Fig. 1: Evolution and hysteresis of CO₂, temperature, precipitation, and TC frequency.

CESM2 ensemble-averaged time series of (a) global averaged CO₂ mixing ratio (unit: kg kg⁻¹), changes in (b) global mean surface temperature (unit: K), and (c) precipitation (unit: mm day⁻¹) relative to the present-day control simulation. Annual TC frequency (unit: year⁻¹) changes in the HiRAM time slice experiments in the (d) global, (e) northern hemisphere, and (f) southern hemisphere of the main TC genesis region. The percentages on the right y-axis represent the fractions of change. (g–i) as (d–f), but for CESM2 ensemble-averaged time series of DGPI (unitless) changes. In each plot, the red and blue colors represent the decarbonization phases of the ZEC and IRCC experiments, respectively, while the gray line represents their common ramp-up period. Dots and vertical dashed lines are used to denote the equally spaced time slices centered at the years 2054 (P1), 2107 (P2), 2160 (Z3/N3), 2213 (Z4/N4), 2266 (Z5/N5), 2319 (Z6/N6), and 2372 (Z7/N7). Colored shading or error bars represent two inter-member standard deviation spreads. The main TC genesis region used in (d–i) is outlined in Fig. 2 and consists of two parts, the northern hemisphere (100°E-360°E, 5°-30°N) and the southern hemisphere (40°E-220°E, 5°-30°S). The Δ symbol indicates the ensemble-averaged change relative to the climatological value (shown in parentheses at the top of each plot) in the control simulation.