The escalating impacts of climate change and the inadequacy of emissions reductions are prompting increased consideration of novel climate intervention technologies, such as carbon dioxide removal (CDR) and solar radiation modification (SRM). While these technologies offer potential solutions, they also present significant risks and uncertainties. The Global South, disproportionately affected by climate change despite contributing less to historical emissions, faces unique challenges in engaging with these technologies. Existing research on public perceptions of CITs primarily focuses on the Global North, neglecting the perspectives of Global South populations. This study addresses this gap by conducting a large-scale, cross-country survey to establish a global baseline of public perceptions of CDR and SRM technologies, comparing and contrasting views between the Global North and Global South. The importance of this study lies in its potential to inform more inclusive and equitable discussions and decision-making processes surrounding the deployment of CITs, considering the varying levels of familiarity, perceived risks and benefits, and support for related policies across different regions and demographics.

Existing research on public perceptions of climate intervention technologies reveals a general lack of familiarity with these methods, particularly among Global North populations. Most studies are quantitative and focus on a limited number of countries, predominantly those in the Global North, with very little engagement with Global South perspectives. Studies that include Global South representation are few and often limited in scope, failing to provide a comprehensive comparison with the Global North. This research gap underscores the need for a large-scale, cross-national study to explore the nuances in public perceptions across different geographical contexts and to determine the generalizability of the existing findings.

This study employed a large-scale, cross-country survey (N=30,284) conducted in 30 countries and 19 languages. The survey samples were nationally representative in terms of age (18-74), gender, geographic region, and included quotas for education and income levels. Participants were randomly assigned to one of three groups, each focused on a specific category of CITs: Solar Radiation Modification (SRM), Ecosystem-based CDR, and Engineered CDR. The survey instrument assessed familiarity with different CITs, perceptions of risks and benefits, support for research, small-scale field trials, and broad deployment, and preferences for national and international policies related to these technologies. Data analysis included descriptive statistics, nonparametric testing (Mann-Whitney U test, Kruskal-Wallis test, Friedman’s two-way ANOVA by ranks, Wilcoxon signed-rank test), and hierarchical linear regression. Ethical approval was obtained from Aarhus University, with informed consent given by all participants. Data collection was conducted online by Norstat using quota sampling, and all data were anonymized.

The survey revealed low familiarity with most CITs globally, except for afforestation and reforestation. However, Global South publics demonstrated significantly higher familiarity across almost all technologies. Significant differences in perceived risks and benefits emerged between Global North and South cohorts. Global South publics perceived greater benefits across all technology categories, particularly for SRM, while expressing greater concern about unequal risk distribution and moral hazard (reduced motivation for mitigation). The Global North expressed more concern about environmental and safety risks. Support for CIT activities (research, field trials, deployment) was generally higher in the Global South, except for afforestation and reforestation, where support was similar. Ecosystem-based CDR received the highest support globally, while SRM and enhanced weathering received the least. Hierarchical regression analysis showed that a country's mean age was a significant predictor of overall support for CITs, particularly for engineered CDR and SRM; younger populations tended to express greater support. Lastly, support for policies was significantly higher in the Global South, mirroring support for the technologies themselves, with a preference for national-level support and information campaigns over restrictive measures.

This study's findings directly address the research question by providing a comprehensive global comparison of public perceptions and support for CITs. The significantly higher support for CITs in the Global South, despite greater concern about moral hazard, challenges the common narrative that these technologies are primarily a 'rich-world' solution. The strong influence of age and climate-related beliefs on support highlights the need to tailor communication and engagement strategies to specific demographics and contexts. The observed differences in salient risks between the Global North and South underscore the importance of culturally sensitive risk assessments and governance frameworks. These findings contribute significantly to the field by providing crucial data for informed policymaking and more equitable global discussions on CIT deployment. They also highlight areas where further research is needed, such as detailed analysis of moral hazard perceptions in the Global South and exploring the complexities of heterogeneity in opinions within countries.

This study provides the first large-scale, globally representative assessment of public perceptions of climate intervention technologies. Key findings highlight significantly higher support in the Global South compared to the Global North, driven by factors such as age and climate vulnerability. The study reveals a need for nuanced engagement with diverse publics, tailored to specific cultural contexts and concerns. Future research should investigate moral hazard perceptions in detail, explore the potential for evolving public opinions, and examine the effectiveness of different communication strategies in fostering informed public discourse on CITs.

The reliance on online surveys may have introduced sampling bias, potentially excluding less digitally connected populations. The cross-sectional nature of the study limits the ability to draw conclusions about causal relationships between variables. The limited depth of questions on certain topics, such as moral hazard and equity concerns, could have constrained the richness of the insights. While efforts were made to ensure consistent information provision, unintended differences in complexity across technologies may remain.