4.2.3 Urban form

Urban form has a considerable influence on many aspects of the transformation towards sustainability, e. g. on the mitigation of and adaptation to climate change, resource use, and access to adequate housing and public spaces. In addition, it has an impact on the local identification and identity of a city’s residents.

At the same time, the long life spans of buildings and urban infrastructures can lead to path dependencies (e. g. energy use, emissions, life styles and consump-tion patterns, etc.) which are difficult to change in the long term (Seto et al., 2014). On the other hand, a long life span can also have advantages in terms of resource efficiency or local identity. Urban development (formal or informal) is therefore a decisive lever for the

initia-155 tion of positive, but also negative path dependencies

of cities.

The structural shape of cities is defined both by buildings and by the public or private free spaces deter-mined by them. Depending on the dimension under observation (parcel of land, block, city district, entire city or region), different aspects come to the fore:

while a parcel of land is marked mainly by the shape and material of individual buildings, when it comes to the city as a whole questions of density, use, intercon-nectivity and access become more relevant (Seto et al., 2014). In this context, there is always an interdepen-dence between the structural aspects of the city layout and city outline and the social aspects of the percep-tion and use of urban spaces (Mayer et al., 2011: 63).

This relationship reveals the added value that the urban spaces have beyond an abstract allocation of functions (Wolfrum and Nerdinger, 2008). According to Mayer et al. (2011), a high quality of the built-up environ-ment leads to a higher level of acceptance among the residents or users, and thus brings more life into urban areas. The more possibilities of space appropriation there are, the more likely the urban population is to identify with the city. Architecture and urban devel-opment must offer a strong framework that can toler-ate changes, additions and enhancements (Mayer et al., 2011: 64). There can never be a constant, time-inde-pendent optimum in structural design because of the permanent changes taking place in the urban envi-ronment, life styles and preferences of the urban population. The built-up environment wears away and

the inhabitants and their life styles change. Buildings and outdoor spaces must therefore be able to adapt without losing quality (Mayer et al., 2011: 64). Accord-ing to Ascher (2011), “new urbanisms should be a flex-ible urbanism, aesthetically opened, reflexive, with active participation and, formally speaking, an urban-ism of devices able to elaborate and negotiate solutions rather than drawing specific plans” (Ascher, 2001: 85, cited in Duarte and Beirao, 2011: 879).

Furthermore, the urban form of cities has a consider-able influence on their use of resources and energy effi-ciency. For example, it is estimated that the worldwide building stock is responsible for approx. 31 % of global energy consumption (Ürge-Vorsatz et al., 2012: 653). In order to lower the high level of urban energy consump-tion, the energy efficiency both of buildings (building insulation) and of the entire city must be improved (Lucon et al., 2014; Seto et al., 2014; World Bank, 2010a).

In view of their geopolitical and cultural diversity, there is no generally valid ‘optimal’ shape or design for cities (Grübler et al., 2012: 1387). Instead, the concept of the compact and well-mixed city offers orientation for locally appropriate solutions (Seto et al., 2014).

The idea is that cities should be planned in a compact way, and existing towns densified. This makes it pos-sible on the one hand to reduce the energy consump-tion and CO₂ emissions of cities, and, on the other, to improve the quality of life and the health of the inhab-itants (Milner et al., 2012). However, possible conflicts of interest can also be observed in this strategy. For

Metro – 188 1863, London, UK Carfree Zones – 360+

1953, Rotterdam, Netherlands Bus Rapid Transit – 160 1974, Curitiba, Brazil Car Sharing – 1,000+

1987, Zurich, Switzerland Smart Card – 250+

1992, Oulu, Finland Bike Sharing – 500+

1998, Rennes, France Low Emission Zone – 210+

2003, Tokyo, Japan

Google Transit Web Apps – 250 2005, Portland, USA

Number of Cities

100 200 300 400 500 600

1960 1970 1980 1990 2000 2010

Year

Figure 4.2-1

Urban mobility in upheaval. First introduction and global spread of progressive approaches to planning and governance.

Source: based on Hidalgo and Zeng, 2013

156

example, if there is too much densification and there are not enough open and green spaces, the urban heat island effect is reinforced (Seto et al., 2014: 977) and social problems exacerbated if population density and anonymity increase (Section 2.4).

