Heat is Reshaping Cities: An Exploration of Urban Heat Islands and Climate Resilience in Asia

Welcome to SEI Asia’s podcast on surroundings and policy in asia. This series invites experts to discuss critical environmental challenges in Asia and explore solutions through policy and partnerships.

In this episode, we’re joined by Andreas Hoy, Senior Expert on Climatology at SEI Tallinn, and Winston Chow, IPCC Co-Chair of Working Group 2 and Professor of Urban Climate at the Singapore Management University. Today’s discussion will focus on how heat is reshaping cities across continents, diving into the science of shifting heat patterns, the inequalities of its impact, urban design innovations, and the urgent need to integrate heat into governance and urban resilience agendas.

Andreas shares his background as a climatologist passionate about making weather and climate data accessible. Winston explains his role as a professor of urban climate at the Singapore Management University and his work as co-chair of the intergovernmental Panel on Climate change’s working group focused on climate impacts, vulnerability, and adaptation.

The conversation begins with the observation that, despite being monsoon season, many parts of Asia – including Singapore, Bangkok, and the Philippines – are experiencing unusually high temperatures. Winston explains this phenomenon, stating that urban heat is a key example of climate disruption.

He outlines the core drivers of global warming – greenhouse gas emissions and land cover change – and introduces the “urban heat island effect.” This effect occurs when natural landscapes are replaced with concrete and asphalt, which absorb and retain heat during the day, releasing it at night and exacerbating regional and global warming. He also points to the contribution of human activities within cities to the overall heat increase.

Protecting Vulnerable Populations from Heat Waves: Insights from Europe

Heat waves pose a significant threat, notably to vulnerable populations.These groups – including the elderly – are at higher risk due to physiological factors, limited mobility, and often, challenging social circumstances. Individuals living alone, those who are socially isolated, have poor housing ventilation, or experience low income are disproportionately affected, frequently enough lacking access to cooler spaces and adequate support.

The 2003 European heat wave served as a stark wake-up call, resulting in an estimated 70,000 to 80,000 excess deaths, with a large proportion being elderly individuals left alone in overheated homes. This event highlighted the critical need for improved health and social care systems preparedness.

Since then, progress has been made with the implementation of heat health action plans, early warning systems, and targeted outreach measures.Though, reaching vulnerable individuals requires tailored approaches – simple smartphone alerts are insufficient. Proactive measures like phone calls, social worker check-ins, and dedicated hotlines for landline phones are essential.

Despite these improvements,coping capacity remains uneven. Wealthier regions are better equipped to adapt quickly and efficiently, while vulnerable groups in less affluent areas continue to face significant risks.

Innovative projects, such as one in Pärnu, Estonia, demonstrate a proactive approach. this project utilizes hazard mapping of urban heat islands, integrating weather data, remote sensing, and socio-economic factors like population density, age, health, income, and social support. Through interviews and focus groups, the project identifies areas with high social vulnerability to heat-related risks, enabling the municipality to prioritize adaptation strategies like tree planting and cooling interventions in areas with high concentrations of elderly residents or disadvantaged households. This data-driven approach empowers cities to take targeted action.

A comprehensive heat action plan should integrate the best available climate data and forecasting to disseminate information effectively, allowing individuals to anticipate and prepare for heat hazards. by combining data-driven insights with targeted outreach, communities can better protect their most vulnerable members from the escalating threat of heat waves.

Adapting to Heat: A Global Challenge with Local Solutions

The impact of climate change and urban heat islands are felt globally, yet effective responses require a nuanced understanding of local contexts. While the drivers of climate impact are largely consistent across regions – from Europe to Asia, South america, and North America – the way communities experience and respond to heat varies substantially due to cultural norms, behavioral patterns, and collective psychology. this dictates the most effective heat action plans and adaptation strategies.

In many parts of the world, air conditioning is commonplace, providing thermal comfort even in extreme temperatures. However, in Western and Northern Europe, a deliberate design choice often avoids widespread air conditioning, prioritizing preparation for colder seasons and utilizing construction techniques focused on heat retention. Smarter urban design, maximizing wind flow, can further enhance thermal comfort and mitigate risk in areas with consistent wind patterns.

However, solutions effective in Europe aren’t universally applicable. Singapore, for example, experiences extremely low wind speeds, necessitating alternative approaches to reduce heat vulnerability.

