In Paris, authorities closed more than 1,000 schools — and the summit of the Eiffel Tower — during last month’s heatwave. In Eastern China, the power grid experienced strain as 40.5°C temperatures brought a spike in electricity demand. In the United Kingdom, public health researchers estimated that 500 people died in just five days due to heat
It’s only mid-July, but in global cities from Buenos Aires to Bangkok, residents and leaders are already feeling a grim array of impacts that underscore the need to adapt to a climate marked by substantially and dangerously hotter summer temperatures.
Urban heat has been squarely on the agenda of mayors from the world’s richest cities for decades. In London, where scientist Luke Howard first observed and described the Urban Heat Island effect in the 1810s, measures now include public health alerts, outreach to vulnerable groups, a network of cool spaces, and mandatory overheating assessment for new-build properties.
Although the study of urban climates is a long-established discipline, its datasets and modeling tools have tended to follow university research budgets, yielding dozens of high-quality studies for the world’s richer cities but far fewer for low and lower middle-income countries where climate impacts are mounting fastest.
For the World Bank’s Global Facility for Disaster Reduction and Recovery (GFDRR) and its City Resilience Program, bridging this gap is critical: connecting the insights that urban climate science can produce with the urgent adaptation needs of cities in low- and lower middle-income countries. At last week’s International Conference on Urban Climate (ICUC12), the program hosted an Urban Heat Hackathon to develop scalable methods that help cities respond to rising heat risks.
From research to resilience: making data work harder
When developing a heat action plan, the stakes are high and the details matter. Take Singapore, where a government-sponsored research program (“Cooling Singapore”) built an evidence base on the causes and consequences of heat stress. This knowledge helped underpin policies and investments that delivered 370 kilometers of green corridors, 300 hectares of added green space by building developers, and building innovations like cool paints.
But most cities in lower-income countries lack the granular data and monitoring equipment available in Singapore. Could improved modeling still provide them with answers to key questions such as which neighborhoods need cooling investments, what building modifications would prevent dangerous indoor temperatures, and who most needs alerts and outreach when a heatwave is impending?
Twenty-four researchers including PhD students and faculty from 19 countries joined the Urban Heat Hackathon to test this.
The Urban Heat Hackathon winning team with members of the judging panel (from left: Claire Gallacher, Flavia Ribeiro, Negin Nazarian, Ariane Middel, Tiago Silva, Felix Adebayo, Nicholas Jones)
The challenge: harness the rapidly advancing knowledge base on scientific techniques to model extreme heat risks and solutions in cities, then apply it to real-world actions such as greening interventions, cooling centers, and public health alerts. For this hackathon, participants focused on two case study cities in highly distinct climate regions: Timbuktu in Mali and Davao City in the Philippines.
Adapting cities to extreme heat is complex, partly because the best responses vary across climate types — temperate, arid and tropical — where seasonal patterns, humidity levels and population exposure differ. Policy-makers need data at multiple levels: city scale to understand which neighborhoods overheat most; at neighborhood level to figure out which local design, greening or material changes work best; and at building level to diagnose indoor heat risks in homes and schools.
Participants tackled these challenges for Timbuktu and Davao City across all three levels — city, neighborhood and building — using datasets and starter code developed by the organizers.
The hackathon winners — Claire Gallacher (UK), Flavia Ribeiro (Brazil), Tiago Silva (Portugal), and Felix Adebayo (Nigeria) — applied neighborhood-scale modeling to recommend targeted investments in urban landscapes and public health. The judging panel praised their practical, data-informed approach and clear case for action.
Bridging science and practice for resilient cities
Just 2-3 years ago, this level of detail was out of reach. Today, globally available datasets, new data layers, and improved modeling tools are opening new possibilities to help cities take on the extreme heat challenge.
Alongside generating new ideas, the hackathon also revealed key gaps and bottlenecks. For example, architects commonly use building simulation tools to assess energy needs and indoor temperatures, but the “weather files” behind these tools often ignore the Urban Heat Island effect. Incorporating future climate conditions and urban effects into these tools could enable the design of homes, schools and workplaces that are more fit for the rising temperatures of coming decades.
As cities seek to translate science into action, initiatives like GFDRR’s City Resilience Program — which has worked in 366 cities in 94 countries, helping to inform over $8 billion of World Bank investments in urban resilience investments — are well-positioned to scale up these innovations. By harnessing cutting-edge data and the expertise of researchers like those at the hackathon, practical solutions for extreme heat can be brought to more cities, faster.
Source : World Bank