According to UN-Habitat (2015a) the principles of sustainable city districts comprise, among other things, the following: a high (population) density (more than 15,000 inhabitants per km²); mixed land use (more than 40 % of the ground-floor surfaces should be allo-cated for economic use); a good social mixture in the city districts (20-50 % of the residential use should be allocated for low-cost housing); a limit on the number of single-family homes (less than 10 % in a district);

and the creation of adequate space for streets and an efficient street network (30 % of the land should be made available for roads and traffic use). The compact city districts should furthermore make public life pos-sible for the urban population, be bicycle- and pedes-trian-friendly and affordable for all income groups (UN-Habitat, 2015a, b).

Even though these general principles of a sustain-able urban form are known and supported internation-ally (UN-Habitat, 2015b), they are often not imple-mented. External influences such as planning regula-tions and economic factors still promote urban sprawl or the construction of low-density settlements with single-family dwellings. Similarly, the possibilities of passive or active energy saving in buildings or city dis-tricts are often not taken up due to the absence of any incentives, or out of ignorance on the part of planners and investors (Ürge-Vorsatz et al., 2012: 702). The pre-requisite for a transformative urban design is the devel-opment and implementation of locally adapted, ade-quate design strategies for low-carbon and people-ori-ented urban and city-district planning. In addition to the geographical circumstances and technical possibil-ities, the socio-cultural context in particular must be taken into consideration. In addition, the urban form should always take its orientation from the ‘human scale’ (Gehl, 2010; Box 2.4-3).

The compact districts and cities should be designed to be adaptable and flexible, making it possible to react e. g.

to a change in life styles or to environmental disasters.

Especially for cities in risk-exposed locations (e. g. storm and flooding risks), uncertainty-oriented planning can be a sensible option (Jabareen, 2013: 222). After all, greater flexibility makes it easier to integrate new knowledge and technical innovations into the urban infrastructure.

As many actors as possible should be involved in urban development when it comes to the urban form of a city.

This not only increases the local identification of the residents, but also promotes the creative search process of transformative urban design (Section 8.3).

4.2.4

Adaptation to climate change

Climate change will increasingly impact indirectly and directly on city dwellers’ living conditions. Climate risks in cities vary from region to region and are very uncer-tain. They can involve direct effects, such as tempera-ture extremes, droughts or floods, or indirect effects like climate-related changes in food availability in the cities, or effects on the water-supply or electricity sys-tems. Global climate change interacts with a city’s cli-matic peculiarities (Rosenzweig et al., 2011). The urban heat-island effect is an example of this: concrete and other building materials absorb heat; evaporation and its cooling effects decline as vegetation is removed and surfaces are sealed.

It is estimated that a sea-level rise of half a metre could already more than triple the number of people at risk and increase more than tenfold the number of endangered assets (e. g. port cities or industrial instal-lations; Hanson et al. 2011; Revi et al., 2014a: 19). The 20 most vulnerable cities in terms of their people and assets include Mumbai, Guangzhou, Shanghai, Miami, Ho Chi Minh City, Kolkata, New York, Osaka-Kobe, Alexandria, Tokyo, Tianjin, Bangkok, Dhaka and Hai Phong.

The aim must be to reduce such risks and to improve resilience and adaptation to climate risks. In the context of disaster prevention, cities must develop strategies to protect the population, prioritize future infrastructure investments, and integrate the mitigation of and adap-tation to climate change in long-term planning. The costs can be considerable; adapting urban water-sup-ply and sanitation systems in Sub-Saharan Africa alone is expected to cost US$ 2.7 billion per year (without the cost of overhauling today’s infrastructure; Revi et al., 2014a). Adaptation to climate change is an iterative learning process that should be incorporated into urban planning as a cross-cutting subject through both incre-mental and drastic measures (e. g. relocations, with-drawal from formerly populated areas).

The ability of cities to deal with climate risks can be significantly improved by complex urban risk gover-nance and disaster preparedness (Butsch et al., 2016).

Municipalities are at the centre of successful urban adaptation policies, because the successful adaptation of cities depends largely on its integration into local investments, policies and the legislative framework (Birkmann et al., 2010; Heinrichs et al., 2011). Con-crete action fields include, for example, the protection of vulnerable population groups by building housing in more sheltered locations, improved integrated land-use planning, and changes in building regulations to make structures flood-proof (Revi et al., 2014a).

Fur-157 ther building blocks for improving crisis-management

capacity include offering training courses for the popu-lation and boosting the capacity of the emergency ser-vices in the event of a disaster.

