Earlier in 2023, Arup launched UHeat, a tool that identifies areas of towns and cities that are experiencing the urban heat island (UHI) effect.
It’s a growing problem in many cities, with profound health impacts, particularly for older, more vulnerable members of the population and those who work outdoors.
Assessing where the issue is being caused, and by what, is where UHeat has particular value. UHeat takes advantage of the power of machine learning to analyse huge volumes of satellite imagery. It then tags the materials and other causes that are pushing up the temperature, those combinations of glass, steel, tarmac, vehicles, air conditioning units, data centres and other urban development that are raising average temperatures, compounding the effects of climate change.
For city authorities and commercial developers, UHeat is a valuable tool, offering new insights to those tackling a problem that damages lives and cities’ future viability at the same time. It enables those in power to understand where the problem is, what the causes are, and to model or simulate the most effective mitigations.
But at a greater scale UHeat points to the need for a far more radical vision of urban development, one where nature has fully returned to the cities we live in, where urban greenery and waterways are a central part of what a city ‘is’, not just a peripheral element around which we have built.
Learning from Singapore
The densely populated city state of Singapore shows what is possible. This tropical garden city has long understood the need for natural temperature control and has been pioneering what we now call ‘biophilic design’, where nature is both teacher and solution.
It’s a country that has long known that it’s running out of space. It faces constraints on its natural and forested land. Its tropical climate and humidity are exacerbated by climate change. And with over 8,000 people per square kilometre, the city faces predictably intense UHI problems.
Using UHeat, our latest urban heat snapshot captures what they’ve achieved and where problems persist. We use the tool to analyse the entire city in detail, identifying a large cluster within the Singapore Central Business District (CBD) – including not only high-rise areas but also historical low-rise streets – as the most extreme “hot spots” in Singapore, experiencing temperatures 6°C higher than their rural surroundings. When compared to the city’s coolest spot in the Upper Pierce Reservoir, this cluster is 6.5°C hotter.
Outside the CBD, neighbourhoods experiencing temperatures of at least 5°C above rural surroundings include Orchard, Little India, Marine Parade, Kampong Ubi and Sembawang. The cool zones are mostly located in areas with forests or reservoirs. This includes the central catchment area, the vegetated area located in Lim Chu Kang, Sungei Buloh Wetland Reserve as well as the region located at Khatib Bongsu.
The implication is clear: our cities need to incorporate greenery, water and other natural features if the overheating is to stop.