Wildfire resilience requires action from all, explains IBHS Chief

Roy Wright presents latest scientific guidance during California Department of Insurance Workshop


NEWS PROVIDED BY Insurance Institute for Business & Home Safety (IBHS)

Dec 10, 2020


RICHBURG, S.C., Dec. 10, 2020 /PRNewswire/ -- As California grapples with the wildfire risk across the state, the Insurance Institute for Business & Home Safety (IBHS) today shared the latest science-based guidance to reduce wildfire risk during a California Department of Insurance workshop. Roy Wright, president & CEO of IBHS, brought the organization's scientific expertise from a decade of work at the IBHS Research Center and numerous post-fire field investigations to "Modeling Wildfire Risk and Mitigation in the Era of Climate Change."

"Wildfire risk to communities can be reduced, but it cannot be eliminated. Research in the field and in our lab has demonstrated the clear set of actions that must be taken to give homes a better chance. Yet, this set of actions requires stakeholders to work together to implement and vigilantly maintain wildfire-resistant properties," explains Wright. "Each home is a system with multiple vulnerabilities, so no single action alone will significantly reduce wildfire risk but, collaboratively, communities can bring down their risk."

IBHS lays out the actions for homeowners, neighborhoods and communities in its Suburban Wildfire Adaptation Roadmaps and Wildfire Ready guide for homeowners to walk stakeholders through the opportunities to reduce wildfire risk. Filling the need for actionable guidance specifically for closely-built suburban communities, the Suburban Wildfire Adaptation Roadmaps qualitatively describe the relative vulnerabilities of eight components of the home and actions to improve the risk. Wildfire Ready turns the nuanced technical report into a progressive guide for homeowners that prioritizes the actions that give a home a better chance of surviving a wildfire.

"Embers can pick up and loft regularly more than half a mile. This ability to transport themselves fundamentally changes who is at risk to wildfire because once fire enters a community a domino effect begins as one burning home generates more lofted embers and produces radiant heat making the neighboring homes vulnerable. This domino effect makes community adaptation vital to wildfire mitigation," continues Wright, a northern California native who grew up with wildfire risk. "Communities, neighborhoods, and individuals must work together using wildfire resistant materials and designs as well as vigilant maintenance."

IBHS is committed to producing leading wildfire research that delivers actionable guidance to empower home- and businessowners to prevent avoidable loss.

"As we dive even deeper into wildfire science, we must apply the learnings we already have to improve communities' chances against wildfire. The roof, the 0-5-foot home ignition zone, the area underneath a deck, and vents are the first items that must be addressed," Wright adds.

Home and business owners eager to take action against wildfire can explore Wildfire Ready and Wildfire Ready‒Business at disastersafety.org/wildfire.

About the Insurance Institute for Business & Home Safety (IBHS)
The IBHS mission is to conduct objective, scientific research to identify and promote effective actions that strengthen homes, businesses and communities against natural disasters and other causes of loss. Learn more about IBHS at DisasterSafety.org.

SOURCE Insurance Institute for Business & Home Safety (IBHS)
Related Links

www.disastersafety.org

EXCERPT

Observed Impacts of Anthropogenic Climate Change on Wildfire in California

A. Park Williams 

 

John T. Abatzoglou 

 

Alexander Gershunov 

 

Janin Guzman‐Morales 

 

Daniel A. Bishop 

 

Jennifer K. Balch 

 

Dennis P. Lettenmaier

First published: 15 July 2019

 

