1 How do we perceive carbon-dioxide lifetimes? Thematic Area: Climate change: mitigation and adaptation

Most people think linearly when confronted with constant or non-linear non-proportional problem situations in their day to day lives (Larrick & Soll, 2008; Van Dooren et al., 2005). In this paper, we test evidence of linear human perceptions on non-linear problems that concern the change in carbon dioxide (CO2) lifetimes. The change in CO2 lifetime was presented in two forms: as a percentage removed from the atmosphere every year (percent/year) and as years of stay in the atmosphere (years). The percentage of CO2 removed from the atmosphere is predicted to decrease in the future due to decreased absorption of CO2 by oceans and biomass and this will cause an increase in the lifetime of CO2 on account of global warming. The percentage of CO2 removed from the atmosphere every year is 1 / lifetime of CO2 (in years and thus, non linear). We ran two experiments to investigate the human linear misperception problem and to determine how to possibly cure the problem. In the first experiment, using a survey, we asked people to rank order five changes in percentage of CO2 removed every year from a present value to a future smaller value that would cause the largest increase of lifetime of CO2 in years (and be most detrimental to our climate). We then asked people what would be the actual increase i