Projected increase in lightning strikes in the United States due to global warming

TLDR

Lightning plays an important role in atmospheric chemistry and in the initiation of wildfires, but the impact of global warming on lightning rates is poorly constrained. The study proposes that lightning flash rate is proportional to convective available potential energy (CAPE) times precipitation. Lightning flash rate is modeled as proportional to CAPE times precipitation, with storms converting this product to discharged lightning energy at 1 % efficiency. Observations show that CAPE times precipitation explains 77 % of the variance in CONUS cloud‑to‑ground lightning, and climate models predict a 12 ± 5 % per °C increase, amounting to ~50 % over the century.

Abstract

Lightning plays an important role in atmospheric chemistry and in the initiation of wildfires, but the impact of global warming on lightning rates is poorly constrained. Here we propose that the lightning flash rate is proportional to the convective available potential energy (CAPE) times the precipitation rate. Using observations, the product of CAPE and precipitation explains 77% of the variance in the time series of total cloud-to-ground lightning flashes over the contiguous United States (CONUS). Storms convert CAPE times precipitated water mass to discharged lightning energy with an efficiency of 1%. When this proxy is applied to 11 climate models, CONUS lightning strikes are predicted to increase 12 ± 5% per degree Celsius of global warming and about 50% over this century.