In-depth: How climate change affects health in Africa

§ Climate and health: an overview

On the first day of the conference, attendees heard presentations laying out a range of ways that climate change impacts health. 

In one of the opening plenaries, Dr Rick Spinrad, the US National Oceanic and Atmospheric Administration (NOAA) administrator, told the conference that when it comes to climate change, “the wolf is in the house, and the consequences are hitting us” – in terms of economic, social and health impacts.

He cited data from the World Meteorological Organization (WMO) that identified 1,839 disasters attributable to weather, climate or water hazards that impacted Africa over 1970-2021. 

Those disasters cumulatively led to 733,585 deaths and caused $43bn in economic losses. 

WMO secretary-general Prof Petteri Taalas addressed the conference via a pre-recorded video, highlighting the Early Warnings for All initiative, which aims to increase the proliferation of early-warning systems in 30 countries that are currently under-covered by such systems. The goal is to reach 100 countries by the end of 2027, Taalas added. 

Dr Chris Lennard, a climatologist from the University of Cape Town, pointed out that risk is a function of multiple factors: vulnerability, exposure, hazard and response. He noted:

“Africa has the most vulnerable communities in the world for climate change.”

Infectious disease

Dr Susan Rumisha, a biostatistician and a senior research officer with the Malaria Atlas Project, explained that many climatic variables, including temperature, rainfall and humidity, influence the transmission and distribution of vector-borne diseases such as malaria. 

The relative importance of these factors differs from place to place, attendees heard. For example, in a study looking at the seasonality and geography of malaria in Ethiopia, Dr Asher Siebert from Columbia University’s International Research Institute and his colleagues found that malaria risk was limited by rainfall and humidity in the lowlands, but limited by temperature in the highlands. 

Climate-informed health forecasting can go beyond prediction, Rumisha pointed out, and help set priorities for action areas and develop proactive strategies for dealing with outbreaks.

Dr Madina Doumbia from University Peleforo Gon Coulibaly in Côte d’Ivoire noted that although there is research establishing links between climate and malaria, there are limited studies in Côte d’Ivoire assessing those relationships. She presented work showing that the number of rainfall events in a year is more strongly correlated with malaria incidence than the amount of rainfall. 

Doumbia also showed model results that predict increases in malaria incidence in Côte d’Ivoire in 2030, 2050 and 2080. 

Since systematic surveillance of disease vectors is inadequate, some researchers are supplementing this information with models. Dr Ernest Asare, from Yale School of Public Health, showed results of the potential of the VECTRI model to predict malaria epidemics.

He found that the model accurately predicted the onset and peak timing and duration of malaria in places where malaria follows a seasonal regime – although the model did not accurately gauge the level of malaria prevalence. However, when the model was recalibrated using a high-resolution surface hydrology map, it simulated mosquito abundance much more accurately. 

The climate-related risks of infectious disease go beyond just vector-borne illness. 

Diarrheal disease is a leading cause of child death in sub-Saharan Africa, noted Dr Sheyla Rodrigues Cassy from Eduardo Mondlane University in Mozambique. Cassy looked at correlates of diarrheal disease in children under five years old. 

Among the relationships her work identified, incidences of diarrheal disease increased along with temperature and rainfall. She warned that climate change threatens to slow the advances that countries have made in reducing child mortality.

Dr Sokhna Thiam, from the African Population and Health Research Center in Nairobi, Kenya, added that water-borne enteric diseases are among the “primary expected health impacts” of climate change.

Heat-related illnesses

Heat-related illness is a “low-hanging fruit” in early-warning systems, said Dr Wassila Thiaw, a meteorologist at NOAA’s Climate Prediction Center. Thiaw, who organised the conference, told Carbon Brief: 

“It’s about temperature, it’s about humidity and how it affects health, and we can predict that. And we can provide the forecast to governments and organisations and make them accessible to people.”

Prof Kris Ebi from the University of Washington started off the third day of the conference with a presentation on heatwaves and early action plans. She pointed to the 2021 Pacific north-west “heat dome” event, which resulted in around 800 excess deaths and was later found to be a 1-in-10,000 year event.

The rarity of that event means, in effect, “these people died because of climate change,” Ebi said. She added:

“Every heat-related death is preventable.”

Dr Kiswendsida Guigma, a climate scientist with the Red Cross Red Crescent Climate Centre, noted that although west Africa and the Sahel are among the hottest places in the world, there is very little interest in extreme heat there – in terms of research being done, risk management and even public perception. 

Heatwaves are “not considered as a disaster in many places in Africa”, Guigma said – especially when compared to drought. 

Dr Bethwel Mutai from the University of Nairobi, who also serves as a consultant meteorologist for Somalia, also discussed heatwaves. 

