Limited climate response to extreme Arctic mixed-phase cloud thinning - Preprint

[Geoengineering News]

https://www.researchsquare.com/article/rs-10757569/v1

Authors: Xia Li, Amato Evan, Ian Eisenman, Jasper Kok

18 September 2026

https://doi.org/10.21203/rs.3.rs-10757569/v1

Abstract

Cloud-based climate interventions seek to reduce climate change impacts by altering Earth's radiation budget through targeted cloud modifications. Mixed-phase regime cloud thinning (MCT) is a recently proposed intervention that aims to reduce cloud longwave trapping by seeding mixed-phase regime clouds with ice-nucleating particles, thereby promoting liquid-to-ice conversion and cloud thinning. Although the microphysical basis of MCT is well known, its large-scale climatic potential is poorly known. Here we address this question by evaluating the climatic response to removing all target clouds for MCT in the wintertime Arctic in a climate model. We find that, even under this intentionally extreme scenario, the response remains both localized to the Arctic Ocean and limited in magnitude, producing -0.47±0.08°C of Arctic annual-mean cooling and 0.23±0.04 million km2 of annual-mean sea ice expansion. This offsets 4.3% of Arctic warming and 3.5% of sea ice loss under doubled CO2, or approximately 18% and 13%, respectively, relative to observed changes over the past four decades. These findings suggest limited large-scale climatic leverage of MCT but potential value for locally targeted applications, particularly near susceptible marginal ice zones.

Source: ResearchSquare