Australian summers are getting hotter. Today marks the end of our warmest summer on record, setting new national temperature records. Worsening drought, locally significant flooding, damaging bushfires, and heatwaves capped a summer of extremes.
As we look to autumn, warmer temperatures overall and below average rainfall – especially in eastern parts of the country – are likely.
The starkest feature of this summer was the record warmth. The national average temperature is expected to be about 2.1℃ above average, and will easily beat the previous record high set in summer 2012-13 (which was 1.28℃ warmer than average).
Very low rainfall accompanied the record heat of summer. At the national scale, each month was notably dry, and total summer rainfall was around 30% below average; the lowest for summer since 1982–83. The monsoon onset was delayed in Darwin until the 23rd of January (the latest since 1972–73) and typical monsoonal weather was absent for most of summer.
In December 2018 Australia saw its highest mean, maximum and minimum temperatures on record (monthly averages, compared to all other Decembers). Notable heatwaves affected the north of Australia at the start of the month, spreading to the west and south during the second half of December. Temperatures peaked at 49.3℃ at Marble Bar in Western Australia on the 27th, with mid-to-high 40s extending over larger areas.
The heat continued into January, which set a national monthly mean temperature record at 2.91℃ above the 1961–1990 average. Heatwave conditions which had emerged in December persisted, with a prolonged warm spell and numerous records set. Eight of the ten hottest days for the nation occurred during the month, while a minimum temperature of 36.6℃ at Wanaaring (Borrona Downs) in western New South Wales on the 26th set a new national minimum temperature record.
Temperatures moderated a little in the east of the country for February, partly in response to flooding rainfall in tropical Queensland. Even so, the national mean temperature will come in around 1.4℃ above average, making this February likely to be the fourth or fifth warmest on record.
…and very dry
Australia has seen dry summers before and many of these have been notably hot. The summers of 1972–73 and 1982–83 – which featured mean temperatures 0.90℃ and 0.92℃ above average, respectively – both came during the latter stages of significant droughts, and were both records at the time.
As the State of the Climate 2018 report outlines, Australia has warmed by just over 1℃ since 1910, with most warming occurring since 1950. This warming means global and Australian climate variability sits on top of a higher average temperature, which explains why 2018-19 was warmer again.
A major rain event affected tropical Queensland during late January to early February, associated with a slow-moving monsoonal low. Some sites had a year’s worth of rain in a two-week period, including Townsville Airport which had 1,257mm in ten days. Many Queenslanders affected by this monsoonal low went from drought conditions to floods in a matter of days. Flooding was severe and continues to affect rivers near the Gulf of Carpentaria, as well as some inland rivers which flow towards Kati Thanda–Lake Eyre.
The outlook for autumn
Spring 2018 saw a positive Indian Ocean Dipole which faded in early summer. At the start of summer sea surface temperature anomalies in the central Pacific exceeded 0.8℃, which is the typical threshold for El Niño affecting the oceans, but these declined as summer progressed. Combined with a lack of coupling between the atmosphere and ocean, the El Niño–Southern Oscillation remained neutral, though normal rainfall patterns shifted to oceans to the north and east, leaving Australia drier as a result.
As we move into autumn, the El Niño–Southern Oscillation and Indian Ocean Dipole tend to have less influence at this time of year. The onset of new Indian Ocean Dipole or El Niño/La Niña events typically happens in late autumn or winter/spring.
Over recent years, autumn rainfall has also become less reliable, with declines in cool season rainfall in the southeast and southwest. Temperatures are also rising, in a local expression of the global warming trend.
Explainer: El Niño and La Niña
The Bureau’s outlook for autumn shows high probabilities that day and night-time temperatures will remain above average for most of the country. We expect to see continued below-average rainfall in much of the east, where drought is currently widespread.
Looking to the winter, the Bureau’s ENSO Wrap-Up suggests the Pacific Ocean is likely to remain warmer than average. The potential for an El Niño remains, with approximately a 50% chance of El Niño developing during the southern hemisphere autumn or winter, twice the normal likelihood.
