Increasing Precipitation Efficiency Amplifies Climate Sensitivity by Enhancing Tropical Circulation Slowdown and Eastern Pacific Warming Pattern

Cloud processes are the largest source of uncertainty in quantifying global temperature response to carbon dioxide rise. Still, role precipitation efficiency (PE) -- surface rain per unit column integrated condensation is yet be quantified. Here we use 36 limited-domain cloud resolving simulations from Radiative-Convective Equilibrium Model Intercomparison Project show that they strongly imply climate warming will result increases net efficiency. We then analyze 35 General Circulation Models (GCMs) Coupled Phase 6 and find increasing PE enhances tropical circulation slowdown strengthens eastern equatorial Pacific warming. These changes trigger pan-tropical positive feedback by causing stratiform anvil reduction stratocumulus suppression, thereby amplify overall sensitivity. Quantitatively, 24 GCMs which match cloud-resolving models simulating with greenhouse warming, mean Effective Climate Sensitivity 1 K higher than decreases. The also comprise all estimates effective sensitivity over 4 K. Taken together, these results further constraining reduce future change.