Proserpine Heat Study
Background
It’s hard to believe that a “hot day” in Proserpine will be almost 1.5 degrees hotter by 2050 & around 3 degrees hotter by 2090. Pair this with increased frequency & duration of heat waves, it’s no wonder that heat is one of the priority hazards to manage in regional towns to ensure future liveability. This study called upon our experts to predict future climate, using Proserpine as an example of a typical QLD town.
Proserpine has started to see;
- Hotter days with temperatures reaching over 42 degrees for the first time in 1995
- Heat waves in runs of four or more days over 38 degrees
What?
There are so many different ways to mitigate the effect of rising temperatures in our community, such as planting more trees, changing the colour of hard surfaces, and installing water features or green walls. The challenge is understanding how much action to take, what action is most beneficial and where it needs to be done.
How?
By modelling predicted temperature increases with climate change, using Proserpine as an example of a typical regional town we have improved our understanding of priority areas to manage heat and tested heat mitigation methods to understand which methods are the most financially viable and beneficial for our Community. This will help to assess the actions that need to be taken to manage temperature increases and ensure future liveability of our towns.
Who?
The Whitsunday Climate Innovation Hub worked with Mosaic Insights and NCEconomics to complete the original heat reduction feasibility study for Proserpine. These results are now being used to plan heat mitigation throughout the region.
Aims
This project aims to:
- Identify the most cost-effective ways to reduce heat stress in regional towns
- Provide updates for Councils policy so that all towns are protected from impacts of rising temperature
Get Involved
For more information on Climate change in the Whitsundays, visit Coast Adapt's website. For the 30 year Regional Weather and Climate Guide visit BOM's website.
If you would like to find out more information about the project, contact the Whitsunday Climate Change Innovation Hub on 1300 WRC QLD (952 753) or email us on climate.hub@whitsundayrc.qld.gov.au.
Results
We considered all of the methods we could use to cool towns and conducted a cost benefit analysis. This gives us a clearer picture on which methods we should aim to use as a priority for heat management in the region, because we want to improve our town’s resilience to the impacts of heat and liveability.
Our study found that the most economically viable cooling options based on Benefit Cost Ratios were:
- Street Trees
- Irrigation
- Changing a hard surface to irrigated grass and trees
|
Scenario |
Area average air temperature difference (°C) |
Maximum cooling air temperature (heating) (°C) |
Air Temperature average cooling vs size of application (C/m2) |
Rank (1 best, 11 worst) based on air temperature average difference vs size |
Reason |
|---|---|---|---|---|---|
|
Street trees
|
–0.20
|
–4.82
|
72.30
|
3
|
Trees shade and increase transpiration
|
|
White roads
|
–0.25
|
–1.62
|
12.20
|
8
|
Reflected sunlight off asphalt
|
|
Misting
|
–0.01
|
–0.62
|
200,000
|
1
|
Increased evaporation and very small area of application
|
|
Irrigation
|
–0.18
|
–1.26
|
23.5
|
5
|
Increased evaporation
|
|
White pavement and carparks
|
–0.10
|
–1.18
|
22.9
|
6
|
Reflect sunlight off surfaces
|
|
White roofs
|
–0.06
|
–0.28
|
1.50
|
3
|
Reflect sunlight off roofs
|
|
Water fountains
|
–0.02
|
–1.00
|
130.60
|
2
|
Increased evaporation from surface and small water particles in the air
|
|
Bodies of water
|
0
|
–0.30
|
0
|
11
|
Increased evaporation but over a small area
|
|
Green walls
|
–0.01
|
–0.20 (+0.15)
|
1.1
|
10
|
Work best out of direct sunlight
|
|
Changing a hard surface to grass
|
–0.08
|
–1.35 (+3.47)
|
17.7
|
7
|
Reduced impervious surfaces
|
|
Changing a hard surface to to irrigated grass and trees
|
–0.33
|
–4.82 (+1.29)
|
59.6
|
4
|
Increased evaporation, transpiration and shading
|
| Proserpine site average | Current climate (°C ) | 2050 | 2090 |
| 3pm air temperature | 36.7 | 38.2 | 39.7 |
| 3pm surface temperature | 46.9 | 47.1 | 47.0 |
| 3pm thermal stress | 40.8 - Very strong heat stress | 42.6 - Very strong heat stress | 44.4 - Very strong heat stress |
To improve the effectiveness of street trees it is recommended to:
- Consider tree species that are most adapted to the future predicted climate (heat and higher wind associated with more intense events) and infrastructure for them, such as passive irrigation, to ensure survival in the future climate.
- Create a continuous corridor of shading for pedestrians to walk under, with overlapping tree canopies. Alternatively, based on the modelling, trees with canopies 5m wide and spaced 5m apart will provide sufficient shade for cooling.
- Plant east-west oriented streets first as they have the sun overhead throughout the day making them a higher priority for cooling, than north-south oriented streets.
- Plant the eastern side of north-south streets first as they experience the afternoon sun and are a higher priority for cooling than the western side of a north-south oriented street.
Irrigation could be used as a great heat management tool with the study showing that temperatures could be over a degree cooler in areas that have been irrigated. Early morning irrigation for cooling could be triggered when there has not been any rain and the air temperature is expected to exceed 35˚C the following day in priority areas, for example the main pathways to schools.