SAN JOSE, Calif. — Take a seat, chin to the sky. Insert the swab, rotate slowly and switch nostrils — we know the drill. Only this time, it’s not a COVID-19 test. And the nose is attached to a monkey.
Three years ago, researchers in Davis, Calif., swabbed the nasal cavities of 22 captive rhesus macaque monkeys that were born just before and after the 2008 wildfire season in California. Alterations in their DNA showed, for the first time, that exposure to wildfire smoke can create long-term changes in the way that genes are expressed in primates, they reported in January.
It’s unknown whether the same results will be found in humans, and follow-up studies are underway. But the DNA modifications suggest that like the monkeys, young people breathing in orange skies may be more susceptible to respiratory illness and brain development issues later in life. Such studies of the long-term health effects could also open the door for future treatments to mitigate the damage of smoke, which poses a growing threat amid more frequent and toxic wildfires.
For years, scientists have associated the particulate matter from smoke with respiratory health complications such as COPD and asthma — particularly in children.
“We know air pollution is bad, but we don’t know the specific regions (of the DNA) that it’s targeting,” said Juan Aguilera, a physician-scientist at Stanford University who was not affiliated with the research. “There’s been, also, a need to know more about the long-term effects of the exposure.”
The new study out of Davis addresses both of these gaps — identifying individual pathways by which smoke exposure impacts the body, and following those changes over time. To do so, researchers are looking to the epigenome: the layer of molecules on top of genetic code that dictates how DNA is interpreted, helping turn specific genes on and off.
“We’re talking about a genetic component that basically tells the cells how to act and what to do,” Aguilera explains. “Epigenetics studies how the environment and external exposures change our bodies and how our bodies work.”
Al Seib/Los Angeles Times
Smoke fills the sky as the Alisal fire burns in the distance on Oct. 11, 2021, in Santa Gaviota Coast, Calif.
When Hong Ji and her colleagues from the California National Primate Research Center at UC Davis looked at the monkeys’ nasal DNA, they were surprised to find that over 3,000 regions in the epigenome were different for monkeys that were exposed to the 2008 wildfires and those that weren’t.
“I thought we’d be lucky to see something, but wow. … There’s these unappreciated, huge, massive changes across the genome that people did not realize,” Ji said.
Some of the impacted regions deal with genes typically involved in immune response and neural development, meaning that smoke exposure could impact breathing and cognition in the long run. In fact, the researchers already showed that the monkeys born after the wildfires had reduced lung capacity and impaired lung function. The team is currently looking for signs of brain damage in the exposed monkeys, but previous studies have linked air pollution to autism and other neurodevelopmental disorders.
“Your body actually has the memory of previous exposures stored in the epigenome — the mark is always there,” Ji said. “That memory could change the way you respond to infections or allergens or viruses.”
These findings add to growing concerns for the dangers of inhaling wildfire smoke — particularly at a young age, when individuals haven’t yet developed sufficient protection.
The researchers said they expect to see similar epigenetic effects in people. Ji is teaming up with Rebecca Schmidt at UC Davis to repeat the study in pregnant mothers and young children, and they’re in the process of recruiting participants now.
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How wildfires have worsened in recent years
KYLE GRILLOT/AFP via Getty Images
A series of lightning storms in mid-August 2020 hit Northern California, a region already experiencing a severe drought season, igniting what would become the August Complex fire. Over the course of almost three months, it burned through national forests, destroying 935 buildings and forcing the evacuation of thousands of people. By the time it was fully contained, its total range was over twice the size of California’s previous record and among the largest fires in U.S. history.Â
Less than a year later, the August Complex’s record was nearly broken when the Dixie fires broke out in Northern California, burning more than 963,000 acres and destroying more than 1,300 structures in the region.
Stacker cited data from the National Interagency Fire Center, National Oceanic and Atmospheric Administration, and the California Department of Forestry and Fire Protection to visualize how the spread of wildfires has worsened in recent years.
New breakouts of megafires (fires burning in excess of 100,000 acres) have become a seasonal repetition in the Western United States. Wildfires are innate to forest ecosystems, clearing out dead debris and paving the way for new growth, but climate change has elongated dry seasons, increased temperatures, and widened the potential for large-scale wildfires. Beyond weather-related factors, the prevalence of insects like bark beetles damage trees and make them more prone to burning. Invasive vegetation such as cheatgrass also easily burns and contributes to spread.
Trees, traditionally a storage vessel for carbon, release carbon immediately when burning and during decomposition. The EU’s Copernicus Atmosphere Monitoring Service estimated that global wildfires in 2021 released 1,760 megatonnes of carbon emissions, just over what the nation of Russia emitted in 2020. Black carbon, or soot, can also travel beyond wildfire zones, absorbing sunlight and warming the earth further.Â
Beyond the environmental threats, the widening reach of wildfires threatens the displacement of countless residents. The Marshall fire in January of this year destroyed more than 1,000 homes in Colorado, demonstrating the harm a wildfire can cause in a densely populated area such as the suburbs. The Camp Fire in 2018 permanently displaced an estimated 20,000 residents in California’s Butte County. Despite this, people continue moving to wildfire-prone areas, putting a growing population at risk of longer fire seasons and associated health risks.
