World Health Day

Climate change: an issue for the health sector

Health hazards from climate change are diverse and global in nature. The hazards range from higher risks of extreme weather events to changes in the dynamics of infectious diseases. Many of the leading killer diseases are sensitive to climatic conditions; their incidence and spread are likely to be affected by changing weather patterns.

A woman collecting firewood in a forest in Mexico.
WHO/Guy Smallman
Deforestation contributes to climate change and destroys sources of food and medicinal herbs. In the case of San Isidro Aloapam, Oaxaca in Mexico, the forest also used to protect the village from flooding.

The health impacts of climate change are already evident in different ways: more people are dying from excessive heat than before, changes are occurring in the incidence of vector-borne diseases, and the pattern of natural disasters is altering.

These impacts will be disproportionately greater in vulnerable populations, which include the very young, elderly, medically infirm, poor and isolated populations. Vulnerability is also high in:

  • areas with a high endemicity of climate-sensitive diseases, severe water scarcity, and low food production;
  • small-island developing states and mountainous regions; and
  • megacities and coastal areas in developing countries.

Action needs to be taken now

The health impacts of climate change will be difficult to reverse in a few years or decades. Yet, many of these possible impacts can be avoided or controlled. There are established steps in health and related sectors to reduce the exposure to and the effect of changing climate. For example, controlling disease vectors, reducing pollution from transport, and efficient land use and water management are well-known and tested measures that can help.

Moreover, many of the steps needed to prevent climate change have positive health benefits. For example, increased use of bicycles and public transport instead of personal cars in industrialized countries will reduce greenhouse gas emissions. It will also improve air quality and lead to better respiratory health and fewer premature deaths. The increase in physical activity from cycling and walking may lead to less obesity and fewer obesity-related illness. The sooner these steps are taken, the greater their impact will be on public health.