WHO report Climate change Quantifying the health impact at national and local levels

Climate change is an emerging risk factor for human health. There is now widespread consensus among the scientific community that the earth is warming, that this is mainly due to human activities, and that this will continue for at least the next several decades. It is also clear that weather and climate exert a major influence on human health, both through direct effects of extreme events such as heatwaves, floods and storms, and more indirect influences on the distribution and transmission intensity of infectious diseases, and on the availability of freshwater and food. The general approach consists of; (i) Selecting an appropriate set of scenarios of alternative possible futures (e.g. lower or higher rates of emissions of greenhouse gases, population growth etc.), 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; and (vi) using this information to calculate the climate change attributable burden of specific diseases. Subsequent sections describe assessment methods that were used in the previous global and regional assessments, for a range of climate-sensitive health outcomes.