8.2 Current sensitivity and vulnerability
Systematic reviews of empirical studies provide the best evidence for the relationship between health and weather or climate factors, but such formal reviews are rare. In this section, we assess the current state of knowledge of the associations between weather/climate factors and health outcome(s) for the population(s) concerned, either directly or through multiple pathways, as outlined in Figure 8.1. The figure shows not only the pathways by which health can be affected by climate change, but also shows the concurrent direct-acting and modifying (conditioning) influences of environmental, social and health-system factors.
Figure 8.1. Schematic diagram of pathways by which climate change affects health, and concurrent direct-acting and modifying (conditioning) influences of environmental, social and health-system factors.
Published evidence so far indicates that:
- climate change is affecting the seasonality of some allergenic species (see Chapter 1) as well as the seasonal activity and distribution of some disease vectors (see Section 8.2.8);
- climate plays an important role in the seasonal pattern or temporal distribution of malaria, dengue, tick-borne diseases, cholera and some other diarrhoeal diseases (see Sections 8.2.5 and 8.2.8);
- heatwaves and flooding can have severe and long-lasting effects.