The extreme weather we are currently experiencing is not merely a passing heatwave but a glimpse of what our summers will be like from now on. In simple terms, this is climate change, and it demands immediate attention. Cities worldwide are already seeking ways to address and adapt to these new circumstances.
Heatwaves are becoming more frequent and intense, and the outlook is far from reassuring. According to the United Nations, without prompt intervention, global temperatures are projected to rise by 3.7°C above pre-industrial levels by the year 2100.
This poses significant threats to ecosystems and endangers urban life as we know it. The materials commonly used in cities, such as concrete, asphalt, and metal, easily absorb and retain heat, exacerbating the problem.
Transportation and industrial activities further contribute to rising temperatures, and the extensive paving of surfaces reduces the potential for cooling through evaporation. This also diminishes the soil’s ability to absorb rainwater during heavy downpours, leading to an increased risk of flooding.
Extreme temperatures render outdoor spaces in various parts of the world uninhabitable for extended periods. Urban areas, especially densely populated ones, experience even higher temperatures due to the urban heat island effect.
Neighborhoods within these cities can be up to 10-20 degrees Celsius warmer than nearby rural areas. Moreover, the extreme heat places a strain on infrastructure, leading to failures that create additional risks.
For instance, power outages may occur due to the overheating of transmission lines and transformers. Other systems are also under pressure, as roads, railways, and runways can become unusable. Old public transport vehicles like buses and trams, if not equipped with adequate ventilation and air conditioning, pose health risks to passengers.
Ultimately, the consequences severely impact human health, as evidenced by the rise in respiratory illnesses and heat-related conditions such as fatigue, fainting, exhaustion, and heatstroke.
The need for urban planning to adopt strategies that promote mitigation and adaptation is now more urgent than ever. Strengthening and protecting nature, including local biodiversity, are crucial steps in creating more sustainable and resilient cities. Healthy natural ecosystems can help mitigate the impacts of climate change by absorbing carbon, providing shade, capturing rainwater, and protecting coasts from erosion.
In a joint effort, mayors from 31 cities, including Los Angeles, Mumbai, Paris, Stockholm, and Sydney, signed the Urban Nature Declaration, pledging that 30-40% of their cities’ total area will comprise green spaces by 2030. They also committed to ensuring that 70% of their residents have access to green or blue public spaces within a 15-minute walk or cycle.
Many cities have already begun to incorporate greenery, integrate water features for relief, revive traditional cooling methods, create urban oases to alleviate heat stress in public spaces and invent new ways to tackle the challenges posed by climate change.
Passive design strategies, which utilise natural elements and architectural features to maintain comfort without relying heavily on energy-intensive systems, are becoming increasingly important for mitigating urban heat.
In one of the hottest climates in the world, the United Arab Emirates, the Abu Dhabi Climate Resilience Initiative by CBT Architects aims to enhance public spaces and improve thermal comfort for pedestrians through a series of interventions, including structures, plantings, shading, and cooling zones.
In India, where temperatures soared to 52.9 degrees Celsius in some regions in May, traditional wisdom is being combined with modern technology and urban planning. Many cities are utilising traditional stepwells, known as ‘baolis,’ to replenish groundwater and naturally cool the environment. These stepwells also served as gathering places, fostering social interactions within communities.
Reviving and reintegrating these structures into the urban fabric can significantly impact temperature reduction. Modern infrastructures can incorporate water features and vegetation to act as heat sinks in urban areas. Shaded balconies, green terraces, and roofs can also help protect indoor spaces from excessive heat. Additionally, avoiding reflective surfaces on building facades prevents the redirection of heat into the surrounding environment. And these are just a few examples of the many adaptations needed to make our cities more livable in a warming world.
Apart from soaring temperatures, climate change is also causing more frequent and intense rainfall, leading to devastating floods. Research reveals that large sections of major Asian cities are predicted to be underwater by the end of the century. Even along the coasts of the United States, a substantial rise in sea levels is expected by 2050. To protect themselves, these cities are seeking ways to coexist with water rather than fight against it.
One innovative solution is the Centenary Park at Chulalongkorn University in Bangkok, Thailand. This 11-acre park is built on a slope, designed to channel rainwater through gardens, wetlands, and finally into a retention pond. Beneath the park lie underground reservoirs capable of storing an impressive 160,000 gallons of water. The design was inspired by the cheeks of monkeys, which they use to store food. Green spaces like this park not only enhance the city’s aesthetics but also help reduce air pollution and mitigate the urban heat island effect.
Architect Kongjian Yu has introduced the concept of ‘sponge cities,’ where water is embraced rather than resisted. An example of this approach is the Yongxing River Park in Beijing, China. Once a concrete drainage canal, Yu transformed it into a sponge river to effectively manage floodwater and filter stormwater. The park is now rich in vegetation and connected by a network of pathways leading to playgrounds and sports fields.
The Low Countries, with approximately one-third of their land already below sea level, have been building on water for years. Residences are typically constructed with wooden frames, insulated with linen, and equipped with heat pumps and solar collectors. Roof gardens provide cooling during the summer and help absorb rainwater.
The Maldives, comprising over 1,000 islands in the Indian Ocean, lie less than one meter above sea level, making them extremely vulnerable to climate change. The government is collaborating with scientists to create floating cities as a potential solution.
In 2011, Copenhagen, Denmark, experienced a sudden and devastating storm that unleashed months’ worth of rain in just a few hours, resulting in severe flooding. This disaster catalysed the development of climate-resilient plans, including the Enghaveparken climate park.
Originally designed in 1928, the park has been beautifully redesigned by the architectural firms Tredje Natur and Fleming Rafn. Located at the bottom of a hill, the park utilises water chambers to manage rainwater. It starts with a hockey field that has been lowered by three meters to collect rainwater, which then flows into a rose garden and eventually a lake.
The park boasts underground basins capable of collecting rainwater from the surrounding neighbourhood, and a perimeter wall retains the water while allowing historical trees to remain in place. The park is estimated to handle up to 6 million gallons of water, playing a crucial role in climate change adaptation.
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