Climate change increased the likelihood and severity of record wildfires that devastated Canada parts of the Amazon and Greece last year, according to a groundbreaking and comprehensive review of global wildfire activity.
Why it matters: Scientists are taking stock of increasingly extreme wildfire seasons and are also examining how reliably they can be predicted.
"Wildfires are becoming more frequent and intense as the climate warms, and both society and the environment are suffering from the consequences," lead author Matthew Jones, research fellow at the Tyndall Centre for Climate Change Research, said in a statement.
Zoom in: The " State of Wildfires" report , released Tuesday afternoon, is the first annual comprehensive effort to create a detailed accounting of wildfires and their drivers from the vast boreal biome ringing the Arctic to the African savanna.
Researchers bring new insights with its look at how human-caused climate change is altering wildfire seasons, along with a focus on predictability and prevention.
Published in the journal Earth System Science Data , the report finds that wildfire-related carbon emissions from wildfires globally from March 2023 to February 2024 were 16% above average, amounting to 8.6 billion metric tons of carbon dioxide.
Canada's fire season stood out the most, with the boreal forest — which throughout human history has acted as a giant absorber of carbon , emitting more than nine times the long-term average and amounting to about a quarter of the global emissions.
Fueled by long-term drought, heat waves and other factors, Canada saw wildfires erupt from coast to coast, with smoke pouring across the U.S. border into the large cities of the Northeast and Mid-Atlantic.
The intrigue: Last year also featured unusually high fire activity in Brazil's Amazonas state along with parts of Bolivia, Peru, and Venezuela.
The report documents the causes and consequences of intense, fast-moving and deadly fires that occurred in Chile, Hawai'i and Greece
Scientists found that a relatively quiet fire season in the African savannas prevented the 2023-24 season from setting a new record for global wildfire-related emissions of CO2.
Between the lines: Climate change is altering global fire activity in ways that transform ecosystems that had long served as carbon "sinks," which are the equivalent of a carbon savings account with a steady flow of deposits, into net sources, or withdrawals, of planet-warming CO2.
This acts as a positive climate feedback, worsening global warming.
"In Canada, almost a decade's worth of carbon emissions from fire were recorded in a single fire season — more than 2 billion tonnes of CO2," Jones said. "In turn, this raises atmospheric concentrations of CO2 and exacerbates global warming."
How it works: To arrive at their conclusions, scientists examined satellite data from sensors that pinpoint heat signatures on Earth's surface, along with surface observations and models of climate and fire behavior.
Zoom out: The report stems from a collaboration led by the University of East Anglia, the UK Met Office, UK Center for Ecology and Hydrology and the European Center for Medium-Range Weather Forecasts.
To tease out the human role in altering wildfire risk and severity, researchers at these and other institutions looked closely at last season's fire weather trends in Canada, western Amazonia and Greece.
They found that extreme fire weather conditions that can promote rapid fire growth, such as unusually hot, dry and windy weather, has become more prevalent in each of these regions due to human emissions of greenhouse gases.
The researchers conclude that climate change made the extreme fire weather conditions in Canada at least three times more likely, 20 times more likely in parts of the Amazon , and twice as likely in Greece.
In addition, the report looks at how climate change is affecting the size of the areas burned compared to the preindustrial era, prior to the burning of vast amounts of fossil fuels and the buildup of greenhouse gases such as CO2 and methane.
On this, the findings were about as conclusive as one gets in climate science, showing that climate change was virtually certain to have increased the extent of burned areas in Canada and Amazonia.
What's next: Not surprisingly, climate models project that extreme wildfires will become more common and intense in coming decades, particularly if global warming hews to the upper end of climate scenarios.
Yes, but: Rapid and steep cuts in greenhouse gas emissions now can make a major difference in limiting the increase in extreme wildfires toward the latter part of this century, the study finds.
Similarly, advances in seasonal fire prediction and improved land management can also reduce the prevalence and severity of extreme wildfires.
Andrew Freedman