Referencing this report: CLIMADE Consortium. Summary for Policymakers: COP30 Climate Change and Epidemics 2025 CLIMADE Consortium report CLIMADE, Stellenbosch, South Africa
pp 1–23 wwwclimade health
We develop laboratory assays and tools to predict, track, and control diseases and epidemics in the most affected regions in the world.
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Prof Tulio de Oliveira
Climate Amplified Diseases and Epidemics (CLIMADE) is a global consortium led by scientists from the Global South, aimed at studying and responding to diseases exacerbated by climate change
CLIMADE's primary mission is to bridge knowledge gaps, enhance surveillance tools, and expand effective interventions to mitigate the impacts of climate amplified diseases and epidemics.
The consortium, spearheaded by Prof Tulio de Oliveira (CERI, South Africa), Prof Luiz Carlos Alcantara (FIOCRUZ, Brazil), and Prof Edward C Holmes (University of Sydney, Australia), focus on predicting, tracking, and controlling health threats in the world’s most affected regions
In collaboration with public health agencies, such as the Africa CDC, WHO AFRO and PAHO, the goal is to establish a robust disease surveillance system to swiftly identify and manage pathogens before outbreaks escalate into pandemics.
With a diverse team of academic, government and industry experts, CLIMADE is poised to strengthen global health responses through integrated knowledge and research in genomics and epidemiology
The CLIMADE consortium brings together partners from around the globe that have long-term experience with pathogen genomics and epidemics amplified by climate change Founding partners include public health agencies, academic organisations, and industry
For more information: https://climade.health
Executive Summary for POLICYMAKERS
Climate change is reshaping the world around us, placing immense strain on communities as they navigate the increasing frequency and intensity of extreme weather events and rising temperatures. Yet one of its most critical consequences often goes overlooked; its influence on infectious diseases Research shows that climate change may intensify more than half of all known human pathogens, a reality already unfolding. In recent years, new and reemerging threats – such as Oropouche virus, novel chikungunya variants, explosive dengue outbreaks, Influenza, cholera, and malaria –have underscored this growing risk
Key Mechanisms
Countries in the Global South bear the greatest health burden of these changes. Addressing the intersection of climate change and infectious diseases is therefore urgent. Climate action must go hand in hand with efforts to strengthen health systems, particularly in underserved and climatevulnerable regions Collaborative engagement among researchers, policymakers, and organisations –understanding and addressing the underlying climate drivers and key mechanisms that accelerate the emergence and spread of infectious diseases – is essential to anticipate and mitigate climate-amplified diseases and epidemics.
Gradual Temperature Rise: Climate impacts on the spread of infectious diseases, such as West Nile virus.
Evolving Pathogens: Viral adaptation driven by new vectors and expanding environments.
Extreme Weather Events: Drought as a catalyst for the 2023–2024 Amazon event and Oropouche virus expansion.
Climate Migration: Climate-induced migration in Africa and its implications on infectious diseases.
Summary of KEY MESSAGES & ACTION POINTS
Key Mechanisms for DISEASE AGGRAVATION
“ As climate change accelerates the spread and severity of infectious diseases, building resilient capacities in surveillance, research, and health systems is no longer optional – it is the cornerstone of protecting vulnerable populations and ensuring global health security.”
- Dr Alex Durand Nka, Chantal BIYA International Reference Centre (CIRCB), African STARS Fellow
How does Climate Change impact Emerging Diseases?
The ongoing effects of climate change are profoundly altering ecosystems and influencing patterns of human health across the globe. An increase in temperatures, altered precipitation patterns, and shifting habitats create ideal conditions for the proliferation of infectious diseases
As environmental changes enable pathogens and vectors to expand their geographic
ranges, we are witnessing a rise in diseases that were once limited to specific areas.
Evidence links climate change to increased disease outbreaks, making it a matter of when, not if, the next epidemic will occur.
Let’s take a closer look at case studies within the four key mechanisms for disease aggravation; Gradual Temperature Rise, Evolving Pathogens, Extreme Weather Events, and Climate Migration.
