Cities are defined as densely populated geographic areas characterized by urban development. They serve as economic, political, and cultural centers, offering various services, infrastructure, and opportunities. However, urban densification has been associated with negative aspects such as health issues, pollution, and social problems. Countries like India and China, with their massive populations exceeding billions, face a significant demand for services and housing.
Recent research, including studies by institutions like the Berkeley Cool Climate Network, has brought about a paradigm shift in our perception of urban densification. This shift aims to reduce cities' carbon footprint and support collaborative efforts to achieve Sustainable Development goals. Densification is proposed as a crucial strategy for promoting social prosperity, and well-being, and combating climate change. However, a relevant question arises: How can we effectively achieve densification while addressing global warming? Companies like Holcim have responded to this challenge by developing sustainable building solutions and engaging in meaningful discussions with architects, such as Shajay Bhooshan, Associate Director at Zaha Hadid Architects. These collaborations provide valuable insights into the concept of urban densification as a catalyst for climate action.
Efforts to achieve sustainable architecture with a lower carbon footprint are supported by several strategies. Some of them include the use of low-emission materials and roofing solutions that facilitate the incorporation of vegetation. However, according to Bhooshan, densification is also a crucial aspect of sustainable development, or at least mitigating the impact of the built environment on climate change. Urban densification poses a challenge due to the decline in density in our cities over the 20th century.
Density can be understood in various ways. Fundamentally, it implies the number of buildings in a given area. However, we often overlook an elemental and perhaps more significant concept, which is the intensity of human activity in that area.
'Cities like Barcelona and Tokyo demonstrate that urban density can help provide services to more people using less resources. They are also interesting from the perspective of how they have densified over time.' -Shajay Bhooshan
Satellite cities emerged as one of the urban paradigms of the 20th century, aiming to distribute population and urban activities in a more balanced manner. Nevertheless, Bhooshan argues that this segmentation of uses results in the construction of different buildings for each specific need, which entails individual maintenance and energy supply. Moreover, various economic and regulatory policies have discouraged growth in the core of cities, prioritizing development in peripheral areas. This has led to increased transportation costs, private vehicle usage, per capita infrastructure expenditures, and, consequently, higher CO₂ emissions. Continuing to design and construct cities in the same way would demand building a city the size of New York every month, without considering the resulting CO₂ emissions.
'By 2050, between 60% and 70% of the world's population will be living in cities. If we design and build cities the way we do now, we would need to build one New York City every month.' -Shajay Bhooshan
Understanding density from the perspective of space efficiency is crucial. To achieve this, spaces and buildings must be used more consciously and intensively. This efficiency, coupled with the utilization of recycled or new materials like ultra-high performance concrete, can promote a new aesthetic and foster community living. To accomplish this, people must have a voice in the built environment, which entails acknowledging their significance and involving them in decision-making processes concerning their community.
Designing solutions that meet design and planning needs requires collaboration between companies, architects, and various stakeholders. This is not the sole responsibility of any single entity. Holcim collaborates with architects such as Prof. Dr. Philippe Block to establish new channels that enhance existing knowledge and enrich it with computational technologies. Collaboration among different actors will enable the creation of architectural, engineering, and logistical solutions for densification, thus addressing the challenge of decarbonizing our cities. Understanding the problems we face is of utmost importance, because a lack of understanding may lead to inefficient resource allocation, considering the limited resources provided by the planet.
When building new structures, it is important to do so intelligently, incorporating sustainable materials such as low-carbon concrete, developed and produced by Holcim. Additionally, the integration of waterproofing solutions and smart insulation systems is crucial to make buildings sustainable in use. In urbanizing economies, this may also involve the reuse of existing buildings or their components. For urbanizing economies like India, China, and Southeast Asia, it would mean developing smart building solutions designed for disassembly and reconfiguration, among other approaches.
We need to be more conscious of how we organize our cities and utilize our resources. As Shajay Bhooshan emphasizes, efficiency involves utilizing spaces more intensively. For instance, promoting mixed-use spaces can be advantageous instead of having people living in one part of the city and working in another.
'It’s up to architects to keep investing, digitizing, and developing new exciting design proposals for denser urban areas.' -Shajay Bhooshan
Bhooshan highlights the Striatus project as a prime example of smart building. In this project, Zaha Hadid Architects collaborated with the Block Research Group, incremental3d, and Holcim to construct a bridge using 3D-printed concrete. This project demonstrates that computational skills and digital technologies can achieve various aspects of reuse, recycling, and reduction concerning building materials.
Highlighting innovative approaches to utilizing materials like concrete is crucial. Concrete, being the most widely used building material, offers an opportunity to demonstrate that achieving climate goals doesn't require completely discarding existing materials. Instead, the focus can also be on making them environmentally friendly and low-carbon. By embracing such practices, we can make cities more circular, effectively reducing our reliance on natural resources and alleviating pressure on the planet.
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