Deployment Strategy Shapes the Polar Climate Response to Marine Cloud Brightening - Preprint

[Geoengineering News]

https://essopenarchive.org/users/891919/articles/1377001-deployment-strategy-shapes-the-polar-climate-response-to-marine-cloud-brightening

Authors: Erin J. Emme, Chih-Chieh Chen, Hannah Horowitz

10 January 2026

Abstract

Marine cloud brightening (MCB) is a proposed solar climate intervention strategy that increases marine cloud reflectivity to cool Earth’s surface. While previous studies have examined its global temperature and precipitation effects, less is known about how MCB deployment strategy influences polar climate and sea ice. Here, we use nine MCB simulations with the Community Earth System Model version 2 (CESM2) to evaluate how deployment location and seasonality affect Arctic and Antarctic surface temperature, sea ice area, and thickness. All experiments target restoration of global mean surface temperature to 1.5°C above preindustrial levels but differ in MCB deployment location and timing. We find that MCB is more effective at restoring sea ice when deployed in the same hemisphere and during local summer months, when incoming solar radiation is greatest, whereas opposite-hemisphere or winter deployments are less effective. When deployed in both hemispheres rather than a single hemisphere, midlatitude MCB schemes improve polar temperature and sea ice conditions compared to climate change (the control, following SSP2-4.5), especially in the Antarctic. Our results demonstrate that both the location and seasonality of MCB deployment critically determine its efficacy in polar sea ice and temperature restoration as well as the broader climate consequences. Designing MCB strategies with hemispheric balance and appropriate timing may enhance the feasibility of sea ice restoration without inducing major climate disruptions, such as disrupting the El Niño Southern Oscillation (ENSO) or shifting the Intertropical Convergence Zone (ITCZ).

Source: ESS Open Archive