Beyond the 1984 Perspective: Narrow Focus on Modern Wildfire Trends Underestimates Future Risks to Water Security

Abstract

The western United States remains well below historical wildfire activity, yet misconceptions abound in the public and news media that the area burning by wildfire each year in the American West is unprecedented. We submit that short-term records of wildfire and a disproportionate focus on recent fire trends within high-profile science stoke these misconceptions. Furthermore, we highlight serious risks to long-term water security (encompassing water supply, storage, and quality) that have only recently been recognized and are underestimated as the result of skewed perspectives of wildfire. Compiling several data sets, we illustrate a comprehensive history of western wildfire, demonstrate that the majority of western settlement occurred during an artificially and anomalously low period of wildfire in the twentieth century, and discuss the troubling implications the misalignment of wildfire activity and human development may have for the long-term projections of water security. A crucial first step toward realigning public perspectives will require scientists and journalists to present recent increases in wildfire area within the context and scale of longer-term trends. Second, proper housing development and resource management will require an appreciation for the differing western ecosystems and the flexibility to adopt varied approaches. These actions are critical for realigning public understanding of both the direct and indirect risks associated with wildfire and ensuring adequate and appropriate measures are taken as we navigate a future of increasing fire in the West.

Partitioned by process: Measuring post‐fire debris‐flow and rill erosion with Structure from Motion photogrammetry

“…Modern post-fire erosion demands attention. Anthropogenic climate change is exacerbating the size and severity of wildfires, leading to dramatic impacts on landscapes, ecosystems, human interests, and infrastructure (Goode et al, 2012;Abatzoglou et al, 2016;Sankey et al, 2017;Murphy et al, 2018). Pervasive post-fire erosion across steep landscapes exceeds background erosion rates by water-, gravity-, and wind-driven processes (Roering and Gerber, 2005;Shakesby and Doerr, 2006;Sankey et al, 2009;Moody et al, 2013).…”

“…The majority of post-fire studies have temporal scopes restricted to the present or a few decades prior, and limited work has been done on post-fire erosion over Holocene and Quaternary timescales (Moody et al, 2013;Murphy et al, 2018). A handful of studies investigate erosion and sedimentation responses to wildfire driven by Holocene climate changes by dating charcoal fragments from alluvial fans (Meyer and Pierce, 2003;Pierce et al, 2004Pierce et al, , 2011Bigio et al, 2010;Nelson and Pierce, 2010;Weppner et al, 2013;Riley et al, 2015;Fitch and Meyer, 2016).…”

Altered ignition catchments threaten a hyperdiverse fire‐dependent ecosystem

“…Evidence from charcoal records over the past two millennia (Marlon et al, ) and satellite data over the past two decades (Andela et al, ) show that global fire activity has been declining, yet the scientific literature and news media are dominated by recent increases in fire activity in closed‐canopy forest ecosystems (Andela et al, ; Murphy, Yocom, & Belmont, ). While these patterns may seem at odds, they likely share a common driver in the form of human activities altering ignition catchments and creating anthropogenic fire shadows.…”

Optimizing Forest Management Stabilizes Carbon Under Projected Climate and Wildfires

“…In this water-limited region, streamflow invariably increases following high-severity wildfires due to decreased infiltration and decreased vegetation water use (Bart, 2016;Wine et al, 2018;Wine & Cadol, 2016). However, the measured increase in water yield from severely burned watersheds following precipitation events is paired with a significant detriment to water quality, which has cascading negative impacts on wildlife, riparian biodiversity, and ultimately the provision of municipal water from forested landscapes (Cooper et al, 2015;Jackson et al, 2012;Jones et al, 2016;Murphy et al, 2018).…”