Figure 2.
Representative scenarios used in figures 3–6. (a) CO2-equivalent (CO2e) for representative concentration pathway RCP8.5 (representing a business-as-usual (BAU) scenario), RCP4.5 (to represent mitigation) and RCP4.5 augmented with significant levels of long-term CO2 removal (+CDR) sufficient to reduce concentrations by 1 ppm yr−1. The solar reduction (+ SRM) used in figure 3 is shown in b. For simplicity, the carbon-cycle feedbacks between the reduced temperatures associated with using solar geoengineering and resulting CO2 concentrations is ignored. (Online version in colour.)