Climate change impacts health through complex multidimensional pathways. These impacts include, for example, morbidity and mortality related to extreme climatic events, such as heatwaves and floods, and changes in the length of the transmission season and timing of climatesensitive infectious disease outbreaks. As one of the world’s biggest contributors to cumulative greenhouse gas emissions, countries in the pan-European region have a global responsibility to respond to climate change and transition to low-carbon economies. While evidence and awareness of the health implications of climate change are increasing, there is a need for accessible tools and ready-to-use information that allow effective communication of complex historical, current and projected climate-health trends. This information can help inform advocacy and climate change decision-making.

Responding to this need at a European level, the Lancet Countdown in Europe (LCDE)149 is a transdisciplinary research collaboration to develop indicators that monitor and quantify the health impacts of climate change and the health co-benefits of climate action since the 1950s. These indicators act as summary measures representing the heterogenous relationships between climate change and human health. A subset of LCDE indicators also feeds into the European Climate and Health Observatory (ECHO),150 a partnership between the European Commission (EC), European Environment Agency (EEA), Copernicus Programme Services, European Centre for Disease Prevention and Control (ECDC), European Food Safety Authority (EFSA), World Health Organization (WHO) Regional Office for Europe, Association of Schools of Public Health in Europe (ASPHER), International Association of Public Health Institutes (IANPHI) and the LCDE. The European Climate and Health Observatory portal provides access to information and tools for climate change adaptation to the EEA’s 38 member and cooperating countries. To ensure the reproducibility, scientific validity and relevance of LCDE indicators for policymaking, the project adheres to quality criteria mirroring WMO guidelines for climate indicators. A wide range of experts are involved in an iterative feedback process that further ensures the indicators align with the needs of policymakers – including experts affiliated with ECHO and its partner organizations, as well as EEA member and cooperating country representatives.

In 2022, the LCDE collaboration developed 33 indicators151 tracking the health dimensions of climate change across five key domains: (i) climate change impacts, exposures and vulnerabilities; (ii) adaptation, planning and resilience for health; (iii) mitigation actions and health co-benefits; (iv) economics and finance; and (v) politics and governance. Eleven of these indicators are available as interactive visualizations on the ECHO platform,152 including indicators on allergenic pollen seasons, health impacts of temperaturerelated exposure, and the climatic suitability of several infectious diseases (such as dengue, malaria, non-cholera Vibrio and West Nile virus). These indicator visualizations allow users to interact and engage with the data. For example, users can select their country and time period of interest. Indicators available on the ECHO platform are updated on a yearly basis and complemented with a continuously growing set of indicators tracking different aspects of the health dimensions of climate change, at an increasingly finer scale. This work is instrumental in setting the scene for commitments made under the European Green Deal and the EU4Health programme 2021–2027 – a vision for a healthier European Union, as well as for setting and tracking commitments on climate change and health under the WHO European Environment and Health Process.

Accessible tools and ready-to-use information can enhance effective communication of complex historical, current and projected climate-health trends.