Title: US wildfire potential: a historical view and future projection using high-resolution climate data

Abstract

Recent wildfires in the western United States have led to substantial economic losses and social stresses. There is a great concern that the new climatic state may further increase the intensity, duration, and frequency of wildfires. To examine temporal and spatial features of historical wildfire trends and future changes, a common fire index, the Keetch-Byram Drought Index (KBDI), is calculated over the contiguous United States (CONUS) and Alaska. We introduce an efficient initialization method and calculate 36 years (1982-2017) of historical KBDI at 4 km using a high-quality observational dataset. KBDIs are also calculated at 12 km using regional climate models and extended into the mid- and late-21st century. Based on the observational data, annual mean (and 95th percentile) KBDI over forested regions in the southwestern and northwestern CONUS has risen since 1982 at a rate of 5.2 (4.0) and 2.9 (3.3) per year, respectively, indicating a persistent drying trend fostering fire activities; the number of days exceeding the top 5% historical KBDI has increased by 16 and 25 d in the 36 years. Multiple regional climate model simulations project increasing wildfire potential and longer fire seasons over broader areas based on the estimated KBDI for the mid- and late-21stmore » century. By the end of the century, most of the CONUS would experience about 90-189 more days per year exceeding the historical local maximum KBDI; areas with high KBDI (>600), whose occurrence correlates with large burned area, are projected to broaden by nearly 60 times in the southern CONUS. While both temperature and precipitation contribute to future KBDI changes, warming is the main driver of more frequent, intense and wide-spread extreme wildfires indicated by high KBDIs in future projections.« less

Authors:

Brown, Emily K.; Wang, Jiali; Feng, Yan

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• Search DOE PAGES for ORCID "0000-0001-6464-0785"

Publication Date:

Mon Mar 08 00:00:00 EST 2021

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center; Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Laboratory Directed Research and Development (LDRD) Program

Contributing Org.:

PNNL, BNL, ANL, ORNL

OSTI Identifier:

1835475

Alternate Identifier(s):

OSTI ID: 1773681; OSTI ID: 1774589

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Published Article

Journal Name:

Environmental Research Letters

Additional Journal Information:

Journal Name: Environmental Research Letters Journal Volume: 16 Journal Issue: 3; Journal ID: ISSN 1748-9326

Publisher:

IOP Publishing

Country of Publication:

United Kingdom

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; wildfire potential; Keetch-Byram Drought Index; climate change impacts