2.1. The Role of Urban Planning in Sustainable Urban Development
The world’s first cities can be dated back to 3500 B.C. It is generally agreed by scholars that the Uruk Cluster in Mesopotamia is humanity’s first great urban center and city [9
]. It was located 150 miles south of the modern-day Baghdad and, ever since its establishment, cities have come in to existence all over the world. Early into the 21st century, cities have started to appear with greater frequency. According to statistics calculated by Global Health Observatory, a program run by the WHO, as of 2010, more than half of all people live in urban areas. It is projected that by 2030, six out of every 10 will live in cities, and by 2050, this proportion will increase to seven out of 10 [10
Although cities cover only a trivial percentage of the land, they are densely populated and create a high volume of economic activities. It has been observed by the International Bank for Reconstruction and Development that “by enabling density—the concentration of people and economic activities in a small geographic space—cities have helped transform economies for many centuries” [11
] (p. 1). Statistically, 50% of world gross domestic product (GDP) is generated on just 1.5% of the world’s land, practically all of it in cities [12
]. Cities are characterized by high population densities and prosperous human activities and, as stated above, around 70% of GHGs released into the atmosphere are attributed to urban residents [6
]. It is hoped by focusing on the planning of cities, the most prominent GHGs sources, we might facilitate sustainability and improve human comfort and development at the same time.
Urban planning is defined as “the planning and designing of buildings, roads, and services in a town” [13
]. In “urban planning,” we deal with two concepts: “urban environment” and “planning.” Even though the first term is frequently used, it does not mean that it has a universally-agreed-upon definition. In fact, as to what an urban area stands for or what it is comprised of, we still do not have a consensus [14
]. In most countries, whether a settlement or population should be classified as rural or urban often depends on its population number, density, physical characteristics, or administrative functions [15
]. The International Council for Science proposes a synthesized definition to call urban environment “the natural, built and institutional elements that determine the physical, mental and social health and wellbeing of people who live in cities and towns” [16
] (p. 8). As for “planning,” if used in a city or business context, it usually refers to “the establishment of goals, policies, and procedures for a social or economic unit” [17
]. From the discussion above, we can see that “cities have thus been planned from the beginning, enabling new settlements, economic specialization, and cultural expression” [11
Urbanization is most evident in the context of cities where the majority of global population resides and therefore brings about the most significant environmental impact. It can be reasonably inferred that human activity is the principal driving force of various kinds of environmental problems. With so many residents and properties in them, cities are also the most vulnerable in the face of extreme weather events or other climate-related impacts. For example, compared with rural areas, big cities will encounter a more rapid temperature increase because of the heat island effect. According to the United States Environmental Protection Agency, any city with one million people or more can be 1–3 °C warmer than surrounding areas in terms of the annual mean air temperature [18
]. This shall increase or aggregate health problems. From this point of view, cities are indeed both the victimizers and the victims. To solve this cyclical problem, cities, or urban settlements, should be carefully planned from the beginning.
2.2. Different Views and Aspects of Sustainable Urban Development
To address the challenges of climate change and environmental degradation, more holistic planning of urban development has become our immediate priority. In 1973, the United Nations Environmental Progamme (UNEP) declared 5 June of every year as the World Environment Day to promote global environmental awareness of the importance of taking prompt action to protect and to preserve the Earth. Its theme in 2005 was “Green Cities” and used the slogan “Plan for the Planet!” Starting from 1986, the UN-HABITAT nominated the first Monday of every October as the World Habitat Day. Every year, in the commemoration of this day, a specific topic on urban environment and development is celebrated, such as “Planning Our Urban Future” in 2009, “Better City, Better Life” in 2010, and “Cities and Climate Change” in 2011. They all call for cities around the world to alleviate pressure on the ecosystem and to ensure the quality and security of our living environment.
The aim of sustainable urban development has emerged and spawned numerous urban settlement theories, including the “Healthy City”, “Sustainable City”, “Low-Carbon City”, “Transit-Oriented City”, “Compact City”, “Smart City”, “Green City”, and “Livable City”. These theories may come with different concerns in different areas, but they all share one central idea and ultimate goal: achieving maximum development with minimum resource consumption and environmental impact to ensure the well-being of both humans and the Earth.
