From Watts Up With That?

By Charles Rotter

The third annual State of Wildfires report went up as a discussion preprint in Earth System Science Data on August 3. It covers the fire season from March 2025 through February 2026. By the report’s own count, global burned area was 18% below the 2002 to 2024 average, and fire carbon emissions were 20 to 31% below average.

That gets one sentence. The rest of the abstract goes region by region:

In the Midwestern Canadian Shield Forests, the epicentre of Canada’s anomalous season, we find that anthropogenic climate change has doubled the likelihood of extreme fire weather in this region and made the observed BA around 61 times more likely during July–August 2025, while BA extent in the region is 46 times greater. Many parts of Europe also experienced record or high-ranking BA and fire C emissions, including in Spain, Portugal, and the UK, and a record USD 4.11 billion of physical assets were exposed to fire across the continent. Direct fatalities occurred in Türkiye (17), Spain (8), Portugal (6), Cyprus (2), Greece (1) and France (1), and evacuations in Türkiye, Spain, and Greece totalled over 110,000. In the Northwest Iberian Peninsula, we find that extreme fire weather over August 2025 was around 3 times more likely due to climate change. Under a high-emissions scenario (SSP3-7.0), fires of the same return interval are likely to burn about 78 % more area by the end of the century, with some projections within the same scenario suggesting increases of around sevenfold. In Chile and northwest Argentina, January–February 2026 fires caused 23 fatalities, displaced 55,000 people and threatened a UNESCO World Heritage Site. In the Chilean Temperate Forests and Matorral, the epicentre, we find that BA was around 36 % larger due to anthropogenic climate change.

ESSDD – State of Wildfires 2025–2026

The project chooses its focal events each year by the scale of their burned area, emissions and impacts. So the worst regional fires get the attribution work, and the global total, which went down, gets a clause.

A below average year could be luck. So I went to the satellite record. NASA’s MODIS burned area product, MCD64A1, maps burn scars from the Terra and Aqua satellites every month at 500 meter resolution. The University of Maryland fire group, which produces it, also distributes a quarter degree version for climate work, MCD64CMQ, with the burned hectares already summed into each grid cell. I added up every month from January 2001 through December 2023, the last full year in the files.

The five years 2003 through 2007 averaged 450 million hectares burned. The five years 2019 through 2023 averaged 353 million. The fitted trend from 2003, when both satellites were flying, is a loss of about 1.5% per year, and it is not marginal: the odds of a trend like that turning up by chance are less than one in ten thousand. 2023, the year of Canada’s record-breaking fire season, comes in 14th of 23 globally. The lowest year in the record is 2022.

None of this is a discovery. In 2017 Niels Andela and colleagues, using the same MODIS product along with the GFED4s database, reported in Science that “global burned area declined by 24.3 ± 8.8% over the past 18 years.” They traced most of it to farming, as agriculture spread into savannas and grasslands that used to burn. They also found that fire models could not reproduce the size or pattern of the decline, and suggested the models may overestimate fire emissions in future projections. At the time, MODIS alone gave them −1.15% per year for 2003 to 2015, significant only at the 90% level. Eight more years of data have taken care of that.

MODIS at 500 meters misses a lot of small fires, so in 2023 the GFED team rebuilt the record. Chen et al. corrected MCD64A1 against Landsat and Sentinel-2 imagery, which see small burns MODIS doesn’t, and their total came out 93% higher. The decline survived.

From the abstract:

The global annual burned area during 2001–2020 is estimated to be 774 ± 63 Mha yr−1 or 5.9 ± 0.5 % of ice-free land. Burned area declined by 1.21 ± 0.66 % yr−1, a cumulative decrease of 24.2 ± 13.2 % over 20 years. … The global reduction is primarily driven by a decrease in fires in savannas, grasslands, and croplands. … Forest, peat, and deforestation fires did not exhibit significant long-term trends.

ESSD – Multi-decadal trends and variability in burned area from the fifth version of the Global Fire Emissions Database (GFED5)

So the raw satellite product, the Science paper and the corrected database all point the same way. About a quarter less land burns each year than at the start of the century.

The usual answer is that the decline is African grassland and doesn’t count. Africa is most of it. But I split the totals with a rough box around the continent, and the rest of the world is falling at about the same rate.

The right panel is noisier, and the trend there is weaker statistically, but it is down, not up. North of 50°N, where the boreal forests are, the series jumps around with no significant trend in either direction. Its biggest year is still 2003.

The field has a response to all this. In June 2024 Calum Cunningham of the University of Tasmania and colleagues took roughly 30 million fires, kept the 2,913 most energetic, and found that these extreme events increased 2.2-fold from 2003 to 2023. Cunningham told the Washington Post the work began as a response to skeptics who asked how there could be a growing fire crisis while the area burned was shrinking. The increases are real and concentrated in temperate conifer and boreal forests. But the measure is about one fire in ten thousand, on a record that starts in 2003, and by Nature’s own account the study does not directly connect the trend to global warming.

The new report also “claims”, essentially an unsupported assertion, that mitigation has already reduced end-of-century wildfire risk compared with a worst-case emissions scenario.

Continued climate change is expected to intensify these hydroclimatic extremes, yet mitigation has already reduced projected end-of-century wildfire risk: under a high-end emissions pathway (SSP3-7.0), the extreme BA events in our focal regions are projected to be 4–23 % smaller than they would have been under a worst-case emissions scenario no longer considered credible (SSP5-8.5). emphasis added

ESSDD – State of Wildfires 2025–2026

SSP5-8.5 was never the road we were on. Zeke Hausfather and Glen Peters pointed out in Nature in 2020 that it requires “an unprecedented fivefold increase in coal use by the end of the century,” and that global coal use peaked in 2013.

There was nothing to mitigate.

Global burned area was 18% below average this past season and has been falling for two decades. Why is that one sentence?

If the fire models could not reproduce the decline in 2017, how much weight do their end-of-century projections carry now?

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Quotes from Chen et al. 2023, https://doi.org/10.5194/essd-15-5227-2023, and Burton et al. 2026 (preprint), https://essd.copernicus.org/preprints/essd-2026-587/, used under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/).

Burned area data: NASA MODIS MCD64CMQ Collection 6.1, monthly 0.25° burned area, January 2001 to December 2023, from the University of Maryland fire group (fuoco.geog.umd.edu). Annual totals are sums of the monthly BurnedArea field. “Africa” is the box 36°S to 38°N, 18°W to 52°E.

Link to spreadsheet