Partnering for Health Early Warning Systems

By David P. Rogers*

Health and well-being are the human face of climate change. The potential for climate change to affect human health has motivated much of the past decade’s research into the relationship between disease and climate. Between one quarter and one third of the global burden of disease can now be attributed to environmental risk factors, according to the World Health Organization (1). Because diseases are sensitive to weather and climate conditions, most of the health effects we can expect due to climate change are already occurring.

Public health strategies are focusing on increasing resilience to weather and climate-sensitive illnesses, which will improve our capacity to cope with the health effects of the present and future climate. Whether the climate reduces crop yields or increases extreme weather events, the consequences are ultimately manifest in health impacts.

Achieving the universal aspiration of good health requires clean water and air, food, shelter, sanitation, safety and freedom from disease. Access to medicines and quality health care is vital. Health also requires broad investment in social and environmental measures that help societies adapt to climate change. This will contribute to reducing disaster risks, ensuring access to clean water and improving food security, thus helping to achieve the United Nations Millennium Development Goals (2).

Success depends on the interaction of diverse communities which are not natural partners. It also requires new skills that enable specialists in health, agriculture, water resources, disaster management, weather and climate to work together. Their collaboration in developing systems for early detection or warning of health risks is a key to mitigating the effects of diseases.

National bodies can play an important role in helping to ensure that the essential role of climate is taken into account in the decision-making systems of health practitioners. How can meteorological services work most effectively with public health services to improve health early warning systems? While famine early warning systems have a track record, in comparison, health sector early warning systems are relatively untried (5).

Early warning for malaria in Africa

The most advanced health early warning systems are for malaria (6,7,8). Guidelines developed in 2001 by WHO to establish and implement long-range forecasting and early detection provide concepts, indicators and planning to monitor malaria situations that may escalate towards possible epidemics. Monitoring of climatic indicators, population vulnerability factors and operational and environmental factors help detect when conditions suitable for an epidemic have already appeared at a given time and place. Such early warning systems have the potential to help the health community foresee potential epidemics weeks to months in advance. The aim is to identify the beginning of an epidemic by measuring changes in the incidence of malaria cases. At least eight African countries are developing malaria early warning systems. At present, however, long-range forecasting for malaria remains predominately research-based (9).

Malaria Outlook Forums in Africa are a good example of a user community (in this case health professionals) that is driving a process in which climate information is a key component. These forums were set up following climate information received in WMO Regional Climate Outlook Forums. The aim has been to create an operational early warning system for malaria, using both health and climate information. Malaria Outlook Forums have been held since 2004 in Southern Africa and since 2007 in East Africa and the Greater Horn of Africa (10). Meteorological and health experts from national agencies jointly develop malaria detection and response products best suited to various sectors, locations and time scales.

Early warning systems for heat

The past decade has also seen the development of heat-health warning systems, operating in at east 16 countries around the world. Good communication between meteorological services, emergency response communities and health agencies has been critical to success (8). Developing these relationships is not always easy, but the results are effective. The system can alert medical communities and care facilities (such as nursing homes) to prepare for a rise in patients with syptoms of heat stress.

Heat-health forecasts can also be used to alert people to watch out for family and community members, especially those that are socially isolated; remind patients to take prescribed medications on time; ensure that those at risk have access to health care facilities; and avoid high temperatures, humidity and poor air quality (2,11,12,13,14).

Supporting stronger working relationships

In efforts to improve warning systems, the public health sector increasingly recognizes that collaborative systems have a positive influence on the operational decision-making process (15,16).

A framework to improve communication and planning between health ministries and meteorological services is being developed in Africa. Pioneered in Ethiopia by its Ministry of Health and the National Meteorological Services Agency, a Climate and Health Working Group is becoming a focal point for climate and health issues. The goal is to create a climate-informed health sector and beneficiary communities that routinely request and use appropriate climate information to improve the effectiveness of health interventions (17). The group helps formulate institutional data sharing systems among the sectors and other relevant institutions; fosters research on climate and health; organizes workshops; identifies gaps and bottlenecks which constrain the routine use of climate information by the health sector, and identifies and pursues the means to overcome these problems; and helps build the capacity of national and local community-based organizations to widen and strengthen their services.

Health ministries and meteorological services in Madagascar, Kenya and West Africa are furthering this development. Madagascar, for example, has created a Climate and Health Working Group through an agreement between the Ministry of Health and Family Planning and its National Meteorological and Hydrological Service to reduce the burden of climate-sensitive diseases, focusing on malaria, plague and Rift Valley fever. The health sector in Madagascar can use climate information in warning systems for epidemics. Seasonal forecasts of temperature and precipitation, indicators of probable occurrence of malaria, can trigger greater surveillance of epidemics.

