Satellite mapping is preparing Australian cities for a warming earth

Satellite mapping is preparing Australian cities for a warming earth

Imagine you’re an urban planner, worried about your city’s resilience in the face of the growing threat of climate change. You’ve seen research that shows urban environments – particularly neighbourhoods without tree canopy cover – are up to 10°C warmer than the surrounding area, so you’re trying to plant more trees and expand green spaces.

But how do you know where to focus your attention? And how do you know your efforts are working?

Now imagine if you could receive weekly or monthly reports, containing tailored information from satellites that are regularly mapping your city. As you browse through, the report tells you about how the tree canopy cover has changed and where; how healthy the vegetation is; and the locations of the hottest and coolest neighbourhoods.

When you combine this data with on-ground monitoring, you can start to see the big picture of how your city is adapting – and what decisions you need to make next.

This is the dream for many urban planners, and it’s on the way to becoming a reality.

“You’ll find a lot of people in the industry who want to argue for nature, but they don’t actually have the ability to easily access the data,” says Thomas Gooch, founder of the Office of Planetary Observations (OPO). “Our process is to streamline that data processing pipeline… so the everyday user can access the data to make decisions.”

“You’ll find a lot of people in the industry who want to argue for nature, but they don’t actually have the ability to easily access the data.”

OPO is a newly launched start-up that takes satellite data and turns it into accessible environmental analytics, specifically targeting city planners.

“We focus on urban greening metrics – so vegetation cover, vegetation health, land surface temperature, tree canopy mapping,” Gooch explains. “These are the key metrics for city planners to back up their decisions for nature-based policies such as [creating] urban forests or open space.”

The company draws on data from a mix of government-owned and private satellites, with 30 metre, 10 metre and sub one metre resolutions. Some of the satellites map areas as frequently as once every five days. This is huge for city planners, who might normally only get updated data every few months or even years.

Screenshot of a tool showing vegetation cover of melbourne's suburbs
OPO’s urban greening portal allows you to see the vegetation cover of your own suburb, as a taste of what their tool can do. Credit: OPO

For example, Gooch says, perhaps you want to understand how vegetation cover changes throughout a summer.

“Typically, state government might do an aerial flyover over the summer, and it might end up being quite a hot day of the year,” he says. “They might do that once every four years at a very high cost. Over the whole summer period of three months, we can provide insights every five days – at a much lower cost.”

More frequent monitoring will enable urban planners and policymakers to see a link between their decisions and the changing data from satellite mapping. This will allow them to understand nearly in real time how city planning affects the environment – and help them more efficiently adapt to climate change.

Aerial view of building in honk kong next to a forest. There is a road in the trees.
Hong Kong. Credit: Kiyoshi Hijiki / Getty Images

“We’re really filling a market gap – this is Australia’s first urban greening platform,” Gooch says.

The key thing is that the data is packaged up in a way that is readily accessible by those without a specialist background.

“You don’t need a PhD to get the data,” Gooch says. “The people that make the decisions in cities, who advocate for nature and build the policies to support it, don’t have the expertise or the time to learn how to code or do the analysis themselves.”

Dr Jason Byrne, a researcher specialising in urban greening at the University of Tasmania, agrees.

“We just don’t have that kind of expertise broadly available in government and local government,” he says.

“[The tool] will revolutionise the way we do urban greening strategies. For example, instead of taking months and months or even a couple of years to prepare, we might be able to get them done in a matter of weeks, or a month. Importantly, we could then track over time and evaluate the success of the initiatives that we’re taking.”

These strategies are an important part of combating the ‘urban heat island effect’, adds Byrne, who has previously worked as a town planner and a policy officer.

“The temperatures in cities are [at least] 8–10 degrees warmer than the surrounding countryside. With climate change, this is going to be magnified.”

“The temperatures in cities are [at least] 8–10 degrees warmer than the surrounding countryside,” he explains.

The materials that cities are built from and the activities that go on within them, like factories and cars, mean that cities not only generate heat but trap it, too.

“With climate change, this is going to be magnified,” Byrne says – which is a particular problem when most of the world’s population is now urban.

“This means you’re getting more people living in hotter places, and we’re also seeing populations aging around the world… so we’re getting a lot more older people who are more vulnerable to heat stress living in cities – we’ve got the perfect storm of trouble coming our way.”

He notes that previous research has shown that for every 1°C increase in temperature above 20°C, there is up to a 3% increase in mortality – of people dying from heat effects.

Foggy autumn morning in adelaide suburbs with rubbish recycling on kerb
“Richer people live in greener places, on average,” Byrne says, which means heat impacts disproportionately impact lower socioeconomic communities. Credit: mastersky / Getty Images

Byrne says that OPO’s urban greening tool will allow planners to access thermal sensing data and work out where the urban heat island effects are most pronounced in cities.

Plus, mapping could also tell planners where existing vegetation cover is and quantify the cooling effect from existing trees: “Then we can figure out using models: if we planted certain kinds of trees in certain places, what kind of benefit would that give us in terms of cooling?”