“Climate change fuels epidemics without borders. Urgent action is a matter of global security”
- Abdualmoniem Musa, Department of Medical Microbiology, Faculty of Medical Laboratory Sciences, University of Kassala, Sudan
GRADUAL TEMPERATURE RISE: How Climate Shapes Infectious Disease Spread
Background
Gradual climate change is steadily altering the transmission dynamics of infectious diseases on a global scale. While the most notable effects of a changing climate are the dramatic drying of rivers, melting ice caps and extreme weather events, climate change also drives subtle but significant shifts in ecosystems. Gradual shifts in temperature, rainfall, and humidity patterns are causing important changes in the risk of infectious disease transmission This is particularly evident for vector-borne diseases such as arboviruses (viruses transmitted to humans by mosquitoes and ticks), whereby gradual climatic changes are stimulating outbreaks in new areas and with increased intensity.
How Climate Shapes Disease Spread
Several mechanisms by which climate influences infectious diseases have been documented (Figure 1). Rising temperatures accelerate the development of mosquitoes from larvae to adults, resulting in larger mosquito populations capable of transmitting disease. Higher ambient temperatures also shorten the extrinsic incubation period of viruses (the time it takes for a virus to multiply and cause disease within the mosquito host), allowing for faster replication within mosquitoes, which leads to earlier and more intense transmission seasons.
Figure 1: Mechanisms through which changes in climate may impact virus transmission
Greater rainfall increases the availability of standing water, which mosquitoes use for breeding, leading to surges in mosquito populations For example, higher rainfall and flood-irrigation farming practices significantly increased the populations of primary and secondary vectors of Rift Valley fever virus in Kenya.
High relative humidity increases the longevity of adult mosquitoes, allowing for more opportunities for viral transmission. Such climatic effects can lengthen transmission seasons but also shift geographic ranges suitable for mosquito survival Higher latitude and altitude areas that were previously too cold or dry for certain vector species are now suitable for their survival. For example, Aedes aegypti and Aedes albopictus mosquitoes, vectors of dengue virus, have recently been found in Chandannath, Nepal, at an elevation of 2438 metres This is the first time these vectors have been detected at such a high altitude.
The Changing Geography of Infection: A case study of West Nile virus
Many regions of the world, that were previously unaffected, are now suffering seasonal resurgences of arboviral infections due to favourable climatic conditions. For example, Europe is experiencing a widespread and intense transmission season of West Nile virus (WNV), reporting cases from 13 countries between January and October 2025. Italy alone has reported 718 human cases and 49 related fatalities for 2025 Italy experienced unseasonably warm summer temperatures and sustained humidity. Such conditions likely favoured Culex mosquito proliferation, causing increased transmission of the virus.
These growing concerns were central to this year’s 128th World Mosquito Day, on 20 August 2025, a day when scientists and policymakers reflected on the accelerating spread of mosquito-borne diseases. This year, the European Centre for Disease Prevention and Control (ECDC) used it to highlight transmission of mosquito-borne diseases across Europe.
The ECDC issued a statement noting that Europe's changing climate is stimulating the growth of mosquito populations and the diseases they transmit. The continent is experiencing longer and more intense transmission seasons for mosquito-borne diseases
ECDC described this as part of a “new normal” in which vector-borne disease seasons are intensifying under changing climatic conditions. Pamela Rendi-Wagner, ECDC Director, is calling for strengthened surveillance: “The ECDC is working closely with all Member States to provide tailored support and timely public health guidance to strengthen Europe’s response.”
20th century but WNV is now regarded as an established seasonal pathogen causing increasingly frequent and widespread outbreaks due to changing climate conditions.
The virus did not occur in the Americas until 1999, when it was introduced in New York. Within just a few years, the virus spread across both North and South America, causing tens of thousands of human infections, of which more than 27,000 led to neuroinvasive disease, and establishing itself as the most widely distributed arbovirus in the world
Figure 2: Bivariate map showing WNV circulation (total number of viral occurrences) in purple shades, and the total number of molecular sampling locations in orange shades Grey regions have no molecular data or documented WNV detections Source: Moir et al The Lancet Microbe 2025; 6 (10): 101176
Our analysis shows multiple WNV lineages co-circulate in Africa, some of which are ancestral to strains that caused major outbreaks in Europe and the Americas (Figure 3), highlighting the continent’s role as a key reservoir of genetic diversity However, since surveillance is limited, early emergence of lineages may go undetected.
