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On a still January afternoon in Canberra, the waiting room at the city’s main emergency department is already full before the hottest part of the day arrives.1
Parents fan flushed toddlers, an older man with a heart condition clutches a water bottle, and a young cyclist waits with heat cramps after an ambitious lunchtime ride.2
For clinicians on triage, the pattern has become familiar enough to feel like a seasonal forecast in real time.3
As temperatures climb, emergency presentations rise with them, not only for heatstroke but for asthma, cardiac events, kidney stress and mental health crises.4
New research from the Australian National University suggests these spikes are no longer just bad-luck heatwaves but a measurable signal of climate change in the ACT’s hospital data.5
Inland emergency departments, long geared to cold winters and bushfire smoke, are now functioning as an early warning system for a hotter, more volatile climate.6
What happens at the ED front door in Canberra over the next few summers will help determine whether the health system can keep pace with the climate it is entering, not the one it was built for.5
Historical impacts and trends
Over the last two decades, temperature extremes have quietly become a defining driver of emergency demand in the ACT.1
A study led by ANU researchers found that extreme hot and cold weather together now account for about one in every fifteen emergency department presentations in Canberra, a proportion that has grown as the climate has warmed.2
The analysis, which examined ACT emergency data from 2000 to 2021, identified almost 36,000 heat-related presentations, representing one in forty, or 2.5 per cent, of all visits over that period.3
Over the same years more than 57,600 presentations, roughly 4 per cent, were associated with cold conditions, a reminder that inland cities face a twin burden of winter chill and summer heat.4
Researchers found emergency visits increased not only on very hot days but whenever temperatures rose well above local seasonal norms, and they also climbed when overnight and daytime temperatures fell below about 14 degrees.5
That threshold effect matters because Canberra has already warmed by more than 1 degree since the mid‑20th century, shifting the distribution of days above and below the comfort zone that historically defined local health planning.6
Across these years, climate-sensitive presentations have spanned a spectrum of conditions rather than a single diagnostic category.7
International and national reviews of emergency medicine show that heatwaves increase visits for heat exhaustion and heatstroke but also for cardiovascular events such as heart attacks and strokes, respiratory illnesses including asthma and chronic obstructive pulmonary disease, and renal complications driven by dehydration and electrolyte imbalance.8
Australian studies in Brisbane, Adelaide and Sydney have reported heatwaves increasing heat-related emergency presentations from several-fold to more than tenfold, particularly among older adults, suggesting that the ACT’s emerging pattern is part of a broader national trend.9
The seasonal timing of emergency demand is changing with the climate as well as its volume.10
ACT climate assessments show that hot days and heatwaves are becoming more frequent and intense, especially in spring and summer, which now overlap with the peak of bushfire smoke and pollen seasons to create compound respiratory risks.11
During the Black Summer fires, smoke and heat together produced sharp increases in hospital admissions and emergency visits for asthma and other breathing problems, foreshadowing how multiple climate hazards can converge on EDs within the same season.12
Demographic vulnerability
The ANU study found that climate-related emergency presentations in the ACT are not evenly distributed across the population, with distinct patterns emerging by age.3
Young people under 20 were significantly more likely to present on hot days, often on the day of the temperature spike itself, reflecting activity-related exposure such as sport and outdoor work or study.4
Adults aged 20 to 60 faced increased risk on both extreme and moderately hot days, which researchers linked to occupational exposure, commuting patterns and the cumulative effects of several warm nights on underlying health conditions.5
Older Canberrans experienced a different, but equally concerning, profile.6
People over 60 were more likely to present to emergency departments after periods of extreme cold, consistent with well-documented links between low temperatures, cardiovascular stress and respiratory infections in older bodies, yet they also remained vulnerable during heatwaves.7
That dual sensitivity means older residents in poorly insulated housing or on fixed incomes can be hit twice each year, first by winter bills and cold-related illness, then by summer heat and smoke.8
While the ACT research has not yet published a full breakdown by sex for each diagnostic group, broader Australian and international evidence provides a guide to likely patterns.9
