Regardless of where you look, there’s a media outlet reporting on a record broken, a warning issued, or a life lost due to heat. In London, recent heatwaves ironically overshadowed much of London Climate Action Week. Over 200 million Americans spent the holiday under heat alerts, and the Center for Disease Control is recording a spike in heat-related ER visits. At the beginning of July, the United Arab Emirates entered its peak summer heat period – projected to last 40 days. More frightening, in early June, Mumbai had 45 days of water left – monsoon rainfall was lower than expected and then excessive heat evaporated the limited water reserves.
Extreme heat has a ripple effect. It starts with a rise in temperature that might make us turn up the air-conditioning, but can damage natural and human-made infrastructure, trigger economic loss and threaten social cohesion. And many of our leaders are getting caught flatfooted. For example, according to Mercer only 4% of companies have assessed their workforce’s vulnerability to extreme heat or other climate impacts. After a certain point, simply telling people to stay indoors and be careful will run its course. We need to proactively protect humans and infrastructure as well as the natural environment. New and emerging technologies will have a critical role here, but we’re facing a knowledge gap – what are the best-practice technologies that can help address extreme heat risk? Where is the consolidated mapping or clearing-house that employers, public officials, families and individuals can turn to?
Most fields have developed some type of tech and innovation stack over time. Physicians work across diagnostic tools, treatments, and clinical protocols. Financiers deploy architectures of instruments, platforms, and risk models. At a certain point in a field’s development, there tends to be at least a working awareness of what the universe of solutions looks like. That visibility shapes where capital flows, which problems get prioritized, and how quickly innovations find their way into practice.
Extreme heat is not yet at that point – and the window for us to get it there is small. There is a nucleus of practitioners, including physicians, engineers, insurers, city planners, and founders, who understand both the risk and the technology landscape at once. And that knowledge needs to be distributed rapidly.
What extreme heat actually does
Extreme heat is more severe and systemic than most of us appreciate. The Lancet Countdown’s 2025 annual report found that heat-related mortality has increased 23% since the 1990s, with 546,000 people dying from heat annually.
One common misconception is treating a heatwave as a singular, time bound incident. Dr. Manijeh Berenji MD MPH, an occupational and environmental medicine physician, says: “We tend to treat a heat wave as a single event, but the body keeps score. The danger isn’t usually the hottest afternoon, it’s the fourth one in a row, when the thermostat hasn’t had a cool night to reset.” This cumulative load explains why the 2021 Pacific Northwest heat dome killed 619 people in British Columbia in a single week, and why over 1,300 pilgrims died during the 2024 Hajj pilgrimage, as temperatures reached 51.8°C. “Chronic disease and chronic heat don’t add, they multiply,” Dr. Berenji adds. “The meaningful question isn’t how hot it is today. It’s how much reserve did the last two weeks leave this particular person.”
The economic loss, including productivity loss, is enormous. In the words of Nick Halla, Founder and CEO of GigaClimate, “When temperatures rise, work stops. Extreme heat is becoming one of the defining infrastructure challenges of this century, but most people still think of it as a weather problem. By 2030, heat stress is projected to reduce global working hours by 2.2%, equivalent to roughly 80 million full-time jobs and $2.4 trillion in annual economic losses.”
And extreme heat’s impact reaches far beyond human health. Infrastructure is at risk: asphalt softens, transmission lines overheat, underground pipes expand, and as cooling demand peaks power grids are overwhelmed. When grids fail, populations lose access to air conditioning, medical equipment, and refrigerated medication simultaneously. Heat can also damage the natural environment permanently: at 1.5°C of warming, 70 to 90% of reef-building corals are expected to die; at 2°C, 99% will perish. Let’s not forget about wildfires either – while they aren’t necessarily caused by extreme heat alone, increasing temperatures are an enabler and the damage will become even more profound: A 2025 study from the Proceedings of the National Academy of Sciences of the United States of America found that forest disturbances due to fire for in the 2023-2024 period was the highest since monitoring began in 2001, 2.2 times higher globally than the 2002–2022 average.
Extreme heat cascades – in short order it can move from discomfort and cancellation of events to acute health problems – even death, grid failures, damage to natural and built infrastructure, and increased social inequities. It’s rarely headline-grabbing like a wildfire – the damage accumulates slowly and invisibly, then becomes irreversible out of nowhere. And it enables a vicious cycle – as human-made and natural systems that we rely on weaken and break, our safety nets dissolve.
The knowledge gap and how to fill it
So what explains the lingering knowledge and solutions gap?
Hannah Safford, Associate Director of Climate and Environment at the Federation of American Scientists, identifies a structural reason the knowledge gap persists. “Heat is harder to recognise as an acute threat. Hurricanes displace communities, fires leave charred remnants. These impacts are much easier to communicate than the impacts of extreme heat.” The second half of her explanation is the more uncomfortable one: “The suffering caused by extreme heat is deeply inequitable. Wealthy individuals can afford to escape by living in air-conditioned spaces or leaving town. These individuals also exert significant control over where capital flows and how policy is shaped.” The knowledge gap persists, at least in part, because the people best positioned to close it are also the people least likely to feel it.
In parallel, design failures contribute. Emily Dinino, co-founder of ThermoShade, says: “We have become so dependent on mechanical cooling that we have forgotten how to design places that protect people both indoors and outdoors. That has left the people who are most exposed and least protected especially vulnerable, including during commutes, in public spaces, and at outdoor worksites.”
