Key aspects of the urban physical system
We need to change the urban physical system
The physical system links with the ecological and socio-economic systems of an urban environment, and is connected with governance and knowledge sharing to make up the overall urban system.
The way that we build our cities and towns, founded on their ecological base - that is, the natural environment they exist in - is fundamental to the quality of our lives.
For cities and towns to be thriving, green and resilient places, our physical environment must be integrated with nature and it must be closely connected to responsible socio-economic policy. By designing and creating our urban environments for time, with nature embedded, and in a more inclusive manner, we can create places that are so much more pleasurable and equitable for everyone, leaving no one behind. We have the skills and abilities to make this happen - we just need to all get on board with the journey to collectively ensure that it does.
The importance of public amenities
Let's spend time improving public toilets
Public toilets are found in the street, in public transport hubs, public buildings (e.g. libraries, sports centres), in parks and elsewhere. Whilst some cities and towns make an effort to make their public toilets interesting, most of them are purely functional (if they function and are maintained properly) and ugly to look at: their styling is mundane to say the least.
Not so with the The Tokyo Toilet project (image credit: their website) which has been created to provide more than new, funky toilet facilities. The 17 different designs across Tokyo represent cooperative partnerships across the public and private sectors, and members of the local community. It is hoped that these standard-setting public toilets can help transform the surrounding streets. Public toilets might be small parts of the urban fabric, but they can be a catalyst for imaginative solutions for lots of other things.
Reimagining the humble bench, and bus shelters
Benches are dispersed across cities and towns and they are versatile and valuable parts of urban street furniture. Some cities and towns use one or a few common types across all of their environments, others seem to be more free form. When you stop to think about it, benches are an integral part of society’s comings and goings. They are used by all sorts of people – to have a rest, to stop and chat over lunch, or to have a nap. Can a similar approach to what the City of Tokyo has done with its Tokyo Toilet project be taken by cities and towns to reimagine the purpose of their humble benches? Can we imagine what we would want if it was our very own street furniture?
A well-designed bench blends into its environment, and it leverages local Nature-based Solutions. Clearly, a bench must be durable and easily cleaned. Depending on its location, it may be subject to strong sunlight, perhaps bird droppings and a host of other considerations. In a linkage with smart cities, some benches (but not all) may lend themselves to being “digitally smart”.
Bus shelters are typically very basic in their design. In many urban areas they are old and tatty. Maintenance is of course important. Is there an opportunity to take a new approach with new bus shelters, especially if the bus can be an important part of public transport? For example, as with many other structures in the built environment they often contribute to the urban heat island effect. Can different materials be used that reflect the sun’s incoming energy rather than absorb it, or can bus shelters absorb energy for re-use, including to cool the air within them?
Living Roofs bus stops by the UK company Clear Channel have been nicknamed ‘Bee Bus Stops’. They have been designed in partnership with ecologists to provide a bus stop solution that also supports biodiversity native to local areas and contributes to bringing more greenery back into urban areas. Similarly, the global business JC Decaux has designed bus shelters that can contribute to supporting municipal authorities with air quality measurements. The roof of the bus shelter contains a carpet of moss which captures and absorbs pollutants, and then a ventilation system blows out filtered air towards passengers waiting at the stop. Its intelligent control system activates fans according to perceived pollution levels.
Other examples of living roof bus stops exist, as one example of how we can make bus stops better when we try.
Reimagining urban lighting - for safety and sustainability
Street lighting can consume a significant portion of the electricity budget of municipal authorities – and many of them are still inefficient, even with the installation of better lamps such as LEDs.
Street lamps date back a few hundred years and were originally coal gas powered. Today’s modern street lighting is very different, yet in many parts of the world their style has barely changed for decades and many consume much more energy than they should, in a “continuous way” without any adaptation to the constantly changing weather in their immediate location. Is there an opportunity to take a new approach to urban lighting, in a way that makes it much more versatile and sustainable in its use of energy? Los Angeles is having a go at a new approach.
In November of 2019 the city first announced “L.A. Lights the Way”, a design competition to create a new streetlight for Los Angeles. The winning design, announced in 2020, is called “Superbloom”.
