A new study published in The Lancet Global Health reports on Mar. 16 that international climate policies aimed at protecting developing countries from the costs of cutting carbon emissions could unintentionally limit those countries' air quality improvements and related health benefits. The research, led by teams from The University of Texas at Austin, Emory University, Princeton University, and collaborators across six countries, examined how different approaches to meeting the Paris Agreement's two-degree Celsius target would affect emissions, air quality, health outcomes, and economic welfare in 178 countries through the end of the century.
The findings are significant because they highlight a complex challenge for global climate negotiations: balancing fairness in cost-sharing with maximizing public health benefits. According to the study, achieving the two-degree target could prevent more than 13.5 million premature deaths from air pollution between 2020 and 2050—mostly in low- and middle-income countries (LMICs). However, how these gains are distributed depends on whether emission reductions occur where it is cheapest or where pollution is most severe.
Under a least-cost approach—where emissions are reduced wherever it is most economical—LMICs bear much of the mitigation effort but also receive the greatest air quality benefits. In contrast, an equity-based approach shifts more responsibility to wealthier nations but results in nearly four million fewer avoided premature deaths in LMICs due to less fossil fuel reduction where pollution levels are highest. "We show that there is a difficult tension between international distributive climate justice and the goal of saving lives via air pollution co-benefits," said Mark Budolfson, associate professor at The University of Texas at Austin and co-lead author. "Within the current Paris Agreement climate regime involving Nationally Determined Contributions to global emissions reductions, shifting mitigation from poor countries to rich countries has the perverse effect of reducing the number of lives saved via air quality improvements in poor countries—possibly by millions."
The researchers identified a potential solution: if LMICs use their savings from reduced climate mitigation costs under an equity-based regime to invest in conventional air pollution controls (such as technologies targeting soot and sulfur dioxide), both fairness and health goals can be achieved. This scenario was found to deliver full life-saving potential while maintaining equitable cost distribution. "There is an urgent need to design justice-centered climate mitigation regimes to ensure that developing countries do not miss an opportunity to realize transformative reductions in air pollution," said Noah Scovronick, another co-lead author.
The study's authors suggest these insights should inform future rounds of international climate negotiations as nations update their emission-reduction pledges. Navroz K. Dubash of Princeton University said: "Our research shows the benefits of looking at development and climate policy together." Wei Peng added: "Understanding the complex trade-offs involved between different climate mitigation strategies is politically important, but analytically challenging." The study used advanced modeling tools—including GCAM for energy and emissions analysis—to assess impacts across multiple dimensions.
The research was funded by a United States National Science Foundation grant (#2420344), with Budolfson serving as Principal Investigator.
