylvania recived LIHTCs for meeting Passive House Institute U.S. energy efficiency criteria (Schweitzer, 2016). If that isn’t “tasty” enough for profit-seeking developers, it’s been shown that green apartment buildings often command higher rents than their counterparts, lease-up rates for green buildings typically range from average to 20% above average (USGBC, 2015). So even if some housing units are reserved as “affordable,” the developer can still charge above-market rates for the rest.

So, whether it’s through the lower cost of going green or through the increasing incentives to provide low-income housing, it’s getting easier and easier to develop housing that’s both environmentally friendly and affordable. Admittedly, policy has a large part in the creation of low-income housing, but the long-term cost advantages of going green helps to convince developers that the project is worth the compromises. In the end, the combination of efficient technology and policy allows for a win-win situation for both developers and low-income residents. Though in the past affordability and environmentalism may have seemed mutually exclusive, now the two go hand in hand. As we move forward into the future, we will hopefully continue to see this trend in our urban areas - equity for humanity, and environmental sustainability for the planet.



Remember the Suburbs: Why Suburbs Matter and Need Good Planning Just as Much as Cities Do

By Wendy Sov, Master of Public Policy, Class of 2017

Are cities of the future urban or suburban? What kind of urban developments would you like to live in throughout your life, and how do those desires affect urban systems?

From what I have observed at Stanford, academics in urban planning like to talk about cities as if they are the next big thing, as if cities will increasingly draw people like millennials from suburbs, and as if growth in suburbs will slacken because people are supposedly flocking to cities. However, cities of the future are both urban and suburban because the livelihood of one depends on the livelihood of the other. Contrary to popular belief that urban areas will attract more people from suburbs because of their high commercial activity, suburbs will not be phased out because modern suburban communities provide residents with the same, if not better, amenities as cities do. If anything, suburbs have developed an ability to attract wealth through increasing commercial activity and, as a significant sustainer of cities, must not be forgotten in urban planning considerations.

As mentioned in class, the suburb and city are mutually dependent on one another, so while all the attention for urban development is focused on cities, it is important not to forget the significance of good planning in suburbs. Cities are the hub of economic activity and networks – the type of place that attracts Richard Florida’s so-called Creative Class (Florida). Despite the decentralization of the workplace via new telecommunications technology, there is irreplaceable value in in-person interactions, disproving “the death of distance” concept predicted as a product of globalization. In short, people will continue to flock to cities because in-person networks matter. However, that does not negate the significance of good planning in suburban areas. Suburbs provide the residential space for employees who keep the city employment centers alive. Given the increasing rate of gentrification and the high housing costs in inner-city regions that are displacing low-income workers to outer regions today, suburbs become all the more important to cities’ economic vitality by providing housing for those who can no longer afford to live within the city. While cities provide essential job opportunities and social networks, suburbs provide the necessary housing for the regional population, and it will become increasingly important for suburbs to grow to support cities as this population continues to rise. It is consequently essential for modern urban planning concepts to be applied in not just cities, but also suburbs. Even better, local and state policies should actively take a regional approach, pursuing integrated planning between suburbs and cities.

Furthermore, contrary to what academics suggest, cities will not supplant suburbs because modern suburbs provide not just housing but also the same, if not better, amenities as cities. As much as academics like Richard Florida like to talk up the value of cities, suburbs are here to stay and will continue to grow alongside cities. In part because of the career-centered stage of life they are at, a lot of college students and young professionals see themselves moving to/living in the city and consequently believe cities are the future of society. In all of my urban studies courses, “urbanization” and “globalization” seem to be the sexy, trendy topics of discussion, calling for environmentally sustainable urban development and design strategies to anticipate and plan for future population growth that will supposedly concentrate in inner-urban regions. But when I return home to my suburban community in Chino Hills, CA, no one is talking about environmental sustainability, smart growth, “pedestrianizing” streets and walkability, increasing accessibility to transit, etc. Unless it’s one of my friends in the same career-oriented stage as me – and even then – no one is aspiring to live in the city in the long-run. Big-box retail development and distinguished schools allow modern suburbs to offer the same amenities as a city would without the perceived crime, congestion, and pollution. Furthermore, big box retail development in suburban communities like Chino Hills have been increasing job opportunities and economic growth by attracting more commercial activity to the city. So despite what the academics are saying, globalization and urbanization do not mean the death of suburbs. This is partly due to cultural and policy factors such as our nation’s love for Manifest Destiny and the American Dream, federal mortgage policies promoting homeownership, highway developments, new telecommunications technology, etc. But more importantly, suburbs will continue to persist and grow because suburbs are themselves living, breathing, self-sustaining systems with both housing and similar amenities as those found in urban areas.