Superbloom has been designed by an L.A.-based company, Project Room. The design features a cluster of aluminium (aluminum) tubes, each of which can cater for a different function. It can house pedestrian-side lights or telecommunications equipment, or attachments for shade or a bench, or display art. Instead of being just one pole for lighting it is a collection of poles. The analogy the team used was to think of it as a bouquet of flowers. It is green in colour, to represent closeness to nature. LED lights are more efficient and have been developed to provide a warm light. They also feature a “pedestrian light fixture” which is half-way up to illuminate the sidewalk or pedestrian path, which is hoped will help with public safety at night.
Other examples of imaginative thinking for street lamps exist. This ubiquitous piece of urban furniture could serve a valuable purpose for many other uses - from measuring noise and air pollution, to maybe even being a source of power for EV charging, including receiving their energy when they can through solar panels.
Reimagining urban waste management and cleaning
Much has changed in our awareness and attitude to waste over the past 20 years, but we keep creating it. The World Bank reports that, globally, the amount of waste (food, e-waste, metals, plastic and so on) looks set to keep growing as our global consumption of goods and products increases, despite the efforts many people are making to be more sustainable. Cities and towns have different types of waste collection services, but is there enough focus on reducing waste to begin with? It is a matter that heavily relies on the choices and good behaviour of citizens. The recycling part of the circular economy is often discussed, but recycling should only come after we focus first on reducing waste by not creating it to start with, and finding ways for what we own to be repaired or reused (by ourselves or others), rather than replaced. These two parts of the circular economy must take priority over recycling.
The hierarchy of waste management therefore starts with avoiding waste to begin with by being careful with what we consume. What are the financial benefits of doing so? Authorities will know what their annual waste management budget is and what it is projected to cost in future. Are there ways to reduce it, by society reducing the amount of waste it creates? Is it worth waste collection services having good data-enabled solutions to help them be more efficient? Tariffs and charges for different forms of waste could be useful triggers and nudges to reduce waste. Special waste generated from certain industries obviously needs specific treatment.
Is it feasible for city and municipal authorities to set a zero-waste goal and measure the ecological and socio-economic benefits to citizens and businesses? This goal could tie into SDG 12, in particular SDG indicator 12.5 (By 2030, substantially reduce waste generation through prevention, reduction, recycling and reuse).
Changing our buildings and structures
How to rethink our built environment
Similar to the ethos we take for urban transport & mobility infrastructure, the way we create and maintain our buildings (and structures), and how we change or dispose of them when they have served their purpose, is at the heart of urban sustainability and resilience. The buildings we create shape how we live, where we work and how we consume services and goods, and enjoy arts and entertainment.
The International Energy Agency (IEA) has calculated that the built environment consumes approximately 40 per cent of global energy and contributes to more than 30 per cent of greenhouse gas emissions. Importantly, the IEA has found that energy-related CO2 emissions from the world’s building stock has risen in recent years, after a period of levelling off between 2013 and 2016.
How we design, build, operate and repurpose, recycle and dispose of buildings is critical to achieving emissions targets, and broader sustainability goals. Buildings are fundamental to the circular economy. A key challenge we face is how to ensure building components and materials are designed to be reused and repurposed, and – only if necessary – recycled. An integrated, whole-of-society approach to our buildings and their purpose – bringing together all parts of government, the private sector, academics and civil society – is required to ensure we achieve a good state of sustainable resilience for our built environment.
Two key questions for the built environment
The size of the global urban population, and the continuing growth of urban environments over the coming decades, will require more buildings to be built. We cannot continue to use existing methods to achieve this demand – doing so will result in failure to achieve climate adaptation. As we face up to this challenge, we must ensure our buildings are designed to maximise quality of life, demonstrate strong resilience, and minimise carbon (CO2) and other emissions over their entire lifecycle with the adoption of detailed and specific circular building principles. The nature of urban density in each city and town, linking to the transport & mobility infrastructure and the energy and water to serve our needs, has to be carefully conceived – with the specific context to each specific urban environment being key, and an ongoing focus on ensuring enough greenery to all parts of an urban environment, not merely designing a few parks. As well as the anticipated growth of many cities and towns, many will experience changes to the needs of the people who live there due to demographic change. For example, national census surveys from various countries indicate that, by 2050, some of them will experience a population decline, and an ageing population. The built environment needs of these places in 30- and 40-years’ time will be different to those countries and areas that experience population growth with a younger population.
