Fig. 2. Greater Expressed Familiarity (mean) with Climate-Intervention Technologies in Global South versus Global North countries (1–5 scale: 1 = Not at all (never heard of it); 5= Very familiar).

N = 30,284 participants. Significant differences (p < 0.05) between expressed level of familiarity in Global North versus Global South countries were identified using nonparametric independent-samples (two-tailed) Mann Whitney U tests for nine of the ten technologies: for stratospheric aerosol injection, U = 28.000, Z = −3.293, p = 0.001; marine cloud brightening, U = 18.000, Z = −3.723, p = 0.000; space-based geoengineering, U = 26.000, Z = −3.378, p = 0.000; marine biomass and blue carbon, U = 33.000, Z = −3.077, p = 0.001; soil carbon sequestration, U = 42.000, Z = −2.690, p = 0.006; DACCS, U = 22.000, Z = −3.551, p = 0.000; BECCS, U = 23.000, Z = −3.507, p = 0.000; enhanced weathering, U = 22.000, Z = −3.551, p = 0.000; and biochar, U = 36.000, Z = −2.948, p = 0.002. For all, the level of expressed familiarity is significantly higher for publics in Global South. The one exception is afforestation and reforestation, where there was not a statistically significant difference, although close to the threshold of significance: U = 59.000, Z = −1.958, p = 0.052. Horizontal lines within boxes represent medians, while shaded boxes identify the middle 50% of the data (interquartile range, IQR). Whiskers extend above and below box to either the minimum and maximum values in the sample population or 1.5 times the length of the IQR, whichever is closer to median. Shaded circles and asterisks represent outliers: with circles identifying values within 1.5 times IQR, asterisks those 1.5 to 3 times IQR. Outliers: Turkey (positive) for all technologies; USA (positive) for marine cloud brightening; space-based geoengineering; marine biomass and blue carbon, DACCS, BECCS, and enhanced weathering; and India (positive) for soil carbon sequestration and marine biomass and blue carbon.