Strong linkage between observed daily precipitation extremes and
anthropogenic emissions across the contiguous United States
Abstract
The results of probabilistic event attribution studies depend on the
choice of the extreme value statistics used in the analysis,
particularly with the arbitrariness in the selection of appropriate
thresholds to define extremes. We bypass this issue by using the
Extended Generalized Pareto Distribution (ExtGPD), which jointly models
low precipitation with a generalized Pareto distribution and extremes
with a different Pareto tail, to conduct daily precipitation attribution
across the contiguous United States (CONUS). We apply the ExtGPD to 12
general circulation models from the Coupled Model Intercomparison
Project Phase 6 and compare counterfactual scenarios with and without
anthropogenic emissions. Observed precipitation by the Climate
Prediction Centre is used for evaluating the GCMs. We find that
greenhouse gases rather than natural variability can explain the
observed magnitude of extreme daily precipitation, especially in the
temperate regions. Our results highlight an unambiguous linkage of
anthropogenic emissions to daily precipitation extremes across CONUS.