Climate Change and the Rising Burden of Waterborne Diseases

Climate change is increasingly recognised not just as an environmental issue but as a profound threat to human health and well-being. Globally, the World Health Organization (WHO) estimates that climate change will cause approximately 250,000^[1] additional deaths annually between 2030 and 2050, largely from malnutrition, malaria, diarrhoea, and heat stress, of which nearly a fifth (48,000^[2]) are projected to be due to diarrhoea.

Waterborne infectious diseases^[3], like cholera, typhoid fever, and hepatitis A, primarily affect the human digestive system and are transmitted through contaminated water, food, fruits, and vegetables, and are highly climate-sensitive. Higher temperatures linked to the changing climate enhance the survival, replication, and virulence of many pathogens that cause waterborne diseases. Even a 1 °C^[4] rise in temperature increases Salmonella infection risk by 5–10%, and warmer conditions has been linked with outbreaks of cholera and typhoid^[5]. Similarly, intense rainfall and flooding mobilise pathogens and damage water and sanitation systems, increasing the incidence of waterborne diseases (WBD). For instance, following the 2010 floods in Pakistan, widespread contamination of drinking water sources led to a sharp rise in acute diarrhoeal diseases, with over 1.5 million^[6] cases reported in affected regions. Heavy rainfall and high temperatures can substantially increase diarrhoeal disease^[7] risk, which remains one of the leading causes of child mortality^[8] worldwide. On the other hand, droughts concentrate pathogens in dwindling water sources, raising the likelihood of waterborne diseases. Changing precipitation patterns and rising sea levels are also altering^[9] seawater salinity, which is reshaping pathogen ecology. For instance, in 2014^[10], an increase in sea surface temperature and reduced salinity along the U.S. Gulf Coast created favourable conditions for the proliferation of Vibrio vulnificus, leading to a surge in vibriosis cases.

India’s Worsening Waterborne Disease Burden

India bears a heavy burden of waterborne diseases^[11], and like around the world, climate change is amplifying this challenge in India as well. Heavy monsoon rains, flash floods, and drinking water contamination^[12] have been shown to trigger outbreaks of diarrhoea, cholera, typhoid, and hepatitis A and E across the country. Nearly 70%^[13] of all disease outbreaks reported by the Ministry of Health and Family Welfare are waterborne, and their incidence continues to rise^[14]. Intensifying rainfall and rising temperatures are also extending the transmission season^[15] of waterborne diseases, placing added pressure on already strained health systems. Climate-driven changes are also shifting the geography of these diseases. Warmer water bodies provide ideal breeding grounds for Vibrio cholerae, Naegleria fowleri ^[16] (which causes Primary Amebic Meningoencephalitis or PAM), and enteric viruses. PAM is a rare but almost always fatal brain infection caused by Naegleria fowleri, an amoeba that thrives in warm freshwater. Cases^[17] have been sporadically reported from Indian states like Kerala, Tamil Nadu, Maharashtra, and Rajasthan, often during peak summer when surface water temperatures soar. Although rare, its emergence in new locations highlights how rising temperatures and declining water quality are creating new niches for previously uncommon pathogens. In parallel, urban flooding in megacities like Mumbai and Chennai regularly contaminates piped water supplies, while shrinking glaciers and reduced river flows in Himalayan states threaten clean water access, forcing communities to rely on unsafe water sources and heightening WBD^[18] risk.

Climate - Health Preparedness and Innovation

Across the world, health systems are increasingly treating climate change as a core public health and security threat. The World Health Organization’s Framework for Climate-Resilient Health Systems^[19] urges countries to strengthen disease surveillance, develop climate-informed health plans, build early warning systems, and climate-proof health infrastructure.

Encouragingly, a growing number of countries are heeding this call — with 91% of Nationally Determined Contributions (NDCs)^[20] under the Paris Agreement now including health considerations. This signals a strong and rising acknowledgement that effective climate adaptation must place health at its core.

Innovation is driving part of this shift. Climate-informed disease forecasting platforms using satellite weather data^[21] and artificial intelligence^[22], are being deployed to predict outbreaks of cholera^[23], malaria, and other climate-sensitive infections. For example, one study leveraged six satellite-derived climate variables and a machine-learning classifier to forecast coastal Indian cholera outbreaks with an 89%^[24] success rate, underscoring how these tools are already enhancing outbreak preparedness and early-warning capability. Building on this momentum, several countries are pioneering innovative approaches to protect water resources from climate-related risks and prevent waterborne diseases. In France, the establishment of a national surveillance system^[25] for acute gastroenteritis outbreaks linked to tap water is ensuring early warning of water supply failures. In Sweden, predictive models^[26] for groundwater drought and collaborative wetland restoration projects along shared river basins is helping prevent runoff and protecting drinking water sources. Meanwhile, in Indonesia^[27], coastal and rural communities are deploying rainwater harvesting systems with multi-level filtration and restoring mangrove barriers to buffer against tidal flooding, both of which maintain access to clean water when traditional sources are at risk of contamination. In the Philippines, low-cost Internet of Things (IoT)-based water quality sensors are enabling real-time monitoring in rural areas, allowing health workers to respond quickly to contamination alerts. Climate risk-informed planning in Central Cebu is guiding resilient and affordable water supply options, while participatory watershed management in Silang–Santa^[28] Rosa is reducing flood run-off and protecting drinking water sources. Together, these innovations highlight a multi-pronged strategy—combining monitoring, resilient infrastructure, nature-based protection, and community engagement—essential to prevent waterborne diseases under changing climate conditions.

