Geoengineering options such as negative emissions technologies (NETs) or greenhouse gas removal (GGR) may need to contribute towards decarbonization, by removing CO₂ from the atmosphere and storing it safely in biological or geological sinks, or reflecting sunlight back into space via solar radiation management (SRM). Despite concerns about them, GGR and SRM are increasingly discussed as crucial complements to traditional climate change mitigation. Others routinely dismiss both SRM and GGR methods as a distraction from mitigation, or even as a potential moral hazard that induces complacency in reducing emissions. Yet, if climate impacts turn out to be more sudden and severe than currently known, such strategies could provide a rapid backstop to implement deeper emissions reductions, especially with techniques that require time to scale-up. Despite their importance and controversial status, most research on GGR and SRM remains technical, rather than social, and that knowledge of their technical characteristics remains limited, even within the physical and engineering sciences. Moreover, existing GGR and SRM options are changing rapidly in terms of their technical design, cost, and performance, and therefore scalability and deployment potential. To contribute to the debate, this study reviews and summarizes a large number of geoengineering assessments published over the past decade to document prospective benefits, but also reveal potential risks. It aims to provide a comprehensive evidence base on GGR and SRM technologies that is rigorous, timely, and interdisciplinary. This article begins by briefly defining geoengineering and associated technologies, describing how various techniques work, and summarizing recent market trends up until early 2021. Then, it discusses a series of advantages and disadvantages to these options before identifying tensions, research gaps, and a critical research agenda. It concludes with implications for research, policy, and governance.

诸如负排放技术（NETs）或温室气体去除（GGR）之类的地球工程选项可能需要通过去除CO ₂来促进脱碳从大气中吸收，并将其安全地存储在生物或地质水池中，或者通过太阳辐射管理（SRM）将太阳光反射回太空。尽管对这些问题感到担忧，但越来越多地讨论了GGR和SRM作为传统减缓气候变化的关键补充。其他人则常规地将SRM和GGR方法都视作对缓解措施的干扰，甚至认为是潜在的道德风险，会导致人们自满地减少排放量。但是，如果气候影响比目前已知的更加突然和严重，则此类策略可以提供迅速的支持，以实现更深层的减排，尤其是需要时间扩大的技术。尽管具有重要意义和争议性，但大多数有关GGR和SRM的研究仍是技术性的，而不是社会性的，而且即使在物理和工程科学领域，对它们的技术特征的了解仍然很有限。此外，现有的GGR和SRM选项在技术设计，成本和性能以及可扩展性和部署潜力方面都在迅速变化。为了促进辩论，本研究回顾并总结了过去十年中发表的大量地球工程评估，以记录潜在的收益，同时也揭示了潜在的风险。它旨在为严格，及时和跨学科的GGR和SRM技术提供全面的证据。本文首先简要定义了地球工程和相关技术，描述了各种技术的工作原理，并总结了直到2021年初的最新市场趋势。然后，它在确定紧张局势，研究差距和关键研究议程之前，讨论了这些选择的一系列优缺点。最后总结了对研究，政策和治理的启示。