9. Climate and Health

Dr Menne and Dr Haines presented an overview of the relationship between health issues and climate, from the perspective of terrestrial climate-related observations:

It is anticipated that climate change will have a range of health impacts. Some will result from direct effects (e.g. heatwave-related deaths and skin cancer induced by ultraviolet radiation); others will result from disturbances to complex physical and ecological processes (e.g. changes in patterns of infectious disease, drinking-water supplies and agricultural yields). Some health effects may become evident within the coming decade; others will take longer.

Literature reviews have shown that:

Changes in the frequency and duration of temperature extremes would entail increases in thermal stress and their well-documented impacts on mortality and morbidity, especially in the elderly.

Less severe cold weather would reduce the excess winter mortality.
The increased risk of coastal and riverine flooding has important implications for health (Menne et al., 1999). Floods can cause deaths, injuries, outbreaks of infectious diseases and psychosocial problems.
El Nino and ENSO events have caused droughts, which might cause famine. Famine has severe effects on the health of the population.
Some vector-borne diseases have altered their range: a) within Europe: lead to tick-borne encephalitis, malaria - although it is unlikely that malaria would become re-established in Europe if control measures are maintained (however, the risk of localised (autochthonous) outbreaks of malaria may increase); within Africa (cases of highland malaria have been identified, although its causes have not been conclusively determined); and in the Americas (Hantavirus Pulmonary Syndrome was attributed to weather events in Central America).
There is a correlation between food-borne diseases and air temperature. Increases in temperature may exacerbate the current trend of increases in cases of food-borne illness. There is also an increased risk of diseases associated with microbiological contamination of the water supply system.

Monitoring the potential impacts of climate change on health is important for a number of reasons. The provision of epidemiological data is needed to inform policy-makers about the magnitude of effects. Climate change is currently not seen as a priority within the health sector, although different international mechanisms have been set up to sensitise the public health community. As part of surveillance systems, data can help to determine the requirements for and the effectiveness of preventive and adaptive strategies. The monitoring of climate change impacts requires a more holistic approach to infection etiology, examining the possible influence of climate both on the environmental sources of pathogens and on humans (Stanwell-Smith, 1998).

Why monitor?

To detect early effects
To promote better research
To assist in building integrated assessment models
To improve and evaluate adaptation strategies
To inform policy-makers and the public

What should be monitored?

Climate sensitive diseases
Potential confounders (migration, life-styles, land use, etc.)
Adaptation strategies

Which criteria are used to select the climate sensitive diseases?

Strength of evidence/climate sensitivity
Potential magnitude of the effects (economic considerations)
current availability of data including feasibility and cost of collection
short term benefit of the monitoring process (for example, uses for other health activities and preventive work)

How should we monitor?

Identify minimum data sets
Arrangements for exchange/coordination of data

During a recent consultation of the WHO Working Group on the early health effects of climate change a list of possible mechanisms for monitoring has been prepared (WHO-ECEH, 1998a, b). This list has been reviewed several times, however it still needs substantial rethinking.

Table 1: Issues in Monitoring the Health Effects of Climate Change

Health impacts of:	Where	Data needs: Health	Climate Environment Socio-economic data
Heat stress	Urban population	Daily mortality, by sex, age and cause	Air pollution parameters, others to be defined
Floods	Flood-risk areas	Mortality, morbidity, surveillance data on drowning, injuries, infectious diseases, psychosocial well-being	Early warning data, disaster impact data, meteorological data
Droughts	Vulnerable areas, population	Mortality-morbidity data, population, nutritional status	Early warning data, land use data, data on crops, socio-economic data, food supply, etc.
Other extreme weather events	Vulnerable areas, population	Mortality-morbidity data	Early warning data
Sea level rise	Vulnerable population, areas	Diarrhoeal diseases surveillance	Ground and surface water quality
Changes in marine ecosystems	Oceans, coastal populations	Surveillance data	Chlorophyll a, other indicators for algal bloom, water quality data

Particular Groups of Diseases to be Monitored:

Climate impact on:	Where	Health data	Other data
Water-borne diseases	Current areas of endemicity and sporadic diseases	Mortality and morbidity data; communicable disease surveillance	Essential nutrients and phosphorus levels; water surface temperature and other hydrological parameters; water quantity, etc.
Food-borne diseases	Current areas of endemicity and sporadic diseases	Mortality and morbidity data; communicable disease surveillance Outbreak investigations	HACCP data, etc.
Vector-borne diseases	Current areas of endemicity and sporadic diseases; margins of distribution	Mortality and morbidity data; communicable disease surveillance	Vegetation indices, climatic data, etc.

A number of infectious diseases are likely to be affected by climate change. Monitoring networks exist for some of these diseases. In Europe, WHO had identified Campylobacter spp., Cryptosporidium parvum, malaria and tick-borne encephalitis (see Kovats et al., 1999), as suitable for monitoring. For a worldwide, integrated environmental health monitoring a set of three diseases could be identified to begin with.

TOPC discussed the material presented above. It was agreed that TOPC mandate includes monitoring environmental characteristics that are important to health, and it noted the increasing interest in health issues in various regions of the world (e.g., North America, Europe). From the presentations it became evident that health issues are related to several aspects of GCOS and GTOS, including those that concern other panels (e.g., AOPC) and non-climate foci of GTOS. Further work and experimentation, including pilot projects, are required to identify focused strategies for environmental monitoring that would effectively support health monitoring.

TOPC noted the proposed collaboration in Europe between NoLimits and the European Centre forEnvironment and Health, and considered that this project is an appropriate next step in identifying the ways for collaboration between environmental monitoring and human health communities.