While innovations in surveillance are advancing rapidly, progress^[29] in diagnostics for water-borne diseases remains limited. Most existing^[30] tests still depend on laboratory-based methods such as culture and PCR, which are slow and impractical during climate-related disruptions like floods. Recent advances^[31]—such as new low-cost rapid field diagnostic tests for Enterotoxigenic Escherichia coli (ETEC), Shigella, and Vibrio cholerae—show promise for improving outbreak detection and surveillance in resource-limited settings, offering results within hours instead of days. Yet, large-scale deployment and integration of such tests into national health systems remain limited. Consequently, there is an urgent need^[32] for affordable, portable diagnostics that can withstand climate stressors and support timely outbreak response.

India’s Climate–Health Action and Innovations

India has taken significant steps to align health policy with climate realities through the National Action Plan on Climate Change and Human Health (NAPCCHH)^[33], launched in 2019. Under this framework, states and union territories have prepared State Action Plans (SAPCCHH)^[34] focusing on strengthening surveillance systems like the Integrated Disease Surveillance Programme (IDSP), building climate-resilient primary health centres, training health workers on heat stress, vector- and waterborne diseases, and developing Health Early Warning Systems (HEWS) with the India Meteorological Department to forecast weather-driven disease risks.

The India Meteorological Department (IMD) has strengthened its early warning systems through advanced observation networks, AI/ML-based forecasting, and high-resolution climate models powered by supercomputers. With tools like mobile apps, CAP alerts, and the Panchayat Mausam Seva, it now delivers localized weather warnings, while the Mission Mausam^[35] initiative aims to make India a weather-ready and climate-smart nation. In parallel, several studies^[36] across India are modelling how climate^[37] variability, water-quality dynamics, and sanitation systems^[38] influence the burden of waterborne diseases, alongside the implementation of digital surveillance tools to enhance outbreak prediction and response.

India’s climate tech^[39] startup ecosystem is also growing rapidly, with funding rising from USD 20 billion in 2021 to USD 22.5 billion in 2022, led by energy transition, clean mobility, and sustainable agriculture. Within this landscape, an estimated USD 1 billion, accounting for roughly 4%^[40] of India’s total climate-action financing in 2022, was channelled into projects addressing the links between climate change and health. This limited investment mirrors global trends, in which only around 2% of climate-adaptation funds and 0.5%^[41] of overall climate finance are specifically targeted to strengthen health outcomes. Although global economic pressures led to a 40% funding dip in 2023^[42], the sector in India has demonstrated relative resilience, underscoring its potential for continued innovation and the integration of health-focused solutions.

Yet, fragmented implementation, weak coordination, and underinvestment in local R&D and adaptation financing remain as bottlenecks. Bridging these gaps is crucial to protect India’s climate-vulnerable population from rising waterborne disease risks.

Call to Action

Climate change is no longer a distant environmental concern—it is a rapidly escalating public health emergency. Rising temperatures, erratic rainfall, and declining water quality are transforming the landscape of infectious diseases, especially waterborne illnesses, across India and the globe. These shifts threaten to overwhelm already strained health systems and deepen inequities among the most vulnerable communities.

To protect public health, India must accelerate its climate-health preparedness. This means integrating climate risk assessments into all levels of health planning, investing in resilient health and water infrastructure, and empowering frontline workers with the training and digital tools they need to quickly detect and respond to climate-sensitive diseases, including WBDs. Simultaneously, innovation must be fostered by funding local and contexual R&D, supporting start-ups, and scaling successful models like heat action plans and community-based surveillance networks.

Finally, climate and health must move beyond siloed sectors. Strong coordination across health, environment, water, sanitation, and urban development is essential to build systems that can withstand the shocks of a changing climate. By embedding resilience, equity, and innovation at the heart of health systems, India can not only reduce the burden of waterborne and climate-sensitive diseases but also set a global example for climate-smart public health governance.

Authors:

Dr Anupama D S is an Associate Professor at NIMS Institute of Public Health and Governance at NIMS University, Rajasthan, Jaipur, India, with a keen interest in evidence synthesis, health policy, mixed methods research, and global governance for health.

Prof. Dr Sanjay Pattanshetty is the Director of NIMS Institute of Public Health and Governance at NIMS University, Rajasthan, Jaipur, India, with a keen interest in health diplomacy, international relations, and global governance for health.

Climate Change and the Rising Burden of Waterborne Diseases