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

Air Temperature differences at 3pm

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

 

Modelling Data of Heat Hazard in Proserpine in 2020, 2050 and 2090

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.