Studies of heatwaves in other Australian cities have found that older women are disproportionately represented among heat-related hospitalisations, reflecting longer life expectancy, higher rates of living alone and chronic illness, and gendered patterns of poverty, while men are more prominent among outdoor work and sport-related injuries in extreme heat.10
These subtler demographic gradients mean the same temperature spike can translate into different kinds of risk for different groups, complicating the job of emergency planners seeking to forecast demand.11
Socioeconomic and social isolation factors further heighten exposure.12
The ACT’s climate risk assessment warns that heatwaves, smoke and storms are likely to increase pressure on health, emergency response and recovery services, particularly for people in low-quality housing, those with existing chronic illnesses and community members who are socially isolated or lack access to cool, clean indoor spaces.13
For residents managing conditions such as heart disease, diabetes or chronic lung disease, or for people with severe mental illness, extreme heat can destabilise medication regimes, impair judgement and increase the risk of both physical collapse and acute psychological distress, all of which can bring them to the ED door.14
Future projections
Looking ahead to mid‑century, the ANU team modelled how a warming climate is likely to reshape emergency demand in the ACT under plausible emissions and temperature scenarios.15
They estimated that heat-related presentations could rise to as many as 90,000 between 2040 and 2061, representing about 2.7 per cent of all emergency visits, while the proportion of cold-related presentations declines but the absolute number still exceeds 81,000 over the same period.16
In effect, Canberra’s hospitals are expected to see more patients harmed by heat without a corresponding disappearance of cold-related burden, creating a wider band of climate-sensitive demand rather than a simple seasonal shift from winter to summer risk.17
National and international projections suggest that these dynamics are unlikely to be unique to the capital.18
A narrative review of climate change and emergency medicine concluded that global warming is expected to increase the prevalence of emergency presentations for cardiovascular disease, respiratory conditions, renal complications and some gastrointestinal illnesses, as well as trauma and mental health crises linked to extreme weather events.19
Australian evidence points to similar trajectories, with previous work in Brisbane, Sydney and Adelaide showing that once temperatures cross local thresholds, emergency visits, ambulance callouts and high-acuity presentations all rise steeply, a pattern likely to intensify as heatwaves lengthen and nights stay warmer.20
For Canberra, the ACT State of the Environment reports project more hot days above 35 degrees, longer and more frequent heatwaves and heightened bushfire danger by mid‑century, particularly in the northern parts of the territory.21
These climatic shifts are expected to increase the number of days each year when temperatures exceed the thresholds associated with higher ED presentations in the ANU study, effectively widening the window of risk.22
In practice that means more summers where emergency departments are managing heat illness, cardiac and respiratory flare‑ups and mental health crises on top of smoke exposure and injury patterns linked to storms, fires and flash floods.23
Public health and system implications
The convergence of climate, demographic and health trends has direct implications for how emergency departments in Canberra and inland Australia plan for peak demand.24
Professor Hilary Bambrick, director of the ANU National Centre for Epidemiology and Population Health, has warned that even small increases in local temperature can make people unwell and intensify pressure on hospitals, underscoring that climate change is now one of the country’s biggest public health challenges rather than a distant environmental concern.25
For emergency clinicians, that translates into more high‑acuity patients on heatwave days, more crowded waiting rooms and more difficult decisions about prioritising care when multiple climate-sensitive conditions peak together.26
Peak-period overcrowding is already a chronic issue in many Australian EDs, and climate change risks turning seasonal surges into a more consistent feature of the workload.27
Research on heatwaves in Queensland has shown that high temperatures increase not only the number of ED visits but also the proportion that are high acuity and result in admission, which in turn constrains bed availability and slows patient flow through emergency units.28
Ambulance services face parallel pressures, with warmer nights and multi‑day heatwaves associated with sustained increases in callouts for cardiac events, breathing difficulties and falls, as overheating, dehydration and smoky air interact with pre‑existing illness and medication use.29
The strain is not only on physical infrastructure but on the workforce itself.30
Clinicians and support staff working through rolling climate disasters must manage the emotional load of treating more preventable illness, while dealing with their own heat stress, smoke exposure and family responsibilities during extreme events.31