As may be the case with many other people, where I want to live then depends on at what stage of life I am at, and this in turn affects the demographics of urban forms - namely, concentrating older and wealthier populations in suburbs. The stereotypical millennial, I think I would like to focus on my career after graduation in the city, which according to Florida has high creative capital because of its diversity, abundance of job opportunities, community engagement, “third places,” and authenticity (Florida). But in the long run, I hope to eventually move to a suburb to raise a family. It is this set of desires (that many others probably share, at least from what I have gathered in conversations with friends) that explain more family households and wealth in the suburbs, and more diverse, young people in the city. Both cities and suburbs are attractive, but to different people depending on personal preferences and (to a large extent) what stage in life they are at.

At the end of the day, urban issues are regional issues that cannot be siloed within jurisdictions, so both cities and suburbs need to be planned for. The former will of course continue to grow, but so too will the latter because suburban communities provide housing and attractive amenities for families and older folks. Like cities, then, suburbs need rules to incentivize good planning. As Emily Talen emphasizes in City Rules, urban form is heavily influenced by rules. It is because of rules that cities today have functioning wastewater management, fire prevention and protection, and pervasive accessibility to utilities, but now that conditions have improved, we as society sense less the importance of the connection between rules and physical outcomes. Smart urban planning then becomes all the more important in today’s relatively more sophisticated cities to anticipate and accommodate future growth, and especially because suburbs have carbon footprints that are proportionally and absolutely larger than cities, it is also all the more important for urban planners to focus their attentions on suburbs as well as cities in order to build environmentally, economically, and equitably sustainable regional communities.


Florida, Richard L. The Rise of the Creative Class: And How It's Transforming Work, Leisure, Community and Everyday Life. New York, NY: Basic Books, 2002. Print.

Urban vs. Suburban. Digital image. True Performance. 15 August 2016. Web. 28 November 2016. <>.

The Future of Regulation and Free Markets for Energy

By Melissa Reardon, M.S. Class of 2017, Environmental Fluid Mechanics & Hydrology

Regulation and free markets have both been suggested as ways to encourage decreasing energy consumption and resulting pollution, particularly with regard to greenhouse gases. Regulation comes in a variety of forms, including subsidies, mandates, and cap-and-trade markets, each resulting in different prices for conventional and renewable energy. In free markets, prices are decided solely by competition between privately owned businesses.

Proponents of free markets for energy argue that free markets are more efficient and lead to clearer price signals to consumers (Morgan, 2016; Murphy, n.d.). While a free market certainly sounds appealing, it is not a very realistic end goal. First, the large-scale energy market has never been completely “free”; oil and gas, the main conventional sources of energy, have received subsidies since 1918 (Pfund & Healey, 2011). Second, many of the major technologies in the energy sector required subsidies from the government to become as large-scale as they have (Pfund & Healey, 2011).

Instead, it is more realistic to plan for regulation as the main tool to encourage decreases in consumption in the future. Not only has regulation been a part of the energy market from its beginnings, but it has also led to improvements in efficiencies and technologies. For example, regulation on sulfur dioxide pollution in the form of amendments to the Clean Air Act, new source performance standards, and other mandates led to innovation in sulfur dioxide control mechanisms for power plants (Taylor, Rubin, & Hounshell, 2005).

The Corporate Average Fuel Economy (CAFE) standards are another example of successful regulation. The CAFE standards were created in 1975 to make car manufacturers “increase […] the fuel economy of the passenger car and light-duty truck fleets sold in the United States” (Committee on the Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards, Board on Energy Environmental and Energy Systems, Transportation Research Board, National Research Council, 2002, p. 1). These standards directly contributed to increasing gas mileage efficiencies in cars throughout the United States (Fig. 1) and, as a consequence, led to a decrease in greenhouse gas emissions for drivers across the country (Committee on the Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards, Board on Energy Environmental and Energy Systems, Transportation Research Board, National Research Council, 2002).

Fuel economy.jpg

Fig. 1. Fuel economy of new and on-road cars and light trucks, respectively, from 1965 to 2001 resulting from the CAFE standards. Source: Committee on the Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards, Board on Energy Environmental and Energy Systems, Transportation Research Board, National Research Council, 2002, p. 16.

However, regulation also comes with its own set of problems that will need to be addressed for it to be used effectively. The first problem is rebound effects. Increased efficiency does not necessarily lead to decreased consumption; instead, consumers tend to buy more energy efficient items, resulting in the same amount of consumption (Herring & Roy, 2007). This could be addressed with changes to the price of energy that better encapsulate the negative externalities or “true cost” of energy sources.

