Climate action in space: A sustainable development framework for sunshades at Sun-Earth Lagrange Point 1

[Geoengineering News]

https://www.sciencedirect.com/science/article/pii/S027311772501155X

Authors: Jonas Bahlmann, Zizung Yoon, Vittorio Franzese, Enrico Stoll, Andreas M. Hein a

10 October 2025

https://doi.org/10.1016/j.asr.2025.10.024

Abstract

Sunshades in space have been proposed as a geoengineering solution to mitigate climate change by reducing incoming solar radiation. Sunshade concepts are gaining attention as a lower-risk but higher-cost alternative to terrestrial solar radiation management approaches, such as stratospheric aerosol injection. However, the literature is limited, and the absence of a structured development framework complicates the evaluation, comparison, and maturation of these concepts. A shared standard that reflects the wide-ranging aspects of sunshade deployment could streamline efforts, accelerate progress, and improve the recognition of sunshades in the international climate change debate. While aiming to provide sustainability from space, a deployed sunshade must also follow sustainability principles in space given its scale. At the same time, the required industry on Earth should align with broader sustainability goals, ensuring that it does not undermine ongoing efforts toward a sustainable future. Therefore, as a first step, this paper analyzes the applicability of internationally recognized sustainability frameworks – namely the United Nations Sustainable Development Goals and the European Space Agency’s Environmental Impact Indicators for space systems – by employing a content analysis methodology on a representative selection of literature. The insights gained, along with criteria derived from the geoengineering literature, shaped the 18 Sunshade Development Criteria (SDC), a framework for sustainable development. Subsequently, this paper analyzes the case study literature based on the SDC to draw conclusions on the state of the art of the sunshade domain. This framework is the first of its kind and this study is the first that employs a systematic content analysis to evaluate the sunshade literature. The findings indicate that a detailed assessment and comparison of sunshade concepts remain challenging because of the field’s fragmentation. Although criteria such as side effects, controllability, and the overall context of climate change have been covered, significant gaps remain. These include technical maturity, global warming potential, sustainability considerations, distribution of spatio-temporal radiative forcing, public perception, social acceptability, global inequalities, and impacts on the space segment. Addressing these gaps is essential, and the SDC serve as a crucial tool to facilitate this maturation. Beyond purely technical considerations, this paper introduces an interdisciplinary perspective on the sunshade domain while demonstrating this approach through its methodology and proposed framework. It seeks to advance sunshade concepts and guide their sustainable development and deployment to address climate change. Ultimately, it aims to increase the acceptance of sunshades in the international debate on whether and how we should intervene in the climate.

Source: ScienceDirect