We also identified major disparities in diagnostic capacity, data sharing, and genomic sequencing infrastructure Many African countries lack the laboratory and bioinformatics resources needed for sustained WNV surveillance. The tools to monitor and respond to this virus exist, but equitable access and sustained investment are urgently needed As the climate warms and vector-borne diseases move into new territories, Africa’s capacity to study and share its own data will be crucial to protecting global health
What Must Change
Governments and regional health agencies must adopt proactive, climate-informed strategies.
Surveillance systems designed for past climatic conditions may no longer be adequate for current transmission dynamics. Similarly, vector control programs must adapt to shifting climates
It is crucial to develop and implement an integrated “One Health” surveillance system, which combines human, animal, and environmental data. Monitoring mosquito populations alongside wildlife and livestock infections can provide early warning of viral circulation.
Expanding genomic sequencing capacity across Africa is equally important It is crucial to identify and track viral lineages in near real time for effective disease control Genomic surveillance should be undertaken with regional cooperation and should be coordinated and supported by the Africa Centres for Disease Control and Prevention and the WHO African region Importantly, these actions require national ownership and political will for lasting resilience.
Figure 3: Spatiotemporal dissemination of WNV Lineage 1A across and within Africa, Europe, Asia, and the Americas Inferred dispersal pathways are coloured by the mean date of viral transitions for each route The direction of movement is shown from the origin (black dot) to the destination Source: Moir et al The Lancet Microbe 2025; 6 (10): 101176
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EVOLVING PATHOGENS: Insights from the 2025 Chikungunya Global Outbreak
A Climate-Sensitive Health Crisis
The recurrent chikungunya epidemics are a definitive example of a climateamplified health crisis. Gradual shifts in rising temperature, precipitation, coupled with the increase in frequency of climate events, act as selective pressures that drive the emergence and re-emergence of infectious diseases. These environmental changes are creating ideal conditions for pathogens like the chikungunya virus to evolve and spread
Chikungunya is an acute febrile illness caused by the chikungunya virus (CHIKV), a mosquito-borne alphavirus, transmitted by the Aedes mosquito species
Clinically, the disease is characterised by fever, rash and prolonged joint pain. The virus is genetically divided into three distinct genotypes, East-Central-South-African (ECSA), West African and Asian
In 2025, chikungunya reemerged onto the global health radar with devastating force, with over 400,000 suspected and confirmed cases and 155 reported deaths across 40 countries (Figure 4) The resurgence, driven by the ECSA genotype, is intrinsically linked to climate change, which has expanded the geographical range and lengthened the seasonal activity of Aedes mosquitoes, the virus’s primary vector The surge demonstrates the capacity and adaptation of the virus to the changing climatic realities, rewriting the geography of arboviral transmission.
Figure 4: Countries with Documented Chikungunya Virus Transmission from January to September 2025 (WHO). Source: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON581.
Global Situation: Widespread Heterogenous Transmission
From explosive epidemics in America to reemergence in the Indian Ocean and autochthonous outbreaks in Europe and China. CHIKV is no longer a tropical concern but a global climate-driven threat.
Africa
CHIKV re-emerged in Réunion Island in August 2024, with over 54,517 confirmed cases and 40 reported deaths. The outbreak rapidly spread to neighbouring islands, including Mayotte, Mauritius, and Comoros. In total, 2197 suspected cases were reported across the four other African countries, including Kenya, Comoros, Senegal, and Mauritius.
Mauritius confirmed its first case in March 2025, nearly two decades after the notable Indian Ocean outbreak of 2005-2006. Within weeks, cases climbed, peaking at the end of May (Figure 5), with cumulative cases later surpassing 1,500 by August 2025. After a very dry summer, the outbreak in Mauritius coincided with the start of the rainy season in March 2025, creating ideal conditions for transmission This timing matched the first local cases detected in mid-March The Mauritian outbreak was mainly driven by rainfall patterns, creating an epidemic directly correlated with the increase in rainfall and vector abundance
This Indian Ocean crisis served as a precursor to intercontinental spread, with Europe and Asia later reporting thousands of autochthonous cases
Figure 5: Epidemic progression in Mauritius and Réunion (a) Time-varying progression of total precipitation in Réunion Island (green), overlaid onto epidemic Re curve (red) and weekly recorded cases (orange) (b) In Mauritius, the onset of the rainy season (blue), mosquito larvae density (Breteau Index, light blue), effective reproduction number, Re (purple), and daily cases (grey).