Since hotter areas also use more energy to run air conditioning to cool buildings, Byrne says that “we can also begin to use that satellite data to help us calculate: if we rolled out largescale urban greening, how much energy use would we reduce in cities?”

Dr Scott Hawken, an urban designer, landscape architect and landscape archaeologist at the University of Adelaide, adds that satellite data can help in the equally important task of monitoring the living systems within a city.

“We’re facing a biodiversity crisis, so open spaces and green spaces are essential for maintaining and enhancing biodiversity,” Hawken says. “Living systems are ultimately what sustains a city. They’re the foundation for the city’s endurance.”

“Living systems are ultimately what sustains a city. They’re the foundation for the city’s endurance.”

To monitor biodiversity, he says, different scales of monitoring are necessary.

“Satellite data is very powerful, but it’s only meaningful as much as you can relate it to what’s going on the ground. Part of remote sensing science is what’s called ‘ground truthing’ – monitoring, understanding and linking what is registered from above, or remotely, with the actual events and materials and living things on the ground.”

The top image shows temperature, ranging from blue (warm) to yellow (hot). The bottom image shows vegetation from beige (sparse) to deep green (dense).
NASA’s Landsat program has been helping map the urban heat island effect – and its link to vegetation cover – for many decades. These images show New York City. The top image shows temperature, ranging from blue (warm) to yellow (hot). The bottom image shows vegetation from beige (sparse) to deep green (dense). Credit: Robert Simmon / Landsat Program / NASA

This kind of data fusion is a particularly exciting aspect of this new tool, Hawken says – that is, being able to link satellite data to datasets from different sources and across different scales.

Byrne says that he’d also love to see health datasets become available as part of this fusion. However, these are currently hard to access due to privacy concerns.

“Obviously you don’t want to be able to get access to what your neighbours’ health conditions are,” he says. “But if we’re able to find ways to de-identify that data and to make it available to city planners, then we could be able to track really effectively whether the greening strategy we put in place reduces incidents of heatstroke, but also kidney failure, heart failure, disease and death.”

While urban planners have previously had access to data from satellites like the Landsat program, first launched in 1972, the resolution is much lower than the current generation of satellites. Some of the satellites used by OPO’s urban greening tool can see down below one metre resolution.

“That’s the scale we would want – we’d be wanting to see individual backyards, individual trees in the built environment, to be able to measure their impacts,” Byrne says.

“While some institutions have access to that data, it’s very expensive and it’s not high resolution, so this service would give us presumably not just higher resolution satellite imagery, but at a price point that would work for state government, local government, potentially even some parts of the private sector.”

But Hawken says that though OPO’s tool is an important move in the right direction, it could be even more powerful if it wasn’t a paid service.

“Ultimately, I’d like to see this… as a form of open data,” he says, potentially through collaboration with government.

“The smarter cities in the world realise that information is the bedrock of the economy. If they want people to come up with good solutions, they need to make that accessible – which means covering the initial costs, and then allowing entrepreneurs and inventors and scientists and policy people to then develop solutions based on this freely accessible resource.”

While Hawken notes that places like Finland have adopted this practise of the government reducing costs for companies to access this data, Australia isn’t there yet.

“The paywall model is outmoded as demonstrated by leading smart cities such as Helsinki, which makes city models and remote sensed imagery free of charge,” he says, adding that the open-source portal US ParkServe is a similar example. “Such data and analysis should be funded by a development levy and included as a part of all development applications in Australia.”

Gooch agrees that these are useful models.

“Subsidies would really generate growth in this market and set up longevity in that supply chain,” he says, though he notes that extra costs would still exist to get a product ready, including customising data and marketing it.

“A coordinated, national government-led approach to climate change, connecting tech, data, cities, space and entrepreneurs would be really powerful,” Gooch says.

“What would happen if you took the subsidisation from coal industries and took it to this type of industry where you’re encouraging greening, encouraging nature, really putting the capital behind creating climate-resilient cities in a coordinated effort?”

“Information is the bedrock of the economy. If [cities] want people to come up with good solutions, they need to make that accessible.”

But in the meantime, what’s next for OPO’s urban greening tool?

Gooch says that he’s hoping they can expand the features they can offer and draw on observations from more satellites.

Beyond city planners, he envisions the data could also be useful to “community groups who care for nature, regional land managers who are interested in fire prevention and recovery, [and] the everyday citizens.”

In an Australian first, OPO has already found its way into several city planning documents and council policies, including Victoria’s Strathbogie Shire’s sustainability planning, and Greater Bendigo’s future urban forest strategy.

And while the tool is Australian-focused at the moment, it has the potential to go global.

“We can observe the Earth like we never have, at a time when we really need the data – and as the IPCC report shows, we need to really understand what our actions are doing in the landscape,” Gooch says.

“I think it’s an exciting time for the space industry and Australia. We have such expertise in our research and our science, and taking it to market and being globally competitive is exciting.

“The time is now for nature tech.”

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