Public perceptions of climate engineering: Laypersons’ acceptance at different levels of knowledge and intensities of deliberation

Over the past years, new options for addressing global warming and atmospheric CO₂-concentrations ‐ such as bioenergy carbon capture and storage ‐ have been included in computer models that estimate how much more can be emitted before the global mean temperature increase surpasses 1.5°C. While the public in general remains mainly unaware of these, similar proposals in the past have triggered public protests. The prospect of public opposition therefore calls into question the use of these options in the models.

Even if societies decarbonized rapidly, it is unlikely that they will achieve the 1.5°C target without also resorting to CO₂ removal, by means, for example, of bioenergy carbon capture and storage (BECCS). Such methods were included in the special report Global Warming of 1.5°C published by the Intergovernmental Panel on Climate Change in 2018. This report also discusses solar radiation management, such as stratospheric aerosol injection (SAI) which might be used to change global temperatures. However, public debate about the acceptability of these methods remains absent. We look at laypersons’ perceptions of BECCS and SAI at three stylized stages of increasing knowledge and deliberation. We found a high level of uncertainty among survey respondents as to whether to accept the use of these methods, which decreases when additional information is supplied by stakeholders. When comparing survey participants to members of a citizens’ jury, we found lower levels of acceptance for SAI and similar levels for BECCS among jury members who had deliberated the methods intensively. Despite fears of distracting from the aim of reducing emissions, decision-makers should publicly discuss these methods to avoid planning based on incorrect assumptions about the political feasibility of CO₂ removal. People want to be informed about both approaches and the threat of SAI makes them focus their attention on mitigation.