EXPLAINER: What’s behind Europe’s spate of deadly wildfires?

By BARRY HATTON

yesterday

A local resident fights a forest fire with a shovel during a wildfire in Tabara, north-west Spain, July 19, 2022. Major wildfires in Europe are starting earlier in the year, becoming more frequent, doing more damage and getting harder to stop. And, scientists say, they’re probably going to get worse as climate change intensifies unless countermeasures are taken. (AP Photo/Bernat Armangue, File)

LISBON, Portugal (AP) — Major wildfires in Europe are starting earlier in the year, becoming more frequent, doing more damage and getting harder to stop.

And, scientists say, they’re probably going to get worse as climate change intensifies unless countermeasures are taken.

A mass migration of Europeans from the countryside to cities in recent decades has left neglected woodland at the mercy of the droughts and heat waves that are increasingly common amid global warming. One tiny spark can unleash an inferno.

Fighting forest fires in Europe has never been so hard. Here’s why:

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WHAT’S CAUSING EUROPE’S WILDFIRES?

The continent’s so-called rural exodus since the second half of the last century, as Europeans moved to cities in search of a better life, has left significant areas of countryside neglected and vulnerable.

Woodland is littered with combustible material, says Johann Goldammer, head of the Global Fire Monitoring Center, an advisory body to the United Nations. That includes things like dead tree trunks and fallen branches, dead leaves and desiccated grass.

“This is why we have unprecedented wildfire risk: because never before in history — say, the last 1,000 or 2,000 years — has there been so much flammable material around,” he said.

He adds: “The landscape is getting explosive.”

Carelessness with naked flames is often enough to ignite a wildfire. In Portugal, where more than 100 people died in wildfires in 2017, authorities say 62% of outbreaks stem from farming activities such as burning stubble.

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IS GLOBAL WARMING A FACTOR IN THE WILDFIRES?

Climate change has added a scary new dimension to wildfires and made them more menacing.

That is especially true in southern Europe, where the increasing occurrence of fire weather conditions — high temperatures, drought and high winds — make summer wildfires “the new norm,” says Friederike Otto, Senior Lecturer in Climate Science at the Grantham Institute for Climate Change at Imperial College London.

The European Union noted this month that over the past five years the bloc has witnessed its most intense wildfires on record and that the continent’s current drought could become its worst ever. The Mediterranean region is warming 20% faster than the global average, according to the U.N..

EU fire statistics bear witness to the problem. The amount of burned European countryside has more than tripled this year, with almost 450,000 hectares charred through July 16, compared with a 2006-2021 average of 110,000 hectares in those same months.

By that same date, Europe had witnessed almost 1,900 wildfires compared with an average of 470 for the 2006-2021 period.

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ARE WILDFIRES DIFFERENT NOW?

The droughts and heat waves tied to climate change have made wildfires harder to fight, as conditions make it easier for them to spread quickly. Scientists say climate change will continue to make weather more extreme and wildfires more frequent and destructive.

That includes instances of so-called “megafires” — blazes so big they are virtually unstoppable.

Spain’s wildfire problems this year began with the arrival in spring of the country’s earliest heat wave in two decades. Temperatures rose above 40 C (104 F) in many Spanish cities — levels traditionally seen in high summer.

Neighboring Portugal also saw its warmest May in nine decades, when 97% of the land was classified as being in severe drought. In France, it was the hottest May on record.

“We will not be able to completely prevent wildfires,” says Otto of Imperial College. “We have to learn to live with this.”

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HOW DO WE COEXIST WITH MORE WILDFIRES?

Scientists say there is no need to lose hope, despite the images of terrifying walls of flame and overwhelmed fire services.

“This is not an act of god,” Otto says of the more frequent wildfires. “This is, to a large degree, our doing and we have quite a lot of (power) to do something about it.”

Things we can do to adapt include putting an end to the burning of fossil fuels and educating people about global warming, she says.

Forest management also needs to be reviewed, says Amila Meskin, a policy adviser at the Brussels-based European State Forest Association, which represents governments’ forest companies, enterprises and agencies in 25 European countries.

Projects such as water retention schemes, mixing forest species and the restoration of peat lands are already happening in some places.

The effects are unlikely to be seen soon, however. Short-term planning in forestry can stretch over 50 years, and fundamental change will take decades.

More broadly, Meskin sees a general lack of interest in rural jobs and notes that forestry is not a fashionable business. Those sentiments need to be reversed, but that’s a big ask.

Maybe, she says, the shock of the wildfires will generate renewed public interest in forest care.

“It’s a very emotional thing to see forests burn,” Meskin said. “It’s such a sad, sad, sad situation.”

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REBURN: A new tool to model wildfires in the Pacific Northwest and beyond

by James Urton, University of Washington

This NASA MODIS image shows the Tripod Complex Fire in north-central Washington on 

Aug. 7, 2006. 

