It would be interesting to investigate why heatwaves receive so little attention from the mainstream media and government agencies compared with other natural disasters in Australia, however since 1900 heatwaves have been responsible for more deaths in Australia than all the other natural disasters put together.
From 1844 to 2010, extreme heat events have killed at least 5332 people in Australia. Since 1900 there have been 4555 ‘heat associated deaths’ or ‘excess deaths’.
Over 30 percent of those deaths occurred in just nine events. For example, during the 2009 Victorian Bushfires, 173 people perished as a direct result of the fires; however, there was an excess mortality of 374 people who died in the heatwave that preceded them in Victoria, and a further 58 in South Australia. Currently heat related deaths in Victoria exceed the average annual road toll.
In Australia statistically most excess deaths due to heat waves have been in Victoria, New South Wales with most in South Australia. However Tropical regions, which includes northern Australia are being pushed towards the limits of human liveability, with wet bulb temperatures over 35C potentially creating deadly consequences.
Under climate change, projections of heat-related deaths suggest an increase of 1,250 deaths per year by 2070 leading to as many as 8,628 deaths per year by 2100.
The climate council have reported that Sydney and Melbourne are set to record 50C summer days as the norm by the end of the century and warns that the health and wellbeing of all Australians are at risk, as heatwaves have severe impacts on human health like heat exhaustion or even cardiovascular failure.
Data is available from Riskfrontiers / PerilAUS, ABS & NCIS. There appears to be an overall decline in excess deaths in the historical data from 1939 which could give a feeling that things were getting better due to improving technology, infrastructure, social and health care factors. Then it spikes again with the 2009 heatwave, an increased exposure and failure to adapt, and we know from recent reports that with the overall temperature rise in Australian ‘summers’ that the incidence and severity of heat waves will increase.
The impacts of extreme heat are felt disproportionately within society. The most vulnerable groups are seniors, infants, those with pre-existing medical conditions, and low socio-economic status. Unfortunately, the elderly and those with low income are typically also the group unlikely to use aircon due to the cost of electricity.
In periods of prolonged heat, the urban heat effect increases pressure on the city. People living in high density areas are at greater risk.
Homes and workplaces that rely on grid produced electricity for their comfort are the spaces that make people the most vulnerable to heatwaves. Summer is the time of year when there is the most electricity demand, blackouts can occur, and electricity prices are raised which stops some people from using even ceiling fans. Most of the buildings and housing stock in Australia has a very low energy star rating, are poorly insulated, and early energy modelling software has created more homes with small openings.
Ideally, we would have passively designed homes with great cross flow ventilation, and aircon or heating to cope with extreme temperatures to maintain comfort. This requires a self-sufficient power supply. After any power failure in an extreme heat event there are simply biological limits to the bodies capacity to cope with extreme heat.
Then we will require the aircon bunker (that doubles as a cyclone shelter in the north of the country), powered by pv solar panels, and a battery for storage to make the electricity supply self-sufficient.
This type of set up has already been proposed by the city of Geelong. Geelong Sustainability has had their ‘Climate Safe Rooms’ program to construct a cool space for the event of heat waves.
The Queensland Reconstruction Authority (QRA) has undertaken incredible work since its establishment in 2011. In particular with regard to community engagement and involvement which is the keystone to resilience. In 2019 they published the Queensland State Heatwave Risk Assessment (SHRA) after summer of 2018-19 which was the hottest on record for Australia. There is more work being undertaken in mitigation.
The building code’s more recent improvements to the minimum standards for thermal efficiency and the rewriting of the section J are to be applauded. These measures however only apply to new buildings and the Northern Territory, probably the area that needs it most due to its dependence on air-conditioning for comfort, is still excluded from the Section J requirements in the NCC.
There is still a gulf in the approach to retro fitting older building stock to improve its energy efficiency, which makes up the majority of buildings in Australia. Only in the ACT do existing houses have to declare their energy efficiency when being sold. We use the energy efficiency of white goods to decide which ones we purchase, but not our homes.
The heatwave event of 2009 resulted in excess mortality of 374 deaths. A study by the Centre for Sustainable Infrastructure, Swanbourne University of Technology concluded that, upgrading building energy ratings would have a significant impact on related mortality. On the assumption that occupants of 0.9 energy star homes were the victims of the 2009 heatwave event, the analysis determined that if all Melbourne homes has at least a 1.8-star energy rating, the number of excess deaths would be reduced to around 240. This would further reduce to 37 excess deaths if all houses were to be upgraded to a minimum 5.4 stars.
We should develop estimates of the potential health system savings and other benefits realised through enhanced building standards and call for state and territory governments legislate to require that an energy rating measuring passive energy performance must be disclosed to prospective buyers and tenants for residential as well as commercial properties.
To combat the urban heat island effect, green infrastructure measures are being implemented across Australian’s capital cities as ways to cool them down. Brisbane has their ‘Clean, Green Sustainable’ urban cooling strategies; Melbourne has it’s ‘Urban Forest Strategy’. Extreme heat was identified as one of the key shocks and stresses of the Sydney resilience Challenge under the 100 resilient cities program, with a policy and action to cool homes and streets. They have to as over the 2018-19 summer Penrith experienced 37 hot days over 35 degrees.
This is about lives, and as an example, the ABCB has emphasised that the intention of the NCC is to protect the occupant of the building, not the building itself. We need increased regulation, some of it retrospective, and enforcement to save lives.
We are at a point when the cost of not doing something outweighs the cost of doing something. The social and economic costs of natural disasters are increasing. The costs to communities, the healthcare costs, the cost of lost working days. Australian federal government spending on disaster response currently outstrips that on remediating existing buildings and infrastructure to prepare for future extreme weather events by a ratio of 10 to one. This ratio needs to be reversed.
However, ultimately to prevent increasing deaths due to the increasing frequency of heat waves and other ‘natural’ disasters we must massively reduce methane and CO2 emissions.
By Neil Carter
Neil is an enthusiastic and passionate architect, with a particular interest in sustainability and well being, with over 25 years of professional experience in the UK, Germany and Australia.
“I get immense satisfaction from seeing people interact with their environment with awareness – whether it be on a psychological, visual or textural level.”
Neil has given talks on materials & resilient design. He has a sound understanding of good design solutions that suit the local climatic context, excellent building science skills with an interest in passive design and energy and resource use reduction.