https://doi.org/10.1029/2019EF001210

Abstract

Recent fire seasons have fueled intense speculation regarding the effect of anthropogenic climate change on wildfire in western North America and especially in California. During 1972–2018, California experienced a fivefold increase in annual burned area, mainly due to more than an eightfold increase in summer forest‐fire extent. Increased summer forest‐fire area very likely occurred due to increased atmospheric aridity caused by warming. Since the early 1970s, warm‐season days warmed by approximately 1.4 °C as part of a centennial warming trend, significantly increasing the atmospheric vapor pressure deficit (VPD). These trends are consistent with anthropogenic trends simulated by climate models. The response of summer forest‐fire area to VPD is exponential, meaning that warming has grown increasingly impactful. Robust interannual relationships between VPD and summer forest‐fire area strongly suggest that nearly all of the increase in summer forest‐fire area during 1972–2018 was driven by increased VPD. Climate change effects on summer wildfire were less evident in nonforested lands. In fall, wind events and delayed onset of winter precipitation are the dominant promoters of wildfire. While these variables did not change much over the past century, background warming and consequent fuel drying is increasingly enhancing the potential for large fall wildfires. Among the many processes important to California's diverse fire regimes, warming‐driven fuel drying is the clearest link between anthropogenic climate change and increased California wildfire activity to date.

Plain Language Summary

Since the early 1970s, California's annual wildfire extent increased fivefold, punctuated by extremely large and destructive wildfires in 2017 and 2018. This trend was mainly due to an eightfold increase in summertime forest‐fire area and was very likely driven by drying of fuels promoted by human‐induced warming. Warming effects were also apparent in the fall by enhancing the odds that fuels are dry when strong fall wind events occur. The ability of dry fuels to promote large fires is nonlinear, which has allowed warming to become increasingly impactful. Human‐caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and North Coast, and will likely continue to do so in the coming decades.

1 Introduction

In the western United States, annual area burned increased substantially in recent decades due to increased frequency and size of large wildfires (Abatzoglou & Williams, 2016; Balch et al., 2018; Dennison et al., 2014; Westerling, 2016). It is well established that this observed increase in wildfire activity was promoted in many areas by reduced fuel moisture due to warming‐induced increases in evaporative demand, reduced snowpack, and reduced warm‐season precipitation frequency (Abatzoglou & Williams, 2016; Holden et al., 2018; Kitzberger et al., 2017; Westerling, 2016). These recent climate trends are broadly consistent with those expected from anthropogenic climate change (Abatzoglou & Williams, 2016), but anthropogenic climate effects on wildfire can vary greatly across space and time due to confounding factors such as natural climate variations, land and fire management practices, ignitions from humans, spatial diversity in vegetation type, and the complex ways in which these processes interact (Williams & Abatzoglou, 2016). Therefore, location‐specific adaptation responses to wildfire require understanding how climate affects wildfire locally, how the key climate variables have changed over the past several decades, and whether these climate changes are likely to continue.

Perhaps nowhere on Earth has received more attention regarding recent wildfire trends and their causes than California. One reason for the attention is that increases in statewide burned area over the last several decades were dramatically punctuated in 2017 and 2018 by particularly extreme wildfire activity with substantial loss of life and property. In 2017, modern state records were set for the largest individual wildfire (Thomas Fire: 114,078 ha) and the most structures destroyed by an individual wildfire (Tubbs Fire: 5,636 structures), which led to 22 fatalities (CalFire, 2018). The total area burned in 2017 was also nearly a state record at the time (505,293 ha), behind 2007. In 2018, state records were set for total area burned (676,312 ha), largest individual wildfire (Mendocino Complex Fire: 185,800 ha), and most destructive wildfire (Camp Fire: 18,804 structures destroyed, 85 fatalities). In these 2 years, California spent over $1.5 billion on fire suppression, far more than any previous 2‐year period (CalFire, 2018).