Investigating the relationship between humans and environment has always attracted considerable attention. The concept of the “Healthy City” is used in the field of public sanitation and city design; it emphasizes how policies can influence human health. It originated in the mid-19th century and its modern incarnation appeared in the Initiative on Healthy Cities and Villages advocated by the WHO in 1986 [19
]. At the time, 11 cities were initially chosen to participate in the project and follow the principle of “Health for All (HTA)” [20
]. The WHO points out that many factors, including society, economy, and environment, influence human health, so planning a Healthy City not only involves public health protection, but also requires efforts in political, economic, and social arenas [21
]. A Healthy City will bring many benefits, such as “a clean, safe physical environment of high quality”, “the meeting of basic needs for all the city’s people”, and “an ecosystem that is stable now and sustainable in the long term” [20
The WHO initiated the Healthy Cities Project in 1990 and 47 countries participated in it during the first stage. At the time, the WHO drew up 53 Healthy Cities Indicators as initial references and continued to collected relevant data and statistics. After meticulous study and analysis, the 53 indicators were condensed into 32 and were classified in four categories: Health Indicators, Health Service Indicators, Environmental Indicators, and Socio-economic Indicators [22
Since the urban environment comprises a wide range of elements and its form of planning is varied, the “Sustainable City” has become a major trend in many countries. It takes environmental impacts into consideration during the design phase of city planning and encourages residents to actively reduce their energy and water consumption and to limit their emissions of GHGs and other pollutants. In 2002, the International Environmental Technology Centre of the UNEP and the Environment Protection Authority of Victoria in Australia collaborated to hold an international expert panel in Melbourne. From it, the Melbourne Principles for Sustainable Cities were developed. The vision promoted by the principles is to “create environmentally healthy, vibrant and sustainable cities where people respect one another and nature, to the benefit of all” [23
]. Rather than a fixed framework, the principles are designed to be flexible enough to be adopted by any cities and they provide a starting point for decision-makers on the journey towards sustainability, assisting government officials in understanding the implications of decisions taken at a broad strategic level [23
The “Low-Carbon City” is sometimes referred to as the “Low-Emission City”. To confront the issue of ever-increasing GHGs emissions, the UNEP and the UNFCCC have been advocating Adaption and Mitigation: the former addresses the adverse effects of climate change, responds to the impacts of existing climate change, and improves resilience against future impacts [24
]; the latter refers to reduction or prevention of GHGs emissions. For example, “mitigation can mean using new technologies and renewable energies, making older equipment more energy efficient, or changing management practices or consumer behavior” [25
A Low-Carbon City uses mitigation strategies in urban planning with the aim of enlisting efforts from not only the public and private sectors but the whole community significantly to cut down emissions. In Global Report on Human Settlements 2009—Planning Sustainable Cities: Policy Directions
published by the UN-HABITAT, it has been strongly advocated that “the key objective of the trend towards ‘carbon neutral’ cities is to ensure that every home, neighbourhood and business is carbon neutral. Carbon neutral cities are able to reduce their ecological footprint through energy efficiency and by replacing fossil fuels” [26
] (p. 149). From this statement, we can reasonably infer that “low carbon,” or the ultimate “carbon neutral”, has become the goal of all sustainable urban development. Such awareness and action are essential if the world is to shift to “post-carbon cities” [27
]. The World Bank launched the Low-Carbon Livable Cities Initiative in September 2013 and planned to help 300 large cities in developing countries to transition into low-carbon settlements in the next four years. Assistance will come in the form of planning and financing and necessary assistance will be promptly provided.
Along the same lines, several programs have been in place to help cities reach the goal of carbon emissions reduction or carbon neutrality. Examples include the Cities for Climate Change program by the Local Governments for Sustainability, the Clinton Foundation’s C-40 Climate Change Initiative, Architecture 2030, and the UN-HABITAT’s Cities for Climate Change Initiative. These programs all stress the importance of reducing energy use wherever and whenever possible, especially in the building and transportation sectors. Since transport creates the primary form of any city, it is frequently regarded as the most fundamental infrastructure for a city [28
] and naturally should be the focus of any urban sustainability efforts.
One of the dominant features of modern cities is high density. Those in developing countries often have much higher density than those in developed countries. If vehicles in these confined spaces are not controlled in numbers, or have poorly-maintained fossil fuel engines, serious air pollution will surely follow. Therefore, cities have to rigorously monitor and manage such emission sources [29
]. Transit-Oriented Development (TOD) has the potential to address this issue. TOD represents a neighborhood incorporating a mélange of land uses centered around a transit station [30
]. Within a short walking distance from the core, usually in ten minutes, residents can easily access all kinds of daily services, such as retail stores, offices, and residential quarters. The function and importance of TODs are emphasized as follows [31
] (p. 2):
“the location, mix, and configuration of land uses in TODs are designed to encourage convenient alternatives to the auto, to provide a model of efficient land utilization, to better serve the needs of […] diverse households, and to create more identifiable, livable communities”.
TOD can not only reduce car use per capita by 50%, but save households about 20% of their income because they can manage with average one fewer car, or even none [32
]. It also enables low carbon housing. For instance, in the United States, shifting 60% of new growth to compact/high-density patterns will reduce CO2
emissions by as much as 85 million metric tons annually by 2030 [33
]. Compared with traditional community development, TOD expands facets of economy, comfort, and environment. As identified by Belzer and Autler [34
], measures of livability which relate to TOD include reduction of gasoline consumption, increased walkability and access to public transportation, decreased traffic congestion, positive health outcomes, and more convenient access to services, activities, and public spaces. Cities, or the built environment, are all too often the most prominent GHGs sources. In other words, they are the key to success of any efforts towards emission reduction. TOD illustrates that, in urban development, environmental concerns and human interest can be balanced at the same time under the common goal of sustainability for all.
The “Compact City” also strives for TOD and plans for roads, streets, and neighborhood networks that promote walkability and are convenient for all users. It is high in density and social diversity, emphasizing the optimal provision of infrastructures in cities of small and medium size and advocating local production and consumption. In it, economic and social activities often overlap and community development is focused on the neighborhood. Therefore, energy and space efficiency can be greatly enhanced.