The decisive factor for urban climate-risk manage-ment is to take scientific expertise into account in deci-sion-making processes. Scientists and vulnerable pop-ulation groups should be involved in addition to the decision makers (Revi et al., 2014a). Adaptation mea-sures should not only react to past experience, but must also anticipate future events and changes. Knowledge of future climate changes, however, is limited and involves inherent uncertainties.

There is also a need to reform university curricula, especially for students of urban planning and devel-opment, with the aim of placing more emphasis on the mitigation of and adaptation to climate change in cities (Revi et al., 2014a: 585). The lack of valid and compara-ble data as a basis for urban-planning decisions and the lack of monitoring and evaluation systems, especially in developing countries, are further shortcomings that are frequently mentioned (UKAID and DFID, 2012).

4.2.5

Poverty reduction and socio-economic disparities Overcoming extreme poverty and major socio-eco-nomic disparities in cities (urban divide) is described in many global reports on urbanization as one of the key challenges of sustainable, inclusive urbanization (Revi and Rosenzweig, 2013; UNEP, 2011b, 2012a; UKAID and DFID, 2012; LSE Cities, 2009). The Global Report of United Cities and Local Governments on Local Democ-racy and Decentralization comes to the following con-clusion: “Putting people first means putting basic local services first” (UCLG, 2013: 113). Although cities can-not break up the structures laid down by the national economic and political system, they do have room for manoeuvre when it comes to limiting social inequal-ity and improving living conditions (LSE Cities et al., 2013).

In addition to the ‘traditional’ action field of poverty reduction, municipalities today must be able to respond to closely interrelated and growing multiple risks. The traditional focus on the creation of infrastructure for overcoming urban poverty is no longer enough:

newly emerging multiple risks, such as environmen-tal risks, must also be taken into account (UKAID and DFID, 2012). The report to UN Secretary General Ban Ki-moon, ‘The Urban Opportunity: Enabling Trans-formative and Sustainable Development’ (Revi and Rosenzweig, 2013), therefore identifies extreme pov-erty in cities and the growing vulnerability as a result

of climate change as central challenges. In order to reduce extreme poverty in cities, prevent the emer-gence of new slums, increase productivity and support sustainable development, cities must provide univer-sal access to basic infrastructure and services: housing (affordable housing for all; Habitat II’s motto: adequate shelter for all), water supply and sanitation, healthcare, waste management, low-carbon energy services and transport, and communication technologies. The Third Global Report of United Cities and Local Governments on Local Democracy and Decentralization (UCLG, 2013: 30) concludes: “Access to basic services is key to improving the living conditions of city dwellers, the effectiveness of local businesses, the attractiveness of cities and, in the end, the competitiveness of national economies”. Environmental protection and mitigation of climate change are further key action fields that are closely linked to fighting poverty. On the one hand, it is a matter of access to sufficient clean water and the reduction of air pollution. On the other hand, there should be investment in strategies for improving resil-ience to natural disasters, weather extremes and other climate risks which affect poverty groups with particu-lar frequency (Revi and Rosenzweig, 2013).

An improvement in the living conditions of urban poverty groups can be achieved through an inclusive economic development policy which enables munici-palities to fight poverty, unemployment, social depri-vation and vulnerability by funding development pro-grammes on youth employment, the empowerment of marginalized groups, and promoting gender equal-ity (Revi and Rosenzweig, 2013). However, economic development can only have a positive impact on the living conditions of urban poverty groups if the impor-tance of the informal economy is recognized and ade-quately taken into account. As regards practical mea-sures, the report mentions the development of a sys-tem of urban entitlements (ensuring access to basic ser-vices), the creation of a social safety net, and offers by the public authorities to formalize informal activities.

Municipalities should, says the report, make sure that, in addition to all the other actors (e. g. national gov-ernments, private investors, international implement-ing organizations), urban poverty groups are also given a voice and can help shape the improvement of their living conditions (Revi and Rosenzweig, 2013).

4.3

Transformative action field: ‘urban land use’

Urban land makes up only a small percentage of the global land area. Satellite-based estimates of urban land use currently vary between 0.2 and 2.8 %

world-158

wide (Angel et al., 2005, 2011; Potere and Schneider, 2007; Seto et al., 2011). Although there is relatively little urban land, the influence of cities as drivers of global land-use trends is very large (Section 2.3.3.2).

