Heatwaves and Urban Heat Islands

Street trees don't just cool our footpaths. They stop our roads becoming like giant bar heaters making our homes hotter during the day and well into the night.

This week, I posted on Facebook and on Linkedin and got quite a reaction. As you’d expect the reactions were different on each platform. Here is what I said.

So hot in Brisbane!

These surface temperatures were taken about 4pm yesterday, after the hottest part of the day. They were within metres of each other.

• 66.4 was the hottest - that grey concrete driveway in full sun

• 64.5 the road in full sun was a little cooler

• 48.0 was the driveway in dappled shade from a Brisbane wattle (morning sun)

• 47.5 was the concrete footpath in the shade of the street tree (morning sun)

• 44.8 was the grass verge next door

• 32.6 was the low-growing verge garden under the street tree

You can really feel the difference when you walk from the sun into the shady area next to the street tree and verge garden. Less heat from above and less heat reflecting up from the ground.

Street trees don't just cool our footpaths. They stop our roads becoming like giant bar heaters making our homes hotter during the day and well into the night, and that means lower air-conditioning bills. The native verge gardens increase the cooling effects and help the street trees thrive.

Imagine the difference if we all worked with our councils to transform our hot streets into cool, tree-lined, shady lanes.

What’s Next?

During February, we are planning some collaborative events with Regen Brisbane and ACF Community Brisbane Northside on urban heat and how we might mitigate or adapt to it. Some will be in person, others online. If you’d like to contribute, please contact me or add to the comments below.

In this article, Brisbane’s green future: Climate action strategies aligned with sustainable development goals, Ali Cheshmehzangi talks about the need for “collaborations with local communities, businesses, and academic institutions”, “neighbourhood-based projects” and “collaboration [that] promotes a sustainable culture throughout the city.”

This is spot on but how do we make it happen on the scale and speed required?

If you’d like to contribute, please contact me or comment below. The advantage with comments is that you can share and expand your ideas with others, not just me.