California is a particularly difficult place to disentangle the drivers of changing wildfire activity. California's climate, vegetation cover, and human settlement patterns are highly diverse, causing the influences of these factors on fire activity to be spatially heterogeneous and complex (Jin et al., 2014; Jin et al., 2015; Keeley & Syphard, 2017; Swetnam & Baisan, 2003; Westerling & Bryant, 2008). Humans dominate the wildfire regime across much of the state by altering land cover (Sleeter et al., 2011; Syphard et al., 2018), supplying the vast majority of ignitions (Balch et al., 2017; Nagy et al., 2018), and attempting to suppress essentially all fires. Fire suppression over the past century allowed for artificial buildup of fuels in many regions that historically experienced frequent low‐intensity fires, reducing fuel limitation as a constraint on fire activity and putting many areas into a so‐called fire deficit (Higuera et al., 2015; Marlon et al., 2012; Minnich et al., 1995; Parks et al., 2015). Even under constant climate conditions, changes in California's fire activity over the past century would be expected as populations increased and cities expanded into surrounding wildlands (Radeloff et al., 2018), fire suppression strategies evolved (Stephens & Ruth, 2005), and frequency and type of human‐ignited wildfires changed (Balch et al., 2017; Keeley & Syphard, 2018). Changes in these nonclimatic factors may also promote nonstationarity in fire‐climate relationships, confounding efforts to isolate the influence of climate change on fire activity (Higuera et al., 2015; Hurteau et al., 2019; Littell, 2018; Mann et al., 2016; Marlon et al., 2012; Taylor et al., 2016).

The effect of climate on wildfire in California is highly seasonal and variable across vegetation gradients. In summer, when fires are most frequent in California, large burned areas are promoted by the cumulative drying effects of atmospheric aridity and precipitation deficits mainly in forest ecosystems where fuel availability is not a limiting factor (Abatzoglou & Kolden, 2013; Jin et al., 2014; Keeley & Syphard, 2016; Swetnam, 1993; Swetnam & Betancourt, 1998; Westerling et al., 2003; Williams et al., 2018). In fall, many of California's most destructive fires occur in coastal shrublands and are driven by often extreme offshore downslope wind events, where synoptic conditions advect dry air masses often originating from the continental interior high desert westward and southward across topographic barriers such as the Transverse, Peninsular, and Coastal Ranges (Conil & Hall, 2006; Guzman‐Morales et al., 2016; Hughes & Hall, 2010; Moritz et al., 2010; Nauslar et al., 2018). The most widely studied offshore wind events, termed Santa Ana winds in southern California, increase in frequency in the fall and peak in winter (Abatzoglou et al., 2013; Raphael, 2003). Strong offshore winds with very low relative humidity can quickly dry fuels and spread large wildfires when they occur prior to the onset of the winter precipitation season in California's Mediterranean climate (Billmire et al., 2014; Keeley, 2004; Moritz et al., 2010; Westerling et al., 2004).

The effects of anthropogenic climate change on California's fire regimes are likely to be diverse and complex, varying by region and season (Liang et al., 2017; Pierce et al., 2018; Syphard et al., 2019; Westerling, 2018). Climate model projections of warming and increased atmospheric aridity in California are strong and robust across models (Pierce et al., 2013). It is well established that warming promotes wildfire throughout the western United States, particularly in forested regions, by enhancing atmospheric moisture demand and reducing summer soil moisture as snowpack declines (Abatzoglou & Williams, 2016; Westerling et al., 2006). By contrast, model projections of precipitation in California are highly uncertain but with a tendency toward increased precipitation annual totals, particularly in northern California during winter (Maloney et al., 2013). However, many climate models have systematic biases in North Pacific storm tracks and tropical Pacific sea surface temperatures that should lead to strong skepticism regarding model simulations of future precipitation in California (Seager et al., 2019; Simpson et al., 2016). Climate models also project precipitation frequency declines in spring through fall that would partly offset winter increases, resulting in increased precipitation variability (AghaKouchak et al., 2018; Pierce et al., 2018; Polade et al., 2014; Polade et al., 2017; Swain et al., 2018). In fall, models project reduced frequency and intensity of Santa Ana wind events (Guzman‐Morales & Gershunov, 2019; Hughes et al., 2011). However, concurrent warming and decreased fall precipitation may, to some degree, counteract the effects of reduced offshore winds on fall fire risk in southwestern California (Hughes et al., 2011; Pierce et al., 2018), possibly extending the fire season towards the winter peak of the downslope wind season (Guzman‐Morales & Gershunov, 2019; Syphard et al., 2018).

