The Multi‐Decadal Response to Net Zero CO ₂ Emissions and Implications for Emissions Policy

How confident are we that CO2 emissions must reach net zero or below to halt CO2-induced warming? The IPCC's sixth assessment report concluded “limiting human-induced global warming a specific level requires … reaching at least emissions.” This is much stronger language than the special on of 1.5°C, which would be sufficient. Here show “approximately zero” better supported “at zero.” We estimate rate adjustment (RAZE) parameter (−0.24 +0.17%/yr), defined as fractional change in after cease. RAZE determines compatible with halting over multiple decades: 1.5°C-consistent scenarios, consistent anthropogenic +2.2 GtCO2/yr (5–95th percentile range spans −7.3 +6.2 GtCO2/yr), similar expected from unmodelled Earth system feedbacks.