Mutai noted that different localities may have very different sensitivities to temperature extremes due to differences in local climate, human behaviour and access to air conditioning. He added that local adaptive measures are “very intelligent” and add complexity that is not currently modelled in risk assessments.

Dr Lisa van Aardenne, the chief scientist of the University of Cape Town’s climate system analysis group, discussed the use and utility of thermal stress indices. She pointed out that, by the definitions of the universal thermal climate index, much of Africa is under heat stress most days of the year. 

Van Aardenne noted that these indices have been developed from a European perspective and do not align with the reality on the ground in Africa. She added:

“I’m very concerned that these indices are not fit for purpose here.”

Several researchers from the Climate, Heat and Maternal and Neonatal Health in Africa (CHAMNHA) consortium presented work looking at the effects of heat stress on pregnant women. 

Heat exposure during pregnancy is related to increased mortality in newborn children, explained Dr Adelaide Lusambili from Africa International University in Nairobi. She has studied the effects of behavioural change on maternal health outcomes in Kilifi, Kenya, working closely with the community there to determine what sort of interventions would be useful for them. 

Dr Sari Kovats from the London School of Hygiene and Tropical Medicine presented a meta-analysis of 170 studies looking at risk factors of heat for pregnant women. They found strong effects of heatwaves on pre-term birth, but with some studies indicating effects in opposite directions. However, she pointed out, the rarity of these outcomes mean there is limited statistical power when analysing such data.

During heatwaves, “systemic vulnerabilities are magnified” and the fragility of safety nets is laid bare, said Prof Mary Hayden from the University of Colorado, Colorado Springs. She added:

“If we don’t work with those who are most vulnerable, we place the rest of us at risk as well.”

Other health impacts

Although infectious disease and heat-related illness were the two main focuses of the conference, several speakers discussed other aspects of health. 

Covenant University’s Dr Isaac Akinwumi shared the myriad impacts on wellbeing of coastal erosion and flooding in Lagos, Nigeria, projected to be the world’s most populous city by 2100. 

Drinking-water contamination and injuries are two major issues during flooding events. Following floods in Lagos in 2017, 50% of the hospitalisations were due to water-borne diseases, such as cholera and typhoid, he pointed out. 

Flooding can also lead to building collapse as the groundwater table rises and put strain on healthcare systems by rendering hospitals unusable or inaccessible. In addition, extreme weather events can lead to anxiety, depression and post-traumatic stress disorder through both the events themselves and the subsequent loss of livelihood that people face. 

Addressing these issues will take more than just putting coastal defences into place, Akinwumi said – it will also require tackling issues of housing, waste-management and water security. 

A few presentations also highlighted advances in nutrition and climate research. 

Aishwarya Venkat, a PhD student at Tufts University, presented work looking at seasonal patterns of acute malnutrition in children under five years of age in the Northern African highlands. 

She found stunting – low height for a child’s age group, an indicator of chronic malnutrition – in 22% of the children. The work also found wasting – low weight for a child’s height, an indicator of acute malnutrition which increases short-term mortality – in 7% of children. 

However, she cautioned, surveys of malnutrition are not designed for studying effects on sub-seasonal timescales – often relying on just a few data points throughout the year.

§ Towards early-warning systems

A major focus of the conference was thinking about how to create early-warning systems to better address climate-related health risks in Africa. 

In the opening session, Sarah Charles, from the US Agency for International Development’s (USAID) Bureau of Humanitarian Assistance, spoke about FEWS NET – the Famine Early Warning Systems Network. 

FEWS NET, which began in 1985 as a collaboration between USAID and the US state department, forecasts food insecurity in 30 countries, allowing humanitarian aid and other responses to mobilise several months in advance. FEWS NET incorporates a range of data, including climate, agriculture, livelihoods, nutrition, conflict, floods and other hazards, markets and infectious disease. 

The weakest link in the early-warning system is often the “last mile”, Charles said – making sure that the necessary information reaches the people who need it, particularly the most vulnerable populations. 

Lusumbali, from the CHAMNHA consortium, said that many people she works with do not seek out weather information because it is only available in English. Her team tries to use trusted institutions, such as houses of worship, to disseminate information.

Prof Kacey Ernst, an infectious-disease epidemiologist from the University of Arizona, talked about how to improve early-warning systems, which are often siloed – with academics, governments and the public each contributing to separate parts of the system. A better approach, she said, would integrate government, the academy and community engagement. 

For example, to improve understanding of how the disease system interacts with weather and climate, researchers could engage the community to supplement the data they are already collecting.