Two questions for all building needs are:
1. Can we adapt the buildings that already exist in our urban environments (for all purposes – commercial, housing, industrial and everything else) to be more sustainable and to help support climate adaptation and mitigation?
2. Will all new buildings and property developments (from housing developments and mixed-use developments to commercial centres and industrial units, through to small extension projects) be required by law to show they use appropriate (and approved) sustainable materials?
These two questions are linked to how we transform our transport & mobility infrastructure as a holistic whole of the urban physical system, and they relate to how we see the ecological and socio-economic systems as part of the urban whole.
Rethinking how we create our urban built environments
There are many aspects to achieving a good state of resilience for our built environment, which have strong interdependencies with the ecological and socio-economic systems within the overall urban system, including the amount of greenery that we design into it.
Today’s approach to the urban built environment and the building lifecycle of inception, planning, design, building, maintaining and disposing/re-purposing of buildings has to change. Using a systems approach can help us to think through the many challenges to making this change stick, and to creating and implementing better solutions to make our urban environments green, thriving and resilient places in which to live.
Questions to consider include:
1. How will our existing and future buildings be more efficient over their lifecycle than today’s buildings?
2. How will buildings be designed for an improved way of living and working in urban areas?
3. How will the design and construction of buildings ensure that less carbon (CO2) and other emissions occur throughout the whole product lifecycle?
4. How can buildings use materials from an extensive common catalogue of parts, many of which could be printed on demand, to replace the huge amount of bespoke design and build which continues to dominate the construction industry?
5. How will buildings (existing and new) be intelligently and securely connected to sensible smart city initiatives?
6. How will Nature-based Solutions be integrated into the design and operation of our buildings, including smart use of greenery?
7. How can agile changes to building codes be implemented to allow innovation and new approaches to take place (whilst maintaining safety at all times)?
Future-proofing our urban built environments
The increasing size of the global urban population, and the continuing growth of urban environments in the coming decades, will inevitably require more buildings to be built. We cannot continue to use existing methods to achieve this demand – doing so will result in failure to achieve climate adaptation. We must ensure our buildings are designed to maximise quality of life and efficiency, and minimise carbon (CO2) and other emissions over their entire lifecycle with the adoption of circular building principles. The nature of urban density in each city and town, linking to the transport & mobility infrastructure and the energy and water to serve our needs, has to be carefully designed – with the specific context to each specific urban environment being key, and an ongoing focus on ensuring enough greenery to all parts of an urban environment, not merely creating a few parks.
As well as the anticipated growth, some areas will experience changes to the needs of the people who live there. For example, national census surveys from various countries indicate that, by 2050, some of them will experience a population decline, and an ageing population. The built environment needs of these places in 30- and 40-years’ time will be different to those countries and areas that experience population growth with a younger population.
Three questions for our future building needs are:
1. Can we build less, by adapting existing buildings in our urban environments (for all purposes – commercial, housing, industrial and everything else) to be more sustainable and to help support climate adaptation and mitigation?
2. Will all new buildings and property developments (from housing developments and mixed-use developments to commercial centres and industrial units, through to small extension projects) be required by law to show sustainable materials and resilience, which includes supporting the social and ecological fabric that they are built within?
3. How do we ensure we link the built environment to our transport & mobility infrastructure so that good public transport is available and car use is minimised?
Tackling emissions in design and construction - embodied carbon
The design and construction of our urban environments is tightly linked to the infrastructure linking it together, and how well we establish a resilient socio-economic environment. As noted earlier, buildings are responsible for a large amount of the world’s energy use and greenhouse gas (including CO2) emissions. A critical challenge we face today is how to minimise building emissions throughout their lifecycle, from inception through to construction and operation, and through to their end of life, in what is being termed “embodied carbon” and “operational carbon”. We need to apply good circular building principles whilst ensuring sound building integrity in design. This requires us to understand not only the structural needs of our buildings but also their role within the overall urban system, including their impact on the ecological and socio-economic aspects of urban environments.