Real-time observations of temperature and precipitation can be used to launch selective interventions and help in the early disease detection (2). Spain, through the Agencia Estatal de Meteorología (AEMET) is supporting collaboration in West Africa between meteorological and health services through a project called HEALTHMET. It also contributes to the Meningitis Environmental Risk Information Technologies programme, known by its acronym MERIT. It is one of the first developed jointly between the health and climate communities (led by WHO, WMO and their partners) to develop decision tools to support health operations in the African meningitis belt (2).

Communicating warnings effectively

Communities must be aware of weather and climate-sensitive health risks if they are to protect themselves. Information must reach vulnerable populations, using messages that encourage people to act. Thus health forecasting and early detection must be linked to specific actions to reduce risk that are timely, specific and take into account the social and cultural factors that make people more or less receptive to information.

Météo-France, for example, has pioneered early warning systems for meteorological hazards using a vigilance system charting the severity of hazards with colour codes for each of its 95 French departments. After the 2003 extreme heatwave that resulted in many thousands of extra deaths during a 16-day period in Europe, the French Institute for Public Health Surveillance, in close cooperation with Météo-France, set up a heat-health watch warning system (13). The system aims to warn public authorities and the general public three days before a heatwave may occur, so that a national plan can go into operation, including use of television and radio spots, special assistance to people at risk (many of whom are already registered at their townhalls) and facilities to access clinical information on recent morbidity or mortality (2).

The Canadian Meteorological Service produces a daily air quality forecast with an Air Quality Index. Air Quality Advisories are issued when the air pollution levels exceed national standards. They are issued in partnership with provincial and municipal environment and health authorities, and contain advice on actions to protect health and the environment. A cornerstone is timely health messages encouraging Canadians to avoid exposure to unhealthy air and to take advantage of immediate access to prescription medication. These messages also motivate longer-term actions to improve air quality in Canadian communities. Similar activities are taking place across the border in the USA, as well as in Europe.

In the USA, most information presented by AIRNow, publisher of the Air Quality Index and other air quality guides, is based on observations. The US National Weather Service and the Environmental Protection Agency have also developed an Air Quality Forecast System to predict ozone levels as guidance to state and local air quality forecasters (18). The aim is to provide ozone, particulate matter and other pollutant forecasts with enough accuracy and advance notice to take action to prevent or reduce health effects. This development builds on numerical forecasting advances that incorporate chemical and weather forecasts. Within a decade, reliable air quality forecast guidance beyond two days should be available for an area of 2.5 km.

The United Kingdom has perhaps gone the farthest. It has developed a Health Forecasting Service within the Met Office, in collaboration with the National Health Service. The new service delivers tailored health forecasts to health care providers and individuals with conditions such as chronic obstructive pulmonary disease and seasonal affective disorder. The service predicts periods of increased risk and targets the individual at the right time to elicit a response. For seasonal affective disorder, for example, simple measures such as gentle exercise, keeping rooms at the right temperature and the use of light boxes improve health greatly. There are several applications of these techniques and enthusiasm among the clinical community is growing.

The UK Met Office Hadley Centre is conducting research to understand the impact that climate change is likely to have on human health worldwide, including changing risks of heat stress, air pollution, wildfires, floods, droughts and storms. It is reaching out to the health community to help them with decision-making tools for options to adapt to and mitigate changes in health risks over the next decades (2).

Multi-hazard warning in China

Using systems for multiple purposes can be cost-effective. Multi-hazard early warning systems can forecast a variety of natural hazards and health conditions such as chronic obstructive pulmonary disease, asthma, cardiovascular disease and exposure to infectious diseases. It also facilitates coordination between relevant government agencies. Flood warnings, for example, draw upon government experts dealing with emergency rescue, health and veterinary issues and hazardous materials.

The China Meteorological Admini­stration has such a model in the Shanghai Multi-Hazard Early Warning System, developed jointly with WMO and the Shanghai People’s Municipal Government. The new Shanghai Health-Meteorology Forecasting Service is designed to be an integral part of the warning platform.

How weather and climate affect health

Climate and weather extremes can lead to physical injury, food insecurity, social disruption, population displacement and the spread of communicable diseases (3).

High temperatures, for example, trigger heatwaves and exacerbate poor air quality, which contribute to deaths from cardiovascular and respiratory disease (2). High temperatures also increase aeroallergens that trigger asthma. Changing temperature patterns alter animal and insect habitats, changing the risks of diseases and increasing the need for surveillance and early detection to reduce epidemic risks (4).

