The two most pressing global health threats, epidemics and climate change, share common roots. These issues are reshaping interactions among humans, animals, and the environment, increasing contact between wildlife, livestock, and humans. To reduce risks It is essential to involve communities and civil society, adapt science communication, enhance cross-sector collaboration, and adopt holistic approaches. Read the outputs of PREZODE’s webinar held in June 2025.
Panel discussion
On June 26, 2025, PREZODE hosted a panel discussion on a cross-cutting issue: how climate change acts not just as a background condition but as a super-driver that accelerates the emergence, spread, and severity of zoonotic diseases. The webinar moderated by Dr Elsa Léger, Science Officer at PREZODE, brought together Dr Jon Epstein, Epidemiologist and Founder of One Health Science, Dr Cyril Caminade, physicist, climatologist, specialist of early warning systems at Abdus Salam International Centre for Theoretical Physics, Dr Gladys Kalema-Zikusoka, founder and Chief Executive Officer of Conservation Through Public Health, Prof. Jan Semenza, environmental epidemiologist at the Department of Epidemiology and Global Health at Umeå University and the Institute of Global Health at Heidelberg University.
Shared root of the two most pressing global health threats
Multiple, interconnected factors drive disease outbreaks. The main drivers include land use changes, intensive farming production without adequate biosecurity, international travel and global trade, some of which are also major contributors to climate change. This highlights the shared root causes of the two most pressing global health threats: epidemics and climate change. Moreover, climate change directly contributes to disease emergence by reshaping interactions among humans, animals, and the environment, increasing contact between wildlife, livestock and humans.
Spillover events and the emergence of zoonotic diseases occur on timescales that differ from those of climate change. While epidemics can arise suddenly, climate change unfolds over longer periods, making it challenging to directly attribute specific outbreaks to climate factors. However, climate change plays a critical role. Temperature influences vectors at all their stages of development, with transmission potential depending on species-specific thermal thresholds. Warmer temperatures can accelerate pathogen transmission, and climate-related events like flooding can further exacerbate outbreaks by disrupting access to healthcare services.
In temperate regions, local transmission of vector-borne diseases can occur when infected travelers are bitten by native mosquitoes, starting new transmission chains. Global warming increases the risk of such events by creating tropical-like conditions and extending the seasonal overlap between travelers and active mosquito populations.
Increased exposure to new pathogens
Climate change is also driving disease emergence at higher altitudes and expanding the geographic range of vectors such as ticks and mosquitoes, increasing exposure of immunologically naive populations to new pathogens. Environmental shifts are causing animals to move in search of suitable climates and food, leading to more frequent interactions among wildlife, livestock, and humans, conditions that favor the emergence of new pathogens, particularly those capable of infecting multiple species, or their spillover into novel host species. Additionally, wildlife species that tend to live near humans and use human-provided food resources, like crops or waste, will begin to intermingle with new species whose home ranges shift under predicted climate change scenarios. These interactions are predicted to increase viral exchange among animals, forcing viral evolution and increasing opportunities for spillover of novel zoonotic agents into humans and livestock to occur in populous areas.
Recommandations
Community awareness and civil society involvement
Surveillance and prevention of climate change consequences and zoonosis detection require active and meaningful community engagement. We must work at the community level to build trust. To promote behavior changes and reduce the risk of disease spillover, trained public health stakeholders—such as community health workers involved in conservation—should engage effectively with local populations. Providing communities with reliable health services, food security, and economic alternatives helps reduce high-risk behaviors, such as bushmeat hunting, that drive zoonotic spillover and disease emergence.
Adapt science communication
Effective science communication, especially on complex, multidisciplinary topics, requires individuals who understand local language, culture, and jargon—champions who operate at the interface between science and society. Equally important are credible influencers on social media who can deliver accurate, impactful messages tailored to diverse audiences. Scientists must step beyond their traditional roles and actively engage with the public, policymakers, and professionals across sectors to broaden impact and foster informed action.
Cross-sector collaboration
Building climate resilience requires cross-sector collaboration, with faith-based organizations, the business community, and agricultural stakeholders. While educational efforts have begun to gain traction in universities and international policy circles, they must also be integrated into law and business schools to drive broader systemic change. A major challenge lies in reconciling the economic incentives behind agricultural expansion—one of the primary drivers of both disease emergence and climate change—with the need for sustainable, health-conscious development.
A holistic response
Initiatives like PREZODE are essential for building a robust, science-based understanding of the interconnected drivers of climate change and disease emergence. By promoting interdisciplinary collaboration and systems thinking, these initiatives provide the evidence needed for informed decision-making in both health and environmental sectors. Strengthening collaboration—particularly South-South and North-South partnerships— and expanding such efforts is crucial, not only for advancing research but also for enabling joint fundraising and coordinated One Health actions.