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Rapid phase-out of fossil fuels can save millions of lives annually as a result of reduced global air pollution, according to an international team of scientists including Scripps Institution of Oceanography at the University of California San Diego researcher Veerabhadran Ramanathan.

Researchers led by the Max Planck Institute for Chemistry in Germany used a global atmospheric chemistry and climate model linked to the latest health effects estimates. For the first time, the team studied the combined impact of decarbonization on public health, precipitation, and climate. The results were published in the journal Proceedings of the National Academy of Sciences (PNAS) March 25.

The team headed by atmospheric researcher Jos Lelieveld of the Max Planck Institute calculated that fossil fuel emissions are responsible for about 65 percent of premature deaths from human-made air pollutants globally. Polluted air significantly elevates the risk of cardiovascular and respiratory diseases.

According to Richard Burnett of Health Canada, a co-author of the study, it was recently found that the health burden of fine particulate matter is even higher than previously assumed. Phasing out the use of fossil fuels would therefore prevent more than 3 million premature deaths annually worldwide.

“If all sources of air pollution from human activities could be eliminated, that number would further rise to more than 5 million per year,” said Andy Haines from the London School of Hygiene and Tropical Medicine, a co-author of the study.

Air pollution also influences climate and precipitation patterns. Fine particulates in the atmosphere reflect a fraction of the sun’s radiation and cool the earth surface in polluted regions. Therefore, cessation of air pollution would lead to a fast rise in global temperatures in the short term, and the Paris Agreement’s 1.5°C target would not be achievable. Nevertheless, it is still possible to limit warming to 2°.

“The rise in temperature resulting from the removal of pollution particles from the air can be tempered by a simultaneous reduction of the greenhouse gases methane, ozone and HFCs (hydrofluorocarbons) in the troposphere,” said Ramanathan, a climate and atmospheric scientist at Scripps and study co-author.

Methane, ozone, and HFCs are shorter-lived than carbon dioxide, but they have a particularly strong near-term impact on the climate. They result from a range of human-induced emissions, including the use of fossil fuels.

According to the researchers, the cleaner air would let extra sunlight to reach the surface and cause more water to evaporate from oceanic areas, resulting in more rainfall by about 20 to 60 percent in several regions plagued by drought. The effect is particularly pronounced in monsoon regions and could help improve food security and access to water for people in parts of Africa, notably the Sahel, Central America, northern China and India.

The main implication of the study is that fossil fuel phase out is a major opportunity to significantly improve the health of people from around the world. The scientists advocate a rapid shift from fossil to renewable energies.

“Clean energy sources have the potential to save many lives,” said Lelieveld.

• Adapted from Max Planck Institute release