IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

8.1.4 Methods used and gaps in knowledge

The evidence for the current sensitivity of population health to weather and climate is based on five main types of empirical study:

  • health impacts of individual extreme events (e.g., heatwaves, floods, storms, droughts, extreme cold);
  • spatial studies where climate is an explanatory variable in the distribution of the disease or the disease vector;
  • temporal studies assessing the health effects of interannual climate variability, of short-term (daily, weekly) changes in temperature or rainfall, and of longer-term (decadal) changes in the context of detecting early effects of climate change;
  • experimental laboratory and field studies of vector, pathogen, or plant (allergen) biology;
  • intervention studies that investigate the effectiveness of public-health measures to protect people from climate hazards.

This assessment of the potential future health impacts of climate change is conducted in the context of:

  • limited region-specific projections of changes in exposures of importance to human health;
  • the consideration of multiple, interacting and multi-causal health outcomes;
  • the difficulty of attributing health outcomes to climate or climate change per se;
  • the difficulty of generalising health outcomes from one setting to another, when many diseases (such as malaria) have important local transmission dynamics that cannot easily be represented in simple relationships;
  • limited inclusion of different developmental scenarios in health projections;
  • the difficulty in identifying climate-related thresholds for population health;
  • limited understanding of the extent, rate, limiting forces and major drivers of adaptation of human populations to a changing climate.

Table 8.1. National health impact assessments of climate change published since the TAR.

Country Key findings Adaptation recommendations 


(McMichael et al., 2003b)


Increase in heatwave-related deaths; drowning from floods; diarrhoeal disease in indigenous communities; potential change in the geographical range of dengue and malaria; likely increase in environmental refugees from Pacific islands.


Not considered.



(Programa Nacional de Cambios Climaticos Componente Salud et al., 2000)


Intensification of malaria and leishmaniasis transmission. Indigenous populations may be most affected by increases in infectious diseases.


Not considered.



(National Environment Commission et al., 2006)


Loss of life from frequent flash floods; glacier lake outburst floods; landslides; hunger and malnutrition; spread of vector-borne diseases into higher elevations; loss of water resources; risk of water-borne diseases.


Ensure safe drinking water; regular vector control and vaccination programmes; monitor air and drinking water quality; establishment of emergency medical services.



(Riedel, 2004)


Increase in heatwave-related deaths; increase in air pollution-related diseases; spread of vector- and rodent-borne diseases; increased problems with contamination of both domestic and imported shellfish; increase in allergic disorders; impacts on particular populations in northern Canada.


Monitoring for emerging infectious diseases; emergency management plans; early warning systems; land-use regulations; upgrading water and wastewater treatment facilities; measures for reducing the heat-island effect.



(Hassi and Rytkonen, 2005)


Small increase in heat-related mortality; changes in phenological phases and increased risk of allergic disorders; small reduction in winter mortality.


Awareness-building and training of medical doctors.



(Zebisch et al., 2005)


Observed excess deaths from heatwaves; changing ranges in tick-borne encephalitis; impacts on health care.


Increase information to the population; early warning; emergency planning and cooling of buildings; insurance and reserve funds.



(Ministry of Environment and Forest and Government of India, 2004)


Increase in communicable diseases. Malaria projected to move to higher latitudes and altitudes in India.


Surveillance systems; vector control measures; public education.



(Koike, 2006)


Increased risk of heat-related emergency visits, Japanese cedar pollen disease patients, food poisoning; and sleep disturbance.


Heat-related emergency visit surveillance.


The Netherlands

(Bresser, 2006)


Increase in heat-related mortality, air pollutants; risk of Lyme disease, food poisoning and allergic disorders.


Not considered.


New Zealand

(Woodward et al., 2001)


Increases in enteric infections (food poisoning); changes in some allergic conditions; injuries from more intense floods and storms; a small increase in heat-related deaths.


Systems to ensure food quality; information to population and health care providers; flood protection; vector control.



(Autoridad Nacional del Ambiente, 2000)


Increase of vector-borne and other infectious diseases; health problems due to high ozone levels in urban areas; increase in malnutrition.


Not considered.



(Casimiro and Calheiros, 2002; Calheiros and Casimiro, 2006)


Increase in heat-related deaths and malaria (Tables 8.2, 8.3), food- and water-borne diseases, West Nile fever, Lyme disease and Mediterranean spotted fever; a reduction in leishmaniasis risk in some areas.


Address thermal comfort; education and information as well as early warning for hot periods; and early detection of infectious diseases.



(Moreno, 2005)


Increase in heat-related mortality and air pollutants; potential change of ranges of vector- and rodent-borne diseases.


Awareness-raising; early warning systems for heatwaves; surveillance and monitoring; review of health policies.



(Kaumov and Muchmadeliev, 2002)


Increase in heat-related deaths.


Not considered.



(Thommen Dombois and Braun-Fahrlaender, 2004)


Increase of heat-related mortality; changes in zoonoses; increase in cases of tick-borne encephalitis.


Heat information, early warning; greenhouse gas emissions reduction strategies to reduce secondary air pollutants; setting up a working group on climate and health.


United Kingdom

(Department of Health and Expert Group on Climate Change and Health in the UK, 2001)


Health impacts of increased flood events; increased risk of heatwave-related mortality; and increased ozone-related exposure.