Stronger influences of increased CO₂ on subdaily precipitation extremes than at the daily scale

Based on idealized experiments (preindustrial control experiment (PI) and 1% yr⁻¹ increase (1%CO₂) in atmospheric CO₂) from 10 general circulation models produced under the Coupled Model Intercomparison Project Phase 5 and using the fraction of attributable risk, we examine the CO₂ effects on extreme precipitation at the subdaily and daily scales. We find that the increased CO₂ concentration substantially increases the odds of the occurrence of subdaily precipitation extremes compared to the daily scale in most areas of the world, with the exception of some regions in the subtropics, likely in relation to the subsidence of the Hadley Cell. These results point to the large role that atmospheric CO₂ plays in extreme precipitation under an idealized framework.