The price of energy raises a second problem with the current regulation: subsidies. Worldwide, oil and gas companies today receive subsidies of over $500 billion. By comparison, wind and solar companies receive subsidies totaling $66 billion (Barlag & Bruner, 2014). From a historical perspective, renewable energies have also received significantly smaller subsidies in the United States than oil and gas companies have received over their respective tenures. From 1918 to 2009, the average annual subsidy for oil and gas companies was $4.86 billion 2010 dollars. Renewable energies, by contrast, received an average of $0.37 billion 2010 dollars per year from 1994 to 2009 (Fig. 2, Pfund & Healey, 2011). By equalizing the subsidies, the price of different energy sources could be more accurate and act as a better signal for consumers to switch to renewables.

Subsidies image.jpg

Fig. 2. Historical average annual energy subsidies from the United States federal government for oil and gas (O&G), nuclear energy (nuclear), biofuels, and renewables over their respective tenures. Source: Pfund & Healey, 2011, p. 29.

Regulation has always been involved in the energy markets in the United States and will likely continue to be so. It has been an effective tool in reducing greenhouse gas emissions and sulfur dioxide pollution through, respectively, CAFE standards and changes in legislation, standards, and mandates. However, in the energy market, regulation may need to take on characteristics of free markets, specifically clearer price signals. These price signals may be improved through prices that incorporate negative environmental externalities or through equal subsidies for conventional and alternative energies. With these changes, regulators and legislators should be able to more effectively guide consumer behavior toward energy sources with fewer greenhouse gas emissions.


Barlag, P. A., & Bruner, P. (2014). No Free Market for Energy. MIT Sloan Management Review. Retrieved from

Committee on the Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards, Board on Energy Environmental and Energy Systems, Transportation Research Board, National Research Council. (2002). Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards. Washington, D.C.: National Academies Press.

Herring, H., & Roy, R. (2007). Technological innovation, energy efficient design and the rebound effect. Technovation, 27(4), 194–203.

Morgan, T. (2016). The Case For Free-Market Energy: Removing Energy Subsidies And Price Controls Improves Market. Retrieved from

Murphy, R. P. (n.d.). Why Free Market in Energy? Retrieved from

Pfund, N., & Healey, B. (2011). What Would Jefferson Do?: The Historical Role of Federal Subsidies in Shaping America’s Energy Future.

Taylor, M. R., Rubin, E. S., & Hounshell, D. a. (2005). Regulation as the Mother of Innovation: The Case of SO2 Control. Law & Policy, 27(2), 348–378.

Should cities be planned at all?

By Stanley Gu, Class of 2019

Given the challenges of measuring and providing for quality of life in urban systems, and our successful and failed attempts to do so throughout history, should cities be planned at all? Or are they better off left to grow organically?

A lively street in a haphazardly planned Shanghai neighborhood.

A lively street in a haphazardly planned Shanghai neighborhood.

Planning and organic growth are yin and yang; both contribute to a city’s well-being, supporting and energizing one another. Here, we consider organic growth to be the social and economic activities of ordinary citizens, while planning consists of activities and developments organized by local officials. Many modern metropoles like Shanghai and London started out as small villages, which then grew over time in a patchwork of both planned and organic regions. First, we will examine the separate roles that these two elements play, and how losing one or the other can hurt a city. On the other hand, when planning and organic growth work together, they can benefit urban areas in surprising ways.

Organic growth is the life force of the city. Built completely from scratch, China’s Tianjin eco-city is a prime example of planning without organic growth. In most situations, people and infrastructure grow together. But in eco-cities, the infrastructure is built first, creating empty shells devoid of their organic element: human activity. Urban well-being depends not just on physical capital, but also on human and social capital – the thriving farmer’s market, busy storefronts, neighborhood watch groups, parent-teacher associations, networks of friends, and more. These qualities usually arise organically, as people form grassroots organizations or jumpstart the economy with entrepreneurial activity. Optimizing and building a city from scratch may sound great in theory, but without people and the energy and creativity they bring, urban areas remain dull. Much like a half-empty stadium, the physical infrastructure is there, but the human activity is too small to fill it with life, or even justify it economically. In time, however, people will move in and bring that organic element, and Tianjin eco-city may still prove to be a success.

Nevertheless, planning does have an important role: steering us toward collective goals we cannot achieve on our own. As we learned from the Global Footprint Calculator, most of our ecological footprint comes from our collective infrastructure – roads, waterways, hospitals, and the electric grid – which is most effectively improved through coordinated, planned action. For example, my own hometown of Fremont, California has decided to invest in bicycle and pedestrian paths, which will shape our urban form and well-being in ways beyond any one individual’s capability. In the Bay Area, park agencies like the East Bay Regional Park District protect our shared wildlands and provide access to trails. Moreover, governments can provide for the vulnerable, such as by keeping housing affordable and uplifting distressed citizens.

Considered in isolation, planning and organic growth both have benefits and drawbacks. But the more interesting question is how these two elements interact with and support each other. In many cases, the government kindles a project that takes off when citizens take ownership of it. Conversely, citizen-initiated action can blossom and mature with the help of local officials.