Credit: NASA/MODIS Rapid Response Team/Goddard Space Flight Center

In 2006, the Tripod Complex Fire burned more than 175,000 acres in north-central Washington. The fire, which was within the Okanogan-Wenatchee National Forest, was more than three times the size of Seattle. Yet while considered severe at the time, even larger wildfires in 2014, 2015 and 2021 have since dwarfed Tripod.

Past research shows that large and severe wildfires like these were much rarer in the western U.S. and Canada prior to the late 20th century.

"Fire exclusion policies for much of the 20th century yielded many dense forests with largely uniform composition," said Susan Prichard, a research scientist with the UW School of Environmental and Forest Sciences. "By the turn of this century, we had mature and densely treed, multi-layered forests with high fuel content—and as a result, large, destructive wildfires can ignite and spread more easily. There's simply more to burn across large landscapes."

Prichard, along with colleagues from the U.S. Forest Service's Pacific Northwest Research Station—Paul Hessburg, Nicholas Povak and Brion Salter—and consulting fire ecologist Robert Gray, have created a modeling tool that will allow managers and policymakers to imagine and realize a different future: one where large, severe wildfires like Tripod are once again rare events, even under climate change.

The tool, known as REBURN, can simulate large forest landscapes and wildfire dynamics over decades or centuries under different wildfire management strategies. The model can simulate the consequences of extinguishing all wildfires regardless of size, which was done for much of the 20th century, or of allowing certain fires to return to uninhabited areas. REBURN can also simulate conditions where more benign forest landscape dynamics have fully recovered in an area.

In a pair of papers published in the journal Fire Ecology, the team applied REBURN to the region in north-central Washington where the 2006 Tripod Complex Fire burned. Simulations showed that setting prescribed burns and allowing smaller wildfires to burn can yield more varied and resilient forests over time.

Such forests are made up of forest condition "patches" of different sizes and shapes, and all at different stages of recovery from their most recent fire. Patches that recently burned acted as "fences" to the flow of fire for at least the next 5 to 15 years, preventing wildfires from spreading widely. REBURN simulations showed that a forest landscape comprised of 35 to 50% "fence" areas had far fewer large-scale and damaging wildfires.

"Landscapes had tipped to more 'benign' burning conditions," said Hessburg.

REBURN simulations showed that, when fence areas were less abundant across a region, larger and more severe wildfires tended to dominate how the landscape developed over time.

"The model allows us to simulate what can happen when different management scenarios are applied before the fact, including how small or medium-sized fires in uninhabited areas can reshape forest vulnerability to fires," said Prichard. "We found that having a more complex forest environment—in terms of tree age, composition, density, fuel content—makes it harder for large fires to spread and become severe."

The simulated area (in color) for the REBURN model. The red outline indicates the area 

affected by the 2006 Tripod Complex Fire.

 Credit: Brion Salter/U.S. Forest Service Pacific Northwest Research Station

"We also found that non-forest areas comprised of grasslands, shrublands, wet and dry meadows, and sparsely treed woodlands were key ingredients of wildfire-resilient forests," said Hessburg.

"REBURN showed us that our policy of extinguishing all wildfires created forests like those that exist today, with large, severe wildfires growing more prevalent. In addition to destroying homes and blanketing cities and towns with smoke, conflagrations like these displace wildlife, destroy habitats, and can burn large areas severely, sometimes making it difficult for forests to return."

Short intervals between forest reburns can be especially harmful for long-term recovery by destroying young trees that have not yet produced cones, they added.

From 1940 to 2005 in Washington's North Cascades, fire crews extinguished more than 300 fires in their early stages in the Tripod area—most triggered by lightning strikes. By the 1980s and 1990s, forests in the region had become high-density tinderboxes, loaded with older, dying trees and lots of dead wood and other fuel on the ground.

Research has shown that before large-scale European colonization of the area, smaller wildfires shaped forests in north-central Washington and elsewhere in the Pacific Northwest. The Methow people and other tribes in the region actively set fires through cultural burning practices. Aerial photos show that, as recently as the 1930s, forests in north-central Washington had a "patchwork quilt" structure that kept large wildfires from forming easily.

"Forests with more complex structure—including densely and lightly treed areas like meadows and grasslands, shrublands, and spare woodlands—also create a wider variety of habitats for wildlife," Hessburg said. "Recently burned areas can develop into wet or dry meadows that can host deer or moose. Other, younger tree-dense areas can host lynx and snowshoe hares."

REBURN can be adapted to other regions in the western U.S. and Canada. Prichard, Hessburg and their colleagues are currently adapting it to simulate forest development in the vast forests of southern British Columbia and northern California, including regions recently hit by wildfires and those culturally burned by Indigenous people.

But knowing when—or even whether—to allow a small fire to burn in an uninhabited region is no easy task, since fire managers must protect people, their homes and livelihoods. The team hopes ongoing research will help refine the model and the insight it can provide to modified forest management strategies.

