EGU26 - [Session AS3.43] Effect of stratospheric aerosol injection scenarios on surface irradiation and solar energy production

[Geoengineering News]

https://meetingorganizer.copernicus.org/EGU26/EGU26-3052.html

Authors: Kevin Kilchhofer, Kyriaki Papachristopoulou, Manouk Geurts, Timofei Sukhodolov, and Stelios Kazadzis

13 March 2026

Abstract 

This study aims to quantify how different stratospheric aerosol injection (SAI) scenarios influence clear-sky (cloudless) surface solar radiation (SSR) by applying benchmark radiative transfer calculations. SAI is a solar radiation modification (SRM) method, which is increasingly viewed as a potential backstop against global warming. If SRM techniques are implemented in the future, it will be important to understand their potential financial and societal implications, particularly with respect to reduced solar energy production. Currently, there is limited understanding of how SRM might influence photovoltaic (PV) power generation or which measures could effectively counteract potential declines in SSR.

We obtain SSR estimates of a reference and SAI scenarios using the libRadtran radiative transfer model [1, 2]. The SAI scenarios include an aerosol layer of different solid and liquid materials, including sulfuric acid, diamonds, alumina, and calcite aerosol particles. The optical properties of these particles were determined with the Mie scattering module in libRadtran, using the physical parameters reported in Vattioni et al., 2024 [3] and Hummel et al., 1988 [4]. We performed radiation simulations using location-specific ambient tropospheric composition profiles obtained from the Copernicus Atmosphere Monitoring Service (CAMS). We calculated it for a reference and specified SAI scenarios and for different solar PV geometries (azimuthal orientation and tilting angles).

In summary, the results reveal a slight negative percentage difference (3-12%) for low solar zenith angles (sza < 60°) of the direct horizontal irradiance component when applying an aerosol optical depth of 0.07 for all SAI scenarios. Interestingly, the differences are larger for solid particles (e.g., diamond) and increase further at higher sza values. On average, the diffuse fraction of the irradiance is about 40% higher with an SAI layer than in the reference case, increasing from roughly 110 Wm−2 to 150 Wm−2. The data will be supplied for PV energy production simulations as a function of the PV material, and the resulting outputs will offer valuable insight into how SAI could alter the Earth’s radiation budget.

Source: EGU26

[Robert H. Socolow]

Could geoengineering ever start? Could it ever stop? Grist for “Destiny Studies” and “Continuity Ethics” | Climatic Change | Springer Nature Link, Climatic Change 179,75 (2026). 

In my new article, just published open access in Climatic Change, I introduce two concepts that may be useful in deepening the discussion of geoengineering: we are operating within "Destiny Studies," and we are drawn to "continuity ethics," which gives priority to human flourishing. I have been informed by the experience of setting the Doomsday Clock of the Bulletin of the Atomic Scientists, as one of roughly 15 members of its Science and Security Board, which has required annual assessments of existential risks to humanity.

This article is part of a collection in Climatic Change developed by Arthur Obst and Matthew Harvey, Geoengineering in Crisis: Special Issue on the Ethics and Governance of Climate Intervention. It is the eighth of eight articles that Climatic Change has published so far for this special issue.   

Comments welcome,

Robert Socolow