Before dawn in Mildura, the air already feels spent, as if the sun
has been up for hours, and residents are bracing for yet another day
above 40C in what has become a week-long siege of heat across
south-eastern Australia.1
From
inland South Australia to western New South Wales and Victoria,
maximum temperatures have climbed into the mid to high 40s, part of a
severe to extreme heatwave that forecasters say may break
long-standing records in multiple locations.1
Along the north-west coast of Western Australia, temperatures near 50C
earlier in January set new local January records and came close to
Australia’s all-time highs, underlining how little room remains before
physical limits are reached.1
At
the same time, authorities in Victoria declared a state of disaster as
hot, dry winds and parched fuels drove fast-moving bushfires that
burned hundreds of thousands of hectares.3
Climate scientists now say the early-January heatwave that set the
stage for these fires was made around five times more likely by
human-caused global warming, compared with a pre-industrial climate.2
Hospitals and emergency
services have reported spikes in heat-related admissions, while power
demand for cooling has surged and outdoor work has become dangerous in
many regions.2
For many
Australians, the January 2026 heat is not just another uncomfortable
spell, it is a clear sign that climate change is reshaping the
country’s summer and magnifying the risks that come with extreme heat.2
How climate change drives extreme Australian heat
Climate change increases extreme heat in two main ways: it raises the
average temperature, and it alters weather patterns in ways that make
heatwaves more intense and persistent.7
The Intergovernmental Panel on Climate Change and multiple Australian
studies have found that human greenhouse gas emissions have warmed the
continent by about 1.4C since 1910, meaning that heatwaves now develop
on a much hotter baseline than they did a century ago.7
A landmark analysis of Australian heatwaves by the Climate Council,
drawing on Bureau of Meteorology data, shows that heatwaves have
become hotter, longer, more frequent and are occurring earlier in the
season since the 1950s.8
This
trend is consistent with global attribution studies that compare the
real world with modelled worlds without human emissions to determine
how much climate change has altered the odds of extreme events.9
In January 2026, those background changes combined with short-term
weather drivers to produce exceptional heat.1
A strong, slow-moving high-pressure system over Western Australia
generated sinking, drying air that allowed temperatures in the
north-west to climb close to 50C, before that heat was transported
east across the continent by hot north-westerly winds.1
From 5 to 10 January, south-eastern Australia recorded its most severe
heatwave since 2019–20, with temperatures above 40C in major
population centres and prolonged periods of high overnight
temperatures that prevented homes and infrastructure from cooling
down.2
An attribution analysis
released in late January concluded that this early-January event was
roughly five times more likely because of anthropogenic climate change
and would have been significantly cooler in a pre-industrial climate,
even with the same large-scale weather pattern.2
CSIRO’s event attribution work has found similar human fingerprints on
previous Australian heatwaves, including record-breaking events in
2013 and 2019, reinforcing the conclusion that climate change is now
the dominant driver of extreme heat risk in Australia.9
The geography and physical character of the January heat
The January 2026 heatwave has not been a single, uniform event but a
rolling sequence of extreme conditions affecting different regions in
turn.1
In the first half of the
month, the focus was on Western Australia’s north-west, where Shark
Bay recorded a new January record near 49C and Carnarvon reached its
hottest January day on record at about 48C under a stagnant upper
high.1
As this heat dome shifted
east, inland South Australia, western New South Wales and north-west
Victoria endured days on end above 40C, with forecast peaks up to 48C
in the Murraylands, Riverland, Mallee and lower western districts of
New South Wales.1
Cities such as
Adelaide and Melbourne saw temperatures rebound into the low 40s on
multiple days as relief from weak cool changes failed to reach far
inland, trapping hot air over the interior.1
These conditions translated directly into heightened bushfire danger.1
In South Australia, soil
moisture levels were already extremely low after several years of
below-average rainfall, meaning fuels were dry and highly flammable.1
As hot, dry north-westerly
winds strengthened, fire danger ratings climbed to extreme in many
districts and were forecast to reach catastrophic on the Yorke
Peninsula, a level associated with fast, unpredictable fires that can
overwhelm even well-prepared homes.1
In Victoria, strong winds and severe heat helped several fires burn
out of control, ultimately scorching more than 400,000 hectares and
destroying hundreds of structures, including homes, prompting a state
of disaster declaration.3
CSIRO
and the Bureau of Meteorology have previously projected that climate
change will increase the number of days with extreme fire danger by
5–25 per cent by 2020, relative to 1990, for a modest 0.4C of global
warming, suggesting that risks will continue to escalate as
