Climatic Change, Wildfire, and Conservation

TLDR

Climatic variability dominates large wildfire occurrence in the western U.S., supported by palaeoecological evidence, yet extreme fire weather remains the primary driver of area burned and severity, and linking oceanic patterns to fire occurrence has been inconsistent across regions. The study aims to assess whether incorporating large‑scale Pacific oceanic and atmospheric patterns can extend fire‑weather forecasting beyond short‑term horizons. The authors propose using El Niño Southern Oscillation and Pacific Decadal Oscillation indices to forecast seasonal‑to‑annual climatic variability that drives fire weather. Future warming is projected to lengthen fire seasons, increase area burned, and shift fire timing, which will alter plant community composition—fire‑sensitive species may decline while fire‑favored species may expand—though the magnitude of these ecological impacts will depend on how management changes vegetation and fuels.

Abstract

Abstract: Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire‐scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short‐term predictions of fire weather, but increased understanding of large‐scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi‐periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.