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Scientific studies show that extreme weather events like large storms and floods are likely to become more frequent and intense because of climate change. You might wonder whether our cities are built to cope with huge downpours, damaging wind and other extreme weather in Melbourne.
Can our infrastructure sustain phenomena like La Niña? What about the health impacts – are we equipped to deal with mosquitoes and thunderstorm asthma?
‘The impacts of climate change on the planet and human health are very significant,’ says Robert Faggian, an associate professor of climate change adaptation at Deakin’s Faculty of Science, Engineering and Built Environment. But, he says, our cities have some capacity to adapt to changing weather patterns.
Owing to several recent wet summers, you might be familiar with the term ‘La Niña’ – or ‘little girl’ in Spanish – a climate pattern that describes the cooling of surface-ocean water along the west coast of South America. In Australia, La Niña is shorthand for wet weather in spring and summer.
Assoc. Prof. Faggian says there are links between more intense La Niña events and our changing weather patterns. ‘Increasing severity and frequency of extreme weather events over time is associated with climate change,’ he says.
After experiencing three La Niña summers in a row, Assoc. Prof. Faggian believes it’s unlikely we’ll see a fourth consecutive summer of high rainfall, although ‘our climate system is complex and is changing’ so there are no guarantees.
Looking further ahead, Assoc. Prof. Faggian says the frequency and impact of future La Niña events is uncertain. ‘We’ll have more La Niña events in the future, but whether we’ll have more frequent or multiple La Niña summers is unknown. More research needs to be caried out.’
Now for the good news: most Australian cities are built with impervious surfaces, which allow water run-off during heavy rain. Assoc. Prof. Faggian believes Melbourne’s infrastructure can generally cope with heavy downpours, but still needs to prepare for a more climatically volatile future.
‘Melbourne is reasonably well placed right now, because we have a relatively high percentage of parks and gardens, as well as waterways and lakes,’ he says. ‘This means there are places throughout the city where rainfall can penetrate soil or collect, rather than become flood water.’
Melbourne Water is also making changes to adapt to increasing rainfall. ‘They are doing great things to manage our water and have championed concepts like ‘water-sensitive urban design’, which is an approach that makes water and stormwater a more central component of the planning and design of urban areas,’ explains Assoc. Prof. Faggian.
Flooding because of high rainfall and the influence of La Niña is a major consideration of urban design. Even though levees might seem like an obvious solution to the problem of too much water, they can increase flooding in some situations by forcing water higher and causing faster flow, says Assoc. Prof. Faggian.
‘When the levee fails, the flooding damage is often worse than it otherwise would have been,’ he says. ‘It’s better to work with nature rather than trying to constrain it.’
Assoc. Prof. Faggian says research into nature-based solutions is being conducted at Deakin University’s Centre for Regional and Rural Futures (CeRRF) with a particular focus on the Dutch concept of ‘blue-green infrastructure’.
‘Blue-green infrastructure uses blue (ponds, lakes and waterways) and green (parks and gardens) landscape elements in an interconnected way to accept flood water, slow its progress and give it somewhere to infiltrate, collect or move such that it does not damage urban areas and infrastructure,’ he says.
This approach is used extensively in The Netherlands and other parts of Europe, as well as Japan and the USA.
Assoc. Prof. Faggian says it’s likely that Australian cities will adjust their approach to urban design based on the principles of blue-green infrastructure. ‘We’ll eventually move beyond levees and start to wind back our attempts to surround ourselves with hard engineered solutions that only function according to tightly bound engineering parameters, towards a more nature-centric approach.’
Climate change and associated events like flooding and La Niña don’t just have an effect on our planet – there are also health impacts to consider.
Increased rainfall and stagnate floodwaters are often associated with an increase in mosquitoes, which increases the risk of mosquito-borne diseases like Ross River virus and Barmah Forest virus.
There’s also an increased likelihood of a rise in allergy and respiratory problems like longer hay fever seasons and thunderstorm asthma.
‘Fortunately, with good design, nature-based solutions can mitigate the health risks. They also bring a range of other benefits by improving biodiversity, creating new recreational spaces and moderating local temperatures. Then there are the related measures, like green roofs and green walls, water harvesting, recycling and reuse, and energy-efficiency, which all create more pleasant, liveable and sustainable cities,’ explains Assoc. Prof. Faggian.
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