To date, the property and construction industry has focused its sustainability efforts to a large extent on ways to make buildings more efficient to operate. Whilst there are some exceptions from some in the industry, there has not been enough focus on tackling embodied carbon emissions, which are hard matters to address and solve. Legislation in various countries currently tends to focus more on operational emissions than embodied emissions. As a result, little progress has been made on monitoring and restricting embodied carbon.
Actions are in progress to address this challenge. For example, in 2022 the Institute of Structural Engineers, a UK based professional body, published the second edition of a report, How to calculate embodied carbon. This detailed report puts forward a set of embodied carbon calculation principles for the structural engineering community to follow. Analysis by the report’s authors of recently constructed buildings shows that inefficiencies in the construction process of approximately 50 per cent are common. They stress that the over design of buildings and infrastructure must be tackled to reduce material requirements and help meet carbon targets.
One route to zero carbon structural design put forward in the report is the reuse and life extension of existing buildings and their component parts. In what is termed ‘Building nothing’, it is put forward as a way to meet a client’s brief that requires careful planning and engineering analysis, and it is an important part of our use of buildings if we are to achieve major cuts in carbon and other greenhouse gas emissions. Demolition of a building has for centuries been our default answer to building something new, aided by tax incentives that incentivise demolition over reuse, yet different thinking and a new, joined-up approach is required today. How can buildings be designed so that many of their components can be reused rather than broken up (regardless of whether they are recycled or not)? Building end of life discussions about buildings are an integral part to the construction industry being part of the circular economy.
Five construction materials warrant immediate attention. The first – sand (and gravel) – is about ensuring it is responsibly sourced, and whether there are appropriate alternatives. The second – cement – is concerned with changing its carbon-intensive production. The third and fourth – concrete and steel – are two materials that are major sources of carbon (CO2) emissions and both are viewed as “difficult to decarbonise”. The term “difficult” is relative – the technology exists to decarbonise them, but the economic will to do so is limited. The fifth – gypsum – is used around the world for the plasterboard on our internal walls.
3D printing has been used in various industries for several years. It is still at its infancy in construction, despite being discussed for several years. It holds promise to improve productivity and efficiency, and – crucially – to reduce CO2 emissions and waste.
To properly understand embodied carbon and work towards zero emissions in construction, governance is critical. Legislation such as that which exists in the Netherlands for whole-life carbon assessments for certain types of buildings should be introduced everywhere. For the nitty gritty of the project world, it also means putting appropriate “embodied carbon clauses” into project contracts, including expectations and requirements on performance standards to be met (and financial penalties for not meeting them). The stakeholders who enter into agreement to construct new buildings / change existing structures need to ensure that contractually binding and agreed requirements are in place and enforceable, whilst also being fair and reasonable.
To reduce embodied carbon in buildings and to work towards the goal of net-zero construction, and the net zero operation (operational carbon) of buildings, comes with a cost. Construction is a very competitive industry in which businesses exist on slender profit margins. When construction firms are tendering for projects, will the ones that try to “get to zero” be penalised because their tender prices will be higher? This will be the case as long as “traditional” Business Cases which focus on short-term cost continue to be developed. Small changes in tender pricing can make a major difference and many builders do not have the means to wear the risk themselves. The Business Cases and evaluations of tenders received for building projects, and “packages of work” that go to tender from managing contractors – technical and commercial – need to change in their emphasis, so that weighting is placed on net zero initiatives. This will only happen if the client / investors that are paying for the building are willing to pay for net zero.
These points are as valid for small businesses in the industry as they are to medium and large businesses. For example, the local builder providing a quote for a small house extension or a new retaining wall is unlikely to be asked by the home owner about the materials they propose to use, and how “green” these materials are. But what if this was to change, due to a concerted effort by municipal authorities and the industry to encourage small clients to ask these questions and to be prepared to pay the appropriate price for minimising emissions? Could this change really happen? Would it force a rethink by the industry’s smallest businesses?
