Forest fires are burning nearly twice as many trees as they did just two decades ago, according to a study from the University of Maryland’s Global Land Analysis and Discovery (UMD’s GLAD) laboratory.
In the United States this year alone, several large wildfires in California have burned nearly 200,000 acres and killed at least four people, according to data from CalFire. One notable blaze threatened the country’s oldest trees, in Yosemite National Park, while the largest fire, on the California-Oregon border, killed at least four and burned more than 60,000 acres.
Globally, several massive wildfires have engulfed large forests in different corners of the world, showing the growing extent of damaging blazes.
In Europe, large wildfires have affected at least a dozen countries, burning across 600,000 hectares of land, according to reporting by Reuters. Fed by a dry summer and temperatures that pushed above the century mark, large fires darkened skies in Portugal and France this summer.
Wildfires in the largely untamed wilderness of Russia’s Siberian and Far East regions have scorched upward of 3.2 million hectares of forest this year, according to the Moscow Times, blanketing several towns in toxic smoke. Elsewhere in Asia, parts of China are battling numerous wildfires in the midst of the country’s worst heat wave since 1961.
Rising temperatures caused by human activity are an important driver of worsening wildfire conditions globally. As the atmosphere becomes warmer, typically lush forests dry out and become more vulnerable to fires.
Dried-out forests can act like tinderboxes, allowing fires to spiral out of control. Vast blazes release even more carbon dioxide into the atmosphere, contributing to further warming of the planet. The World Resources Institute refers to this cycle as the fire-climate feedback loop, and little can be done to slow it outside of dramatically lowering greenhouse gas emissions.
A changing climate has caused boreal forests to ignite as never before. About 70 percent of all fire-driven tree loss over the past 20 years has occurred in boreal forests, which are in northern areas of the planet, which are warming at higher rates than other parts of the globe.
In 2021 alone, 6.67 million hectares of tree cover were lost in boreal forests, compared with just 1.16 million hectares lost in tropical forests such as the Amazon, according to UMD’s GLAD laboratory. In both cases, though, the loss of these trees and the thawing of permafrost threatens to release ancient stores of carbon, converting vast forests from climate-healthy carbon sinks into accidental polluters.
“We are seeing some severe fire years in the boreal and tropical forests in recent years,” said Alexandra Tyukavina, assistant research professor at UMD’s GLAD laboratory and the study’s lead author. “This is an alarming sign, and climate change likely plays a role.”
In tropical forests, agriculture and growing deforestation have increased the risk of wildfires while also making the forests less resilient to blazes. The expansion of industry and agriculture into these previously untouched parts of the globe means that most fires in tropical rainforests are sparked by people, as opposed to being ignited naturally by lightning strikes.
Although the analysis shows that fire-related tree loss in Brazil spiked in 2016 and has shrunk since, the number of trees lost to wildfires in the past five years is still many times higher than in the early years of the 21st century.
The threat from wildfires is expected only to grow globally, as the climate is all but guaranteed to continue to warm. Still, mitigation efforts can be implemented.
The 2022 report of the United Nations Intergovernmental Panel on Climate Change (IPCC) found that each increment of additional warming will lead to more devastation and death from a variety of climate hazards, meaning that keeping temperatures even a tenth of one degree Celsius cooler could have a substantial impact.
For boreal forests, restricting warming to under 3.6 degrees Fahrenheit (2 degrees Celsius) is critical. Scientists with the IPCC say that some of the worst-case warming scenarios would lead to 15 years of greenhouse gas emissions being released from the massive stores of carbon in these regions, something that could be curbed if the planet’s temperature increase is kept below the threshold of 3.6 degrees Fahrenheit.
Humans also can change how they interact with forests — ending deforestation and limiting agricultural techniques such as slash and burn can help improve forest resilience, especially in the tropics. Improved monitoring of wildfires will also prove helpful to researchers.
“We need to have timely information on where forest fires are happening and to educate the public on safe fire behaviors,” Tyukavina said. “It is also important to incentivize fire-safe alternatives to land management practices that might result in escaped forest fires, such as burning of logging and crop residue.”