Without adequate staffing buffers, surge protocols and rest periods, a hotter climate risks amplifying burnout, absenteeism and turnover in emergency medicine, especially in smaller inland hospitals with limited redundancy.32
Adaptation and policy response
The ACT government has begun to integrate climate health risks into planning, but the pace and scope of adaptation remain uneven compared with projected emergency demand.33
Territory climate risk assessments highlight increased pressure on health and emergency services from more frequent heatwaves, smoke, dust storms and thunderstorm asthma events, and call for measures such as identifying smoke‑proof refuges and retrofitting public buildings to better control indoor temperatures and air quality.34
These documents frame EDs as part of a broader resilience system that also includes primary care, mental health services, housing, transport and community services, rather than as stand‑alone facilities that can simply “scale up” indefinitely.35
Heat‑health action plans are a central tool in many jurisdictions, combining public alerts, targeted outreach to vulnerable groups, adjustments to ambulance and hospital staffing, and advice to workplaces, schools and sporting organisations when temperatures are forecast to exceed critical thresholds.36
For an inland city like Canberra, effective plans will need to account for both summer heatwaves and cold snaps, the interplay with air pollution episodes, and the different timing of risks facing children, working-age adults and older people identified in the ANU emergency data.37
Without such tailored triggers, there is a risk that EDs will continue to see preventable spikes in presentations among groups that could have been supported earlier through primary care, housing and community services.38
Urban cooling and housing standards are emerging as frontline health interventions in a warming climate.39
The ACT’s planning documents point to opportunities for more tree canopy, water-sensitive urban design and better-insulated, energy‑efficient housing to reduce exposure to both heat and cold, especially in suburbs with higher concentrations of older or low-income residents who are over-represented in climate-sensitive ED presentations.40
For renters and social housing tenants, minimum thermal performance standards can be as important as hospital capacity, because they determine whether people can safely stay at home during a heatwave instead of relying on emergency care once they have already become unwell.41
Hospitals themselves are increasingly the focus of preparedness efforts.42
Reviews of climate change and emergency medicine recommend that health services stress‑test their infrastructure, supply chains and surge plans against scenarios involving prolonged heat, smoke, power disruptions and overlapping disasters, rather than assuming short, isolated events.43
In Canberra, that means aligning ED staffing, triage protocols, backup power and cooling systems, and mental health and social work support with the specific patterns of climate-sensitive demand now emerging in local data, from young people on hot days to older adults after cold spells.44
Five-year horizon
Over the next five years, regional planners and policymakers in the ACT face a narrowing window to align climate, health and urban planning with what emergency departments are already seeing.45
Key priorities flagged by evidence include refining temperature thresholds and early warning systems for ED demand, strengthening links between hospitals, primary care, housing and community services, and embedding climate scenarios into workforce and infrastructure planning so that inland emergency departments are not caught off‑guard by foreseeable heat and smoke seasons.46
How effectively these steps are integrated will help determine whether Canberra’s EDs continue as a barometer of escalating climate risk or become a marker of how a community adapted in time to blunt the worst health impacts of a hotter, less predictable decade.47
References
- Changing climate's impact on our health expected to put more pressure on inland hospital EDs, report warns – Region Canberra.
- 1 in 15 ACT Emergency Department visits linked to extreme weather – ANU National Centre for Epidemiology and Population Health.
- Climate Change Risk Assessment for the ACT – ACT Government summary report.
- Dalla Vecchia C et al, Impact of climate change in emergency medicine: a narrative review – Journal of Public Health and Emergency, 2024.
- Two decades of climate change and its impact on health in the Australian Capital Territory – Australian and New Zealand Journal of Public Health (ScienceDirect index S1326020025000780).
- Heatwaves and emergency department visits in Brisbane – Toloo G et al, BMC Emergency Medicine, 2014, and related Australian heatwave ED literature.
- Climate change and environmental sustainability in emergency departments – narrative review of emergency attendances and climate impacts.
- Climate Change – ACT State of the Environment web section on current and projected climate trends.