Short-lived Halogens: A Key Component of Atmospheric Chemistry and Climate

We demonstrate that short-lived halogens (SLH) are a critical yet previously overlooked component in atmospheric models. Their inclusion significantly improves the agreement between models and observations across key parameters, establishing SLH as one of the few compounds that influence nearly all atmospheric regions. Despite extensive laboratory, observational, and modelling evidence over the past two decades, current air quality and climate models used in international assessments omit detailed SLH sources and chemistry. Such omissions yield inaccurate evaluations, incomplete budgets of atmospheric constituents, and flawed projections of ozone, methane lifetimes, and the global radiation budget. This Nature review presents a detailed list of the effects of SLH on the atmosphere and future research directions while advocating for their systematic inclusion in air quality and climate models.

Reference: Saiz-Lopez, A., Mahajan, A.S., Abbatt, J., et al. (2025). The influence of short-lived halogens on atmospheric chemistry and climate. Nature, 648, 289-299. https://doi.org/10.1038/s41586-025-09753-x