Digital is critical for 'green and blue infrastructure'

Will Cavendish, global digital services leader for Arup explores the digital solutions to climate change.

Will Cavendish
17 October 2023

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This year is on track to being the hottest on record. Heat in our cities has soared, leaving people – particularly the vulnerable – struggling to cope. 

Climate change means our cities are only going to get hotter. It’s estimated that by 2050 the number of cities exposed to extreme temperatures, 35°C and above, will triple. This is especially worrying for lower-income communities, for older adults, for infants and for those with underlying health complaints. 

The way we have designed and built our cities – pushing out nature, using concrete and steel – is contributing to this heat. Only by bringing back nature to our cities and viewing it as critical infrastructure will we be able to cope with the challenges of climate change, like rising urban heat. And advanced digital tools are critical to us being able to do this. 

Demonstrating the power of nature-based solutions

Digital solutions are providing a step change. They are allowing those shaping the built environment to give real, quantified evidence on the value of using nature-based solutions to tackle problems such as urban heat and flooding.  

This summer we launched our Urban Heat Snapshot – to show how AI and advanced digital tools can be used to help cities become more resilient to rising heat and showcase the power of nature-based solutions. 

In our Snapshot, we used rapid, complex modelling to map the most extreme “hot spots” in six major cities around the world from New York to Mumbai. It allowed us to give greater insight into how heat was impacting these cities, and the role of the built environment in this. 

Our UHeat tool helped us to reveal how the urban heat island (UHI) effect is pushing up urban temperatures. Such complex heat modelling has historically been time-consuming and reserved for academics. But UHeat bridges this gap, drawing on the technical work and methods developed by researchers and combining them with increasing amounts of city data available through remote sensing. 

Now, city leaders, designers, and planners can rapidly understand what interventions will be effective in bringing down temperatures in their local climate and context at a street, neighbourhood, and city scale – before they make decisions.

The study showed that, for example, UHI can vary drastically neighbourhood to neighbourhood: cities saw up to an 8°C UHI swing within short distances. It also helped identify common features – such as the fact that in most cities, the hottest spots had less than 6% vegetation cover, while the coolest spots in most cities had over 70%.

The tool has also been used in Tanzania’s largest city, Dar es Salaam, to evaluate its future urban heat profile based on projected increases in population. This has helped show the potential of nature-based solutions to tackle the UHI effect, reducing temperatures across the city.

Prioritising green infrastructure over grey 

Studies have shown that nature-based solutions are up to 50% more cost effective than man-made alternatives and deliver 28% more added value. However, unlocking finance for nature-based solutions can be difficult. 

Institutions and governments are used to investing in traditional concrete and steel infrastructure and there is a lack of data and understanding of the wider benefits of nature-based solutions. But advanced digital tools are helping make green infrastructure projects bankable. 

We used another one of our digital solutions – Terrain, an AI land-use digital mapping tool which is so powerful it can distinguish between a tree nursery and a forest – to help cities rapidly understand how land is being used. This precise insight can provide the evidence for moving away from “grey thinking”, and instead bringing in green and blue infrastructure solutions. 

In a town in the UK, Terrain helped a water utility company demonstrate that, while a traditional grey concrete design method would cost marginally less, when examining the whole value case a green structure would be more cost effective.

For example, green spaces could provide health benefits to the local population and result in significant long-term savings for the NHS from the air quality improvements.

Cause for hope

There are digital tools out there to help us understand the impact of design choices on heat, and to adjust them accordingly.

This can help cities invest in and deploy green and blue infrastructure in a way not seen at scale before.

This gives us cause for hope: we have the tools to continue on our pathway to net zero and restoring nature, while meeting human needs.