How Climate Change Fueled Deadly Los Angeles Fires
As unusually strong winds swept across a parched Los Angeles, spreading more than half a dozen firestorms that have now burned an area nearly the size of San Francisco, the fingerprints of climate change were all over the unfolding disaster. The underlying dynamic feeding the flames was a wet-and-dry whiplash in which vegetation, supercharged by heavy rain, dried out and became fuel for fires that left the city all but encircled in flames. It was not difficult for climate experts to connect the dots. Greenhouse gases, mostly from burning fossil fuels, linger in the atmosphere where they heat up the planet, leading to more to extreme weather. A hotter atmosphere holds more moisture, causing rain to fall in intense bursts. The hotter air also increases extreme temperatures and makes dry seasons drier by increasing evaporation. In Pasadena, a California city on the edge of a major fire burning through Eaton Canyon, where researchers have collected data on precipitation since 1893, they recorded that half of its 20 rainiest days ever occurred since 2000. That includes one day last February when nearly 5 inches of rain fell. Yet not a single drop has fallen in Pasadena and much of Los Angeles County since early May, according to data from the National Centers for Environmental Information. All the vegetation that grew during the rains in the first half of the year dried out when the rains stopped, transforming Southern California into a vast landscape of tinder that exploded this week. The intensity of extreme precipitation will continue rising through the century, according to Cal-Adapt, a data analysis initiative sponsored by the California Energy Commission. The state also forecast longer periods of drought exacerbated by rising heat, according to its Fourth Climate Assessment summary report, released in 2018 and currently being updated. These two factors will likely increase the wet-dry cycle, fueling more intense and erratic wildfires, say climate experts. In 2021, the National Oceanic and Atmospheric Administration concluded that drier air due to climate change was the “dominant” cause of variations in wildfire behavior in the West. The effect of the current fires on Los Angeles’ massive population will present researchers with a grim opportunity to study how wildfires can affect large numbers of people in a short period of time. Among the effects is the release of fine particles, called PM2.5, a pollutant that is found in wildfire smoke and that can find its way into the lungs and bloodstream of those exposed to the smoke. Exposure can lead to decreased lung function, nonfatal heart attacks and death in people with heart or lung disease, according to the U.S. Environmental Protection Agency. Shahir Masri, associate specialist in air pollution exposure assessment and epidemiology in the University of California, Irvine’s Department of Environmental & Occupational Health, studies climate change modeling and air pollution exposure. He published a study in 2022 that linked rising PM2.5 levels in California to wildfires and, to a lesser extent, heat waves. His previous work found that the number of census tracts in California that experienced major wildfires nearly doubled from 2000 to 2020. Capital & Main spoke to Masri about his work as the fires in L.A. County continued to burn. This interview has been edited for clarity and brevity. Capital & Main: Could you describe how climate change is making wildfires worse? Shahir Masri: It’s a variety of factors linked with climate change. Increasing temperatures and aridity in places like the Western U.S, and in more mountainous areas, you can have earlier snowmelt, which leaves downstream riparian areas desiccated and more fire-prone. But you also have these earlier spring onsets, which generally speaking means an earlier arrival of spring and warm temperatures. You basically get longer warm summer windows, which has ultimately become a longer wildfire season. Landscapes are drying out more quickly, and the wildfire season begins more quickly and ends later. [The Southern California fires] remind me of 2017-’18, the Thomas fire, which burned from December through Jan. 8. Shahir Fouad Masri. Photo courtesy Dr. Masri. So these later-burning fires are becoming more frequent. And when you add unprecedented heat waves on top of it, you get yet another scenario where you’re setting the stage for a major wildfire. In 2018, we saw a major wildfire season. The following year, we saw a major rainy season. Then in 2020, we saw the biggest wildfire season in the state’s history. That was a combination of huge growth in 2019 of shrubs and plants and a lot of things in the wet seasons, then the following year we got slammed with aggressively oppressive summer heat. I fear some of this may have been at play in these fires. The last few years we’ve had really wet winters, and this is now the driest winter we’ve seen in a while. We didn’t get our holiday rain. This area burning now would have been much more resistant to a fire breaking out if we had that rain. So those are some of the factors at play and linked with climate change. In your study, you concluded that higher levels