You may also like:Â How climate change impacts extreme weather across America
KYLE GRILLOT/AFP via Getty Images
A series of lightning storms in mid-August 2020 hit Northern California, a region already experiencing a severe drought season, igniting what would become the August Complex fire. Over the course of almost three months, it burned through national forests, destroying 935 buildings and forcing the evacuation of thousands of people. By the time it was fully contained, its total range was over twice the size of California’s previous record and among the largest fires in U.S. history.Â
Less than a year later, the August Complex’s record was nearly broken when the Dixie fires broke out in Northern California, burning more than 963,000 acres and destroying more than 1,300 structures in the region.
Stacker cited data from the National Interagency Fire Center, National Oceanic and Atmospheric Administration, and the California Department of Forestry and Fire Protection to visualize how the spread of wildfires has worsened in recent years.
New breakouts of megafires (fires burning in excess of 100,000 acres) have become a seasonal repetition in the Western United States. Wildfires are innate to forest ecosystems, clearing out dead debris and paving the way for new growth, but climate change has elongated dry seasons, increased temperatures, and widened the potential for large-scale wildfires. Beyond weather-related factors, the prevalence of insects like bark beetles damage trees and make them more prone to burning. Invasive vegetation such as cheatgrass also easily burns and contributes to spread.
Trees, traditionally a storage vessel for carbon, release carbon immediately when burning and during decomposition. The EU’s Copernicus Atmosphere Monitoring Service estimated that global wildfires in 2021 released 1,760 megatonnes of carbon emissions, just over what the nation of Russia emitted in 2020. Black carbon, or soot, can also travel beyond wildfire zones, absorbing sunlight and warming the earth further.Â
Beyond the environmental threats, the widening reach of wildfires threatens the displacement of countless residents. The Marshall fire in January of this year destroyed more than 1,000 homes in Colorado, demonstrating the harm a wildfire can cause in a densely populated area such as the suburbs. The Camp Fire in 2018 permanently displaced an estimated 20,000 residents in California’s Butte County. Despite this, people continue moving to wildfire-prone areas, putting a growing population at risk of longer fire seasons and associated health risks.
You may also like:Â How climate change impacts extreme weather across America
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How wildfires have worsened in recent years
Emilia Ruzicka / Stacker
Throughout the mid-20th century, forest management largely focused on preventing forest fires of all scales. Smokey the Bear was a national mascot for fire prevention, overseeing a multi-decade decrease in the number and average size of fires. But without regular fires, debris built up. This, combined with other environmental factors, eventually fueled costlier, large-scale blazes that have come to define the current wildfire season.Â
Despite having nearly 10,000 fewer fires per year on average from 2011-2021 compared to 1983-2010, the average acreage burned by those fires per year has more than doubled. From 1983-2010, the average number of acres burned per year was about 4.4 million. That number has jumped to 7.5 million acres per year for the 2011-2021 time period.
Emilia Ruzicka / Stacker
Throughout the mid-20th century, forest management largely focused on preventing forest fires of all scales. Smokey the Bear was a national mascot for fire prevention, overseeing a multi-decade decrease in the number and average size of fires. But without regular fires, debris built up. This, combined with other environmental factors, eventually fueled costlier, large-scale blazes that have come to define the current wildfire season.Â
Despite having nearly 10,000 fewer fires per year on average from 2011-2021 compared to 1983-2010, the average acreage burned by those fires per year has more than doubled. From 1983-2010, the average number of acres burned per year was about 4.4 million. That number has jumped to 7.5 million acres per year for the 2011-2021 time period.
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How wildfires have worsened in recent years
Emma Rubin / Stacker
The total acres burned by wildfires in December 2020 was three times greater than the 10-year average for the month. The following year also experienced a damaging December, with a less extensive but still above average spread covering 336,984 acres. Wildfire season traditionally lasts May through October, but shorter winters and earlier snow melts have extended wildfire risk. 2021 set a record for days at preparedness level 5, the highest alert for wildfire risk.Â
The USDA Forest Service warned in 2021, “For years, agencies relied on seasonal firefighters for summer months, but now that wildfires are burning into the winter, they need to reevaluate their hiring plans.”
Â
Emma Rubin / Stacker
The total acres burned by wildfires in December 2020 was three times greater than the 10-year average for the month. The following year also experienced a damaging December, with a less extensive but still above average spread covering 336,984 acres. Wildfire season traditionally lasts May through October, but shorter winters and earlier snow melts have extended wildfire risk. 2021 set a record for days at preparedness level 5, the highest alert for wildfire risk.Â
The USDA Forest Service warned in 2021, “For years, agencies relied on seasonal firefighters for summer months, but now that wildfires are burning into the winter, they need to reevaluate their hiring plans.”