"This is a new type of tool that couples forest and non-forest development models over time, fuel fall-down after fires, and a fire growth model," said Hessburg.

"We hope that it will help people who make major decisions about our forests understand the long-term consequences of different practices and policies when it comes to wildfires," said Prichard. "We hope it will make these conversations easier to have by grounding our predictions in sound forest science."

More information: Susan J. Prichard et al, The REBURN model: simulating system-level forest succession and wildfire dynamics, Fire Ecology (2023). DOI: 10.1186/s42408-023-00190-7

Nicholas A. Povak et al, System-level feedbacks of active fire regimes in large landscapes, Fire Ecology (2023). DOI: 10.1186/s42408-023-00197-0

Provided by University of Washington Research supports use of managed and prescribed fires to reduce fire severity

Study: Survivors of wildfires face greater risk of cancer
By Denise Mann, HealthDay News

"We saw a consistent signal for lung and brain cancer risk among people who live near wildfires," study author Scott Weichenthal said. 

File Photo by Peter DaSilva/UPI | License Photo

Wildfires, like the one raging in New Mexico, are known to cause upticks in breathing issues and heart attacks in their immediate wake for folks who live nearby.

Now, new Canadian research shows that these fires may also increase the risk for lung and brain cancer over time.

People who lived within about 30 miles of wildfires over the prior 10 years were 10% more likely to develop brain cancer and had a 5% higher risk for lung cancer, compared to folks living further away from these fires.

"We saw a consistent signal for lung and brain cancer risk among people who live near wildfires," said study author Scott Weichenthal, an associate professor in the Department of Epidemiology, Biostatistics and Occupational Health at McGill University in Montreal.

"We know that a whole range of carcinogens are released during wildfires that may increase the risk for these cancers."

Wildfires typically begin in forests, grassland or prairies, and are often caused by campfires left unattended, still-lit discarded cigarette butts, sparks from power lines, or arson.

These fires tend to occur in similar parts of the country, so people living in these areas can be continuously exposed to the potentially cancer-causing wildfire pollutants, the study authors noted.

RELATED Worsening drought fuels 'catastrophic' wildfires in New Mexico

Making matters worse, "wildfires are occurring more frequently, covering larger parts of the country, and wildfire season is starting earlier," Weichenthal said. These changes are likely due to global warming and climate change, he believes.

For the study, Weichenthal and his colleagues (including doctoral student Jill Korsiak, who led the analysis), tracked 20 years of data on more than 2 million Canadians to learn more about how wildfires affect people's risk for certain cancers.

The study wasn't designed to look at specific toxins in smoke that may increase cancer risks. "There's still a lot to learn about the kind of pollution that sticks around after the fire," Weichenthal said.

RELATED New Mexico wildfire exceeds 176,000 acres officials urge residents to evacuate

It's not just about outdoor air pollution: "Wildfires also pollute water, soil and indoor air," he noted.

Dr. Mary Prunicki, who reviewed the new study, stressed that "we know more about the short-term effects of wildfires than we do about their long-term impact." She directs air pollution and health research at the Sean N. Parker Center for Allergy Research at Stanford University School of Medicine in California.

On the day of and days immediately following a wildfire, there's an uptick in hospital visits for asthma attacks, chronic obstructive pulmonary disease (COPD) exacerbations, and other lung conditions, Prunicki said.

"There is a strong literature showing an increase in heart attacks, cardiac arrests and strokes among people who have been exposed to wildfire smoke, especially those who have a pre-existing condition," she explained.

Anyone living near wildfire smoke may have burning eyes, a runny nose, cough and/or difficulty breathing.

Exactly what's in the smoke depends on what is burning, Prunicki said, but "in general, wildfires contain small particulate matter that can penetrate deep into the lungs and cause health problems.

"There are various toxins that could be in the smoke that have already been associated independently with increases in lung cancer, including polycyclic aromatic hydrocarbons [PAHs]," she added.

There are steps you can take to protect your health if you live in a part of the country where wildfires are common.

According to Prunicki, these including understanding your indoor air quality, and if it's poor, using an air purifier or a high-efficiency particulate air (HEPA) filter in your central air conditioning or heating unit. These filters can help remove pollutants from the air you breathe.

Also, "if you have underlying heart or lung conditions, make sure you have your medication at the ready, too," Prunicki said.

It's important as well to reduce the risk of wildfires when you're enjoying the great outdoors, including dousing your campfire with water until it's cold to make sure it is really out.

The study was published in the May 2022 issue of The Lancet Planetary Health.

More information

Sign up for local air quality notices via the Environmental Protection Agency.

Copyright © 2022 HealthDay. All rights reserved.