David Jones, Climate Scientist, Australian Bureau of Meteorology; Lynette Bettio, Senior Climatologist, Australian Bureau of Meteorology, and Skie Tobin, Climatologist, Australian Bureau of Meteorology
Heatwaves have killed more Australians than road accidents, fires, floods and all other natural disasters combined. Although recent research shows extreme cold is a worry in some parts of Australia, our hottest summer on record points to more heat-related deaths to come. The record heatwaves have highlighted the damaging effects of heat stress. Understandably, it’s becoming a major public health challenge.
The risk of extreme heat events and the adverse impacts on older people has been extensively discussed in research. Remarkably, very little attention has been paid to the role of urban greenery in reducing heat stress for seniors.
Older people are particularly at risk of heat stress. Pre-existing medical conditions and limited mobility increase their vulnerability. Deaths of older people increase during extreme heat events.
The physical features of urban areas shape the capacity of older adults to engage in many activities when it’s hot. These include vegetation volume and coverage, thermal design, and the extent of shading in public areas and walkways. Increasing urban greenery may offer a way to improve older people’s comfort and social experience.
Building cool cities for a hot future
Ageing adds urgency to greening
It is expected 20% of the global population will be older than 60 by 2050. The figure for Australia is even higher, at 23%. This means that by 2050 around one in four Australians will be more vulnerable to extreme heat.
Climate change may make the problem worse by fuelling even more extreme heat events.
Planning our urban centres to meet the needs of a rapidly ageing population is a matter of urgency. Urban greening to reduce their vulnerability to heat stress should be central to this agenda. It can also improve people’s quality of life, reduce social isolation and loneliness, and ease the burden on health systems.
An important task is matching the design of communities with the needs of an ageing population. Where older adults live and the quality of their local areas strongly influence their lived experiences. Yet recent research found the experiences of seniors were often not accounted for in research on neighbourhood design.
What about aged care?
People face choices about where they live as they age. The common choices are to “age in place” or to move into aged care.
If one in ten Australian seniors live in aged-care facilities, it is clear these should be designed to minimise heat stress. This isn’t just good for residents; it may also benefit operators by lowering health-care and electricity costs.
While these facilities are purpose-built for older people, many in Australia were built well over a decade ago, when heat stress was not such a large concern. Many more facilities are being built now and will be into the future. Yet it is uncertain whether they are being actively designed to reduce the impacts of heat.
What has our research found?
We recently conducted a focus group to investigate this issue. Participants were senior managers from four large corporate providers of aged care in Australia. We investigated if and how providers try to minimise heat stress through design. We also sought to understand the rationales used to support these design approaches.
Several participants reported on refurbishments that they expect will have cooling effects. Cited design approaches included green roofs and walls, as well as sensory gardens. Other expected benefits included reducing anxiety and improving the mental health of residents.
The fact that single design interventions could produce multiple benefits improved the potential for corporate buy-in. Participants expected that increasing green space and green cover would give their facilities a competitive advantage by attracting more clients and providing a better working environment for staff.
Participants also reported on challenges of including greening in their projects. For example, the benefits of trees were weighed against concerns about roots disrupting footpaths and becoming trip hazards. Species selection was another concern, with fears that inappropriate plants could die and undermine support for greening programs.
Our research suggests that more can be done to make cities hospitable for older people, especially during extreme heat. Urban greening is a start. Encouraging aged-care providers to adopt green infrastructure will have benefits. But we should also consider reforms to planning systems and urban design to better protect older people who choose to age in place.
Claudia Baldwin, Associate Professor, Urban Design and Town Planning, Sustainability Research Centre, University of the Sunshine Coast; Jason Byrne, Professor of Human Geography and Planning, University of Tasmania, and Tony Matthews, Senior Lecturer in Urban and Environmental Planning, Griffith University