|Volume 62 (Special Issue) 2013
Global climate change is now a reality. The Earth’s surface temperature has risen by more than 0.8°C in the past century and by approximately 0.6°C in the past three decades. This global change has led to extreme weather events such as floods, droughts and heavier and more frequent storms that have had negative public health impacts on vulnerable populations. In Africa, the health impacts of global warming include increased vulnerability to diseases borne by vectors, air and water as well as food insecurity. It has been demonstrated that the majority of African countries are ill-prepared to cope with the negative impacts of climate change. These countries lack solid evidence that links health to climate and the capacity to understand and apply climate and environmental information to decision‑making and resource management. They conduct few risk assessments of the health impacts of climate change.1
Climate-related public health impacts are especially pronounced in developing countries, which lack the protection of basic infrastructure and public health services. The poorest populations in Africa bear the heaviest burden of infectious diseases transmitted by insect vectors and through poor water and sanitation and unsafe food. The livelihoods and nutritional security of millions of people on the continent, especially women and children, are heavily dependent on rain-fed agriculture and seasonal water resources. The same populations are also particularly exposed to the harmful health effects of chemical pollutants, and other environmental factors, in the air, water, food and soil. All these health risks are highly sensitive to extreme weather events and climate variability. These risks tend to be exacerbated by climate change. An indirect public health impact of climate-induced changes will be observed in the distribution of productive ecosystems and availability of food, water and energy supplies. The distribution of infectious diseases, nutritional status, chemical exposure and patterns of human settlements will also be affected.
Climate services provide critical information for understanding the characteristics of hazards and their changing patterns. Forward-looking predictions and projections enable prevention and planning to increase resilience to the climate extremes that can result in disasters or epidemic outbreaks. However, the capacity to use climate information to reduce climate-related risks is limited by knowledge gaps on the linkage between climate and environmental health and by institutional challenges hindering effective response. The WHO-led Climate and Health Consortium for Africa (Clim-Health Africa), which responds to the political will of African governments to address climate change in general and its health impacts in particular, will address these challenges. Clim-Health Africa will support the Climate for Development in Africa2 (ClimDev-Africa) initiative by addressing its health aspects.
Goals and expected outputs
The goal of Clim-Health Africa is to strengthen the resilience of African countries and communities by improving management of the effects on public health of climate variability and change and planning for resources to cope with climate-sensitive health outcomes, moving from the current reactive to a proactive mode. The five-year (2014–2018) Clim-Health Africa projects proposes to address the following specific objectives:
Capacity building will be a key component in this project. There is a shortage of climate and health scientists in Africa to support the fast-moving climate change and health agenda. Therefore, efforts will be made to offer hands-on training courses to public health practitioners so that as early warning and response systems are developed and field-tested, there will be operational capacity in the countries to understand and use them effectively. One key strategy of this project is the development of a doctoral programme to breed a new generation of young African and non-African climate and health scientists.
Founding institutions of Clim-Health Africa
The expected outputs of the project are:
Clim-Health Africa is a tangible contribution to the Global Framework for Climate Services. It will provide internationally coordinated support to the WHO Member States in Africa to develop, use, monitor and evaluate public health early warning and response systems in order to effectively respond to public health effects of climate variability and change. This will be achieved through implementation of joint projects.
Clim-Health Africa has opted for a multi-stakeholder approach involving multi-disciplinary and trans-disciplinary teams are to be used to deliver on the project objectives. This is because the development and operationalization of the early warning and response systems require that many scientific disciplines be connected, such as climate science, meteorology, demography, epidemiology, statistics, computer science, public health, social sciences, health economics etc. Various organizations are working in one or more of these disciplines but no single organization will has the necessary competencies to develop and apply early warning systems. In this context, each organization that is a member of the Consortium will have a specific role based on its area of expertise or mandate and taking into account its comparative advantage. This will allow synergy and complementarity. The project will build on existing initiatives and contribute to the achievement of their objectives.
Technical and training opportunities
Advances in climate sciences, computing and telecommunications now allow forecasts ranging from a few hours to many years and climate projections. In addition, country-led integration of observations and global products has provided a new opportunity for user communities to access high quality information at the national level. These new capabilities allow the production and delivery of services whose application offers great benefits for many socioeconomic sectors that are climate sensitive. In addition, new field-based epidemiological data-gathering tools, including SMS and rapid diagnostic kits, have dramatically improved the opportunity for increasing resilience of communities to weather and climate-related health emergencies if information is integrated and presented in an actionable manner to proactive decision-makers.
Integrating climate knowledge and information into epidemiological training: There are several training opportunities for integration of climate change. These include the field epidemiology and laboratory training programmes, which are the most elaborate training programmes for developing competencies in field epidemiology, and the current International Health Regulations courses developed by WHO and partners, which support its Member States in their effort to strengthen their surveillance, alertness and response to public health events.
Integrated Disease Surveillance and Response: Countries in the WHO African Region are implementing the Integrated Disease Surveillance and Response (IDSR) strategy. IDSR focuses on a selected number of diseases including epidemic and climate-sensitive diseases such as malaria and cholera. IDSR data are being used to assess the impact of climate on meningitis epidemics in the Sahel (Perez et al. submitted) and malaria in Eritrea and Ethiopia (Graves et al. 2008, Thomson et al. 2012). So far limited attempts have been made to integrate environmental data with public health data generated by IDSR implementation for comprehensive and simultaneous action on both disease determinants and their outcomes. This has delayed epidemic detection and response. IDSR implementation is facing several challenges, one of which is the difficulty to provide timely data for immediate decision-making. The use of climate signals that precede disease outbreaks would vastly improve the decision-making process and that way improve the interventions.