While much has been published on projected changes in wildfire activity due to climate change (e.g., Barbero et al., 2015; Hurteau et al., 2019; Krawchuk & Moritz, 2012; Littell et al., 2018; Westerling, 2018; Westerling et al., 2011; Westerling & Bryant, 2008), less has been done to evaluate observed seasonal trends in fire‐relevant climate variables and whether these trends are consistent with those expected to arise from anthropogenic climate change. Here we provide a comprehensive empirical assessment of the observed effects of climate variability and change on California wildfire by season, region, and land cover. We first use wildfire and climate data within California to evaluate trends in seasonal burned area by region during 1972–2018, resolve the distinct seasonal and regional influences of climate and weather factors, and assess the stationarity of the dominant fire‐climate relationships over the past five decades. We then use climate model simulations to determine whether observed trends in the climate variables most pertinent to regional wildfire activity are consistent with expectations of anthropogenic climate change. A thorough and nuanced understanding of how, when, and where anthropogenic climate change has or has not affected wildfire in California over the past several decades is critical to guide sustainable societal decisions ranging from where to develop housing to how limited resources can be optimized for landscape management.

4 Conclusions

California has been the geographic focus of extensive speculation among scientists, politicians, and media as to the biophysical and societal factors that have contributed to recent exceptional wildfires and large increases in wildfire activity in recent decades (e.g., Krieger, 2018; Pierre‐Louis, 2018; Vore, 2018). Anthropogenic climate change is commonly debated as a driver of these recent wildfire changes, but there are many ways in which anthropogenic climate change could conceivably affect wildfire and many variables that wildfire in California is sensitive to. A nuanced understanding of how, when, where, and why California wildfire activity has increased in recent decades is critical for sustainable environmental and development decisions that specifically take into account how anthropogenic climate change is likely to proceed and affect wildfire across California's diverse landscapes. Our methods should be increasingly applicable to other regions globally, as governmental and satellite‐based records of wildfire activity are steadily alleviating observational duration as a major limiting factor for empirical studies of wildfire.

In this study we evaluated the various possible links between anthropogenic climate change and observed changes in California wildfire activity across seasons, regions, and land cover types since the early 1970s. The clearest link between California wildfire and anthropogenic climate change thus far has been via warming‐driven increases in atmospheric aridity, which works to dry fuels and promote summer forest fire, particularly in the North Coast and Sierra Nevada regions. Warming has been far less influential on summer wildfire in nonforest areas. In fall, the drivers of wildfire are particularly complex, but warming does appear to enhance the probability of large fall wildfires such as those in 2017 and 2018, and this effect is likely to grow in the coming decades.

Importantly, the effects of anthropogenic warming on California wildfire thus far have arisen from what may someday be viewed as a relatively small amount of warming. According to climate models, anthropogenic warming since the late 1800s has increased the atmospheric vapor‐pressure deficit by approximately 10%, and this increase is projected to double by the 2060s. Given the exponential response of California burned area to aridity, the influence of anthropogenic warming on wildfire activity over the next few decades will likely be larger than the observed influence thus far where fuel abundance is not limiting.

Below, we conclude with executive summaries of our primary findings for summer wildfire in forests, summer wildfire in nonforests, and fall wildfire.

4.1 Summer, Forest

Annual statewide burned area increased significantly during 1972–2018, largely due to an eightfold increase in annual summer forest‐fire extent, most of which occurred in the heavily forested North Coast and Sierra Nevada regions. Summer forest‐fire extent is strongly dictated by heat and atmospheric aridity, which reduce snowpack and dry out fuels. Warm‐season atmospheric aridity (vapor‐pressure deficit) increased significantly across California since the late 1800s, driven largely by daytime warming of approximately 1.8 °C (1.4 °C since the early 1970s). Based on a regression analysis, the vast majority of the observed increase in summer forest‐fire extent since 1972 is accounted for by observed significant increases in warm‐season vapor‐pressure deficit (caused by warming). Importantly, the sensitivity of burned area to aridity is modulated by background conditions such as fuel abundance and connectivity, ignition frequency, and resources dedicated toward suppression, all of which changed over the past century. However, the statistical relationship between vapor‐pressure deficit and forest fire area remained stable during 1972–2018, supporting the interpretation that increased aridity was the primary driver of the increase in summer forest‐fire area during this time. The observed rates of warming and increasing vapor‐pressure deficit are consistent with those simulated by climate models when forced by anthropogenic emissions, indicating that these trends are extremely likely to continue for decades to come. The large increase in California's annual forest‐fire area over the past several decades is very likely linked to anthropogenic warming.