Asia
The 2024–2025 outbreak revealed the heterogeneous nature of CHIKV transmission across Asia Large-scale epidemics in India, Pakistan, and Bangladesh were driven by heavy monsoon rains and dense urban mosquito–human contact, while Sri Lanka and Thailand saw smaller, localised clusters. China illustrated the virus’s explosive potential: after decades of sporadic imported cases, the country reported 16,452 locally transmitted cases in 2025 – the largest outbreak on record. Neighbouring countries such as the Philippines, Malaysia, and Singapore also experienced outbreaks The rapid spread of CHIKV in 2024-2025 highlights the need for country-specific surveillance, rapid detection, and adaptive vector control.
Europe
Since the first European outbreak in Italy in 2007, CHIKV has become a recurring summer concern across 22 countries
Warmer temperatures, expanding urban Aedes populations, and increased international travel now enable sporadic outbreaks even in temperate regions In July 2025, France reported 1,911 imported cases mostly linked to travel from Réunion Island and, for the first time, local transmission was detected across five French regions, driven by established Ae albopictus populations By September 2025, Italy had reported 41 imported cases and 323 locally acquired infections, marking its highest number of CHIKV cases since 2017
The Americas
The Americas faced the highest global burden, with 431,417 cases and 245 deaths between 2023 and 2024 Severe epidemics hit Brazil, Argentina, Paraguay, and Colombia, with spread extending northward into Central America and the United States by 2025.
“Before 2020, Mauritius had no in-country sequencing capacity. With CLIMADE’s support we built genomic surveillance for SARS-CoV-2, dengue, and chikungunya – turning outbreaks into actionable evidence for faster, targeted public-health responses. At COP30, our request is clear – sustain and scale these networks so frontline laboratories stay connected to decisionmakers, and communities most exposed are first protected.”
Climate change has increased the risk of local outbreaks in previously unaffected regions by creating conditions suitable for these vectors to thrive The spread of Ae. albopictus into temperate zones, with established populations now in southern and central Europe, not only introduces vectorborne diseases to new populations but also actively drives viral evolution
A major turning point occurred during the 2005–2006 Réunion Island outbreak, with the emergence of the E1-A226V mutation on the envelope 1 glycoprotein
This adaptive mutation enhanced infectivity in Ae. albopictus, a mosquito species with a much broader global distribution than the virus’s primary vector, Ae aegypti (Figure 6) Since 2004, this adaptation has been a pivotal factor in the virus's spread, establishing local transmission in new temperate, non-endemic regions such as Italy and France
The E1-A226V and E2-L210Q mutations are prime examples of adaptive evolution The emergence of these adaptive mutations indicates that the virus is not a fixed threat but an evolving challenge, capable of developing new ways to spread. This highlights the need for ongoing surveillance, climate-informed risk assessments and adaptive vector control strategies
What Must Change
To counter this evolving threat, we must build a dynamic and equitable global response. This begins by integrating climate, vector, and genomic surveillance into early warning systems that can predict outbreaks before they occur We must simultaneously strengthen on-the-ground defences by investing in diagnostic lab capacity, training personnel, and implementing standardised vector control. Furthermore, the accelerated and equitable distribution of vaccines such as IXCHIQ and VIMKUNYA is a moral and strategic imperative for high-risk regions. Ultimately, the success of these measures hinges on enhanced regional coordination, where shared data and pre-positioned rapid response teams can effectively contain cross-border outbreaks
Figure 6: Global map showing the probability of occurrence and predicted distribution of Ae aegypti and Ae albopictus
Source: Adapted from Kraemer et al (2015), eLife, 4 https://doi org/10 7554/eL ife.08347.