 

Possible future for Western wildfires: Decade-long burst, followed by gradual decline

by University of Washington

The model used in the study simulates past and future wildfires in California’s

 drought-prone Sierra Nevada region, using the actual landscape of the Big Creek

 watershed outside Fresno, California. The model simulates soil moisture, plant growth 

and wildfires for past conditions and in 60-year projections of future climate, with the dial 

at the upper left showing rising temperatures. Results show a decade-long burst of 

severe wildfires, followed by recurring wildfires that gradually get smaller. Credit: Ethan Turpin & David Gordon/UC Santa Barbara

In recent years, wildfires on the West Coast have become larger and more damaging. A combination of almost a century of fire suppression and hotter and drier conditions has created a tinderbox ready to ignite, destroying homes and polluting the air over large areas.

New research led by the University of Washington and the University of California, Santa Barbara, looks at the longer-term future of wildfires under scenarios of increased temperature and drought, using a model that focuses on the eastern California forests of the Sierra Nevada. The study, published July 26 in the journal Ecosphere, finds that there will be an initial roughly decade-long burst of wildfire activity, followed by recurring fires of decreasing area.

"That first burst of wildfire is consistent with what we're seeing right now in the West. The buildup of fuels, in conjunction with the increasingly hot and dry conditions, leads to these very large, catastrophic fire events," said lead author Maureen Kennedy, assistant professor at the University of Washington Tacoma. "But our simulations show that if you allow fire to continue in an area, then the fire could become self-limiting, where each subsequent fire is smaller than the previous one."

How climate change, tree growth and wildfires will interact over coming decades is only beginning to be explored, Kennedy said, through experiments and simulations. Existing models of vegetation often assume wildfires will strike at set intervals, like every 10 years, or based on past patterns of wildfire risk for that ecosystem. But those previous patterns may not be the best guide to the future.

"The big question is: What's going to happen with climate change? The relationships that we've seen between climate and wildfire over the past 30 years, is that going to continue? Or is there going to be a feedback? Because if we keep burning up these fuels, and with extreme drought that limits new growth, there will eventually be less fuel for wildfires," Kennedy said.

The new study used a model that includes those feedbacks among climate, vegetation growth, water flows and wildfire risk to simulate the Big Creek watershed outside Fresno, California, near the site of the September 2020 Creek Fire. Climate models suggest that here, as in other parts of the West, conditions will likely continue to get hotter and drier.

Results of the 60-year simulations show that under increased drought and rising temperatures, the large wildfires will continue for about a decade, followed by recurring wildfires that occur in warm and dry conditions, but are smaller over time. Even without wildfire the trees in the forest declined in number and size over time because they were less productive and more stressed in the hot and dry conditions. These findings would likely apply to other forests that experience drought, said Kennedy, who's now using the model on other regions.

What happens with wildfires over the longer term matters now for planning. Current understanding is that communities will have to coexist with wildfire rather than exclude it entirely, Kennedy said. A combination of prescribed burns and forest thinning will likely be the future of managing forests as they contend with both wildfires and climate change.

"With such high density in the forest, the trees are pulling a lot of water out of the soil," Kennedy said. "There is growing evidence that you can relieve drought stress and make more drought-resilient forests if you thin the forests, which should also help with, for example, reducing the impact of that initial pulse of wildfire."

After thinning out smaller trees, managers could then do controlled burns to remove kindling and smaller material on the forest floor. But knowing how to manage forests in this way requires understanding how local weather conditions, plant growth and wildfire risk will play out in future decades.

"It's important to include climate change so we have an idea of the range of variability of potential outcomes in the future," Kennedy said. "For example, how often do you need to repeat the fuels treatment? Is that going to be different under climate change?"

Kennedy was also a co-author of another recent study that uses the same model to tease apart how much climate change and fire suppression increase wildfire risk in different parts of Idaho.

"Our 'new normal' is not static," said Christina (Naomi) Tague, a professor at UC Santa Barbara who is a co-author on both studies and developed the RHESSys-FIRE model that was used in the research. "Not only is our climate continuing to change, but vegetation—the fuel of fire—is responding to changing conditions. Our work helps understand what these trajectories of fire, forest productivity and growth may look like

Climate change is fueling record-high heat, drought, wildfires in Western U.S.

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More information: Maureen C. Kennedy et al, Does hot and dry equal more wildfire? Contrasting short‐ and long‐term climate effects on fire in the Sierra Nevada, CA, Ecosphere (2021). DOI: 10.1002/ecs2.3657

Journal information: Ecosphere 

Provided by University of Washington 

Smoke from the Black Summer wildfires in Australia impacted the climate and high altitude winds of the southern hemisphere for more than a year and a half

Wildfire smoke becomes increasingly important for climate models due to climate change, study

Peer-Reviewed Publication

LEIBNIZ INSTITUTE FOR TROPOSPHERIC RESEARCH (TROPOS)

 

IMAGE: JANUARY 2020: DENSE PLUMES OF SMOKE FROM THE AUSTRALIAN FOREST FIRES DRIFTED THROUGH THE OTHERWISE VERY CLEAN ATMOSPHERE OVER PUNTA ARENAS. SEEN HERE IN THE LIDAR MEASUREMENTS AS A GREEN-YELLOW LAYER AT AN ALTITUDE OF 20 TO 25KM. view more 