temperatures climb further.10
Heat, health and the economy
Heatwaves already kill more Australians than any other natural
hazard, and January 2026 has underlined why health experts describe
extreme heat as a “silent emergency”.8
A 2025 scoping review of extreme heat and health in Australia found
strong evidence that hot days and heatwaves increase deaths and
hospitalisations from cardiovascular disease, diabetes, respiratory
illness and mental health conditions, particularly among older people,
those with chronic disease and people in low-quality housing.11
The review reported, for
example, that people with kidney disease in the Northern Territory
faced a 29 per cent higher risk of heat-associated hospitalisation
during extreme heat, and that heatwaves were linked to higher rates of
stroke admissions in Brisbane.11
During the early-January 2026 heatwave, one major hospital reported a
25 per cent jump in emergency department presentations, highlighting
the stress that even a single event can place on the health system.2
The economic impacts of extreme heat are similarly broad but less
visible.11
The same 2025 review
noted estimates that more than 10 million Australians are exposed to
hazardous heat, with potential losses of about $211bn in agriculture
and labour productivity by 2050 under current warming trajectories, as
well as large projected losses in the property sector from climate
extremes including heatwaves.11
January’s heat has already affected productivity by forcing outdoor
work to pause during the hottest hours, increasing cooling costs for
households and businesses, and adding pressure to electricity networks
as demand for air conditioning surged.2
In some regions, authorities issued public health alerts urging people
to stay indoors, check on neighbours and limit physical activity,
measures that are essential for safety but that also curtail economic
activity and social life.20
Ecology, wildlife and culture under stress
Australia’s plants and animals are adapted to heat and fire, but the
intensity and frequency of recent heat extremes are pushing many
species beyond their limits.12
Previous heatwaves have caused mass deaths of flying foxes, fish kills
in inland rivers and coral bleaching on the Great Barrier Reef, and
scientists warn that similar impacts are likely when air and water
temperatures spike for prolonged periods.13
The January 2026 heat has coincided with high fire danger across
forested regions of south-eastern Australia, raising the risk of
habitat loss for species still recovering from the 2019–20 Black
Summer fires.3
CSIRO has noted
that hotter, longer fire seasons and more frequent extreme heat will
make it harder for ecosystems to recover between disturbances, leading
to shifts in species composition and, in some cases, permanent loss of
biodiversity.10
These changes also carry deep cultural consequences.14
First Nations communities whose traditions are tied to specific
landscapes, seasonal cycles and species face the prospect of losing
key cultural practices as fire regimes, water availability and
wildlife distributions change.14
In some regions, extreme heat has already disrupted community events,
ceremonies and sporting fixtures, with summer activities cancelled or
shifted to early morning or night to avoid dangerous conditions.20
For many Aboriginal ranger
groups, intense heat waves can limit the window for cultural burning
and land management work, even as the need to reduce fuel loads and
manage Country becomes more urgent in a warming climate.14
Heat, rivers and water security
Extreme heat does not operate in isolation from Australia’s water
systems; it interacts with rainfall, evaporation and land management
to shape river flows, water quality and the security of supplies for
towns, farms and ecosystems.15
In the Murray–Darling Basin, which supports much of the country’s
irrigated agriculture, higher temperatures increase evaporation from
rivers, dams and soils, reducing the efficiency of rainfall and
increasing the risk that moderate dry spells turn into severe
droughts.16
During intense
heatwaves, low, slow-moving rivers can warm rapidly, reducing
dissolved oxygen levels and raising the risk of hypoxic fish kills,
particularly when combined with nutrient run-off or sudden changes in
flow.16
Heat also increases
water demand from irrigators, towns and ecosystems at the same time as
supply is constrained, a tension that plays out in water markets and
environmental flow decisions long after the immediate event has
passed.16
Northern Australia’s wet-dry tropics face a different but related set
of challenges.17
Projections
suggest that while total wet-season rainfall may not decline strongly
in some northern basins, higher temperatures will increase potential
evaporation and may shorten the period of high flows, concentrating
ecological stress into longer, hotter dry seasons.17
Wetlands and floodplains that depend on seasonal inundation, including
culturally significant sites for Indigenous communities, become more
vulnerable when extreme heat accelerates drying between floods.17
For remote communities that
rely on shallow groundwater or small surface storages, heatwaves can
also worsen water quality by promoting algal growth and increasing the
concentration of contaminants as volumes drop, adding to existing
infrastructure and health challenges.15
Long-term implications for key sectors
