Health and community services are being urged to prepare for extreme heat this summer – as is now being experienced by many in the northern hemisphere – as the World Meteorological Organization says countries such as Australia should prepare for El Niño increasing the risk of extreme weather.
Jason Staines writes:
As much of Australia endures cold mornings, rain and flooding, elsewhere in the world communities are already confronting the conditions many scientists and health experts warn will become increasingly common in a warming climate.
Across parts of India, temperatures have climbed above 45°C during an early and prolonged heatwave that has disrupted daily life and strained health systems, with schools closing and people shopping in the relatively cooler evenings. “It’s just dealing with the heat and making sure people survive and don’t fall ill,” former World Health Organization chief scientist Dr Soumya Swaminathan told ABC’s The World.
At the same time, the United Nations has warned countries around the world to prepare for the likely return of El Niño, the climate pattern associated with hotter global temperatures and increased risk of drought in countries including Australia.
The World Meteorological Organization says there is an 80 percent chance El Niño conditions will develop before September and a 90 percent chance before November. Most forecast models suggest the event will be “at least moderate and possibly strong”.
“The world must treat it as the urgent climate warning it is,” UN Secretary-General António Guterres said.
For Australia, the warnings are arriving months before summer; an article in the global health publication, Health Policy Watch, specifically mentions the risks to Australia.
The question is whether governments, health systems, employers and communities use this time to prepare.
Public health emergency
Heat is often discussed as a weather story, illustrated in the media with benign photos or clips of people enjoying time at the beach or water sports.
Increasingly, health experts are recognising it as a public health emergency. The International Federation of Red Cross and Red Crescent Societies says more than 500,000 people die each year from heat-related causes globally. Older people, infants, people with chronic illnesses and people living in cities are among those most at risk.
This year’s Heat Action Day, a global awareness initiative coordinated by the IFRC on 2 June, focused specifically on indoor heat – the growing risks posed by overheated homes, workplaces, schools and care facilities.
The organisation warns that heatwaves are becoming both hotter and longer due to climate change, but says many deaths are preventable through preparation and early action.
One challenge is that heat-related mortality is often hidden. Dr Soumya Swaminathan said heat deaths in India were likely under-reported because many people die outside formal healthcare settings, making heat difficult to identify as a contributing factor.
The impacts also extend well beyond mortality. “Heat-related deaths were also just the ‘tip of the iceberg’ of this heatwave’s impact,” she said. “[Hot weather] affects a much larger base of ill health, of people not being able to perform, of people not being able to work.”
“We also know that women face a disproportionate burden of heat, that domestic violence, for example, goes up during the hottest days of the summer, and they also suffer a lot of physical, reproductive health and mental health disorders. It has an impact on the social fabric, on communities, on productivity and on the economy.”
Researchers say official heatstroke statistics can substantially underestimate the mortality burden associated with extreme heat because many deaths are recorded under other causes rather than heat itself.
A recent paper published in Frontiers in Environmental Health estimated that a single day of extreme heat in India causes approximately 3,400 excess deaths nationally, while a five-day heatwave causes nearly 30,000 excess deaths.
The paper notes that official heat statistics “substantially underreport heat-related deaths” because many deaths are recorded under cardiovascular, respiratory or other causes rather than heat itself.
What lies ahead
Scientists stress that El Niño itself is not caused by climate change. However, a warmer atmosphere and warmer oceans can amplify its impacts. The most recent El Niño event in 2023–24 was one of the five strongest on record and contributed to record global temperatures in 2024.
Major El Niño years have historically been associated with drought, fires, crop failures, coral bleaching and heatwaves around the world. The WMO says forecasts for the June to August period show above-average temperatures across nearly all parts of the globe, increasing risks of heat stress and drought.
Australia is among the regions typically associated with hotter and drier El Niño conditions and importantly, the warnings are arriving well in advance.
“We need to prepare for a potentially strong El Niño event, which will exacerbate drought and heavy rainfall and increase the risk of heatwaves both on land and in the ocean,” WMO Secretary-General Celeste Saulo said.
“The WMO community will be carefully monitoring conditions in the coming months to inform decision-making by governments, humanitarian agencies and climate-sensitive sectors.”
That emphasis on preparedness is becoming increasingly central to public health discussions about heat.
Extreme heat is no longer an unforeseeable emergency. Seasonal forecasting systems now provide months of warning. The challenge is whether institutions act on those warnings before temperatures spike.
For health services, that preparation can include reviewing heatwave response plans, identifying vulnerable patients who may require additional support during periods of extreme heat, and ensuring hospitals, ambulance services and aged-care facilities are prepared for increased demand, as well as the direct impact upon health and aged care workforces and infrastructure.