But early-warning systems are not enough, Guigma told the conference – it is more important that responders are able to actually prevent the impacts of the disaster. There is a “critical lack of understanding” of the direct impacts of heatwaves, including for food security, power supplies, water access and human health, he said. 

§ Successful cases

The conference heard about a few successful cases where early-warning systems are already being developed. 

Dr Ousmane Ndiaye, the director of Senegal’s national meteorological service (ANACIM), and Papa Ngor Ndiaye, who is ANACIM’s head of weather forecasts and risk reductions service, shared details of a pilot project called the “heat-health early warning system”. 

Every week from March to June, ANACIM puts out a heat-health bulletin, which uses a heat early-warning system product from NOAA and maps of health risk in the country. It is disseminated in a range of ways, Papa Ngor Ndiaye said – via text message and voice message, radio, television and over the internet. 

The project has been in place since 2020 and will be evaluated at the end of this year. 

Haingotiana Rakoto Ramambason, the climate and health manager from Madagascar’s ministry of public health, spoke about her country’s health and climate bulletin. It integrates meteorological and health data to forecast six climate-sensitive diseases. 

This information is disseminated to the general public via mobile phones. It includes not just what diseases are projected to increase in the coming month, but also preventive measures people can take.

The UK Centre for Ecology and Hydrology’s Dr Josh Talib worked with the African Centre of Meteorological Applications for Development on a project to create sub-seasonal forecasts of meningitis risk. 

Using subseasonal atmospheric forecasts from the European Centre for Medium-Range Weather Forecasts, Talib and his collaborators created hazard maps, where warm, dry and dusty conditions meant that meningitis would be favourable. 

Talib told the conference that using these subseasonal forecasts could be “transformational for early action”. For example, he said, the meningitis forecasts could be used to target vaccination campaigns on the ground. However, it is hard to quantify the impact on the ground, he added.

§ Challenges remain

One major challenge highlighted by many of the conference participants was the access to resources – not just in terms of funding, but also in terms of personnel, data access and institutional support. Ernst told the conference:

“All the top science in the world will not solve these issues.”

“We have never had enough money to apply to anything, in health or in climate,” Rumisha told the conference on the first day. Given the limited resources available, they will need to be well-allocated to create equitable climate-informed health systems, she added. 

The relative lack of ground-truthed climate data over much of Africa also poses a problem to forecasters. “The observing system is sometimes not as long-term or dense” as would be ideal, said Prof Kerry Cook from the University of Texas, Austin. Accurate projections of health indicators require accuracy from the climate side, she added. 

Van Aardenne, from the University of Cape Town, added:

“The data you have to work with is never at the right scale. It’s never equally valid. It’s hard to work with.”

And yet, in some senses, “climate data is easy”, van Aardenne said. Health data comes with a suite of its own issues: it is rarely collected at high temporal resolution, it may not be standardised or digitised and sharing it comes with ethical concerns. 

Thiaw told Carbon Brief that “tremendous strides” have been made in forecasting ability. He added:

“Where the gap really is in terms of advancing climate-based health early-warning systems is in the vulnerability data. That is, the social aspect of the early-warning system.”

Some of that data has not been collected – and where it has been, it is not always well-organised or accessible, Thiaw said.

Lennard, from the University of Cape Town, showed down-scaled climate models – high-resolution climate-model runs focused on a small area – over Cape Town. He pointed out that Africa does not have the facilities necessary to do the type of computation needed to make those models a reality. As a result, regional contexts are ignored and adaptive capacity is reduced, he said. 

And even when those simulations are run elsewhere, Lennard added, many places do not have the bandwidth to download all of the model output data. He highlighted the Coordinated Regional Downscaling Experiment (CORDEX), a global effort for producing regional downscaled climate model projections worldwide. CORDEX is attempting to mitigate some of these limitations by both running simulations and allowing researchers to access them via the cloud. 

Being attentive to local contexts and needs was another challenge identified by the conference participants.

Ernst said it was necessary to apply a gendered lens to early-warning systems, in order to centre the most vulnerable in the conversation. Building trust with community leaders – who can, in turn, disseminate information to their communities more easily – is also key to successful systems, she said.

Lusumbali, from the CHAMNHA consortium, stressed the need to co-design studies with communities to understand their needs and priorities. 

The siloing of research and funding was another gap that attendees pointed out. 

Ndiaye, from ANACIM, noted that climate and health are very different sectors – they have their own agendas and even their own definitions of the same words. Working together requires common understanding and common thresholds, he added. 

This sort of collaboration is what Thiaw hopes the conference will result in. He told Carbon Brief:

“Ultimately, what we want to come out of this conference are strong recommendations as to what are the steps that we need to take to really advance climate-based health early-warning systems, to implement them – even if it’s just with pilot projects – and then to sustain them and expand them.”