4.2 Summer, Nonforest

Annual summer burned area did not increase in nonforest lands in the Central and South Coast regions, and increases in nonforest burned area were weak in the North Coast and Sierra Nevada. Summer nonforested burned area is most strongly promoted by high precipitation total in the year or two prior to the fire year, reflecting the necessity of precipitation for growth of fine fuels that can facilitate fire spread in the subsequent year. Fire‐year precipitation deficit and atmospheric aridity also appear to promote summer wildfire in these regions, but this effect is relatively weak. Over the past century, the frequency of wet years followed by dry years increased, which should have promoted nonforest summer wildfire. The lack of large increases in nonforest summer burned area may reflect the counteracting effects of the other factors such as human fire suppression, reduced ignitions, and reduced vegetation cover due to drought. Climate models do not represent the observed increase in interannual swings from wet to dry years as a robust result of anthropogenic climate change thus far. The link between anthropogenic climate change and summer wildfire in nonforest appears weak thus far.

4.3 Fall

Large fall wildfires became more frequent in California over the past several decades, mainly due to increases in the North Coast and Sierra Nevada regions. In all regions, large fall wildfires often occur when strong offshore wind events coincide with dry fuels. These conditions were extreme throughout California in 2017 and 2018, driving very large fall wildfires in all regions in one or both years. The character of offshore wind events did not change since records began in the mid‐1900s. Climate models project these wind events to decrease in frequency and intensity in the future. Fall fuel moisture is dictated largely by fall precipitation, but nonetheless is calculated to have declined significantly since the mid‐1900s due to warming. This warming‐induced drying was likely caused by a combination of anthropogenic forcing and natural multidecade variability and caused an 8‐day increase in the number of days per October–December with a high probability of large wildfires. This exemplifies an important secondary effect of background warming, which is projected to continue, on fall wildfires. In the South Coast, fall drying was also promoted by a small reduction in the frequency of fall precipitation, consistent with climate model projections. The link between anthropogenic climate change and fall wildfire appears weaker than in summer thus far but is likely to strengthen if continued warming and possibly delayed onset of winter precipitation counteract projected decreases in the intensity and frequency of offshore wind events.

Acknowledgments

All data sets used are publicly available, and the sources are listed in Table S1. A.P.W. was funded by Columbia University's Center for Climate and Life and the Zegar Family Foundation. We also acknowledge support from University of California Office of the President MRPI grant MRP‐17‐446315 (D.L., A.G., and J.G.M.), from NOAA via the CNAP RISA (D.L. and A.G.), from DOI via the Southwest Climate Adaptation Science Center grant G18AC00320 (A.G. and J.G.M.), the Visiting Scholar Program and Fire Centre Research Hub at the University of Tasmania (J.T.A.), Earth Lab through CIRES and the University of Colorado, Boulder's Grand Challenge Initiative (J.K.B.), and the USGS North Central Climate Adaptation Science Center (J.K.B.). LDEO publication 8332.

Crews ignite planned burns in effort to contain B.C. wildfires; blaze near Penticton grows by 52%


Wed, August 3, 2022 

B.C. Wildfire Service crews monitor small-scale fires they have lit as planned ignitions beside Highway 3A north of Keremeos, B.C., near a wildfire just 21 kilometres from Penticton. 

(Submitted by B.C. Wildfire Service - image credit)

Crews are literally fighting fire with fire in the southern Okanagan as the B.C. Wildfire Service takes advantage of cooler weather to try to contain a blaze that has forced hundreds from their homes.