EXTREME WEATHER EVENTS:
Drought as a Catalyst for Oroupuche Expansion
The 2023–2024 Amazon Event and Oropouche Virus Expansion
The 2023–2024 Amazon Basin drought was one of the most severe hydro-climatic anomalies on record (Figure 7). Beyond record-low rivers and heat extremes, such events reshape ecological and social systems in ways that can reignite viral transmission. For Oropouche virus (OROV) –primarily spread by the biting midge Culicoides paraensis – drought does not halt transmission by drying habitats
Instead, it concentrates moisture into small, nutrient-rich pockets (shoreline puddles, refuse, stored water, agro-residues) while raising temperatures within optimal biological ranges
These conditions accelerate vector development, increase biting activity, and bring breeding sites closer to people
Drought also indirectly heightens risk by disrupting transport, supply chains, and livelihoods – delaying vector control and case investigations, crowding people into settlement edges, and reducing surveillance responsiveness Collectively, these factors form a coherent, testable pathway linking climate extremes to OROV resurgence and range expansion. Together, these mechanisms outline a potential ecological pathway through which drought conditions may have amplified OROV transmission and geographic spread.
Figure 7: Interannual monthly precipitation anomalies for the period 2005–2024 averaged over the Amazon Basin Monthly time series are provided for each year (grey lines), and for some selected years characterised by low precipitation anomalies (2015, yellow line; 2020, green line; 2023 red line and 2024, blue line).
Environmental Suitability Modelling
To explore this pathway, ecological niche models (ENMs) were built for OROV using presence data and systematically sampled pseudo-absences. The resulting virussuitability surface identified areas historically favourable for OROV and served as a baseline for assessing change (Figure 8a)
By integrating 2023–2024 drought-year climate data into a time-varying environmental suitability index, researchers pinpointed temporary “risk windows” –locations and periods where suitability rose above seasonal baselines. These transient windows mark critical periods for intensified vector surveillance, clinical vigilance, and community risk communication (Figure 8b)
Vector–Virus Co-Suitability
Because transmission depends on both vector presence and virus viability, a parallel ENM was developed for C. paraensis (Figure 9b). Key predictors (Figure 9a) included agricultural intensity, soil moisture, and relative humidity, consistent with a peridomestic vector exploiting organic-rich habitats. Shapley-value analysis underscored the role of agricultural landscapes and moisture availability in defining the vector’s niche
Combining both models revealed zones of virus–vector co-suitability (Figure 9c) –regions where environmental shocks are most likely to trigger transmission.
Figure 8: Consensus map and temporal environmental suitability trends. (a) The consensus map of environmental suitability for Oropouche virus transmission across Brazil, highlighting areas with persistent high suitability (red) and regions with lower suitability (blue) (b) Monthly projection of environmental suitability index across Brazil (maps) with temporal trends in case counts (stacked bars) and suitability index (lines) for the year 2024, with separate trends for Amazonian and non-Amazonian states. Shaded regions represent the variability in suitability estimates, with darker lines indicating mean suitability Source: Poongavanan, J , et al https://doi org/10 1101/2025 02 28 25323068
Figure 9: Environmental drivers and spatial suitability of C. paraensis and bivariate suitability map of Oropouche virus (OROV) and its primary vector: (a) Variable importance plot showing the mean SHAP values for environmental predictors contributing to C paraensis suitability (b) Predicted spatial distribution of C paraensis suitability across the Americas (c) Bivariate suitability map of OROV and C paraensis The color gradient represents the combined suitability of OROV and each vector, with light gray indicating low suitability for both, pink/purple hues representing higher suitability for the vector, blue tones indicating higher suitability for the virus, and dark purple signifying high suitability for both Inset highlights Central America and the Caribbean Source: Poongavanan, J , et al https://doi org/10 1101/2025 02 28 25323068
Interpretation and Implications
The 2023 Amazon drought likely amplified Oropouche virus risk by shifting residual moisture into small, human-adjacent habitats, accelerating vector development, and exposing system fragility when river transport failed While drought alone may not have caused the surge, it clearly tilted an already vulnerable system toward outbreak conditions.
This integrated analysis; linking climate anomalies, temporal suitability, and cosuitability mapping, illustrates how extreme weather acts as a stress test for arboviral transmission systems.
The practical takeaway is clear:
Integrate climate monitoring with disease surveillance.
Plan for access and supply disruptions during climate extremes Prioritise regions and timeframes where virus–vector co-suitability spikes.
