Indicator Specification

Heat and health

Indicator Specification
  Indicator codes: CLIM 036
Published 08 Sep 2008 Last modified 25 Aug 2017
7 min read
This is an old version, kept for reference only.

Go to latest version
This page was archived on 25 Aug 2017 with reason: A new version has been published
Daily mortality rates in 15 European cities by apparent temperature in summer time

Update planned for November 2012

Assessment versions

Published (reviewed and quality assured)
  • No published assessments


Justification for indicator selection

Populations typically have an optimum temperature at which the (daily or weekly) death rate is lowest. Mortality rates rise at temperatures outside this comfort zone. Figure 1 shows a typical U/J-shaped relation (in 15 European cities assessed in the PHEWE project). The trough represents the comfort zone; the steeper (right) arm of each line shows the mortality increase at high temperatures, and the left arm of each line shows the increase at low temperatures. Overall, the impact of hot weather and heat waves depends on the level of exposure, the size and structure of the exposed population, the population sensitivity, the preparedness of health systems, and the prevention measures in place. In temperate countries, there is a seasonal variation of mortality, with higher mortality in winter than in summer. There is uncertainty on whether some current observed reductions in winter mortality can be attributed to climate change (Confalonieri et al., 2007). People with cardiovascular diseases are more at risk in winter, because of the cold-induced tendency of blood to clot.
Heat waves have caused significant mortality in Europe in recent decades. However it is difficult to compare the heat-wave effects across Europe and over time. Heat directly affects the human physiology: thermoregulation during heat stress requires a healthy cardiovascular system. When environmental heat overwhelms the heat-coping mechanism, the body's core temperature increases. This can lead to heat illness, or death from heat stroke, heart failure and many other causes.
Several medical factors can increase the risk of heat-wave mortality, including dehydration, drugs, ageing, and having a chronic disease that affects cardiac output and skin blood flow, as well as being confined to bed. Social factors, such as social isolation, may also be important, although there has been little research in Europe (Bouchama, 2007). Many housing and urban factors have also been assessed, in particular for their role in high indoor temperatures (Kovats and Hajat, 2008). One special concern relates to indoor temperatures in health-care facilities and nursing homes. Increasing numbers of older adults in the population will increase the proportion of the population at risk (Confalonieri et al., 2007). Health-system action will be needed to ensure adequate planning of locations for health care and nursing institutions, as well as for the thermal protection of their facilities.
The EuroHEAT project concluded that heat-related illnesses and deaths are largely preventable. In the long term, the most important measure is improving urban planning and architecture, and energy and transport policies. Such improvements should begin now, as the lead time for policy development is very long. Heat-wave effects can be reduced by keeping indoor temperatures low, keeping out of the heat, keeping the body cool and hydrated, and helping others. Health-system preparedness planning is essential, by collaborating with weather services in providing accurate, timely weather-related health alerts and developing strategies to reduce individual and community exposures to heat, especially among vulnerable populations, planning health and social services and infrastructure, and providing timely information to the population (Matthies et al., 2008).

Scientific references

  • No rationale references available

Indicator definition

  • Daily mortality rates in 15 European cities by apparent temperature in summer time



Policy context and targets

Context description

In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The aim is to increase the resilience to climate change of health, property and the productive functions of land, inter alia by improving the management of water resources and ecosystems. More knowledge is needed on climate impact and vulnerability but a considerable amount of information and research already exists which can be shared better through a proposed Clearing House Mechanism. The White Paper stresses the need to mainstream adaptation into existing and new EU policies. A number of Member States have already taken action and several have prepared national adaptation plans. The EU is also developing actions to enhance and finance adaptation in developing countries as part of a new post-2012 global climate agreement expected in Copenhagen (Dec. 2009). For more information see:


No targets have been specified

Related policy documents

No related policy documents have been specified



Methodology for indicator calculation

Methodology for gap filling

Methodology references

No methodology references available.


Data specifications

EEA data references

  • No datasets have been specified here.

External data references

Data sources in latest figures



Methodology uncertainty

Data sets uncertainty

Rationale uncertainty

No uncertainty has been specified

Further work

Short term work

Work specified here requires to be completed within 1 year from now.

Long term work

Work specified here will require more than 1 year (from now) to be completed.

General metadata

Responsibility and ownership

EEA Contact Info

Hans-Martin Füssel


European Environment Agency (EEA)


Indicator code
CLIM 036
Version id: 1


DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)


Document Actions