Fire information officer Marg Drysdale told a news conference Wednesday that crews were conducting controlled burns on the southeastern flank of a wildfire burning southwest of Penticton, which the B.C. Wildfire Service says grew by more than 50 per cent on Wednesday.

That blaze, the Keremeos Creek wildfire, now covers an estimated 42 square kilometres.

An aerial ignition was planned for the region as crews burned off trees and bush not far from Highway 3A, which was closed briefly on Tuesday as flames moved closer.

"It will be highly visible,'' Drysdale said of the planned burn aimed at creating containment lines around the flames.

Days of searing heat and low humidity helped fuel the wildfire after it was sparked July 29, but Drysdale said winds Wednesday were "not much of a factor'' and "pretty flat,'' while the heat was "a couple of degrees cooler,'' at higher elevations.

Environment Canada was calling for temperatures to drop by almost 10 degrees in the Penticton area from the low 30s recorded Wednesday to expected highs of no more than 23 C on Thursday and Friday.

The Regional District of Okanagan-Similkameen confirmed 479 properties, including the Apex Resort village west of Keremeos, remained evacuated, while residents of another 324 properties in the area were on evacuation alert.

Two hundred and fifty-two firefighters were assigned to the wildfire, said Drysdale, backed by 10 helicopters and four pieces of heavy equipment, with additional heavy equipment set to be assigned in the coming days.

The south Okanagan fire is among six now listed by the wildfire service as either highly visible or a threat to public safety, up from just two so-called "wildfires of note'' a day earlier.

The blazes newly identified as "fires of note'' include a 10-square-kilometre fire northwest of Cache Creek in the Kamloops Fire Centre and another that had burned roughly two square kilometres northwest of Kamloops.

There are also two in the Southeast Fire Centre, one covering nearly 17 square kilometres between Kaslo and New Denver and the other south of Cranbrook, which was sparked Aug. 1 and had burned five square kilometres by Wednesday.

The wildfire service warned that activity on that suspected lightning-caused blaze was expected to pick up late in the day as winds increased and a cold front moved in.

Conair Group Inc. confirmed by email that one of its planes was involved in a forced landing while battling the Cranbrook-area wildfire Tuesday.

"We are happy to report that following the forced landing of our Fire Boss Airtanker yesterday, the pilot was able to walk away from the aircraft to a suitable helicopter landing site for a flight back to Cranbrook,'' said Conair communications manager Shannon De Wit.

Conair is working with the BC Wildfire Service, Transportation Safety Board and Transport Canada on the investigation,'' she said and continues to provide contracted aerial firefighting to the wildfire service.

The wildfire service said roughly three-quarters of B.C.'s active wildfires were caused by lightning, while 11 per cent are linked to human activity.

One unoccupied cabin has been destroyed southwest of Penticton, and numerous structures were lost in the early days of the wildfire west of Lytton, but there are no reports of losses related to any other wildfires in B.C.

B.C. Wildfire Service

B.C.'s wildfires of note

Across B.C., 154 new wildfires broke out in the past week — many sparked by thousands of lightning strikes on the weekend, according to the wildfire service's dashboard. Nearly half of the new fires were sparked in the Kamloops Fire Centre region.

Another significant wildfire in the Interior, the 37-square-kilometre Nohomin Creek fire northwest of Lytton, is still growing "steadily" in steep, rocky terrain.

Three other fires have been upgraded to fires of note, meaning they are highly visible or pose a potential threat to public safety:

The Connell Ridge fire around 15 kilometres south of Cranbrook, about five square kilometres in size.


The Watching Creek fire around 16 kilometres northwest of Kamloops, nearly two square kilometres in size.


The Maria Creek fire around 30 kilometres northwest of Cache Creek, about 10 square kilometres in size.


The Briggs Creek fire around 12 kilometres west of Kaslo, about 17 square kilometres in size.

 

Wildfires Have Long-Term Health Effects, Both Direct and Indirect, Several Studies Show

 

A recent systematic review of studies on long-term impacts of wildfires finds they are associated with mental health disorders, COVID-19 complications, death from heart disease, shorter height in children and poorer overall health.