Future droughts, heatwaves, or floods need not escalate into arboviral crises –if climate and health systems respond in tandem.
“Preparedness against climate-amplified epidemics must be a global policy priority.”
- Isaac Emmanuel Omara, Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
CLIMATE MIGRATION: Pathways, Impacts, and Health Implications
Climate Change in Africa
Africa is the most climate-vulnerable region in the world, with temperatures rising faster than the global average By mid-century, the continent could warm by up to 3°C or more, posing serious threats to livelihoods, ecosystems, and economic stability. Despite contributing less than 4% of global greenhouse gas emissions, Africa bears a disproportionate share of climate impacts, underscoring the profound climate injustice experienced by its populations.
This vulnerability is shaped by multiple and interlinked factors including geographic exposure to extreme weather, dependence on climate-sensitive sectors like agriculture and fisheries, limited adaptive capacity, and rapid population growth and urbanisation Rising temperatures, prolonged droughts, floods, irregular rainfall, and outbreaks of crop and livestock diseases are among the major forms of climate-related disasters in Africa Semi-arid areas such as the Sahel are warming fastest, driving desertification and soil degradation, while coastal nations like Nigeria, Senegal, and Mozambique face sealevel rise and storm surges. Increasing rainfall variability has made both droughts and floods more frequent, damaging agriculture, livestock, and fisheries that sustain most Africans. Since over 60% of Africans rely on rainfed farming and more than half the subSaharan workforce depends on agriculture, even small climate shocks can cause severe food and livelihood crises
Climate change acts as a “threat multiplier,” exacerbating existing vulnerabilities and intensifying the underlying conditions that already contribute to migration. The nature of migration varies widely, it may be temporary or permanent, internal or cross-border, depending on local circumstances and the availability of adaptation options. However, internal mobility far exceeds cross-border movement, reflecting the predominance of displacement within national boundaries in response to climate-related challenges
Internal migration is a major concern in Africa, with up to 113 million people projected to be displaced by climate impacts by 2050. Yet, the scale and intensity of these migrations will vary greatly between countries and regions, with some being far more affected than others. Such a large-scale movement exerts extreme pressure on their already inadequate resources and threatens the homes and livelihoods of thousands of vulnerable migrants who depend on agriculture and animal husbandry. Since much of this migration is caused by sudden-onset climate events, women, children, and the elderly are exposed to an increased risk of poverty, hunger, and health problems during displacement
Our findings in this report show that by the middle of the century, significant internal displacement within African countries due to climate change stressors will occur Western and Eastern Africa will likely set the pace among the hotspots for climate migrants (Figure 10). Indeed, up to 10.5% of the population in IGAD member states in East Africa may internally migrate due to increasing climate pressures Many of these movements will be seasonal or temporary: people move to cities or less climatically vulnerable regions in search of work, safety, or food security. There is a high possibility of increased pressure caused by migration in border regions, where populations are already on the move, with a high risk of outbreaks of disease and social tension.
When adaptation at home becomes unviable, migration often extends beyond borders By 2050, climate change may drive about 1.2 million cross-border displacements in Africa, around 10% of total migration. The Horn of Africa, Sahel, and parts of Southern Africa are most affected, as fragile ecosystems, poverty, and instability converge Pastoralists and smallholder farmers frequently cross into neighbouring countries seeking land, water, or work, straining host communities and resources Our analysis suggests that by midcentury, Southern Africa will experience the highest levels of cross-border climate migration (Figure 11). Countries such as South Africa, Zimbabwe, Mozambique, and Botswana are projected to receive the largest inflows of migrants, while Namibia, Zambia, and Malawi may face significant outflows. While such movement poses social and governance challenges, it can also support adaptation and resilience if guided by stronger regional cooperation and migration governance .
Implications for Infectious Disease
Climate-driven migration, both internal and cross-border, significantly influences the distribution and incidence of infectious diseases across Africa by reshaping patterns of exposure, vulnerability, and transmission. As climate shocks such as droughts, floods, and heatwaves force people to move, migrants are often exposed to regions where diseases like malaria, dengue, and chikungunya are already endemic, heightening their risk of infection
Simultaneously, population movements can introduce new pathogens into vulnerable host communities, expanding the geographic range of infectious diseases.
