Tracking Heat Health Impacts: Global Experts Meet in London
Published: June 27, 2025
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Scientists, public health officials, and policy experts from around the world came together in London this week to confront a significant blind spot in health policy and practice: the lack of reliable estimates on the human health toll of extreme heat.
The three-day technical workshop, held at the London School of Hygiene and Tropical Medicine, focused on one urgent question: how can we better measure heat-related illnesses, injury, and death?
Hosted by the Global Heat Health Information Network, the International Association of National Public Health Institutes (IANPHI), Santé Publique France, the Robert Koch Institute, and the London School of Hygiene and Tropical Medicine, the meeting brought together over 40 participants from national public health agencies, academic institutions, and international and regional organizations.
Inconsistent and missing data undermines response
In many parts of the world, the health impacts of extreme heat are not systematically detected, recorded and tracked. Even where data standards or surveillance exists, approaches vary so widely that the data often cannot be compared or aggregated reliably. As climate-driven heatwaves grow more intense and frequent, the absence of consistent diagnosis and monitoring has compromised the ability of governments and other organizations to target the best ways to reduce the health risks that vulnerable communities face.
“We know that extreme heat kills, but we still don’t have an accurate picture of how many people are affected in the most at risk areas, or where impacts might be disproportionately high,” said Joy Shumake-Guillemot, Global Heat Health Information Network Co-chair and WHO-WMO Climate and Health Joint Programme lead, “We also know the interventions that can reduce heat risks. What we’re missing is stronger data to drive decisions about when and where to deploy them.”
International collaboration targets common standards
The workshop was convened as part of a wider international effort to close this knowledge gap. Participants reviewed how heat exposure is measured and characterized, how clinical diagnoses are detected and recorded, and how routine surveillance, health information systems, tools, and statistical approaches are currently used to estimate heat-related mortality and morbidity. They also examined the current data and models behind global mortality estimates produced by initiatives such as MCC, IsGlobal, Lancet Countdown, and IHME, which consistently produce differing estimates. This offered public health researchers and practitioners a timely opportunity to share opinions and explore closer collaboration.
Participants also agreed that harmonization and collective understanding of different approaches to track heat related illnesses and deaths will be instrumental in expanding the use of the broad and expanding range of data-related tools and approaches across the world.
During the workshop, experts also began working towards common standards and guidance for how public health professionals and researchers can measure and monitor heat impacts more consistently. That included defining key decision needs, proposing common indicators to track outcomes like hospital admissions and deaths, as well as more detailed measures to detect and assess risks to groups such as outdoor workers, pregnant women, and older adults.
“Availability of timely and local health data related to heat exposure can greatly improve our ability to respond better during heat emergencies, drive targeted investments in heat resilience and assess if heat risk reduction strategies are effective in reducing adverse health outcomes” reflected Shubhayu Saha, a Global Heat Health Information Network Management Committee member with expertise on linking health surveillance and climate services.
Overcoming implementation challenges key to meaningful impact
Another key focus was implementation. Participants emphasized the importance of building registry and tracking systems that are both scientifically robust and practical for countries to adopt. Discussions covered how to integrate death registry and surveillance into existing public health reporting systems, how to support cross-sector collaboration, and how to ensure that resource-limited countries are not left behind.
“There’s a real opportunity to work together on something that’s both globally consistent and locally useful, where we can make a meaningful and lasting impact,” said Angelina Taylor, Climate Change and Health office lead at the Robert Koch Institute.
“The goal is not only to define what should be measured, but to ensure that the numbers serve those who need them most by informing policy processes: governments planning for future heatwaves, hospitals preparing for seasonal surges, and communities living on the frontlines of climate change” said Sari Kovats, Health Protection Research Unit in Climate Change and Health Security at LSHTM and GHHIN Management Committee member.
“This is about making sure no one is invisible in the data,” said Mathilde Pascal, Climate Change and Health Project Manager of Santé Publique France and Global Heat Health Information Network Management Committee member.
Looking ahead: laying the groundwork for more effective heat health impact tracking
The meeting also helped lay the groundwork for a convening of national public health leaders this November, where advanced versions of technical guidance will be discussed. That event, organized by IANPHI and hosted alongside the One Sustainable Health Forum in Lyon France, will give political and institutional weight to the technical work undertaken in London.
Participants represented institutions from across Europe, Africa, Asia, and the Americas, including the national public health agencies of 17 countries. Experts from LSHTM, University of Tokyo, European Centre for Medium-Range Weather Forecasts, ISGlobal, and Institute for Health Metrics and Evaluation, also contributed, alongside representatives from the World Health Organization, World Meteorological Organization, UK FCDO, Wellcome, and the Lancet Countdown.
The workshop outcomes will be refined in the coming months and shared via GHHIN and IANPHI networks for peer review and learning. Organizers hope the work will lead to stronger, more coordinated systems for tracking the health effects of heat, so that in the years to come, the world is not only hotter, but better prepared.
Learn more at www.heathealth.info