Floods increase the likelihood of bacterial contamination of water and alter the habitats of rodents. This increases the risk of diseases such as cholera and leptospirosis. It also improves breeding conditions for insects responsible for the transmission of dengue, malaria and other diseases.

Urban areas pose particular risks. Diseases can spread rapidly in urban areas, and the built environment can reinforce high temperatures and poor air quality.

The World Health Organization identifies several major climate-sensitive communicable diseases including malaria, meningitis, cholera and dengue, and acknowledges that many non-communicable coronary and respiratory diseases are also climate-sensitive. Many other largely neglected diseases are also sensitive to climate and weather.

Epidemic potential of some climate-sensitive common communicable diseases




Climate–epidemic link

Temporal climate sensitivity




Decreases in temperature (winter) associated with epidemics. A range of human-related factors are more significant.


Diarrhoeal diseases

Food-and water-borne


Increases in temperature and decreases in rainfall associated with epidemics. Sanitation and human behaviour are probably more important.



Food-and water-borne

Africa, Asia, Russian Federation South America

Increases in sea and air temperatures as well as El Niño events associated with epidemics. Sanitation and human behaviour are also important.



The bite of female Anopheles mosquitoes

Endemic in > 100 countries in the tropics, subtropics and some temperate areas

Changes in temperature and rainfall associated with epidemics. Many other locally relevant factors including vector characteristics, immunity, population movements, drug resistance, environmental changes, etc.


Meningococcal meningitis



Increases in temperature and decreases in humidity associated with epidemics.


Lymphatic filariasis

The bite of female Culex, Anopheles, Aedes and Mansonia mosquitoes

Africa, India, South America, South Asia and Pacific Islands

Temperature and rainfall determine the geographical distribution of vectors and disease.



The bite of female phlebotomine sand flies

Africa, central Asia, Europe, India, South America

Increases in temperature and rainfall associated with epidemics.


African trypanosomiasis

The bite of male and female tsetse flies, Glossina spp.

Sub-Saharan Africa

Changes in temperature and rainfall may be linked to epidemics. Cattle density and vegetation patterns also are relevant factors.



The bite of female Aedes mosquitoes

Africa, Europe, South America, south-east Asia, western Pacific

High temperature, humidity and rainfall associated with epidemics in some areas. Non-climatic factors also have an important impact.


Japanese encephalitis

The bite of female Culex and Aedes mosquitoes

South-east Asia

High temperature and heavy rains associated with epidemics. Reservoir animal factors are also important.


St Louis encephalitis

The bite of female Culex and Aedes mosquitoes

North and South America

High temperature and heavy rain associated with epidemic. Reservoir animal factors are also important.


Rift Valley fever

The bite of female culicine mosquitoes

Sub- Saharan Africa

Heavy rains associated with onset of epidemic. Cold weather associated with end of epidemic. Reservoir animal factors are also important.


West Nile virus

The bite of female culicine mosquitoes

Africa, central Asia, south-west Asia, Europe

High temperatures and heavy precipitation associated with onset of epidemic. Non-climatic factors may have more important impact.


Ross River virus

The bite of female culicine mosquitoes

Australia and Pacific islands

High temperature and heavy precipitation associated with onset of epidemic. Host immune factors and reservoir animals are also important factors.


Murray Valley fever

The bite of female Culex mosquitoes


Heavy rains and below average atmospheric pressure associated with epidemics.


Yellow fever

The bite of female Aedes and Haemagogus mosquitoes

Africa, South and central America

High temperature and heavy rain associated with epidemic. Intrinsic population factors are also important.


Adapted from Kuhn, K., D. Campbell-Lendrum, A. Haines and J. Cox . Using climate to predict infectious disease epidemics, World Health Organization, 2005.


Health and climate, the way forward

There has been much progress over the past decade in understanding the relationship between weather and climate and disease, which can serve as a basis for recommendations for National Meteorological and Hydrological Services.

  • Work jointly with health professionals. Health forecasting is best as a joint venture of the health service and meteorological service (19).
  • Focus on multi-hazard systems. Weather and climate forecasting has advanced and early warning systems have focused on multiple hazards. This approach is critical to cost-effective health forecasting and early detection since it leverages the extensive investment of National Meteorological and Hydrological Services in the core infrastructure of the warning system. It also facilitates communication and coordination among the many agencies that can be involved in climate and health issues, such as those dealing with agriculture, water resources, and emergency management, for example. Meteorologists have an important role in bringing these pieces together to create more timely and integrated warning systems that reflect the multiple risks that affect human health and well-being.


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