of PM2.5 were strongly associated with nearby wildfires. Why did you study PM2.5? PM2.5 is arguably the most robustly associated pollutant associated with adverse health effects. There have been nearly countless studies looking at the effects of PM2.5 and the increase of asthma, hospital admissions, exacerbated [chronic obstructive pulmonary disease] and short life expectancy. It’s not entirely clear what causes PM2.5 to be more toxic than PM10 [a type of pollutant in the form of relatively larger particulates], and it’s not clear which forms of PM2.5 are most toxic. Is it because of a higher heavy metal content, or is it worse if it has a higher organic composition or sulfur content? The verdict is still out on that. But setting those composition differences aside, PM2.5 is the main characteristic of this particular type of air pollution that is most associated with adverse health effects. What would you expect the health effects to be from these fires, particularly for poorer communities that you found were most vulnerable to PM2.5 from wildfires? About 7% to 8% of Californians are asthmatics. Asthma attacks are exacerbated by things like air pollution — about 38% to 39% of asthmatic individuals will have an attack at least once a year. Therefore, these wildfires will likely result in quite a few asthma attacks. We will probably also see increased hospital admissions for the exacerbation of chronic conditions such as chronic obstructive pulmonary disease. There’s a whole separate series of health impacts we’re actually looking at through a survey of people exposed to the Tustin [north] hangar fire in 2023. There were a whole host of impacts, including mental stress. In an upcoming paper, we’re talking about mental stress as it relates to wildfires and environmental catastrophes. And I don’t think that should be overlooked, even though it’s less studied. That, I would presume, will play a role here as well, especially given people abandoning their cars, losing their homes. It’s clearly a lot of trauma inflicted on this population. Post-traumatic stress disorders, anxiety disorders, those are things we see after major wildfire events, especially [in] people close to the fire. These impacts can be quite prevalent and can take quite a long time to dissipate, up to 10 years. So I think smoke-related impacts are one thing. I think direct injuries from the fire, thermal injuries, are another. Property loss is another as well. But those mental impacts are also a major factor. The volume of greenhouse gases in the atmosphere is at record levels. Do you expect more events like the current Los Angeles fire outbreak? Warming trends in the atmosphere don’t bode well. In addition to wildfire smoke, we also see higher energy demands [to run air conditioners] concurrent with heat waves. And that, depending on which state you live in, translates to greenhouse gas emissions from people using more electricity. Wildfires can wipe out the gains we’ve made from lowering emissions by reducing the prevalence of coal, [for example]. I think there’s a lot of work to be done on climate change in the United States. We have an incoming [presidential] administration notorious for disregarding climate change. And even though President [Joe] Biden acknowledged the importance of climate change and did a lot with the Inflation Reduction Act, we see a reluctance to shift away from fossil fuels even as we see more investments in renewable energy. Biden broke his promise to end offshore drilling, so we’re seeing this fossil fuel addiction play out and remain, regardless of what political party is in office. In one case, it’s “drill baby drill”; in another, it’s “drill baby drill,” but we’ll also use the sun and wind. So we’re so far off from where we need to be from policies to get us on the right track. And to highlight extensiveness needed for targets, the COVID-19 pandemic provided clear examples of just how dramatic a shift we’re talking about. We saw an 8% reduction in greenhouse gas emissions during the first year of the pandemic, which is what is needed to comply with the U.N.’s target of an 8% reduction year-over-year for 10 years. That’s hard to fathom, given that our economy is globally grinding to a complete halt. That was an important lesson, and unfortunately we’re not taking steps to get on that track; we’re just ramping up emissions globally. What gives you hope? What gives me hope is the youth community. My generation was basically much quieter on this issue than the current college generation. With every generation moving forward, the situation becomes all the more dire. It’s been quite inspirational to see them almost single-handedly get major attention and support and popularity around the Green New Deal; those are really youth-driven policy agendas. I think they’ve played a big role in popularizing those ideas. I think those are major steps that cannot be overstated, and that generation now will be moving into politics, and that’s the most encouraging thing for me as I grapple with these issues.
A whipsaw swing from very wet to very dry weather exposed millions to flames, smoke and pollutants. The post How Climate Change Fueled Deadly Los Angeles Fires appeared first on .