Overcrowded and poorly serviced temporary settlements, displacement camps, and informal urban neighborhoods further intensify outbreak risks by creating ideal conditions for waterborne and vector-borne disease transmission. Limited access to clean water, inadequate sanitation, and close human contact amplify the spread of pathogens These pressures are compounded by climate-induced changes in temperature, precipitation, and humidity, which expand vector habitats and prolong breeding seasons, allowing mosquito-borne illnesses to persist and spread into new areas.
In addition, climate-related migration places a heavy burden on already fragile health systems, stretching limited resources and impeding the delivery of essential services Local health facilities often struggle to meet the increased demand for diagnosis, treatment, vaccination, and disease surveillance, reducing their capacity to prevent or respond effectively to outbreaks By linking environmental change with largescale human mobility, climate-driven migration thus acts as a powerful amplifier of infectious disease risks, broadening their reach, increasing their frequency, and deepening their impact on already vulnerable populations.
What Must Change
Climate-driven migration in Africa represents a growing and complex challenge, where environmental stress, recurrent displacement, and fragile health systems intersect to exacerbate the spread of infectious diseases and amplify vulnerabilities.
Both internal and cross-border movements place pressure on communities, increase exposure to endemic diseases such as malaria, dengue, and chikungunya, and strain health services already operating under limited resources.
Addressing this multifaceted challenge requires integrated strategies that connect climate adaptation, public health resilience, and migration governance. Effective public health planning requires a nuanced understanding of how climate stressors drive population movements By anticipating migration patterns, authorities can design interventions to reduce the spread of infectious diseases. Predicting these movements remains challenging due to the interplay of environmental, social, economic, and political influences on migration decisions
Equally important is enhancing regional and cross-sectoral cooperation, enabling countries to share information, coordinate responses, and manage migration flows effectively By tackling the intertwined challenges of climate migration and infectious disease, African countries, supported by regional bodies and the international community, can safeguard public health, promote sustainable development, and reinforce social and economic resilience in the face of a rapidly changing climate.
CALL TO ACTION: Join
Us in Combating ClimateAmplified Diseases and Epidemics
Climate change and infectious diseases have emerged as intertwined challenges that demand our immediate attention. The impacts of climate change on health and disease are undeniable, and governments, academic institutions, private sector industries, and health organisations must unite to combat this threat. It is imperative that we address this intersection of climate change and infectious diseases, prioritising the most vulnerable populations and fostering health equity.
While countries in the Global South contribute less than 10% of greenhouse gas emissions, they are likely to suffer the largest health impacts from climate change because of proximity to hotspots of disease emergence (biodiversity),
an already high burden of infectious diseases in these countries, geographical association with the tropics where temperatures are high year-round, and critically, because of its large vulnerable populations, which typically have inadequate access to functional health systems.
Not only are developing countries more at risk of climate disasters and harm, but they also have less adaptive capacity and preparedness to respond to these threats, making developing countries highly vulnerable (low preparedness vs climate risk). The response to climate change should be used as an opportunity to build capacity to protect and support health, especially in underserved and underrepresented communities.
THE TIME TO ACT IS NOW!
The intersection of climate change and infectious diseases poses a formidable challenge to global health, and we cannot afford to delay our response. By taking the actions above, we can work collectively to mitigate the impending public health crisis and build a more resilient, equitable world for all.
“Climate risk isn’t tomorrow’s story – it’s today’s patient list and disasters. Fund the science, finance the response, and count the lives saved.”
- Sikhulile Moyo, Botswana Harvard
Strengthening Surveillance
Governments, academic institutions, and health organisations must adopt a One Health approach by investing in and expanding genomic surveillance systems that connect human, animal, and environmental health data. Expanding genomic sequencing capacity is essential for real-time tracking of viral lineages, enabling earlier detection of emerging pathogens, stronger cross-sector coordination, and proactive interventions to prevent outbreaks before they evolve into global crises
“
The monitoring of pathogenic agents through the study of their behaviour in the face of climate change will make it possible to anticipate actions to prevent epidemics.
- Nkuurunziza Jerome, World Health Organisation, Burundi
Reporting Outbreaks Timeously
“Early detection of an outbreak can help to guide the response and reduce the spread of diseases.