Â
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How wildfires have worsened in recent years
Emilia Ruzicka / Stacker
With the increasing severity of wildfires every year, it follows that more resources are required to tame the blazes. In 1999, just before the turn of the century, the Forest Service and all other Department of the Interior agencies spent a combined $515.5 million on wildfire suppression. During the course of the last decade, the average cost of wildfire suppression has skyrocketed to nearly $2.1 billion annually. The Forest Service carries the brunt of this cost, contributing approximately three-quarters of the funds each year.Â
Though there is not currently an official tracking mechanism for the cost of wildfire damages, academics across the country have attempted to estimate the economic impact of wildfires. In 2020, a team of researchers estimated that the 2018 California wildfires caused $148.5 billion in economic damages.
Emilia Ruzicka / Stacker
With the increasing severity of wildfires every year, it follows that more resources are required to tame the blazes. In 1999, just before the turn of the century, the Forest Service and all other Department of the Interior agencies spent a combined $515.5 million on wildfire suppression. During the course of the last decade, the average cost of wildfire suppression has skyrocketed to nearly $2.1 billion annually. The Forest Service carries the brunt of this cost, contributing approximately three-quarters of the funds each year.Â
Though there is not currently an official tracking mechanism for the cost of wildfire damages, academics across the country have attempted to estimate the economic impact of wildfires. In 2020, a team of researchers estimated that the 2018 California wildfires caused $148.5 billion in economic damages.
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How wildfires have worsened in recent years
Emma Rubin / Stacker
At the national level, 89% of wildfires were caused by humans in 2021, but human-caused wildfires contributed only to 42% of total acreage burned. In the Southern and Eastern U.S., human-caused fires still cause the most damage, but elongated dry seasons in the West have intensified the impact of lightning when it does strike.
Dry lightning is created through high-altitude thunderstorms. Extreme heat and drought can cause rain to evaporate before it reaches the ground. Lightning fires can also pose greater damage because it can take longer for them to be detected, whereas human-caused fires are often closer to towns and high-traffic areas. Winds associated with dry thunderstorms can further fan the flames as well. These factors mean that even as the West is less prone to lightning than other parts of the country, the bolts can spark more damage.
Â
Emma Rubin / Stacker
At the national level, 89% of wildfires were caused by humans in 2021, but human-caused wildfires contributed only to 42% of total acreage burned. In the Southern and Eastern U.S., human-caused fires still cause the most damage, but elongated dry seasons in the West have intensified the impact of lightning when it does strike.
Dry lightning is created through high-altitude thunderstorms. Extreme heat and drought can cause rain to evaporate before it reaches the ground. Lightning fires can also pose greater damage because it can take longer for them to be detected, whereas human-caused fires are often closer to towns and high-traffic areas. Winds associated with dry thunderstorms can further fan the flames as well. These factors mean that even as the West is less prone to lightning than other parts of the country, the bolts can spark more damage.
Â
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How wildfires have worsened in recent years
Emma Rubin / Stacker
While lightning has sparked some of the most devastating fires in California including the August, SCU, and LNU complex fires, powerlines have also fueled far-reaching damage. Contact with overgrown trees, downed lines, and frayed wires can spark flames. Pacific Gas & Electric was held responsible for the 2018 Camp Fire and 2019 Kincade Fire and has instituted rolling blackouts on high-risk wildfire days.
Even as the origin of fires varies, each is exacerbated by existing environmental factors. A 2018 survey from the USDA Forest Service identified nearly 150 million trees that died between 2010-2018 in California. Two years later, 2020’s record season burned nearly 4.4 million acres and the five largest megafires happened concurrently in August and September. The season demonstrated how the buildup of vulnerable trees can ignite unprecedented spread.
A 2021 aerial survey by the USDA Forest Service offered some hope. Annual tree mortality has declined over the past five years, with an estimated 9.5 million dead trees in the state spanning more than 1 million acres, although tree mortality remains at a much higher rate than California’s pre-drought levels in the early-2000s.
You may also like: Climate change’s impact on the wine industry
Emma Rubin / Stacker
While lightning has sparked some of the most devastating fires in California including the August, SCU, and LNU complex fires, powerlines have also fueled far-reaching damage. Contact with overgrown trees, downed lines, and frayed wires can spark flames. Pacific Gas & Electric was held responsible for the 2018 Camp Fire and 2019 Kincade Fire and has instituted rolling blackouts on high-risk wildfire days.
Even as the origin of fires varies, each is exacerbated by existing environmental factors. A 2018 survey from the USDA Forest Service identified nearly 150 million trees that died between 2010-2018 in California. Two years later, 2020’s record season burned nearly 4.4 million acres and the five largest megafires happened concurrently in August and September. The season demonstrated how the buildup of vulnerable trees can ignite unprecedented spread.
A 2021 aerial survey by the USDA Forest Service offered some hope. Annual tree mortality has declined over the past five years, with an estimated 9.5 million dead trees in the state spanning more than 1 million acres, although tree mortality remains at a much higher rate than California’s pre-drought levels in the early-2000s.
You may also like: Climate change’s impact on the wine industry