CREDIT: CRISTOFER JIMENEZ, TROPOS

Leipzig. The 2019/20 wildfires in Australia transported more smoke into the atmosphere than observed ever before anywhere in the world. In the so-called Black Summer, three times as many particles reached high air layers as in the previous record wildfires in Canada during summer 2017. Two analyses led by the Leibniz Institute for Tropospheric Research (TROPOS) now reveal the climate impact of these huge fires: Smoke particles with a total mass of around one million tonnes spread across the southern hemisphere and affected the climate for about one and a half years by warming the upper atmosphere and cooling the lower atmosphere close to Earth’s surface. From the subtropics to Antarctica, sunlight was dimmed even more than during the eruption of the volcano Pinatubo in 1991. The smoke probably also contributed to the record ozone hole over Antarctica in 2020, forming a vortex of 1000 kilometres in diameter that passed over the southern hemisphere for several weeks, which is considered the first evidence that smoke from wildfires can also alter high-altitude winds in the stratosphere. Since such extreme fires are expected to become more frequent due to climate change, it is very important to consider the smoke and its effects on the Earth's energy balance in climate scenarios, the researchers write in the journal Atmospheric Chemistry and Physics (ACP).

 

Record forest fires in Australia

Between September 2019 and January 2020, almost twice as much area burned as in any other extreme fire in Australia documented to date. The fires peaked between 29 December 2019 and 4 January 2020, which is why they are now referred in scientific literature as the Australian New Year Super Outbreak (ANYSO) and colloquially known as the Black Summer bushfires. Due to the high heat, 38 fire clouds (Pyrocumulonimbus, PyroCb for short) were formed, which transported the smoke to great heights at ten times the speed of an elevator. More than half of these PyroCb clouds transported the smoke particles directly up to a height of 14 to 16 kilometres into the lower stratosphere. As with a volcanic eruption, the same applies to wildfires: the higher the particles reach, the further they spread and the more long-lasting is their effect on the climate. Particles in the lower atmospheric layers are usually washed out quickly by precipitation (within days to a few weeks) and therefore have little effect on the climate.

The wildfires in South-eastern Australia emitted about 1 million tonnes of smoke particles into the atmosphere around the turn of the year 2019/20. This is about four times as much as in previous years' forest fires. The smoke particles dispersed through the mid-latitudes of the southern hemisphere within a few days due to the high-altitude winds and contain, among other things, soot aerosol. These dark particles absorb solar energy and are among the strongest warming short-lived climate forcers. However, smoke from such extreme forest fires has not yet been adequately represented in aerosol climate models. An international research team led by TROPOS has therefore analysed the Black Summer wildfires to better understand the impact of such events on the climate.

  

CAPTION

The measuring containers of TROPOS with the PollyXT lidar during DACAPO-PESO in Punta Arenas, Chile.

CREDIT

Patric Seifert, TROPOS

Many measurements in the southern hemisphere provide a puzzle picture

For their study, the researchers used satellite data of the optical thickness of aerosol layers (AVHRR of the National Oceanic and Atmospheric Administration (NOAA) and the CALIOP space lidar). They compared the atmospheric opacity with the solar photometer measurements of the international AERONET network, which operates stations in Punta Arenas (Chile), Amsterdam Island (Indian Ocean), Marambio (near the Antarctic Peninsula), Vechernaya Hill (East Antarctica) and at the South Pole, among others. Moreover, the long-term observations carried out with two ground-based Raman lidars in Punta Arenas (Chile) and Río Grande (Argentina) at the southernmost tip of South America were decisive. These measurements can be considered representative of the southern part of the Southern Hemisphere and also allowed comparisons with other extreme wildfires in the Northern Hemisphere. Both measurements originally had different scientific objectives: The lidar observations in Punta Arenas took place as part of the DACAPO-PESO campaign (Dynamics, Aerosol, Cloud And Precipitation Observations in the Pristine Environment of the Southern Ocean) from November 2018 to November 2021. The main objective of this measurement campaign by the University of Magallanes (UMAG), TROPOS and Leipzig University was to study aerosol-cloud interaction processes under the clean conditions of the Southern Hemisphere. The lidar observations in Río Grande were part of the HALO mission SOUTHTRAC-GW (Southern Hemisphere Transport, Dynamics, and Chemistry-Gravity Waves), in which a large international team led by the German Aerospace Center (DLR) investigated atmospheric gravity waves in South America with the HALO research aircraft in September 2019. DLR's Compact Rayleigh Autonomous Lidar (CORAL) was also used, providing important data on the optical properties of the smoke between 15 and 30 kilometres altitude. The large amount of data made it possible to observe a new phenomenon, to compare the wildfires with previous record wildfires in North America and also to establish connections to the ozone hole:

CAPTION

Polarstern during MOSAiC in the Arctic.