Community organisations and local governments can assess whether cooling centres, outreach programs and welfare checks are available for people most at risk, including older people, those living alone and people without access to effective cooling.
Employers, particularly those with outdoor workforces, can review heat management plans, work schedules, hydration and rest arrangements, and procedures for modifying or suspending work during dangerous conditions.
While the specific measures vary, the common theme is that the most effective responses are usually put in place before the first heatwave arrives.
Beyond health
The impacts of extreme heat extend beyond hospitals and emergency departments. Across Australia, researchers are increasingly concerned about food production, energy systems, labour productivity and infrastructure resilience.
South Australian grower Anthony De leso told the ABC that three heatwaves during summer 2026 wiped out crops of coriander and other leafy vegetables, forcing some fields to be replanted. “The last heatwave we had was probably the worst in memory,” he said.
Australian National University plant scientist Professor Owen Atkin told the ABC that the temperatures recorded during the summer heatwaves represented a warning about future conditions. “
Last January was a real wake-up call in regards to the types of temperatures we’re likely to experience in the future,” he said. He said heatwaves should not be viewed solely as a summer problem.
Heat is also increasingly acting as a stress test across entire systems. Heatwaves are becoming a structural drag on India’s economy, reducing labour productivity, disrupting agriculture and increasing pressure on energy systems.
Researchers estimated that heat exposure in India during 2024 resulted in the loss of 247 billion potential labour hours, mostly in agriculture and construction.
At the same time, extreme heat compounds other risks.
In the United States, wildfire experts are warning that widespread drought, low soil moisture and poor snowpack conditions are increasing the likelihood of a severe fire season. Some experts have described large parts of the country as a “tinderbox”.
Heat, drought and fire increasingly overlap rather than occurring as separate crises. This growing complexity has increased the importance of forecasting and monitoring systems that can provide governments and emergency services with early warnings.
Yet some scientists are warning that the infrastructure used to monitor climate systems is itself at risk. In the US, the Trump Administration is planning to dismantle key parts of a deep-sea ocean monitoring network that has provided long-term climate and ocean data for more than a decade.
Scientists say that reducing monitoring capacity will make it harder to understand, predict and prepare for climate-related risks.
“As we reduce the amount of data that we have, the observations, as well as the science more generally to understand what’s happening in the climate system, it makes it much harder for us as a society to understand what we’re facing and what we need to do to plan for and adapt to it,” oceanographer Hilary Palevsky told The Guardian.
What preparation looks like
India’s experience highlights the range of systems affected by prolonged heat. Hospitals and ambulance services can experience surges in demand; electricity systems come under pressure as cooling use rises; outdoor work becomes dangerous; food production and supply chains are disrupted; and vulnerable people become increasingly isolated indoors.
Kayly Ober, a visiting scholar with the Sustainability, Climate, and Geopolitics Program at the Carnegie Endowment for International Peace, described India’s 2026 heatwave as an “energy stress test”, with electricity demand already hitting record highs and some cities experiencing overnight power outages as cooling demand surges.
Her report warned that nights are no longer providing sufficient relief from daytime temperatures, increasing physiological stress and mortality risks. The issue of indoor heat is becoming increasingly important globally and for many vulnerable people, the danger is not only direct sun exposure outdoors, but consecutive nights in overheated homes without relief.
In India, only about eight percent of households have access to air conditioning. Many households rely on fans or open windows, which become less effective as humidity rises. But the broader issue – unequal access to cooling and protection from heat – is not confined to developing countries.
Heat vulnerability is shaped by housing quality, income, employment conditions, healthcare access and energy affordability. Outdoor workers, older people, renters, people in poorly insulated housing and people with chronic illnesses are often among the most exposed.
The India mortality study found that economically weaker regions carried disproportionate heat mortality burdens despite having lower economic capacity to invest in adaptation and resilience.
Plan ahead
The warnings now emerging internationally point to a broader shift in how extreme heat is understood.
Heatwaves are no longer rare or isolated weather events. Increasingly, they are recurring public health, economic and infrastructure challenges that governments are being urged to plan for well in advance.
By the time temperatures rise into the 40s, hospitals are overwhelmed, power demand surges and emergency warnings are issued, many opportunities to reduce harm have already passed.
The work of preparing for extreme heat – identifying vulnerable people, strengthening health services, protecting workers and ensuring access to safe cooling – begins long before summer arrives.
Further reading
From Duke University in the United States:
- Resilience: The Capability Every Organisation Needs as Summer Begins
- Extreme Heat Is Rising. What Are Duke Researchers Learning About Its Impacts?
See Croakey’s archive of articles on heat and health, and fossil fuels
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