(Bloomberg) -- Efforts to slow the process of global warming focus on the future harms of continuing to burn fossil fuel, but new research released Tuesday shows that deadly consequences from pollution are killing larger numbers of people right now than had been assumed.

Fossil fuels are alone responsible for more than 8 million premature deaths annually, according to new research by a team of U.S. and U.K. scientists published in Environmental Research . That's double the previous high-end estimate of fine-particle pollution mortality, and three times the combined number killed by HIV/AIDS, tuberculosis, and malaria in 2018. 

Even though air quality has improved in many countries, particularly wealthier ones, the findings suggest that even at lower concentrations pollution caused by fossil fuels is deadlier than previously understood. In the U.S., for instance, the researchers found that 350,000 premature deaths per year are attributable to fine-particulate pollution generated by fossil-fuel combustion, up from previous estimates of roughly 100,000 to 150,000. This means even successful pollution-fighters have more work to do—particularly in poor and historically disadvantaged areas, where pollution is even more concentrated.

The new study improves on previous methods in several ways. Much previous work—including past editions of the influential Global Burden of Disease study—relied on equivalents extrapolated from studies of cigarette smoking. Now, however, there’s enough data on the real health effects PM₂.₅, the deadliest type of airborne particulate matter made up of particles smaller than 2.5 millionths of a meter, that the researchers were able to refine their findings. 

The scientists also made other methodological improvements, including by deriving a tighter relationship between levels of air pollution and their effects in different regions from a comprehensive survey of research from around the world. An improved model of how air pollution travels gave scientists greater confidence in their numbers.

The results underscore a fact absent from much public debate and discussion about climate change. While the fight to stop greenhouse gas pollution by curtailing fossil fuel use is framed in terms of how it would improve the future, it’s also true that fossil fuels are killing millions of people right now. That’s how Aaron Bernstein, interim director of the Center for Climate Health and the Global Environment at Harvard’s Chan School of Public Health, understands the new research.

“I’m a pediatrician,” said Bernstein, who is familiar with the new study but not involved in it. “When I’m taking care of a child who’s struggling to breathe because they breathe polluted air, the parent of that child is maybe very concerned about the world that their child is going to grow up into, and lead their lives in, when they're 40, 50, 80 years old. But I assure you they worry a lot more about the child not breathing right now.”

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