The season for large fires in Southern California is projected to lengthen in a changing climate

Abstract Southern California is a biodiversity hotspot and home to over 23 million people. Over recent decades the annual wildfire area in coastal southern region has not significantly changed. Yet how fire regime will respond future anthropogenic climate change remains an important question. Here, we estimate probability at station scale daily resolution using random forest algorithms downscaled earth system model simulations. We project that large days increase from 36 days/year during 1970–1999 58 under moderate greenhouse gas emission scenario (RCP4.5) 71 by 2070–2099 high (RCP8.5). The season be more intense have earlier onset delayed end. Our findings suggest despite lack of contemporary trend regime, projected emissions substantially danger 2099.