But at the same time, we have a growing set of innovations that are being built and brought into the market that can be put to use here. This “extreme heat tech stack” spans the built and natural environment, as well as human health and safety and overall systems.
Let’s look at how each layer works.
Layer 1: Sensing and Intelligence – The solutions needed detect, quantify, and communicate heat risk before it causes harm: physiological monitors, AI forecasting platforms, and analytics tools that translate physical exposure into financial terms. Companies like SlateSafety and VigiLife flag dangerous core temperatures before symptoms appear. VigiLife’s pilot with Rogers-O’Brien Construction reported zero heat-related illnesses and over $200,000 in savings in a single season.
Layer 2: Built Environment – Low to zero-energy cooling systems, low-carbon alternatives to conventional AC, and city-scale interventions that reduce ambient temperature are all needed. Safford is direct: “Overreliance on AC strains power grids, leaves people more exposed to energy price spikes, and contributes to a vicious cycle by producing more of the emissions warming the planet.” SkyCool Systems has demonstrated 15 to 40% energy reduction through radiative cooling panels backed by ARPA-E; ThermoShade is deploying modular shade structures for transit, public spaces, campuses, worksites, and events that combine passive radiative cooling and phase change material to create cooler outdoor spaces. And the economics are compelling: every dollar invested in passive cooling returns between $1.50 and $15, according to FAS research.
Layer 3: Human Response – Even the best-designed environment will leave some people exposed. Dinino puts it plainly: “The answer can’t just be to go inside or seek AC. People still need to wait for the bus, tend to crops, attend school and play sports.” Mexar builds evaporative cooling garments co-designed with frontline workers; Becklar’s WorkerSafety Pro uses Wet Bulb Globe Temperature-based alerts to meet Occupational Safety and Health Administration (OSHA) heat standards; while ColdVentures’ ColdVest reduces core body temperature by up to five degrees in under three minutes without electricity.
Layer 4: Systems and Capital – Heat resilience requires the economic infrastructure that determines whether food reaches people, whether crops survive to harvest, and whether workers have the financial protection to make safe choices. ColdHubs in Nigeria and SokoFresh in Kenya are expanding solar-powered cold storage; Elicit Plant’s biostimulants protect crops from heat stress following a $48M Series B investment.
Layer 5: Infrastructure Resilience – We need to protect our roads, railways, bridges, and grids that keep society functioning. AI grid monitoring, demand dispatch under heat stress, heat-resistant asphalt, and rail sensor systems are several examples. GridBeyond’s AI demand-response platform launched in the PJM market with Constellation Energy in July 2025; Polymer Modified Bitumen is scaling across the US transport network backed by $2 billion in federal IRA grants; and Form Energy’s long-duration batteries are providing grid backup capacity at scale.
Layer 6: Ecosystem Response – Unlike the other layers, the damage to natural ecosystems cannot be undone. Coral Vita is growing heat-tolerant corals using assisted evolution, with documented doubled fish populations at restoration sites; IntelliReefs has developed an engineered substrate that enhances coral settlement; and NOAA Coral Reef Watch, WRI’s Global Forest Watch, and the Allen Coral Atlas provide the monitoring data that makes global detection and response possible.
And the heat stack is still being built and opportunities abound. In the words of Halla, “ At GigaClimate, we see this not only as one of the world’s most urgent challenges, but also as an opportunity to improve billions of people’s lives while strengthening the global economy through an entirely new generation of technologies that keep people productive, healthy, and safe on an increasingly hotter planet.”
What leaders can do now
Cleantech 1.0 in the mid-2000s gave the world an early glimpse of what was possible. Since then, with more financial resources, human capital, policy and collaboration, the overlap of tech solutions and climate risk, as well as opportunities, has become more durable. Climate technology is now a serious investment category. Each sector within it went through the same arc: early confusion about what the solutions were, followed by a gradual adoption of shared vocabulary, awareness of the full value chain, and a maturing investment thesis. Climate adaptation technology is now entering that arc, and extreme heat may indeed be the most immediate opportunity for action.
We’ll need much more research, testing and market access pathways to build and operate the full spectrum of solutions. In particular, Dinino calls for more infrastructure for adoption: “We need more pilots and field data, and easier procurement pathways for cities and public agencies. Funding programmes can help by treating heat mitigation as essential infrastructure and creating faster ways for new technologies to be tested and adopted.”
How we communicate heat risk has to be part of this agenda. Informing people of what is coming, how to adjust, and what protections are available is itself a form of heat resilience. Fortunately, we’re not starting from scratch here. Groups like The Health Action Alliance’s Extreme Weather + Work focuses on getting organizations to move from awareness to action. The Federation of American Scientists’ HeatAgenda.US identifies more than 400 evidence-based heat policy solutions that state and local leaders can put in place today, with examples from all 50 US states. Climate Mayors has launched an Extreme Heat Communications Toolkit specifically to advance shared communications strategies and resilience solutions across member cities. Clear, accessible, and actionable public communication about heat risk is as much a part of the stack as any technology.
Not every heat solution will come with a clear ROI or a venture-backed company behind it. Countries and cities will still need well-functioning public health systems, enforceable labour standards, and cultures that take the threat seriously. Without these basic ingredients, the tech stack has limited value.
Every decision made today about where to build, where to source, where to hire, and how to insure is already a heat decision, whether leaders recognise it or not. As Dr. Berenji would say: act before the reserve is spent.
