Extreme Wildfires have Doubled in 20 Years

Recently, over 70 wildfires burned simultaneously in Greece. In early 2024, Chile experienced its worst wildfire season ever, resulting in over 130 fatalities. Last year, Canada endured record-breaking wildfires from March to November, and in August, flames ravaged Maui in Hawaii. And the list continues.

Watching the news, it seems like catastrophic wildfires are occurring more frequently, and unfortunately, this perception is accurate. A recent study in Nature Ecology & Evolution confirms that the number and intensity of the most extreme wildfires on Earth have doubled over the past two decades.

Researchers from the University of Tasmania calculated the energy released by various fires from 2003 to 2023 using a satellite-based sensor that detects heat, measuring the energy as “fire radiative power.”

Focus on Extreme Fires

The study identified 30 million fires (technically “fire events,” including some clusters) and focused on the top 2,913 with the highest energy output—the 0.01 percent most extreme wildfires.

Their findings reveal a doubling in the number of these extreme wildfires over the past 20 years. Since 2017, the Earth has seen the six years with the most extreme wildfires (excluding 2022).

Moreover, these extreme wildfires are becoming even more intense, with recent ones releasing twice the energy compared to those from the beginning of the studied period.

These findings are consistent with other recent evidence indicating that wildfires are becoming more severe. For example, the area of forest burned annually is increasing slightly, causing a rise in forest carbon emissions. Although the total land area burned each year is decreasing, this is mainly due to a reduction in grassland and cropland fires, which are less intense and emit less carbon compared to forest fires.

Additionally, burn severity—an indicator of the extent of ecosystem damage—is worsening in many areas, and the proportion of burned land experiencing high-severity fires is rising globally.

Regional Variations in Extreme Wildfires

While the global outlook appears grim overall, significant regional variations exist. The new study highlights boreal forests in the far north and temperate conifer forests (depicted as blue and light green on the map) as key ecosystems contributing to the global rise in extreme wildfires.

These forests experience a higher number of extreme fires relative to their size, show the most pronounced worsening over time, and are seeing increases in both the total burned area and the percentage of land affected by high-severity fires. These trends are especially prominent in eastern Siberia, as well as in the western United States and Canada.

However, numerous other regions are also at risk of experiencing more significant impacts from fires. The transformation of a fire into a disaster depends not just on fire trends but also on the environmental, social, and economic contexts.

For example, temperate broadleaf forests around the Mediterranean have not seen major changes in fire activity or behavior. Yet, the increasing construction of homes in and around wild vegetation in fire-prone areas exemplifies how human actions can heighten risks and potentially lead to catastrophic outcomes.

Read the original article on: Science Alert

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