The nature of heat-related challenges also differs. While overheated flats are a growing concern in europe due to limited air conditioning use, this may be less prevalent in parts of Asia. Instead, outdoor workers in both regions face significant risks, though this issue receives less attention in Europe. Ultimately, vulnerability isn’t solely about age or health, but about access to resources – greenery, cooling opportunities, and overall support systems.

prosperous adaptation requires localized strategies, as demonstrated by projects in places like Parnu, Estonia, and initiatives undertaken with the Singapore government, highlighting the importance of tailored solutions to address the unique challenges each community faces.

Cooling Cities: Combining Top-Down and Ground-Up Approaches

The key to successful urban heat adaptation lies in a combined approach – integrating strong governmental initiatives with community-led action. Cities like Copenhagen, Tallinn, and Singapore demonstrate this potential, though Singapore often leans heavily on top-down strategies.Though, even within Singapore, citizen communities are creating spaces like community gardens that not only mitigate heat but also foster social interaction for all ages.

This aligns with the core benefits of city-wide flood control and temperature regulation through ecosystem services,such as parks. Singapore’s experience,particularly in a low-wind environment,highlights the effectiveness of well-known strategies like expansive,connected green spaces and improved urban design.

Specific examples include orienting new financial districts towards prevailing monsoon winds and employing staggered building heights. This design acts like a sail, drawing cooler air down to pedestrian level, flushing out pollutants, and enhancing thermal comfort.

Interestingly,conventional Southeast Asian architecture offers valuable lessons. Houses built on stilts – kelongs and kampongs – were originally designed to prevent flooding but also maximized airflow,a principle later incorporated into Singapore’s public housing with the inclusion of open “void decks” to promote natural cooling for the majority of residents.

Financing Adaptation, Behavioral Changes, and Lessons from Ahmedabad

Winston highlights the critical need for financial mechanisms to support adaptation projects, moving beyond the expectation that these are solely a public good funded by governments. He notes a growing momentum,accelerated since the Paris Agreement,to find complementary funding sources.

However, Winston emphasizes that adaptation isn’t solely a supply-side issue. Demand-side changes are equally vital, requiring communities to adopt lasting behaviors and purchasing choices – such as utilizing public transportation and transitioning to electric or hybrid vehicles.

He cautions against assuming that only resource-rich cities offer solutions, citing Ahmedabad, India, as a “gold standard” example of effectively addressing heat-related mortality. Despite limited resources, Ahmedabad successfully responded to a 2011 heatwave by prioritizing extended weather forecasting (requesting 14-21 day forecasts instead of five), cross-sector coordination, strategic deployment of medical professionals to vulnerable communities, and leveraging traditional communication channels like radio and television to warn outdoor workers.

Crucially, Ahmedabad engaged community and religious leaders to disseminate information and gather feedback, and invested in non-air conditioning cooling strategies like green and blue spaces, applying scientific insights to areas of highest vulnerability.

Preparing Cities for Extreme Heat: A Multifaceted Approach

The increasing threat of extreme heat, intensified by climate change, demands a proactive and comprehensive approach to urban planning and infrastructure development. Experts Andreas and Winston discuss the challenges and necessary strategies for cities to adapt and protect their populations.

The Expanding Threat of Heat Extremes

Andreas highlights the growing problem of heat extremes, noting their intensification and expansion into previously unaffected regions like Northern Europe. He emphasizes the need for cross-sectoral coordination and evidence-based urban design improvements, including updated building codes, to address this challenge. (38:13 – 38:55)

From Reactive Measures to Long-Term Planning

A shift from reactive measures to long-term, institutionalized planning is crucial. This requires dedicated financial investment in green and blue infrastructure, which should be considered a mandatory component of city planning, not simply a desirable addition. Prioritizing these investments will facilitate the creation of more livable and heat-adapted cities. (38:56 – 39:28)

The Cascading Impacts of Heat

Winston warns that the current impacts of climate change are just a preview of what’s to come, particularly if global temperatures surpass 1.5°C and reach 2°C or 2.5°C. He points to food insecurity as a significant concern, particularly for cities like Singapore, were heat impacts agriculture and food sourcing. (39:29 – 39:58)

Beyond Urban Heat Islands: A Systemic Risk

The risks extend beyond the direct effects of heat within cities. Ignoring the broader impacts on essential resources and supply chains can create cascading problems. Uncomfortable heat combined with other climate-related hazards – such as droughts, floods, and storms – can drive residents, including high-net-worth individuals who contribute significantly to tax revenue, to relocate. (39:58 – 41:15)