Ethical aspects

Although the ethics of climate engineering technologies have been discussed for over a decade, the focus has largely been on Solar Radiation Management (SRM) or Solar Geoengineering (see, e.g., Gardiner, 2011; Preston, 2012). Recently, interest in the ethical aspects of Carbon Dioxide Removal (CDR) has notably increased, but existing contributions typically address terrestrial methods, particularly Bioenergy with Carbon Capture and Storage (BECCS) (e.g., Lenzi, 2018; Lawford-Smith and Currie, 2017; Gough et al., 2018). The main ethical discussions here revolve around the likelihood, scale, and ethical relevance of the so-called Moral Hazard effect, which refers to the potential that the use or even consideration of CDR might hinder the reduction of greenhouse gas emissions (Morrow, 2014; McLaren et al., 2019). Very few studies have, however, examined marine CDR methods from an ethical or justice-theoretical perspective. Minx et al. (2018), in reference to both terrestrial and marine CDR, recently concluded that ‘there are currently very few ethical analyses of NETs [Negative Emissions Technologies].’ Others argue that ethics, as well as the social sciences and humanities, should play a much more central role in future CDR research (Lenzi et al., 2018; Markusson et al., 2020).

While there is now a substantial body of literature on the normative evaluation of climate engineering (see above), little has been written about the criteria for evaluating these technologies (see, for example, Stelzer and Schuppert, 2016, in relation to Solar Radiation Management). However, an emerging debate on evaluation criteria for climate policies is beginning to take shape (see, e.g., Gewirtzmann et al., 2018). A recent contribution to this debate is a study by Zimm et al. (2023), which claims to offer a systematic representation of all justice criteria relevant to climate research. Yet, as with other studies, this approach—unlike in ASMASYS II—does not reflect on how these considerations interact and can potentially be aggregated to form a higher-level judgment on the (in)justice of a climate policy option.

From an ethical perspective, it is also important to emphasize that the latest version of the IPCC’s assessment framework (IPCC, 2023) still does not explicitly separate desirability from feasibility. As a result, normative considerations, such as those related to justice, continue to play an unclear role in feasibility analyses, rather than being used for their primary purpose: to assess the desirability of climate change mitigation measures and their impacts.