July 30, 2023 by The Journalist's Resource 

By Naseem S. Miller

From the U.S. to Canada to Greece, wildfires have been wreaking havoc across the globe in recent months, burning land, forests and homes, and killing or displacing wildlife and humans. The smoke can affect people near and far from the fires.

Wildfire smoke is a mix of gases and fine particles from burning trees, plants, buildings, and other material, according to the Centers for Disease Control and Prevention. The smoke contains small pollutants known as particle matter, or PM 2.5, which are 30 times smaller than the diameter of a human hair. These particles can go deep into the lungs and reach the bloodstream.

Exposure to wildfire smoke can irritate the lungs, cause inflammation, alter immune function, and increase susceptibility to respiratory infections, including COVID-19, according to the CDC. In June, the agency issued an advisory to health professionals about the acute signs and symptoms of smoke exposure, as smoke from wildfires in Canada affected air quality in parts of U.S.

https://journalistsresource.org/health/lancet-climate-countdown-2022/

Moreover, wildfires can upend people’s lives, leading to mental stress.

Several studies have established the short-term health effects of wildfire exposure, finding an association with higher risk of death and respiratory and cardiovascular complications. A 2022 study, published in Science of the Total Environment, finds the Australian bushfires in 2019 and 2020 were associated with a 6% increase in emergency department visits for respiratory diseases and 10% increase for cardiovascular diseases.

But there’s still a dearth of population-based high-quality evidence on the long-term health effects of wildfires, according to the authors of “Long-term impacts of non-occupational wildfire exposure on human health: A systematic review,” published in Environmental Pollution in March 2023.

The authors review 36 academic studies, mostly from Australia, Canada and the U.S., which were published between 1987 and 2022. The majority focus on health impacts one to two years after exposure to a wildfire. More than half of the studies focus on mental health. The authors note that most of the included studies were from developed countries with limited data.

Study findings

The analysis finds in the long term, wildfires and wildfire smoke are associated with mental health disorders, including post-traumatic stress disorder, respiratory diseases and COVID-19 complications, death from heart disease and poorer general health.

Among the findings:

There was no significant long-term association between wildfire exposure and child mortality and hospitalization due to respiratory diseases.

Several studies showed an association between wildfire exposure and increased risk of flu rates, asthma in children and different types of cancer.

One study from Israel found higher hospitalization rates two years after wildfire exposure compared with the year before the wildfire occurred. In addition, people with underlying health conditions, such as overweight or obesity, diabetes and heart disease, and lower income had higher rates of hospitalizations than those without underlying health conditions and higher income.

Two studies found that wildfire exposure is associated with shorter height in children, especially when moms were exposed to the smoke during the pregnancy. One study suggests that may be due to the impact of wildfire smoke on pregnant moms’ respiratory health.

The authors of the systematic review add that current evidence, although limited, suggests people with certain vulnerabilities — including smoking, lower levels of education, obesity, older age, underlying diseases and lower income — might be at higher risk of negative long-term effects of wildfire exposure.

All 21 studies that assessed the association between wildfire exposure and mental health found negative impacts in adults. Those associations include anger problems, possible post-traumatic stress disorder, depression and heavy drinking. Most studies found a higher rate of PTSD symptoms after exposure to wildfires.

There are several reasons why wildfires have long-term impacts on health, the authors of the systematic review explain.

• Direct impact, including long-term injuries, and even death, resulting from burns and inhalation of smoke during the fires.
• Indirect impact via air pollution and mental stress resulting from economic loss, casualties and forced evacuations.
• Damage at the cellular and molecular level. Air pollution, including smoke, might cause DNA damage, decrease the viability of cells and result in cell death. The smoke can also lead to inflammation in the body and the brain.

“The population-based high-quality evidence with quantitative analysis on this topic is still limited,” they write. “Given the long-term projections of increasing frequency of wildfires and length of the wildfire season due to climate change, the anticipated increase in the frequency and acreage burned by prescribed fires, and the increasing aging population that is more vulnerable to suffer from long-term impacts of wildfire exposure, more scientific evidence is urgently needed to determine long-term impacts of wildfire exposure on human health.”