- James Ayei Maror, National Public Health Laboratory, South Sudan
Policy responses must centre on the populations most exposed to the intersection of climate change, migration, and disease Vulnerable communities are disproportionately affected and often least equipped to cope. Governments and private sector actors must prioritise these populations by investing in resilient healthcare systems, infrastructure, and disaster preparedness, while ensuring safe, equitable access to vaccines and preventive care for those at greatest risk.
Immediate and transparent reporting of infectious disease outbreaks is paramount. Governments and health organisations should commit to reporting outbreaks promptly and openly, sharing crucial data with relevant stakeholders This transparency is essential for coordinated early warning systems and global response efforts.
Prioritising Vulnerable Populations “
Promoting Climate Resilience
Academic institutions and private sector industries should collaborate to develop innovative solutions that enhance climate resilience within healthcare systems This includes designing infrastructure to withstand extreme weather events and ensuring the availability of essential medical supplies during crises.
Committing to Sustainable Funding
Governments, private sector industries, and health organisations must commit to sustainable, wellcoordinated funding for climate–health resilience, aligned across ministries and regional priorities to strengthen the fight against climate change–related infectious diseases. This funding should support research, capacity building, and community engagement to build a robust defence against these converging threats.
Our CONTRIBUTORS
The Core Writing Team: CLIMADE Consortium
Contributors:
Monika Moir (CERI, South Africa), Jenicca Poongavanan (CERI, South Africa), Desalew Moges (CERI, South Africa), Haingo Andry (CERI, South Africa), Yajna Ramphal (CERI, South Africa), Marta Giovanetti (FioCruz, Brazil), Luiz Carlos Junior Alcantara (FioCruz, Brazil), Houriiyah Tegally (CERI, South Africa), Maambele Khosa (CERI, South Africa), José Lourenço (Universidade Católica Portuguesa, Portugal), Edward Holmes (University of Sydney, Australia), Samuel Oyola (International Livestock Research Institute (ILRI), Kenya), Moritz Kraemer (Oxford University, U K ), Richard Lessells (KRISP, Durban, South Africa)
The designations employed and the presentation of material on maps do not imply the expression of any opinion whatsoever on the part of the institutions of the authors or funders, the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries The mention of specific companies or products does not imply that they are endorsed or recommended by CLIMADE in preference to others of a similar nature, which are not mentioned or advertised Short extracts from this publication may be reproduced without authorisation provided that the complete source is clearly indicated
Editorial correspondence and requests to publish, reproduce or translate articles in part or in whole should be addressed to: CLIMADE Secretariat, Centre for Epidemic Response and Innovation (CERI), Level 3, Biomedical Research Institute (BMRI) Building, Tygerberg Medical School Campus, Stellenbosch University. Address: Francie Van Zijl Dr, Tygerberg, Cape Town, 7505. Tel.: +27 82962 4219. E-mail: ceri@sun.ac.za. Website: https://climade.health.
Edited
By:
Tulio de Oliveria Director
Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
Cheryl Baxter Head Scientific Support Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
Compiled & Edited By:
Yajna Ramphal Research Project Manager Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
Katrine Anker-Nilssen Media Editor
Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
Creative Support, Media & Communications: Maambele Khosa Head of Communications Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, South Africa
Acknowledgements
CLIMADE is a global programme that is led by Global South with European, American and Oceania partners. The CLIMADE consortium expresses its gratitude to the following funders for their support: The Rockefeller Foundation, South African Medical Research Council (SAMRC), European Commission (EC), Abbott Pandemic Defense Coalition (APDC), UK’s Medical Research Foundation, Novo Nordisk Foundation and the World Bank.
The report is published as open access: https://climade.health/climade-cop30report/ and is available in printed format, as well as electronically and as a downloadable PDF The contents of this report and the opinions expressed herein are solely the responsibility of the authors and do not necessarily represent the official views or policies of any of the funders.
CLIMADE Secretariat, Centre for Epidemic Response and Innovation (CERI), Level 3, Biomedical Research Institute (BMRI) Building, Tygerberg Medical School Campus, Stellenbosch University, Francie Van Zijl Dr, Tygerberg, Cape Town, 7505
ceri@sun.ac.za
https://climade health/ https://x.com/climade health
