Rapid unplanned development with poor urban
infrastructure is a leading cause of disease in
populations in Africa and South Asia. Many urban
populations are currently not well adapted to extreme
weather, and now the climate is changing. Climate
change is expected to negatively impact on health
through increasing seasonal temperatures, changing
rainfall patterns, increases in frequency of weather and
climate extremes, and sea level rise
This report describes the sources and types of health
data available to assess the current effects of climate
and weather exposures on urban populations in Africa
and Asia, with a focus on informal settlements in Dar es
Salaam (Tanzania), Ibadan (Nigeria), Nairobi (Kenya),
and Dhaka (Bangladesh).
Current disease burdens have been estimated for
specific environmental factors (e.g. household air
pollution, outdoor air pollution, water/sanitation) and
for specific diseases. However, scientific evidence
regarding the environmental determinants of health
is limited in informal settlements. Recent burden of
disease analysis has only been conducted for Nairobi.
An older project estimated disease burdens in Dar
es Salaam, but it was not been updated in the past
decade. There are no comparable studies for Dhaka
or Ibadan.
Observational studies can improve our understanding
of how populations respond to extreme weather events.
Several epidemiological study designs can be used to
assess the relationship between weather and climate
variables, and human health, including episode analyses,
time-series regression and cross-sectional studies.
The main sources of health data available in the four
cities are described. Data from long-term demographic
surveillance sites provide the most useful health
information, and these are available for populations in
Nairobi and Dhaka. A key data limitation is the poor
coverage of vital registration systems in all four cities.
Urban populations are particularly vulnerable to
disasters, due to the concentration of persons and
infrastructure. Global level disaster data related to health
are limited to mortality data associated with specific
events and often impacts in populations in informal
settlements are not identified. Current knowledge of the
impacts of weather disasters (floods, heat waves, and
droughts) is derived from published studies, indicators
on a range of impacts on mortality, injuries, infectious
diseases and nutrition-related outcomes.