Although these models have existed for several years, their wide application and use by national public health programmes to manage disease outbreaks and epidemics have remained very limited. One of the underlying issues is the applicability of the modelling systems in various ecosystems for diseases other than malaria. Applied research is required to adapt the existing models for application in different climate variability and change scenarios, taking into consideration other environmental factors that may prevail in these local ecosystems.
African countries more than other countries need to use early warning and early response systems to forecast, prevent and manage public health impacts of climate variability and change. However, currently only a limited number of institutions specialize in climate services, especially with a focus supporting such public health functions. Only a very few African scientists have worked to develop predictive models. In contrast many institutions in the United States and Europe have a longstanding history in the development of climate science, technology and weather services, including their application in public health.
How climate affects health
Ecosystem services are indispensable for the well-being of all people in the world. Healthy, well-functioning ecosystems enhance natural resilience to the adverse impacts of climate change and reduce the vulnerability of people. Human health is likely to be affected indirectly by climate-induced changes in the distribution of productive ecosystems and availability of food, water and energy supplies. These changes will in turn affect the distribution of infectious diseases, nutritional status, chemical exposure and patterns of human settlement.
Climate and disease
Vector-borne infections, diarrhoeal diseases transmitted through water and food and airborne diseases are some of the most important health burdens of the poorest communities. The burden of infectious diseases is particularly heavy in Africa.
Epidemic forms of these diseases are particularly damaging to health and health services. For example, mortality rates are comparatively higher in malaria epidemics than in endemic situations, and other mosquito-borne epidemic diseases such as dengue and chikungunya can cause high mortality and disrupt control and treatment programmes. Among water- and food-borne diseases, cholera brings high mortality rates with overloading of public health systems. Meningococcal meningitis, associated with dry conditions, causes seasonal epidemics with both acute and long-term health impacts. There is strong evidence that both the spatial distribution and triggering of epidemics of each of these diseases is associated with meteorological conditions interacting with socioeconomic and public health determinants. For example, the meningitis belt in Africa is loosely defined by isohyets with the northern limit set at 300 mm rainfall per year and the southern limit at 1100 mm (Lapeyssonie 1968). The 2008–2009 rainy season in Zimbabwe triggered the worst outbreak of cholera in recent African history, causing more than 92 000 cases and 4 000 deaths from August 2008 to June 2009. Climate change is expected to alter, and in many cases exacerbate, the incidence and spatial and seasonal distribution of these and other infectious diseases such as leishmaniasis and tick-borne diseases.
Climate and environmental degradation are also linked with the transmission of diseases from animals to humans and emergence of new diseases. For example, the plague, which is transmitted by fleas that infect rodents such as the common rat, is associated with flooding, which forces the rodents to seek shelter and food from human dwellings (Ogen-Odoi et al. 2006), and with rainfall, an association that has been verified in Uganda (MacMillan et al. 2012), Madagascar and Namibia.
Climate and nutrition
Malnutrition remains an underlying cause of half of the approximately 10 million annual deaths in children under age five, as well as generating long-term effects on child development (World Bank 2008). This is partly due to a lack of calories, which leads directly to protein-energy malnutrition, but more importantly is due to the interactive effect of malnutrition, which causes increased susceptibility to infectious diseases such as diarrhoea and malaria.
Extreme weather events as well as seasonal flooding and drought affect crop production and thereby food availability, particularly for subsistence farmers and those who are vulnerable to increases in food prices. Over the long term, higher temperatures and reduced and more variable precipitation associated with climate change are projected to decrease crop production, particularly in Africa, and significantly increase food insecurity and malnutrition.
In addition to their effects on food security, weather and climate affect nutritional value and food safety. For example, outbreaks of mycotoxins, which contaminate food supplies and can cause high levels of morbidity and mortality, occur in unusually warm and humid years (Muthomi et al. 2009). Increasingly, noncommunicable diseases associated with environmental threats, including salination of water supplies through the rise of sea level, threaten the health of urban and coastal communities. For example, there is emerging evidence that increased salination of water supplies not only compromises agricultural production but also increases hypertension and miscarriage among pregnant women (Khan and Islam 2011).
Climate and chemicals
In 2004 WHO found that globally 4.9 million deaths (8.3 per cent of the total) and 86 million disability-adjusted life years (5.7 per cent of the total) were attributable to exposure to a group of selected chemicals for which data were available. Climate change may alter human chemical exposure through extreme precipitation, drought and increased temperatures. Changes in temperature may affect the transformation and breakdown of chemicals, in some cases contributing to reductions in the effectiveness of vector-control measures. Extreme precipitation affects water quality by increasing runoff of agricultural and industrial chemicals. Drought threatens water quality by increasing the concentration of nonvolatile chemicals and toxic metals. The effect on humans of chemical exposure will vary widely according to the properties of the specific chemicals, chemical combinations, soil and water conditions, wind patterns, topography, land use, level of development, and human population characteristics.