Participatory budgeting in New York.

Participatory budgeting in New York.

Planning is often most successful when it stimulates and supports the city’s creative energy. More and more, a big part of planning is listening to and engaging with the community. The point of this long and frequently frustrating process is to instill a sense of ownership and potentially tap into the enormous power of everyday citizens. In the case of the Participatory Budgeting Project, a local government sets aside funds and lets the public decide how to spend that money through in-person or online forums. What starts out as a government-led procedure transforms into grassroots community engagement. Another example of planning that engages communities is the Tule Ponds Wetland Preserve in my hometown of Fremont. The City and county water district put in the initial investment - new stormwater percolation ponds and an educational center. With the efforts of a dedicated geologist, hordes of high school volunteers who descend upon the site every year, and funding from local businesses, that initial investment has bloomed into a community project. In addition to the habitat restoration done by volunteers, the preserve has educated thousands of young children and exposed even more high schoolers and college students to environmental education. That is something one cannot plan for.

Other times, citizens are the ones who initiate an effort, which is amplified when governments lend their funding and support. Guerrilla urbanism projects, in which citizens install their own crosswalks, parks, gardens, or bicycle lanes, are famous for their daring nature and complete lack of bureaucratic red tape, but can fail to produce lasting change without administrative support. Such projects really become interesting, though, when leaders take notice and incorporate those changes into their own policies. This is precisely what happened in Hamilton, Ontario, when citizens deployed traffic calming measures and painted crosswalks. Though confrontations with the municipal government were tense at first, officials grew more receptive over time and even considered extending the idea to other intersections.

Making the relationship between planning and organic growth work is by no means easy. Humans are complex – we have subconscious desires, cultures, histories, memories, emotions, and entrenched habits. It’s difficult to engage with citizens when people are busy with their own lives, when bureaucracy doesn’t allow it, or when opinions and voices conflict and confuse. In the face of these challenges, it seems easier to start with a blank slate and plan everything to perfection, or to simply give up on planning altogether and leave things in the hands of pure free market economics. Though these shortcuts may seem to cut through the frustration, they are also potentially dangerous to our well-being. But when planning, governance, and organic growth interact symbiotically, the result can be more rewarding than anyone first imagined.


As we face global challenges of sustainability, are cities part of the problem or part of the solution?

By Katherine Phan, B.S. Computer Science, Class of 2017

Congested, polluted, unsustainable: these are words that have been used to describe San Francisco and other cities that share the same issues surrounding transportation, air quality, and even sanitation. Growing cities around the world have contributed to the majority of global ecological deterioration: it is estimated that they have added to 75% of global carbon dioxide emissions, affordable transportation does not exist in a majority of most cities; and there is not enough agriculture to affordably and fairly feed everyone in the world. Though shelter is a human right, homelessness is also pervasive in many developed cities--for example, San Francisco’s shelters can barely accommodate half of the city’s homeless population.6 As cities grow in size (with up to 66% of the world’s population living in one by 2050), so will these issues, causing escalating damage nationally and globally.

Yet though they’ve contributed to their fair share of human rights issues (water quality, air quality, shelter), cities are an important center of development, and should be the focus of most urban planners in the near future.  Cities are also extremely important for developing solutions to sustainability challenges, due to the high density of people, which could offer more potential to scale up to other cities. Grouping large populations together actually increases transportation efficiency, and cities have already been improving carbon emissions per capita. According to Citylab, “twelve large metros – including New York, (2.3 tons per person), Los Angeles (1.8 tons), San Diego (1.9 tons), Phoenix (1.9 tons), Washington, D.C. (2.3 tons), Miami (2.2 tons) and Seattle (2.2 tons) – rank among the 50 lowest emitting metros.” Abroad, Barcelona is converting itself to a pedestrian city, in which cars are banned within a series of “superblocks” to eliminate traffic from approximately 60% of roads. Similarly, Los Angeles, a city with double the population, has successfully implemented similar “road diets” that reduce the number of car-only roads, decreasing the number of pedestrian and cyclist collisions without decreasing traffic flow. Though each city has its own cultural idiosyncrasies, they all share similar urban systems properties; one solution in Gresham, OR can be expanded to Seattle, and to San Diego, and so forth.

It may be easy to categorize cities as either strictly part of the problem, or pinpoint them as the sole solution for the future, but population density is a fundamental property of urban systems. Thus, urban planners should understand the ever-growing importance of developing cities for high volumes of people; with an exponentially increasing world population and the rise of “mega-cities”, it is imperative to implement the correct infrastructure and policy solutions. Failing to do so is to risk the consequences of more flawed approaches to wicked problems, and to risk the slow but sure demise of the city, the environment, and humankind.