Co-benefits of avoided air pollution mortality have been costed at US$50-380 per tonne of CO2.

23 September 2013 — A study has found global abatement of greenhouse gas emissions could save between 1.4 and three million premature deaths in the year 2100.

The report, Co-benefits of mitigating global greenhouse gas emissions for future air quality and human health, published in Nature Climate Change, found that improved air quality had been underestimated in studies of how reductions in greenhouse gas emissions decreased co-emitted air pollutants.

The researchers said previous studies had analysed air pollution-related mortality as a near-term and local effect, with little attention to international transport of air pollutants, long-term changes in human populations and the indirect influence of climate change on air quality.

The new, comprehensive analysis has used global modelling methods, likely future scenarios and newly affirmed relationships between chronic mortality and exposure to particulate matter and ozone to find that 0.3–0.7 million premature deaths could be avoided in 2030, of which two-thirds would be in China.

By mid-century, 0.8–1.8 million premature deaths could be avoided in a single year, and 1.4–3 million by 2100.

The authors also estimated the monetary value of avoided deaths for each tonne of CO2 abated, and found a global average of between US$50 and $380.

This value exceeded previous estimates and is higher than marginal greenhouse gas reduction costs by 2030 and 2050.

This result suggests that climate mitigation is financially worthwhile even aside from the benefits of slowing down changes in climate.