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Step 1
STAGE 3 TEACHER RESOURCE
Planning is an important step in any project, whether exploring our parks for the day or creating an action research plan
The first step in any action-based research plan is to identify and define what it is you want to find out more about. You might already have an idea, but this part of the planning process encourages you to dig deeper, exploring the impacts of the problem. And importantly, the consequences of not taking any action at all.
In this action research plan, urban heat is the issue we want to learn more about. We know many urban communities face this problem, and that it has negative impacts on those communities as well as on the environment. There are also growing concerns for the future as a result of climate change processes and surging population numbers, expected to increase the warming of urban areas.
At the end of this step, students will:
understand what urban heat is and what causes it
discover the ways urban heat impacts people and places
learn how climate change affects the impacts of urban heat
investigate the different ways people manage heat in their homes and communities.
What is urban heat?
What is urban heat?
Urban housing developments such as this one in western Sydney tend to be hotter than the surrounding natural or rural areas
When lots of people live close to one another, as they do in Sydney for example, we call this an ‘urban’ environment. Urban heat is the name given to the warmer temperatures experienced in these urban environments compared to nearby rural areas.
The difference in temperature between these areas is partly due to the different surfaces in each environment, and how well they absorb and hold heat.
For example, urban areas tend to have large amounts of artificial and dark-coloured surfaces, which absorb the sun’s heat and cause air temperatures to rise. These surfaces also tend to hold onto heat for longer periods of time, giving urban areas less chance to cool down even after the sun has set.
This is sometimes called the ‘urban heat island’ effect.
Whereas in rural areas, surfaces are natural and lighter coloured, thanks to the number of trees and other plants. Not only do these plants provide natural shade, many of them can actually cool down air temperatures by releasing water vapour and consuming carbon.
As a result, temperatures in cities and urban areas can be up to 3 degrees higher than rural areas.
The western suburbs of Greater Sydney are particularly vulnerable to the urban heat island effect. Temperatures in this region can reach 10°C higher than in eastern Sydney on days of extreme heat.
Plants provide natural shade and release water vapour to keep temperatures cool
What causes urban heat?
What causes urban heat?
Did you know 55% of the world's population live in urban areas, and this is expected to increase to 68% by the year 2050? And that more than 86% of all Australians live in major cities?
When lots of people live close to cities, it is known as urbanisation and leads to suburbs developing around the edges of cities. These suburbs usually feature a mixture of residential buildings, roads, shops and schools as well as industrial estates. They do also have parks and plenty of gardens, but the large amounts of concrete versus relatively low numbers of plants creates urban heat.
A lot of surfaces are good at absorbing the sun’s heat, and this causes the air temperature around them to rise. Artificial surfaces can usually also trap heat within them for longer periods of time than natural surfaces. This means they stay hotter for longer and so does the air around them, preventing the temperature from cooling when the sun goes down.
Black and dark colours absorb more heat than white and pale colours (which actually reflect heat away from them). Surfaces like tarmac and asphalt, found in roads, carparks, playgrounds and roofs, are known to increase urban heat.
Urban heat increases as population numbers increase. This is because a lot of the things people need are made out of artificial materials. Asphalt cement in roads, plastics in traffic lights, and synthetic glues used in construction are just some examples. People then create additional heat in urban areas by running machines like cars and air conditioning units. The pollution from vehicles, equipment and factories in these environments also adds to the amount of heat that gets trapped.
Climate change and urban heat
Climate change and urban heat
Climate change is making the Earth’s weather patterns more extreme, unpredictable and harder to manage. 9 of Australia’s top 10 hottest years on record have occurred since 2005. This trend is expected to continue, with urbanisation and an increase in urban heat adding to the negative effects of climate change. The resulting impacts on people and places are likely to be quite significant.
One impact is a possible increase in extreme heat events, or 'heatwaves', that have negative impacts on people’s health. Heatwaves are times of abnormally hot weather, with temperatures remaining at abnormal levels for at least 3 days. Whether a heat event is classed as a heatwave depends on minimum and maximum temperatures.
If the air temperature doesn’t cool overnight, people often can’t sleep. This means they can’t recover from the adverse effects of the hot day. This lack of recovery is bad for our health, particularly young children and people with long-term illnesses.
9 of Australia's top 10 hottest years on record have occurred since 2005
Learn more about urban heat in Greater Sydney
Learn more about urban heat in Greater Sydney
The urban heat island effect [1:39]
Why are Sydney's western suburbs heating up so much? Watch the video to find out how the urban heat island effect is contributing to warmer temperatures in Western Sydney.
How will urban heat change in Sydney? [1:59]
Air temperatures in Sydney are expected to increase in the future, as a result of climate change and increasing urbanisation. Explore the hottest areas in Sydney and discover some actions we can take to reduce heat in these areas.
Activities
Activities
Exploring your environment
How much do you know about the natural environment, climate change and urban heat?
How do you think these things might impact you and your school?
Use worksheet 1.1 to answer questions and draw a picture showing what you imagine your school will look like in the future. Teachers can refer to the 1.1 activity instructions.
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