Tackling emissions in design and construction - operational carbon
Our built environments consume a large amount of energy, and the energy efficiency of buildings is key to being more responsible with our energy footprint. Achieving energy efficiency in buildings is tightly connected with our use of smart technology including digital automated solutions to control building energy use.
In December 2023, more than 60 countries committed to answering a key question at the United Nations climate summit known as COP28: How can communities stay cool in a warming world without generating more greenhouse gas emissions?
At COP28 these countries signed a first-ever Global Cooling Pledge. The pledging nations promise to reduce cooling-related emissions 68% by 2050 in comparison to 2022 levels.
Along with the Global Cooling Pledge, the UN Environment Programme (UNEP) released a report examining how the world can reach near-zero emissions in key cooling sectors, including refrigeration and air conditioning.
Three key takeaways are:
1. Passive cooling can reduce a building’s energy consumption by 8% to 70%, suggests research cited in the report.
2. One of the most effective regulatory actions to reduce cooling demand is building energy codes that explicitly include the passive cooling measures mentioned above, the report says.
3. Local and regional climate or heat action plans “offer a key opportunity for [countries] to identify the size of their cooling challenge,” it explains.
Can we change our relationship with housing?
The world's housing needs are daunting. In 2016 the World Bank estimated that 1.2 billion people were living in substandard housing, that 3 billion people would need new housing by 2030, and that 300 million new homes would be required to house the global population by 2030, the majority of these required in Africa and Asia. They also added that housing financing was not meeting demand.
Ensuring a standard of housing that is sustainable, resilient, aesthetically pleasing and safe should be a fundamental right for everyone – yet perhaps 20 per cent of the world lacks even the most basic form of shelter. For those that are fortunate to live in good housing, these properties are responsible for generating far too much CO2 and other greenhouse gas emissions – both in terms of embodied carbon and operational carbon. The housing challenge is a difficult problem to solve, and it has very different context in different parts of the world. In developing economies, land rights and land value is still a problem, and many new homes need to be built at low cost whilst also being sustainable. In the Global North people need to change their living habits, with changes to existing housing stock requiring a cost outlay that many baulk at and do not see as a worthwhile investment, even with governments trying to provide incentives. How can the world make the transition that we need to achieve for sustainable, resilient and affordable housing that it is better adapted to the climate challenge, socially equitable and provides decent and respectable living? A key principle to always adhere to is to ensure maximum collaboration between citizens, local businesses, municipal authorities and other stakeholders: what works in one part of the world may not work in another.
The housing debt that many people have taken on in developed economies could lead to major national and global economy problems in the coming years (taking into account borrowing costs and inflation). The high cost of housing is causing many people all over the world, especially the young, to abandon hope of ever being able to own their own home. For urban planners, the situation is forcing fresh thinking about urban zoning and density. Taxation rules on property may have to change, with measures that take account of capital appreciation and income levels.
In developing economies, achieving new affordable housing is a critical issue. There are opportunities to build better with smart solutions and some innovative housing suppliers are working on great low-cost solutions, but many challenges still exist, not least of which is the ratio of the value of land to property in these parts of the world.
The problematic situation is not only affecting would-be buyers – it is also impacting renters, who face rising rental costs (which has been seen during 2023). A perennial issue is housing inequality, and an entire generation is at risk of being left behind.
Adding to this problem is the rising costs of energy to power our households. In many parts of the world, energy bills have risen sharply in 2022 as a result of geopolitical impacts on the supply of electricity and gas.
Various national and city governments around the world are trying to work out how best to respond to the challenges they face and their different housing conundrums – and they know that there are no easy solutions. City authorities and politicians are examining a variety of measures, ranging from building low-cost affordable housing to mandating caps in rent amounts and rises to special taxes on landlords, nationalising property, banning foreign buyers, or turning buildings that were previously offices into housing. To mitigate the impact of rising energy costs, financial measures are being reviewed.
A leading building standard in reducing the amount of energy that houses use has been developed by the Passivhaus Institute. If adhered to it can reduce space heating requirements by around 75 per cent compared to a typical new build and can cut fuel bills by up to 90 per cent.
