Despite providing significant benefits for human health, energy systems also negatively affect global health in major ways today, causing directly perhaps as many as five million premature deaths annually and more than 5% of all illhealth (measured as lost healthy life years). Air pollution from incomplete combustion of fossil fuels and biomass fuels is by far the single major reason that energy systems negatively affect global health, although ash, sulfur, mercury, and other contaminants in fossil fuels also play a role. Effects on workers in energy industries are the second biggest health impact globally.
The largest exposures to energy-related air pollution occur in and around households, particularly in developing countries where unprocessed biomass (wood and agricultural wastes) and coal are used for cooking and heating in simple appliances.
This chapter does not focus on differences in impacts among alternative energy systems that have minor impacts on global health; rather, the focus is on the most significant impacts of energy systems on health. The important positive impacts of energy systems on health are mostly addressed in Chapter 2.
Given the importance of avoiding climate change, there is secondary focus on the ways that mitigating climate change through changes in energy systems might achieve important health improvements: co-benefits.
Unless major policy interventions are introduced, energy systems are expected to continue contributing significantly to the global burden of disease for years to come.