Melting permafrost will cause an increase in the number of forest fires. Also, the number of fire-hazardous days on Earth has doubled, and the speed of forest fires is increasing.
Melting permafrost will cause more wildfires. An international team of climate scientists and permafrost experts in their study, published in the journal Nature Communications, concluded that global warming will accelerate the melting of permafrost and, as a result, lead to a sharp increase in wildfires in the subarctic and arctic regions of northern Canada and Siberia.
Scientists from the Institute of Basic Science in South Korea, in collaboration with researchers from the National Science Foundation’s National Center for Atmospheric Research (NSF NCAR), studied the interactions of permafrost and wildfires in a simulation run using data from the NSF NCAR-based Community Earth System 2 model.
According to the Institute of Fundamental Sciences, this is the first model of its kind. It comprehensively captures the relationship between soil water, permafrost, and wildfires. Using this integrated modeling approach, the team showed that anthropogenic permafrost thawing in subarctic and arctic regions will be quite intense by the mid- to late 21st century. In many areas, excess soil water can quickly dry up, leading to a sharp decrease in soil moisture, subsequent surface warming, and atmospheric drying. Under these conditions, model calculations show a sharp transition to very intense wildfires in just a few years in the second half of this century.
Fire in Canada. News
The researchers also found that these trends will be exacerbated in the future by the fact that vegetation biomass is likely to increase in high-latitude areas due to increasing atmospheric CO2 concentrations. This so-called CO2 enrichment effect thus provides additional “fire fuel.”
Forest fires release carbon dioxide, soot and organic carbon into the atmosphere, which could accelerate climate change and the melting of Arctic permafrost.
The number of fire-hazardous days on Earth has doubled. Annual carbon dioxide emissions from forest fires increased by about 60% between 2001 and 2023, primarily due to the impact of global warming on northern forests in Eurasia and Canada, TASS reports, citing the press service of the British University of East Anglia (UEA).
The increase in the size and intensity of wildfires over the past two decades has led to a sharp increase in associated emissions globally. The geography of fires is also changing, primarily due to how climate change is affecting northern forests. This underscores the need to combat global warming.
Scientists came to this conclusion while studying how natural and climatic conditions have changed in the so-called “pyromes” – isolated regions of the world where the probability of forest fires is affected by similar natural, anthropogenic and weather factors. In total, scientists identified 12 pyromes, four of which are located in the temperate and polar regions of the Earth, five in the subtropics, and three more in the equatorial and tropical regions.
The researchers then used data from the Terra and Aqua climate satellites to estimate how greenhouse gas emissions have changed in all pyromes over the past two decades, and also looked at shifts in wildfire frequency in these regions. To do this, the scientists analyzed data on individual wildfires that were recorded in these regions from 2001 to 2023 using NASA satellites.
Calculations by climatologists have shown that during this time, the annual volume of CO2 emissions from forest fires has increased by 60% globally, with most of this growth occurring in two of the four pyromes located in the polar and temperate latitudes of Eurasia and North America. The area of fires in their territory has increased by 2.5 times, which has led to a doubling of the volume of CO2 and other greenhouse gas emissions, which is especially true for the forests of Eastern Siberia.
Such changes in the frequency and area of fires, as scientists note, are primarily due to the fact that the number of potentially fire-hazardous days per year in these regions of the world has increased by 50-100% over the past two decades. This is due to both rising temperatures in the polar and northern regions of Eurasia and Canada, and the melting of permafrost, a decrease in precipitation and soil moisture.
Until now, this increase in forest fire frequency has remained hidden from view by observers due to a decrease in the frequency and scale of fires in savannas and steppes. But researchers have found that fires are increasingly occurring in the very places we don’t want them to be – in forests, where they not only pose a huge threat to human well-being and life, but also destroy some of the largest carbon reserves on Earth.
Wildfires are spreading faster around the world. Rapidly spreading fires are rare, but they account for much of the destruction and cost of firefighting. They can outpace evacuations and defeat efforts to fight them, as happened in recent disasters in Colorado and Hawaii. A new approach to assessing wildfire risk is needed that focuses not only on the area they burn, but also on how quickly they spread.
A study by researchers at the University of Colorado Boulder shows that the rate of wildfire growth in the U.S. has increased dramatically by more than 250% over the past two decades. While fast-moving wildfires, which burn more than 1,620 hectares in a single day, accounted for just 2.7% of all wildfires between 2001 and 2020, they accounted for 89% of damaged or destroyed structures and more than half of suppression costs. This highlights the need to better understand these “fast fires” to improve wildfire risk assessment, firefighting tactics, and community preparedness.
Some of the most destructive wildfires in the United States in recent memory, such as the Marshall Fire in Colorado in 2021 and the Lahaina Fire in Hawaii in 2023, have one thing in common: they grew rapidly within hours of starting. These fast-moving fires pose significant challenges by outpacing evacuation efforts and overwhelming suppression efforts, resulting in greater loss of life, greater damage to infrastructure, and higher suppression costs. However, traditional wildfire risk models still focus on the probability of starting, fire size, and burn intensity, rather than how quickly wildfires can spread.
Fire. Belarus today
The lack of comprehensive national fire growth rate data hinders understanding the behavior of modern wildfires and their impacts, according to researchers. Using NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS), the researchers developed a dataset of fire event delineation parameters. Using this dataset, the authors analyzed the daily growth rates of more than 60,000 fires from 2001 to 2020 across the United States.
By identifying the fastest-growing fires during this period, the scientists found that nearly half of all neighborhoods experienced destructive flash fires. By comparing these events with data from a collection of historical U.S. settlement records and government reports on fire suppression efforts, they found that flash fires accounted for 78% of structure destruction, 66% of fire fatalities, and 61% ($18.9 billion) of total fire suppression costs between 2001 and 2020.
Moreover, the study results show that the average number of fires in the Western United States in 2020 increased by 249% compared to the 2001 average, and in California, peak daily growth rates increased by 398%, indicating a significant increase in the rate of fire spread over the past two decades.
For example, over the past two years, wildfires in the Amazon region have been more intense and longer lasting than usual. The 2024 wildfire season has produced exceptionally heavy smoke and large amounts of smoke and gases that have been carried into the Andes Mountains. Satellite images show large areas of South America covered in smoke, particularly in Bolivia, where numerous wildfires have been reported since August.
The Global Atmosphere Watch station in Chacaltaya, Bolivia, located at 5,240 meters above sea level, and other Bolivian stations monitored the smoke transport, recording a nearly 10-fold increase in aerosols. These observation stations are equipped with various types of instruments to monitor the composition of the atmosphere, including data from sun photometers and gas analyzers, which help accurately record the transport of smoke from wildfires even to these relatively high locations.
The observations were compared with values that were already high, as September is the month with the most fires in the region, which historically produce large amounts of smoke in the lowlands, the World Meteorological Organization said. Together, these measurements confirm that the transport of combustion products from wildfires to the Central Andes region in 2024 was among the most intense in the last decade.
In early September 2024, a forest burned in the Chernobyl Exclusion Zone. In the event of a release of radioactive substances from the Chernobyl Exclusion Zone into the lower boundary layer of the atmosphere, from the earth’s surface to 3 km, the trajectory of the particles will shift across the northern regions of Ukraine and reach Poland within 24 hours.