Perhaps some of the innovations in construction, such as 3D printing, may help to curb the costs of construction and also help us to achieve aesthetically pleasing structures, but the economics of housing around the world remain a thorny problem.
As an example of government action to drive change, n 2015 the city of Brussels, in Belgium, passed legislation making it mandatory for all new buildings (both residential and commercial) as well as all retrofits to meet stringent passive house standards. Whilst it has taken a few years to become widespread, change is gathering momentum.
In the private sector, various housebuilders are working on concept houses that demonstrate low carbon housing construction. For example, in the UK Barratt Developments has created a “Zed House” which contains various construction techniques and technologies to create the house of the future.
Four key challenges
Whilst there is action on large-scale property development, how will small construction and property businesses around the world be supported to implement the right environmental and social measures? Without small businesses being involved, the dial will not fully turn. Construction is a very fragmented industry, with low cost of entry and a dispersed supply chain that operates on low profit margins. It is an industry that has historically been a laggard in adopting change. Whilst major construction businesses can dedicate time towards so-called ESG (Environment, Social and Governance) at the corporate level and on their major projects, will this fragmented global industry and its supply chain of many small businesses around the world be supported to introduce proper environmental and social measures?
Four challenges need to be addressed by the industry, globally, if it is to progress towards a zero emissions goal:
1. It all starts with design – does the design of buildings need to go through a radical overhaul that focuses on genuine and technically proven circular usage principles with structures that have components that are easily reused and repurposed, and/or easily deconstructed for their parts to be reused in different ways?
2. How can emissions caused through the production of key building materials, including their raw material sources, be drastically reduced?
3. Can the investment proposals for property developments of all sizes, which includes the way they are designed and constructed integrate an approach to achieve zero emissions for the property lifecycle in a way that maintains strong commercial viability?
4. Can the vast number of small construction (and property developer) businesses around the world get to zero?
For operational carbon emissions, our built environments consume a large amount of energy, and the energy efficiency of buildings is key to being more responsible with our energy footprint. Achieving energy efficiency in buildings is tightly connected with our use of smart technology including digital automated solutions to control building energy use.
What are cities and towns doing about construction?
Many challenges lay ahead for commercial and residential construction to reduce the embodied carbon and operational carbon of buildings. For example, for changes planned and proposed for house construction there are concerns about who can and will do the work and who will pay for it to be done.
The C40 Cities coalition of mayors has put forward a “Clean Construction Declaration”, which describes how they commit to helping the global construction industry in their cities (not all have signed up). In this declaration, clean construction prioritises building retrofits and ensures that new buildings and infrastructure embed circular economy principles in their design, material and construction choices.
Some cities are introducing dedicated roles in their municipal teams to focus on the decarbonisation of buildings. For example, the city of Denver climate office is establishing a building decarbonisation incentives manager. City officials have stated that the role is designed to help Denver achieve its goal of dramatically lowering greenhouse gas emissions from buildings and homes. This role is being “enabled” by the city's voter-backed Climate Protection Fund, which is funded by a 0.25 per cent sales and use tax increase that was approved through a 2020 ballot initiative. The fund is expected to generate up to US$40m per year to support the city's climate and decarbonisation efforts.
Elsewhere, in an example of legislation being used to drive change in the way that buildings are designed, built and operated, under a new ordinance the Boston City Council approved on 22 September 2021 the city of Boston will require all buildings over 20,000 square feet to achieve zero carbon (CO2) emissions by 2050. The ordinance applies to about 4 per cent of the city’s structures, including commercial and residential buildings that produce 60 per cent of the city’s building emissions. In an example of cooperative stakeholder engagement, environmental groups and people representing building firms worked with the city to agree the ordinance. The city also made sure to include representation for marginalised communities.
On a local, small builder level, it seems that change is not really happening. Small businesses are not impacted by or included in C40 agreements, Global Building Councils or global Getting to Zero forums. They are not being driven by their small clients (right down to individual citizens) to change how they design and build their projects – and local authorities are not pushing for big change from them either. Yet “the small end” is where the majority of the work takes place. If it was approached in the right way, it could be one of the easiest parts to change.