As unusually strong winds swept across a parched Los Angeles, spreading more than half a dozen firestorms that have now burned an area nearly the size of San Francisco, the fingerprints of climate change were all over the unfolding disaster.
The underlying dynamic feeding the flames was a wet-and-dry whiplash in which vegetation, supercharged by heavy rain, dried out and became fuel for fires that left the city all but encircled in flames. It was not difficult for climate experts to connect the dots.
Greenhouse gases, mostly from burning fossil fuels, linger in the atmosphere where they heat up the planet, leading to more to extreme weather. A hotter atmosphere holds more moisture, causing rain to fall in intense bursts. The hotter air also increases extreme temperatures and makes dry seasons drier by increasing evaporation.
In Pasadena, a California city on the edge of a major fire burning through Eaton Canyon, where researchers have collected data on precipitation since 1893, they recorded that half of its 20 rainiest days ever occurred since 2000. That includes one day last February when nearly 5 inches of rain fell.
Yet not a single drop has fallen in Pasadena and much of Los Angeles County since early May, according to data from the National Centers for Environmental Information. All the vegetation that grew during the rains in the first half of the year dried out when the rains stopped, transforming Southern California into a vast landscape of tinder that exploded this week.
The intensity of extreme precipitation will continue rising through the century, according to Cal-Adapt, a data analysis initiative sponsored by the California Energy Commission. The state also forecast longer periods of drought exacerbated by rising heat, according to its Fourth Climate Assessment summary report, released in 2018 and currently being updated. These two factors will likely increase the wet-dry cycle, fueling more intense and erratic wildfires, say climate experts. In 2021, the National Oceanic and Atmospheric Administration concluded that drier air due to climate change was the “dominant” cause of variations in wildfire behavior in the West.
The effect of the current fires on Los Angeles’ massive population will present researchers with a grim opportunity to study how wildfires can affect large numbers of people in a short period of time. Among the effects is the release of fine particles, called PM2.5, a pollutant that is found in wildfire smoke and that can find its way into the lungs and bloodstream of those exposed to the smoke. Exposure can lead to decreased lung function, nonfatal heart attacks and death in people with heart or lung disease, according to the U.S. Environmental Protection Agency.
Shahir Masri, associate specialist in air pollution exposure assessment and epidemiology in the University of California, Irvine’s Department of Environmental & Occupational Health, studies climate change modeling and air pollution exposure. He published a study in 2022 that linked rising PM2.5 levels in California to wildfires and, to a lesser extent, heat waves. His previous work found that the number of census tracts in California that experienced major wildfires nearly doubled from 2000 to 2020. Capital & Main spoke to Masri about his work as the fires in L.A. County continued to burn.
This interview has been edited for clarity and brevity.
Capital & Main: Could you describe how climate change is making wildfires worse?
Shahir Masri: It’s a variety of factors linked with climate change. Increasing temperatures and aridity in places like the Western U.S, and in more mountainous areas, you can have earlier snowmelt, which leaves downstream riparian areas desiccated and more fire-prone.
But you also have these earlier spring onsets, which generally speaking means an earlier arrival of spring and warm temperatures. You basically get longer warm summer windows, which has ultimately become a longer wildfire season. Landscapes are drying out more quickly, and the wildfire season begins more quickly and ends later. [The Southern California fires] remind me of 2017-’18, the Thomas fire, which burned from December through Jan. 8.
Shahir Fouad Masri. Photo courtesy Dr. Masri.
So these later-burning fires are becoming more frequent. And when you add unprecedented heat waves on top of it, you get yet another scenario where you’re setting the stage for a major wildfire. In 2018, we saw a major wildfire season. The following year, we saw a major rainy season. Then in 2020, we saw the biggest wildfire season in the state’s history. That was a combination of huge growth in 2019 of shrubs and plants and a lot of things in the wet seasons, then the following year we got slammed with aggressively oppressive summer heat.
I fear some of this may have been at play in these fires. The last few years we’ve had really wet winters, and this is now the driest winter we’ve seen in a while. We didn’t get our holiday rain. This area burning now would have been much more resistant to a fire breaking out if we had that rain. So those are some of the factors at play and linked with climate change.