The use of land by and in cities and their surrounding areas is rising significantly as a result of the pressure being exerted by the number of people currently liv-ing in cities – 54 % of the world’s total of over 7 billion people (UN DESA, 2015). This leads to land shortages and increased competition for land use, because land is a limited resource in cities and – depending on the geographical location – also in suburban regions. Urban plots of land with different uses (e. g. for housing, busi-ness, infrastructure or green areas) compete with each other within cities, often embedded in a highly dynamic land and real-estate market.

As a result of the current urbanization, suburban-ization and peri-urbansuburban-ization processes (Section 2.2.1), farmland and uncultivated land on the city outskirts are continuously being converted into urban land and sealed. These are usually irreversible interventions in nature and the landscape (Seto et al., 2011: 1). At the same time, the pressure is increasing on inner-city green areas, which, because of their central location, are highly sought-after as residential and office loca-tions. It is predicted that future land consumption by cities will increase disproportionately to population growth. In developing countries, a doubling of the pop-ulation is expected to lead to a tripling of urban area growth by 2030 (Angel et al., 2011). There is a great need for land, above all in the rapidly growing cities of Asia and Africa. Precisely here, however, rapid urban land consumption often encounters inadequate struc-tures of land-use planning, as well as weak urban gov-ernance. The distribution, new and re-designation of land, and the management of urban land uses signifi-cantly influence the sustainability, functionality and quality of life of a city over a long period of time. The type and manner of urban land use are key and funda-mental determinants of urban development as a whole.

In addition, urban actors have a considerable impact on land use in rural areas as a result of the need to sup-ply the urban population with food, energy and raw materials, which are sourced outside of urban areas (Section 2.3.3.2), and the disposal of urban waste, e. g.

in landfills outside of urban areas (Section 4.4). This urban-rural relationship leads to complex, fundamental problems for global and local land use; some of these are analysed in the following with regard to land in the city and its surrounding area (see Box 4.3-1 on the impact of cities on the use of land far outside of urban areas).

4.3.1

Urban land use

In the current global urbanization process, existing cities are growing and changing on an unprecedented scale. The stronger the dynamic with which cities grow and change, the more complex are the processes of urban-land development and use. As a rule, these pro-cesses are influenced by property-ownership systems, the sovereign or customary-law that govern them, and the related economic mechanisms on the disposaland use of land.

4.3.1.1

Land tenure systems

Worldwide there is a wide diversity of tenure systems regulating the use of land and the ‘whether’ and ‘how’

of the disposal of land – in this context particularly urban land. In addition to public or private land tenure, there are further systems which, based on complex cul-tural and historical influences, also recognize collective tenure categories.

Land can be divided up, i. e. plots of land are cre-ated for which ownership can be purchased. Legislation in each country governs who gains usage and disposal rights over land and how this is organized. Such rights can be derived from a fundamental right to property, as is regularly the case in the western industrialized coun-tries. The owner can usually grant other people pos-session and thus the right to use the land. As a rule, urban land in industrialized countries is either publicly or privately owned. Other forms of rights of use, such as community use or traditional local rights, can be found in developing countries and emerging economies (Payne et al., 2014; UN-Habitat and GLTN, 2012). Not infrequently, different systems overlap, e. g. when the collective usage forms of rural areas meet urban mod-els of private and public property as a result of urban expansion.

The disposal and use of land can be based on cus-tomary-law, religious or informal land-use systems (Payne et al., 2014; UN-Habitat, 2008; Box 4.3-2).

Codified legal systems distinguish primarily between private and public property, but they also recognize community property. Private land ownership guar-antees the owners (natural or legal persons governed by private law) a wide-ranging power of disposal over the land, i. e. a private owner can usually use, modify, let and re-sell the land. Furthermore, private property enjoys ( constitutional) protection from state interfer-ence. At the same time, the owner has the option of excluding others from using the land. The main purpose of this form of property is to guarantee the individual

Codified legal systems distinguish primarily between private and public property, but they also recognize community property. Private land ownership guar-antees the owners (natural or legal persons governed by private law) a wide-ranging power of disposal over the land, i. e. a private owner can usually use, modify, let and re-sell the land. Furthermore, private property enjoys ( constitutional) protection from state interfer-ence. At the same time, the owner has the option of excluding others from using the land. The main purpose of this form of property is to guarantee the individual

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