Dr. Mirianna Budimir is senior climate and resilience expert at Practical Action, and early warning systems lead for the Zurich Climate Resilience Alliance (ZCRA). Francisco Ianni is senior officer for climate resilience initiatives at the International Federation of Red Cross and Red Crescent Societies, and heat hazards lead for the ZCRA. Carolina Pereira Marghidan is a technical advisor at the Red Cross Red Crescent Climate Centre.

Across the world, instances of extreme heat are occurring more frequently than ever. News of temperature records being shattered – all too often accompanied by reports detailing tragic loss of life – appear with frightening regularity. The threats posed by heatwaves are considerable, and due to the climate crisis are expected only to get worse.

It’s hard to think of any aspect of daily life unaffected by an extreme heat event. Health services quickly become overstretched; power systems buckle; and economic productivity grinds to a halt.

A new study by Mercy Corps in the rural region of Madesh in Nepal reveals the impact heatwaves are having on children’s education. “The classrooms feel like furnaces,” said one student. “The air is thick with hot air and foul smell of sweat, the walls trap the heat, and all I can think about is when I can escape.”

Scientists predict global warming of more than 1.5C for 2025-2029 period

Today is Heat Action Day, a global moment for raising awareness of heat risks. While we welcome and encourage the sharing of practical advice for staying safe, there’s so much more that needs to be done.

Knowing when and where these extreme heat events will occur is key to tackling the problem, and early warning systems hold enormous potential to reduce losses, suffering and death across the world. So why do they often fall short?

The fragmented landscape of heat warnings

Given the risks presented by heatwaves, and the relative ease of predicting temperature well in advance, over a hundred meteorological services – more than half of the global total – do provide warnings for instances of extreme heat.

However, many of these are informed solely by maximum temperature, and don’t capture prolonged, intense periods of heat. When the mercury refuses to drop for consecutive days and nights, the dangers are far greater.

This points to a bigger problem with heatwave warning systems: the lack of standardization. Analysis led by the Red Cross Red Crescent Climate Centre has revealed stark inconsistencies in approaches to the monitoring, research and forecasting of heat across the world. This is in no small part due to the differing levels of capacity from region to region; but even the terminology varies wildly, with literally hundreds of definitions of extreme heat in use right now.

Then there’s an even greater concern, which is that many countries – particularly lower-income nations in Africa, Latin America, and parts of Southeast Asia – have no such warning system at all. As is too often the case, those most vulnerable to the risks are the ones with the least protection, with potentially lethal consequences.

Climate change-driven heatwaves hit Delhi’s Red Fort market traders

Break the silos to enhance resilience to heat

Closing these gaps requires the urgent scaling up of effective early warning systems for heatwaves. While national governments and donors have their part to play (particularly in the development and financing of low-cost solutions), improved coordination and cooperation at the global level would give these efforts a much-needed boost.

More standardization will certainly improve matters, and it is promising to see progress being made on this front. The World Meteorological Organization recently published a new definition for heatwaves, one that crucially captures their prolonged nature. In partnership with the World Health Organization, the WMO is also updating its decade-old guidance on heatwave warning system development. And a new handbook of extreme heat indicators, indices and metrics is expected later this year.

To continue this momentum, far greater transparency is required of all governments, institutions and organizations engaged in addressing heat-related risks. This should include the proactive sharing of knowledge, data and best practices, and collaborating wherever possible.

Low-income countries currently without protection from extreme heat events can use this information to