In your study, you concluded that higher levels of PM2.5 were strongly associated with nearby wildfires. Why did you study PM2.5?
PM2.5 is arguably the most robustly associated pollutant associated with adverse health effects. There have been nearly countless studies looking at the effects of PM2.5 and the increase of asthma, hospital admissions, exacerbated [chronic obstructive pulmonary disease] and short life expectancy.
It’s not entirely clear what causes PM2.5 to be more toxic than PM10 [a type of pollutant in the form of relatively larger particulates], and it’s not clear which forms of PM2.5 are most toxic. Is it because of a higher heavy metal content, or is it worse if it has a higher organic composition or sulfur content? The verdict is still out on that. But setting those composition differences aside, PM2.5 is the main characteristic of this particular type of air pollution that is most associated with adverse health effects.
What would you expect the health effects to be from these fires, particularly for poorer communities that you found were most vulnerable to PM2.5 from wildfires?
About 7% to 8% of Californians are asthmatics. Asthma attacks are exacerbated by things like air pollution — about 38% to 39% of asthmatic individuals will have an attack at least once a year. Therefore, these wildfires will likely result in quite a few asthma attacks. We will probably also see increased hospital admissions for the exacerbation of chronic conditions such as chronic obstructive pulmonary disease.
There’s a whole separate series of health impacts we’re actually looking at through a survey of people exposed to the Tustin [north] hangar fire in 2023. There were a whole host of impacts, including mental stress. In an upcoming paper, we’re talking about mental stress as it relates to wildfires and environmental catastrophes. And I don’t think that should be overlooked, even though it’s less studied.
That, I would presume, will play a role here as well, especially given people abandoning their cars, losing their homes. It’s clearly a lot of trauma inflicted on this population. Post-traumatic stress disorders, anxiety disorders, those are things we see after major wildfire events, especially [in] people close to the fire. These impacts can be quite prevalent and can take quite a long time to dissipate, up to 10 years.
So I think smoke-related impacts are one thing. I think direct injuries from the fire, thermal injuries, are another. Property loss is another as well. But those mental impacts are also a major factor.
The volume of greenhouse gases in the atmosphere is at record levels. Do you expect more events like the current Los Angeles fire outbreak?
Warming trends in the atmosphere don’t bode well. In addition to wildfire smoke, we also see higher energy demands [to run air conditioners] concurrent with heat waves. And that, depending on which state you live in, translates to greenhouse gas emissions from people using more electricity. Wildfires can wipe out the gains we’ve made from lowering emissions by reducing the prevalence of coal, [for example].
I think there’s a lot of work to be done on climate change in the United States. We have an incoming [presidential] administration notorious for disregarding climate change. And even though President [Joe] Biden acknowledged the importance of climate change and did a lot with the Inflation Reduction Act, we see a reluctance to shift away from fossil fuels even as we see more investments in renewable energy.
Biden broke his promise to end offshore drilling, so we’re seeing this fossil fuel addiction play out and remain, regardless of what political party is in office. In one case, it’s “drill baby drill”; in another, it’s “drill baby drill,” but we’ll also use the sun and wind.
So we’re so far off from where we need to be from policies to get us on the right track. And to highlight extensiveness needed for targets, the COVID-19 pandemic provided clear examples of just how dramatic a shift we’re talking about. We saw an 8% reduction in greenhouse gas emissions during the first year of the pandemic, which is what is needed to comply with the U.N.’s target of an 8% reduction year-over-year for 10 years. That’s hard to fathom, given that our economy is globally grinding to a complete halt. That was an important lesson, and unfortunately we’re not taking steps to get on that track; we’re just ramping up emissions globally.
What gives you hope?
What gives me hope is the youth community. My generation was basically much quieter on this issue than the current college generation. With every generation moving forward, the situation becomes all the more dire. It’s been quite inspirational to see them almost single-handedly get major attention and support and popularity around the Green New Deal; those are really youth-driven policy agendas. I think they’ve played a big role in popularizing those ideas.
I think those are major steps that cannot be overstated, and that generation now will be moving into politics, and that’s the most encouraging thing for me as I grapple with these issues.