Extreme Heat is a Health Crisis, An Open Letter to The Global Fund and Global Community
We are long-standing admirers of The Global Fund’s historic leadership in the fight against HIV, tuberculosis, and malaria. Your efforts have saved over 59 million lives by addressing the world’s most pressing health crises through global partnerships and evidence-based solutions. We applaud your recent launch of the Climate and Health Fund, a bold and urgent step that reflects what science and frontline realities have made clear: climate change is already reshaping the health landscape, especially in the most vulnerable communities. The Global Fund can drive a paradigm shift by bridging climate adaptation and global health, harnessing the power of innovation ecosystems to deliver integrated, scalable solutions.
As you develop your strategy, we encourage you to focus on extreme heat, which is increasingly shaping the global health landscape. According to the World Health Organization, nearly half a million people die each year from heat-related causes, a challenge that is growing as 2024 marked the hottest year on record. With heatwaves becoming more frequent and intense, there’s an urgent need to better understand their impact on health and livelihoods. At BFA Global, we work at the intersection of financial inclusion, technology, and climate resilience, and we are increasingly seeing the impact of extreme heat in the emerging markets where we work. We see a unique opportunity to bring together diverse sectors to co-create innovative, multidisciplinary solutions that can build resilience in the face of rising temperatures.
Heat and disease: A hidden connection
People are not only sicker during extreme heat, but they also struggle to maintain treatment, further weakening outcomes.
Warmer temperatures expand the transmission range of malaria, speeding up mosquito breeding and parasite development. In East Africa, highland areas once protected by cooler climates see malaria reemerge. Extreme heat also exacerbates tuberculosis (TB), primarily through risk factors like undernutrition and poor living conditions during heatwaves.
Extreme weather, including drought and heatwaves, disrupts access to antiretroviral therapy (ART) for people living with HIV (PLHIV) by damaging health infrastructure, interrupting supply chains, and driving food insecurity and migration. A systematic review found that drought in sub-Saharan Africa significantly reduces ART adherence. Heat stress also threatens vaccine stability, especially for temperature-sensitive vaccines like polio, by compromising cold chain systems. Moreover, polio survivors, who often have mobility or respiratory challenges, may be particularly vulnerable to extreme heat and other climate shocks.}
Extreme heat threatens lives and livelihoods
When people are too hot to work, they are too poor to rest. When they can’t work, they can’t afford treatment. Extreme heat drives a downward spiral: increased exposure, lost income, and worsened disease vulnerability.
Heat also limits the ability to work, compounding health impacts. The ILO projects heat stress could cost the world 80 million jobs by 2030, due to lost productivity, equivalent to a global economic loss of 6.7% of GDP in low-income regions, primarily in agriculture and construction sectors that support low-income populations and often include those affected by TB and HIV. Productivity can drop by 50% at 40°C. In industries like construction and agriculture, productivity can drop by as much as 50% when temperatures exceed 40°C, leaving families without income and putting workers’ health at risk. Women, who already perform more unpaid labor, lose up to 19% of their paid working hours due to heat while facing higher caregiving demands (as much as 90 extra minutes of unpaid labor each day).
Occupational exposure to extreme heat can cause dehydration, heat stroke, and cardiovascular strain, particularly during heavy physical work with poor ventilation. In the U.S., OSHA has identified extreme heat as one of the leading weather-related causes of death among workers. In countries like India, informal construction and waste management workers are especially vulnerable. A Lancet Planetary Health study (Sahu et al., 2021) found that over 60% of outdoor workers experienced heat-related illness during the summer. While some companies have begun adapting with revised schedules and hydration stations, these efforts remain limited and uneven without systemic support.
Why we need a multidisciplinary approach
No single sector can solve this crisis alone. Integrated solutions, combining finance, climate information, and health services, have the highest impact on vulnerable populations. In practical terms, this means a farmer or street vendor should benefit from weather forecasts and heat alerts, have access to financial safety nets when heatwaves hit, and receive guidance on protective measures for their health.
At BFA Global, we have spent over a decade designing inclusive innovations that reach low-income and climate-vulnerable populations. Through initiatives such as TECA (Triggering Exponential Climate Action) and Catalyst Fund (pre-seed VC fund and accelerator), we support locally-led startups developing tech-based solutions to climate-linked challenges, including in health, from early warning systems to climate-responsive financial products. We combine policy engagement, deep action research, and venture-building support to bring early-stage innovation into systems-level change. We believe that innovators, when connected to public-private partnerships and supported by catalytic capital, can generate scalable solutions to health resilience in a warming world. These include smart insurance mechanisms that respond to temperature thresholds, digital health platforms that ensure ART delivery during disruptions, and cooling tech to protect workers vulnerable to malaria-bearing mosquitoes.
Innovative solutions are within reach
Innovation offers real promise in reducing the health risks of extreme heat. Across the globe, startups and policymakers are testing solutions that could be scaled in disease-prone regions.
Embracing technology from AI-driven climate forecasting to simple SMS alert systems can empower communities with information and protective tools. From wearable cooling gear and mobile heat alerts to AI-driven hotspot mapping, help vulnerable populations, including outdoor workers and immunocompromised individuals, better manage heat stress. These tools can reduce malaria exposure by preventing nighttime outdoor activity and lower the risk of heat-triggered ART interruptions for people living with HIV.
Innovative financing can buffer the economic shock of extreme heat, such as heat-triggered microloans or parametric insurance, and can ensure treatment adherence even when work stops. These tools help informal workers avoid falling into poverty when heatwaves shut down income, preventing treatment lapses for TB or HIV. Similarly, parametric insurance for heat is emerging. These insurance policies automatically pay out when temperatures exceed critical levels, ensuring that a farmer or street vendor has income even when work is unsafe. Other ideas include climate-adaptive credit lines (to help small businesses finance cooling equipment, shaded workspaces, or water stations) and dedicated heat resilience savings accounts to help families set aside funds for medical bills or days when work is cancelled due to extreme heat. Such financial tools can turn a potentially catastrophic heatwave into a manageable challenge.
Public health and infrastructure interventions, like shaded clinics, cooling centers, and rest break mandates, are already saving lives. However, they must be linked to health system responses, especially in high-burden regions, and scaled through cross-sector partnerships.
A call to partnership and action
The Global Fund is uniquely positioned to lead in this space, drawing on its global health expertise, multisectoral reach, and commitment to strengthening climate-resilient health systems. While extreme heat is not a communicable disease, it intensifies health risks, worsening dehydration, cardiovascular strain, kidney failure, and complicating the treatment of HIV, TB, and malaria. With the launch of the Climate and Health Fund, the Global Fund has taken an essential step in addressing this nexus. The opportunity now is to deepen its impact by supporting locally led adaptation and innovation, enabling communities to develop and scale context-specific solutions. From heat-resilient clinics to financial tools that help maintain ART adherence or malaria prevention during extreme events, community-driven initiatives are already showing promise.
BFA Global stands ready to contribute our ecosystem-building experience, policy insights, and global network of inclusive innovators to this collective mission.