Wildfires and climate change

https://journalistsresource.org/media/scientific-consensus-news-tips/

Compared with 2001 to 2004, nearly 60% of countries experienced an increased number of days that people were exposed to very or extremely high fire risk and 72% of countries had increased human wildfire exposure during 2017 to 2020, the study authors note.

The intensity and frequency of wildfires is increasing in the U.S. and worldwide. According to the National Oceanic and Atmospheric Administration, there were 20 wildfires that caused more than $1 billion in damage between 1980 and 2021 in the U.S. Sixteen of those have occurred since 2000, according to data from the National Interagency Fire Center.

Wildfires are among the Environmental Protection Agency’s climate change indictors, which show the causes and effects of climate change. Wildfires occur naturally and play a role in maintaining the ecosystems in forests and grasslands, but too many wildfires can throw off the nature’s balance.

Wildfire season has gotten longer and there are more wildfires affecting more areas. This increase is due to several factors, including warmer springs, longer dry summers and drier soil and vegetation, according to the EPA.

Funding

The study was funded by the Australian Research Council and the Australian National Health and Medical Research Council. The authors declared no competing financial interests.

How to access this study

Environmental Pollution is published by Elsevier, a Dutch publishing company specializing in scientific research. This study is behind Elsevier’s paywall, but there are several ways you can access it, including emailing the senior author, Shanshan Li. We also have a list of academic journals and publishing companies that offer journalists access to their content upon request.

Additional research

• Preterm birth and term low birth weight associated with wildfire-specific PM2.5: A cohort study in New South Wales, Australia during 2016–2019 Yiwen Zhang, et al. Environment International, April 2023.
• Wildfire smoke and symptoms affecting mental health among adults in the U.S. state of Oregon Maria C. Mirabelli, et al. Preventive Medicine, November 2022.
• Exposure to wildfire-related PM2.5 and site-specific cancer mortality in Brazil from 2010 to 2016: A retrospective study Pei Yu, et al. September 2022, PLOS Medicine.
• Long-term health effects of wildfire exposure: A scoping review Emily Grant and Jennifer D. Runkle. The Journal of Climate Change and Health, May 2022.
• Long-term exposure to wildfires and cancer incidence in Canada: a population-based observational cohort study Jill Korsiak, et al. The Lancet Planetary Health, May 2022.
• Wildfire exposure during pregnancy and the risk of adverse birth outcomes: A systematic review Sana Amjad, et al. Environment International, November 2021.
• Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations
  Gongbo Chen, et al. The Lancet Planetary Health, September 2021.
• Risk and burden of hospital admissions associated with wildfire-related PM2·5 in Brazil, 2000–15: a nationwide time-series study Tingting Ye, et al. The Lancet Planetary Health, September 2021.
• Psychological effects of the 2017 California wildfires on children and youth with disabilities Elizabeth McAdams Ducy and Laura M. Stough. Research in Developmental Disabilities, July 2021.
• Wildfires, Global Climate Change, and Human Health Rongbin Xu, et al. The New England Journal of Medicine, November 2020.
• The health impacts and economic value of wildland fire episodes in the U.S.: 2008–2012 Neal Fann, et al. Science of The Total Environment, January 2018.

Resources to track wildfires and air quality

• The Fire Information for Resource Management System (FIRMS) U.S./Canada shows all active fires in the two countries. FIRMS also provides a map of wildfires around the world.
• The U.S. Environmental Protection Agency’s AirNow shows the level of air quality based in ZIP code, city or state. AirNow also has a fire and smoke map.
• The National Interagency Fire Center provides current data on wildfires in the U.S., including the number of firefighters fighting the fires and the acres burned.
• The CDC has a guide on how people can protect themselves from wildfire smoke.
• The wildfires layer on Google Maps shows active wildfires.
• Several news outlets track wildfires or air quality and smoke from wildfires, including The New York Times and CNN.

 

This article first appeared on The Journalist’s Resource and is republished here under a Creative Commons license.