In Urban Patterns for A Green Economy—Leveraging Density
, a report published by the UN-Habitat in 2012, five Ds that characterize a compact city are proposed: Density, Diversity, Design, Destination, and Distance to Transit. The five Ds show the importance of making good decisions on locations, urban structures, and street networks in order to weave an urban fabric conducive to walking, cycling, and public transit [35
]. With similar ideals in mind, the Institute for Transportation and Development Policy (ITDP) released a report named Europe’s Vibrant New Low Car(bon) Communities
. It puts forth eight principles for smart urban growth, or a smart city: promote walking, prioritize bicycle networks, create dense street networks, support high-quality transit, plan for mixed land use, match density with transit capacity, create compact regions, and regulate parking and local road use [36
]. In the report, the ITDP emphasizes the importance of walking, cycling, and quality public transportation and believes that the key to emission reduction is to cut back on the use of vehicles that burn fossil fuels. The belief is actually summed up in the title of the report, Europe’s Vibrant New Low Car(bon) Communities
, as the word “car” is plainly stated.
In literature on the subject on sustainable urban settlements, the notion of “greenness” has also become influential in recent years. It is frequently presented as “greening” or “green”, and can be found in various city rankings, such as the European Green Capital Award (EGCA) and the Green City Index. The EGCA aims to “reward cities which are making efforts to improve the urban environment and move towards healthier and sustainable living areas” [37
]. Siemens AG and the Economist Intelligence Unit (EIU) collaborate to survey cities in more than 120 countries. The focal geographical regions cover Europe, Latin America, United States, Canada, Asia, and Africa. Cities are assessed and compared in terms of environmental performance. The final evaluation results will be compiled and presented as the Green City Index, showing weaknesses and strengths of each region and each city. The Green City Index is targeted to measure and to rate the environmental performance of cities, “touching on a wide range of environmental areas, from environmental governance and water consumption to waste management and greenhouse gas emissions” [38
] (p. 4).
As urban settlements represent a built environment with various man-made architectural structures, the concept of greenness is also embodied in contemporary building standards. Both homes and commercial buildings use large amounts of energy for heating, cooling, cooking, and management of waste. Attempts to rein in such energy use and its subsequent GHGs emissions from fossil fuel combustion have led to an increase of green building standards that promote better occupant comfort and lower environmental impacts at the same time. In general, a green building aims to be responsible to the environment during its entire life cycle and to increase its energy efficiency at different stages, including siting, design, construction, operation, maintenance, renovation, and demolition. It requires close cooperation among design teams, architects, engineers, and clients [39
]. Compared with traditional ones, green buildings expand concerns of economy, utility, durability, and comfort [40
]. Around the world, “incentives or requirements for buildings to meet green-building standards have been used in some cities as part of a move towards carbon neutrality” [26
] (p. 41).
The notion of “livability” is also highly noteworthy. It is sometimes presented as “liveability” or “livable/liveable”, and appears in numerous documents from both public and private sector organizations. For efforts made by public organizations, the most recent and significant one is the Better Life Initiative, which is the culmination of research results published by the Organisation for Economic Co-operation and Development (OECD) in 2011. The OECD has put in more than a decade of work and has subsequently assembled internationally comparable measures of well-being, called the Better Life Index. The Index is one of the core products from the Initiative. It invites users to compare well-being across countries according to the following 11 topics: community, education, environment, civic engagement, health, housing, income, jobs, life satisfaction, safety and work-life balance [41
]. The OECD’s goal lies in “developing statistics to capture aspects of life that matter to people and that shape the quality of their lives” [41
] (p. 1).
For notions deployed by private sector organizations, there are also numerous examples. By way of example, the EIU runs a global survey of livability entitled the “EIU Liveability Ranking”. It states that livability “assesses which locations around the world provide the best or the worst living conditions” [42
] (p. 1). Mercer, a global leading human resources consultancy, publishes “Quality-of-Living Reports” that rank cities in terms of quality factors including political/social/economic environment, medical/health considerations, and education [43
]. Monocle, a global affairs magazine, holds its annual “Quality of Life Survey”, previously named “The Most Liveable Cities Index”. It rates the “components and forces that make a city not simply attractive or wealthy but truly liveable” [44
] and announces every year its top 25 livable cities in the world, based on “statistics collected on population, international flights, crime, sunshine, tolerance, unemployment rate, upcoming developments, electric car charging points, culture, bookshops, green space, street life, and dinner on a Sunday” [45
Presented above are some of the most notable and most frequently-cited global livability rankings. Through them, we may get a fuller understanding of what livability is. However, livability “does not come packaged in a single accepted definition” [46
] because the concept has constantly been associated with an abundance of social characteristics and physical aspects. It involves not only elements of the daily physical environment but ideals of placemaking. From this point of view, “a livable community is one that has affordable and appropriate housing, supportive community features and services, and adequate mobility options, which together facilitate personal independence and the engagement of residents in civic and social life” [47