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Guidance Document

Climate change - Quantifying the health impact at national and local levels


It is clear that weather and climate exert a major influence on human health, both through direct effects of extreme events such as heat-waves, floods and storms, and more indirect influences on the distribution and transmission intensity of infectious diseases, and on the availability of freshwater and food.
It is therefore important to obtain the best possible assessment of the likely health impacts of climate change. This is a particularly challenging task. Compared to other environmental risk factors, climate range is a newly recognized phenomenon, with global scope, operating over long time periods and affecting an unusually wide range of health outcomes. The guidance presented here therefore outlines a general approach, and describes how the methods that were applied in the World Health Organization global comparative risk assessment project, and a regional assessment in Australasia, can be "down-scaled" to the national or sub-national level. It also highlights where further research is likely to improve the assessment. It should therefore be useful in generating preliminary estimates of some of the health effects of climate change, and as a guide to developing more comprehensive and accurate assessment in the future.
The general approach consists of:
(i) Selecting an appropriate set of scenarios of alternative possible futures and the timescale over which to carry out the assessment;
(ii) Mapping the corresponding projected changes in climate properties;
(iii) Identifying the range of health outcomes that are both climate-sensitive and important in public health terms within the assessment population;
(iv) Quantifying the relationship between climate and each health outcome;
(v) Linking the exposure measurement to the climate-health model;
(vi) Using this information to calculate the climate change-attributable burden of specific diseases.
Estimates of the health impacts from climate change have two main uses in policy-making. Firstly, they provide a fuller picture of the consequences of mitigating, or failing to mitigate, emissions of greenhouse gases that are the main anthropogenic contribution to climate change. Secondly, they can help to identify which populations are likely to suffer the greatest impacts of climate change, and from which specific diseases. They can therefore help inform policies and allocate resources to adapt to climate change.

Reference information


World Health Organization

Published in Climate ADAPT Jun 07 2016   -   Last Modified in Climate ADAPT Feb 15 2021

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