Phasing out fossil fuels could save millions of lives

A new study estimates that the mortality burden attributable to air pollution from fossil fuel use is considerably higher than most previous estimates – a phaseout of fossil fuels would have tremendous, positive health outcomes

November 29, 2023

A new study by an international team of scientists provides new evidence to motivate rapid fossil fuel phaseout. The science team determined exposure to ambient air pollution and its health impacts using an updated atmospheric composition model, a newly developed relative risk model and recent satellite-based fine particle data. They estimated all-cause and disease-specific mortality and attributed them to emission categories. They show that phasing out fossil fuels is a remarkably effective health-improving and life-saving intervention. About 5 million excess deaths per year globally could potentially be avoided. 

The study was conducted by researchers from the Max Planck Institute for Chemistry (Germany), the London School of Hygiene & Tropical Medicine (UK), the University of Washington (USA), the Barcelona Institute for Global Health (Spain) and the University Medical Center Mainz (Germany). It was recently published in The British Medical Journal (BMJ), a renowned medical journal.

Air pollution continues to be a leading public health risk. Previous estimates of the attributable mortality burden varied significantly between studies, primarily due to differences in the exposure-response relationships and the causes of death included. Furthermore, only a few global studies attributed mortality to specific air pollution sources. In a new study, the research team led by Jos Lelieveld and Andrea Pozzer from the Max Planck Institute for Chemistry and Andy Haines from the London School of Hygiene & Tropical Medicine assesses the consequences of a fossil fuel phaseout for disease-specific and all-cause mortality through the concomitant effects of air pollution. 

The researchers find that most (52%) of the mortality burden is related to cardiometabolic conditions, particularly ischaemic heart disease that can cause heart attacks (30%). Stroke and chronic obstructive pulmonary disease both account for about 16%. About 20% is undefined, with arterial hypertension, diabetes mellitus, and neurodegenerative diseases possibly implicated. 

“We estimate that 5.13 million excess deaths per year globally are attributable to ambient air pollution from fossil fuel use and therefore could potentially be avoided by phasing out fossil fuels,” states atmospheric chemist Jos Lelieveld, director at the Max Planck Institute for Chemistry. “This corresponds to 82% of the maximum number of air pollution deaths that could be averted by controlling all anthropogenic emissions”.

The new results were accomplished by applying a new relative risk model which optimizes the exposure-response relationship throughout the global range of ambient exposure levels. In addition, estimates of cause-specific and all-cause mortality due to long-term exposure to particulate matter (PM2.5) and ozone (O3) are attributed to pollution sources in this study.

“Air pollution causes cardiovascular disease (CVD) but also exacerbates existing CVD, demonstrating in particular the vulnerability of the cardiovascular system to PM 2.5. Thus, it is time now and of utmost importance to acknowledge air pollution as a significant cardiovascular risk factor, e.g., in the ESC and AHA/ACC guidelines for prevention, ischemic heart disease and stroke,“ adds the cardiologist and coauthor, Thomas Münzel from University Medical Center Mainz. 

Study design: Atmospheric modelling method distinguishes source categories
The scientists developed a data-constrained global atmospheric modelling method to compute gaseous and particulate air pollutants and attributed them to source categories. The atmospheric model was used to calculate the fractional changes in PM2.5 related to emission sectors based on computer simulations in which source categories have been sequentially switched off. 

“Our model calculated fractional changes were then applied to the high-resolution observational particulate pollution data to determine exposure reductions according to four emission scenarios,” explains Andrea Pozzer. The first scenario assumes that all fossil fuel-related emission sources are phased out. The second and third, “quarter way” and “half way” scenarios assume that 25 per cent and 50 per cent of the exposure reduction towards the fossil phaseout are realised, respectively. Finally, the fourth removes all anthropogenic sources for reference, thus only accounting for natural sources such as aeolian dust, marine and terrestrial biosphere emissions, and natural wildfires. Since the responses are not strongly non-linear, the team of scientists concludes that fossil fuel-related emission reductions at all levels of air pollution can decrease the number of attributable deaths substantially.

“Ambient air pollution would no longer be a leading environmental health risk factor if the use of fossil fuels were superseded by equitable access to clean sources of renewable energy,” emphasizes epidemiologist Andy Haines from the London School of Hygiene & Tropical Medicine. “This study provides new evidence to motivate rapid fossil fuel phaseout”. Phasing out fossil fuels is a remarkably effective health-improving and life-saving intervention and a major co-benefit of the United Nations' goal of climate neutrality by 2050.

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