CREDIT

Hannes Griesche, TROPOS

A unique smoke vortex

It has long been known that wildfires virtually make their own weather, but a new phenomenon was observed in connection with the Black Summer fires in January-March 2020: A self-sustaining vortex with a diameter of about 1000 km and a vertical extent of about 5 km. This extremely stable vortex persisted in the stratosphere for over 13 weeks, crossed the Pacific eastwards within two weeks and hovered over the tip of South America for more than a week. This was followed by a 10-week journey around the world in a westerly direction that could be tracked for more than 66 000 km by early April 2020. The vortex transported smoke and moisture up to an altitude of 35 km - an altitude not reached by tropospheric aerosols since the eruption of the Pinatubo volcano. This vortex trapped the smoke particles, keeping them from being dispersed and diluted. The absorption of solar radiation by the smoke in the centre led to warming and counter clockwise circulation, like a high-pressure area in the southern hemisphere. "Nothing like this has been observed before. This is the first evidence that smoke also causes changes in winds in the stratosphere and opens up a whole new direction of scientific research. The influence of wildfires on the atmosphere could be much greater than we previously thought," underlines Dr Albert Ansmann from TROPOS.

 

CAPTION

Interior of the OCEANET container with the green laser of the TROPOS lidar during the MOSAiC expedition in the Arctic 2019/2020.

CREDIT

Martin Radenz, TROPOS

ANYSO as the new "record holder

Lidar measurements by TROPOS from previous years made it possible to compare the wildfires in Australia with two other large fires: The record-breaking wildfires in Canada (Pacific Northwest Event, PNE) in August 2017 had transported only about a third of aerosol mass into the upper stratosphere in comparison. During this event, the smoke from five fire clouds over British Columbia could be observed over Europe until January 2018. Extremely strong fires also occurred in July/August 2019 in Siberia north and northeast of Lake Baikal (SIberian Lake Baikal Event, SILBE), where no fire clouds were observed. The smoke therefore probably rose slowly to high altitudes via solar radiation within a week. Through lidar measurements on the research icebreaker Polarstern, smoke from these fires could be observed in the region around the North Pole during the international MOSAiC expedition between October 2019 and May 2020.

The smoke from the 2017 Canadian wildfires (PNE) comprised about 0.3 million tonnes of material, formed a layer about 1 to 4 kilometres thick, rose to an altitude of 20 kilometres and hovered in the atmosphere for about 8 months. The smoke from the 2019 Siberian wildfires (SILBE) formed a layer about 7 to 10 kilometres thick, rose to an altitude of 18 kilometres and remained suspended in the atmosphere for about 5 months. The smoke from the 2019/20 Australian wildfires (ANYSO) comprised about 1 million tonnes of material, formed a layer about 10 to 14 kilometres thick, rose to an altitude of 24 kilometres and hovered in the atmosphere for about 20 months. "The Australian wildfires of 2019/20 are definitely the wildfires with the largest impact on the atmosphere and global climate to date. The dimensions are comparable to the eruption of Pinatubo in the Philippines in 1991. At that time, the particles reached heights of 25 kilometres and hovered in the atmosphere for about 14 months. Only the size of the particles differs significantly: The ash particles of the volcano, with a diameter of about 1 micrometre, were about twice as large as the smoke particles of the Australian wildfires," reports Albert Ansmann from TROPOS.

  

CAPTION

Lidar of the OCEANET container during the polar night at MOSAiC.

CREDIT

Ronny Engelmann, TROPOS

Smoke as a catalyst for the ozone hole?

In 2020/21, three events with record-breaking ozone depletion were observed: An extremely strong ozone hole formed over the central Arctic in March/April 2020, and further extreme ones over Antarctica in September to November 2020 and 2021, respectively. During all three events, an unusually large amount of smoke floated in the atmosphere of the polar regions, as shown by the lidar measurements. From the researchers' point of view, this is a clear indication of correlations, as they observed a clear correspondence between the layer with the strongest ozone depletion above the stations of the ozone probes (14-25 km altitude), the layer with an increased particle surface concentration above Punta Arenas (10-24 km altitude) and the altitude range in which the CALIOP satellite data detected polar stratospheric clouds (mainly above Antarctica at 13-26 km altitude). "Polar stratospheric clouds (PSCs) are known to have chemical processes at their surfaces that accelerate ozone depletion. Therefore, we strongly suspect that the smoke has led to these high clouds and that these clouds in turn have led to severe ozone depletion. This would not be good news for the people in and around the polar regions. If, as expected, climate change leads to more frequent and more severe wildfires, the ozone holes would spread over the Arctic and Antarctic, and with them the risk of skin cancer," explains Kevin Ohneiser from TROPOS.