The conditions Australians have faced in January 2026 are consistent
with what climate models project will become far more common unless
global emissions fall steeply.7
Under a high-emissions scenario, much of inland Australia could
experience several additional weeks per year of days above 35C by
mid-century, with large increases in the number of days above 40C,
particularly in already hot regions.7
For agriculture, this means more frequent heat stress on crops and
livestock, reduced yields during key growth stages and increased
irrigation demand at the same time that water resources are under
strain.18
CSIRO has warned that
without adaptation, heat and water stress will erode productivity in
sectors such as grains, cotton, dairy and horticulture, and could
force shifts in where some industries are viable.18
For the energy sector, rising temperatures create a dual challenge of
soaring demand for cooling and reduced capacity of some generation and
transmission assets to operate in extreme heat.19
Coal and gas plants can become less efficient at high temperatures and
may face cooling water constraints during drought, while transmission
lines can carry less power when air temperatures are very high,
increasing the risk of blackouts during heatwaves.19
At the same time, distributed rooftop solar performs well during sunny
heatwaves, although output can dip slightly on the hottest days, and
storage and demand management will be critical to smoothing evening
peaks when residual heat lingers but solar generation falls.19
Urban planning will also need
to confront a much hotter future, as more frequent days above 35C make
existing housing, transport systems and public spaces increasingly
uncomfortable and, at times, unsafe.18
Strategies such as tree planting, reflective surfaces, better building
insulation and design, and accessible cool refuges will be central to
reducing urban heat islands and protecting vulnerable residents.18
What planners and policymakers must do now
For regional planners and policymakers, January 2026 is less a
surprise than a stress test for systems that were largely designed for
a cooler climate.7
The first
priority is rapid emissions reduction, because every fraction of a
degree of additional warming will compound the risks of extreme heat,
bushfire, water insecurity and ecosystem loss documented by Australian
and global assessments.7
In
practice this means phasing out coal and gas power, supporting the
rapid build-out of renewables and storage, and integrating heat risk
explicitly into national and state climate targets and sector plans.19
At the same time, governments must treat extreme heat as a core
planning constraint, not a seasonal inconvenience.8
Heat-health action plans that identify vulnerable populations,
establish cool refuges, set work and school protocols, and improve
housing quality can reduce deaths and illness, but they need
consistent funding and coordination across health, housing, education
and workplace safety agencies.11
Land-use and bushfire planning should incorporate the latest
projections of fire weather and extreme heat, limiting development in
the most exposed areas and strengthening building standards,
evacuation routes and early warning systems.10
Water planning in basins such as the Murray–Darling must assume higher
evaporation and more intense heatwaves, securing environmental flows
and town water supplies under a hotter, drier climate, while involving
First Nations communities in decisions about Country and cultural
water.16
The January 2026
heatwave shows that Australia still has choices: the more decisively
it cuts emissions and designs for a hotter world, the less brutal its
future summers are likely to be.2
References
- ABC News, Seven-day heatwave to engulf south-east
states, raising bushfire danger (22 January 2026)
- Earth.org, Climate change made Australia’s
early-January 2026 heatwave five times more likely (20 January
2026)
- Earth.org, Heightened fire risk and bushfires
during the January 2026 heatwave
- Climate Council, Heatwaves: hotter, longer, more
often (2014)
- Murray–
Darling Basin Authority, Climate change and the Basin’s water
resources
- CSIRO, Climate Change: Science and Solutions for
Australia – climate impacts and sectors
- IPCC, Sixth Assessment Report Working Group I: The
Physical Science Basis (2021)
- Climate Council, Summary of Australian heatwave
trends and risks
- CSIRO, Climate change attribution – calculating
the role of climate change in extreme events (2022)
- CSIRO, Climate Change: Chapter 4 – Climate change
impacts and fire weather
- Nitschke et al, Impact of extreme heat on health
in Australia: a scoping review (2025)
- Department of the Environment, Climate change
impacts on biodiversity in Australia
- Great Barrier Reef Marine Park Authority, Climate
change and the Reef
- Central Land Council, Climate change policy and
impacts on Aboriginal communities
- Bureau of Meteorology, State of the Climate –
Australia’s changing water resources
- Murray–Darling Basin Authority, Climate change and
its impacts on the Basin (2020)
- CSIRO, Climate change information for northern
Australia
- CSIRO, Climate change impacts on Australian
agriculture
- AEMO, Integrated System Plan – climate and heat
implications for the energy system
- ABC News, What makes a heatwave in Australia and
why they are so dangerous (23 January 2026)
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