 

Cooling effect like a large volcanic eruption

The data were also used for a simulation with the modern global aerosol climate model ECHAM6.3-HAM2.3. This model uses an aerosol microphysics model to describe the development of different aerosol types. This allows to estimate their influence on the radiation balance of the atmosphere: The model simulations determined a heating effect in the upper atmosphere (TOA) of +0.5 watts per square metre in the southern hemisphere and +0.25 watts per square metre globally. At the Earth's surface (bottom of the atmosphere, BOA), the solar radiative forcing was estimated to be about -0.75 watts per square metre under clear skies. This corresponds to the cooling effect caused by a large volcanic eruption. "We were surprised at how much the wildfires in southeastern Australia increased the opacity of the upper air layers of the southern hemisphere, hence, changing the radiation balance. These changes influenced the climate in the southern hemisphere for one and a half years. However, they can essentially be attributed to only four days of smoke from pyroconvection," emphasises Dr Bernd Heinold from TROPOS.

 

Wildfires become more important for climate models

The impact of wildfire aerosol on the energy balance of fires with such high-level fire clouds has probably been underestimated in models so far, as the vertical smoke distribution is crucial for the radiative effect, but there has been little knowledge about this wildfire property. "Such improvements are essential for any estimate of the Earth's energy balance and climate state. Therefore, it is becoming increasingly important to better enable climate models to deal with the impact of wildfires on the atmosphere, as they are expected to increase in frequency and severity worldwide in response to anthropogenic climate warming," explains Prof. Ina Tegen from TROPOS. "The increased risk of severe wildfires is related to extreme drought. More frequent and intense weather extremes also increase the likelihood that these very high reaching fire clouds will form more frequently in the future." Record-breaking fires like the one in Australia in 2019/20 could be repeated in other regions of the world in the years to come and have an increasing impact on the global climate.

Tilo Arnhold

 

Further information and links:

 

Updrafts crucial - clouds in the southern hemisphere more precisely understood (Press release, 26 Jan 2022): https://www.tropos.de/en/current-issues/press-releases/details/aufwinde-entscheidend-wolken-in-der-suedhemisphaere-genauer-verstanden

Climate change and wildfires could increase ozone hole (Press release, 21 Jan 2022): https://www.tropos.de/en/current-issues/press-releases/details/klimawandel-und-waldbraende-koennten-ozonloch-vergroessern

High-flying wildfire smoke may threaten ozone layer. Record Arctic ozone loss linked to Siberian wildfires (SCIENCE, 18 Nov 2021): https://doi.org/10.1126/science.acx9681

Californian smoke drifted as far as Central Europe in autumn 2020 and caused heavy clouding of the sun (Press release, 01. Jan 2021): https://www.tropos.de/en/current-issues/press-releases/details/kalifornischer-rauch-zog-im-herbst-2020-bis-nach-mitteleuropa-und-sorgte-fuer-starke-truebung-der-sonne

Smoke from Pacific forest fires spreads over Germany - TROPOS lidar detects American smoke particles over Leipzig. (Short news, 11 Sep 2020): https://www.tropos.de/en/current-issues/press-releases/kurzmitteilungen/rauch-von-us-waldbraenden-zieht-ueber-deutschland

Australian forest fires are felt as far away as Chile (Short news, 06 Jan 2020): https://www.tropos.de/en/current-issues/press-releases/kurzmitteilungen/rauch-aus-australien

 

Project „Dynamics, Aerosol, Cloud and Precipitation Observations in the Pristine Environment of the Southern Ocean (DACAPO-PESO)“: https://dacapo.tropos.de/

HALO-Mission “SouthTRAC”: https://www.pa.op.dlr.de/southtrac/

CORAL: https://www.dlr.de/pa/desktopdefault.aspx/tabid-8858/15305_read-42504/

Expedition “MOSAiC - Multidisciplinary drifting Observatory for the Study of Arctic Climate”: https://www.awi.de/im-fokus/mosaic-expedition.html & https://www.tropos.de/en/current-issues/campaigns/blogs-and-reports/mosaic-2919-2020

---

JOURNAL

Atmospheric Chemistry and Physics

DOI

10.5194/acp-22-7417-2022 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Australian wildfire smoke in the stratosphere: the decay phase in 2020/2021 and impact on ozone depletion

COI STATEMENT

At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.

Europe is burning: Four explanations

Barely halfway through summer, the area burned by wildfires raging through the Balkans, Italy and the southeastern Mediterranean has already eclipsed yearly averages.


Sheep are shepherded away from an advancing fire in Marmaris in western Turkey, a region struggling against its deadliest wildfires in decades

Wildfires burning across southern Europe in the last month — whether sparked naturally by lightning, or by arsonists — have been flamed by drought and extreme heat.

Scientists have no doubt that climate change is the key driver of yet another extreme fire season. They also understand that climate adaptation in fire-prone countries is inadequate to deal with wildfires that are set to worsen.

We look at why Mediterranean and Balkan countries are so prone to wildfires and explore the consequences of a warming world.

1. Why is the Mediterranean region burning now?

Summer wildfires are a natural and often necessary part of the life of Mediterranean forests. In the decade before 2016, around 48,000 forest fires burned 457,000 hectares annually across the five southern European nations where wildfires are most prevalent: Spain, France, Portugal, Italy and Greece. According to the scientists, fire can also breed renewal and foster biodiversity in these regions.

Indeed, communities have learned to cope better with the average annual fires in hot and arid regions across southern Europe, with more sophisticated fire prevention strategies leading to an overall decline in the number and size of fires since 1980.

But too often in recent years, fire events have escalated way beyond their normal size and intensity.

Devastating 2017 and 2018 wildfires claimed hundreds of lives across an area stretching from Turkey to Spain, while countries in central and northern Europe, including Sweden, were also scorched.

Such unprecedented fire events are inevitably linked to extreme droughts and heat waves.




2. What is starting the fires?

The month of July was the second-hottest ever recorded in Europe (and the third hottest globally). The south of the continent has been the focus of this extreme heat, with temperatures in Greece this week expected to peak at 47 degrees Celsius (117 degrees Fahrenheit).

Greece and neighboring Turkey are in the midst of a heat wave that could be the worst in 30 years — invoking memories of the nightmarish 1987 fire season that claimed more than 1,500 victims in Greece alone.

In Turkey, almost 200 separate wildfires have raged through the country in just over a week, forcing some coastal residents and tourists to flee into the Aegean for safety.

So while arson and natural causes such as lightning are equally to blame for starting the fires, extreme heat has increased their intensity and is the real culprit for the destruction wreaked across fire-hit regions. This is why at least 55% more area has burned across Europe by August 5 than the average over the previous 12 years.



This fact is compounded by outdated forest management, and sometimes even the over-protection of natural forests.

A fire on August 1 blazed through the Pineta Dannunziana, an urban pine forest in the Italian city of Pescara, forcing 800 people to evacuate. But because the area is a protected nature reserve, it is not subject to forest management such as regular clearing of undergrowth or being subjected to controlled burns. "The undergrowth burned very quickly," said Carlo Masci, mayor of Pescara.

Meanwhile, existing fire suppression policies do not account for the impact of global heating on the flammability of areas where wildlands (sometimes grown up on abandoned agricultural land) and expanding urban centers more commonly interface. This was evidenced by the flaming outer suburbs of Athens this week.

"In most Mediterranean regions, the current wildfire management policies are generally too focused on suppression and are no longer adapted to the ongoing global change," wrote the authors of a 2021 study on "Understanding Changes to Fires in Southern Europe."

3. So what has climate got to do with it?

While the burned area of the Mediterranean region has decreased slightly over the last 40 years, this is mainly due to more effective fire control efforts, according to the European Environment Agency (EEA).

Global heating increases the frequency and severity of fire weather conditions globally — as witnessed during the unprecedented wildfires across Australia and California in recent years. And inevitably, climate change has increased forest fire risk across the whole of Europe, including central and northern regions that are not typically fire-prone.

The current record droughts and heat waves across the Mediterranean region echo the events of 2018 when "more countries suffered large fires than ever before," according to the EEA.

In Greece, more than 100 people died in the so-called Attica fires of 2018 — the second-deadliest fire event this century after the 2009 "Black Saturday" fires in Australia.

"An expansion of fire-prone areas and longer fire seasons are projected in most European regions," stated the EEA.

Carbon emissions are not decreasing fast enough to limit this heating, despite climate agreements such as the European Green Deal and Paris Climate Accord.

"They put out plans, they define goals, but they don't really act," said Mojib Latif, a climate scientist at the Helmholtz Center for Ocean Research. "Since 1990, global carbon emissions increased 60%," he told DW, adding that emissions will rise again in 2021 following the pandemic-related slowdown the previous year.

4. What are the global climate change repercussions?

Globally, wildfires are responsible for significant greenhouse gas emissions, and for 5% to 8% of the 3.3 million annual premature deaths from poor air quality, according to climate group Carbon Brief.

But carbon emissions from wildfires have been on the decline in recent decades. This again is due to improved fire prevention.

The problem remaining is fire severity or intensity, which has a more far-reaching effect on carbon sequestration since forests burn so badly that they do not regrow.

In 2017, CO2 emissions from extreme wildfires across southwestern Europe (namely the Iberian Peninsula, southern France and Italy) were the highest since at least 2003, reaching approximately 37 teragrams of CO2.

To put this in context, the exceptionally wide-ranging wildfires over the Iberian Peninsula and the Mediterranean coast in 2003 accounted for the same level of anthropogenic emissions as all of western Europe for that year.

And if the wildfire intensity kills off significant forest cover in 2021, the resulting loss of carbon sinks could be even more devastating for the climate.


DW RECOMMENDS


Turkey: Death toll rises as wildfires rage along coastal resorts

Wildfires on Turkey's southern coast have killed eight people and forced residents and tourists to flee. Italy and Greece are also seeing blazes amid high temperatures across the Mediterranean.

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