State of Wildfires 2023-24: CAMS data supports assessment

The report catalogues several high-impact wildfire events during 2023-24, including those in Canada, Greece, and the western Amazon. Notably, 2023-24 saw a total of 3.9 million km² burned globally, which is slightly below the average of previous years. However, fire carbon emissions were 16% above average, totalling 8.6 billion tonnes of carbon dioxide (CO2). This discrepancy is largely attributed to record-breaking emissions in Canadian boreal forests, which were over nine times the historical average.

In Canada last year, a combination of severe drought conditions and an abundance of dry fuels resulted in the most extensive wildfire activity ever recorded, with over 150,000 km² burned, prompting the evacuation of over 232,000 people, highlighting the severe human impact of these events. Similarly, Greece experienced its largest wildfire on record, with around 900 km2 burned. This is the largest wildfire on record for the European Union, exacerbated by a combination of high fire weather and fuel availability. The report also documents significant events in other regions, including devastating fires in Hawai’i and Chile, which claimed numerous lives and led to large-scale evacuations.

Analysis supported by CAMS data

CAMS data was extensively used in the analysis presented in the report. CAMS provided critical data on fire carbon emissions and air quality impacts, contributing to the understanding of wildfire dynamics and their broader impacts.

The report used daily data from the CAMS Global Fire Assimilation System (GFAS) to estimate fire carbon emissions for the period from March 2023 to February 2024. Emissions were calculated as the mean of GFAS, which uses fire radiative power (FRP), and data from the Global Fire Emissions Database (GFED4.1s), which uses burned area to calculate estimated emissions. In particular, the report used PM2.5 surface concentration estimates from the CAMS reanalysis of global atmospheric composition in evaluating the air quality impacts of the emissions, noting that that “CAMS reanalysis provides a 3-dimensional time-consistent dataset of atmospheric composition, including aerosols, chemical species and greenhouse gases for the period 2003-2023.”

According to the report, during peak events in North America many regions in Canada and the United States experienced PM2.5 levels that exceeded recommended limits. CAMS reanalysis was used to calculate the number of days in which the daily mean PM2.5 concentration was above the 35 ug/m3 threshold set in the National Ambient Air Quality Standards (NAAQS). Citing the CAMS reanalysis, the report notes that people living within over half of US states experienced up to two weeks of PM2.5 exposure at or above the 35 µg/m³ threshold. The biggest impacts on air quality were experienced close to the fires, particularly in western and northwestern Canada and in Quebec in the east of the country.

For its assessment of the contribution of weather and fuel moisture to the anomalous events, the report also took several predictors from ERA5, specifically variables that are known to correlate with active fires or burned area. This information helped highlight the conditions that led to the anomalous fire events, providing a comprehensive picture of the contributing factors.

CAMS provides regular up-to-date information on the location, intensity and estimated emissions of wildfires around the world, as well as tracking smoke transport and composition. The CAMS website provides ongoing updates on wildfire activity around the globe (such as this review of 2023, or this update on wildfire activity this summer). To learn more about CAMS monitoring of wildfires and smoke, visit our page on Global fire monitoring.

The role of climate change

The report found that climate change increased the probability of high fire weather conditions, long-term average burned area, and extreme burned area during 2023-24. In some areas, the area burned by fires would have been larger if the landscape had not been altered by people. Activities such as agriculture and forestry influence the landscape and can reduce the density of vegetation, such as in Canada and Greece for example, but in other areas these can create additional ignitions that exacerbate fires, such as in Western Amazonia.

In Canada, the results show that human influence increased the chance of high fire weather in 2023. In June last year, human influence is estimated to have increased the probability of experiencing high fire weather three-fold. Looking exclusively at the areas that burn most each year (areas in the top 5%), the results show that climate change caused fires to burn up to 40% more land than usual. Socioeconomic factors such as population and land-use change likely decreased fire extent in those areas.

The report notes a similar dynamic in Greece, where human influence increased the probability of experiencing high fire weather in August 2023 by up to a factor of 4. The analysis shows that climate change has increased the average burned area of recent decades in the Mediterranean region, but this has been partially offset by socio-economic factors.

“In Canada and Greece, a mix of severe fire weather and plenty of dry vegetation reinforced one another to drive a major uptick in the number and extent of fires last year,” said Dr Francesca Di Giuseppe, Senior Scientist at the European Centre for Medium-Range Weather Forecasts (ECMWF). “But our analysis also shows that factors such as suppression and landscape fragmentation related to human activities likely played important roles in limiting the final extent of the burned areas,” she added.

Meanwhile, in western Amazonia it is virtually certain that climate change has led to higher burned area, and very likely that socio-economic factors also contributed. The analysis shows that human influence increased the probability of experiencing high fire weather by a factor of more than 20. While in the western Amazonian region, the results show that climate change caused fires to burn up to 50% more land than usual, with socioeconomic factors likely to have decreased fire extent, in the northwest region the effects of climate change and land use changes combined have led to an overall increase in burning.

Future projections and implications

For the 2024 fire season, seasonal predictions of fire weather through August 2024 highlight moderate positive anomalies (75th percentile) in parts of Canada and much of South America, consistent with recent reports of wildfires in Canada, California, and the Brazilian Pantanal. In addition, a moderate positive anomaly in Eastern Europe has been confirmed by recent fire activity in the Balkans. However, there is no clear regional signal of extreme (95th percentile) fire weather anomalies in the global forecast.

The report notes that, while the positive El Niño phase of ENSO (El Niño–Southern Oscillation) is subsiding towards a neutral phase in 2024, the Indian Ocean Dipole is persisting in its positive phase, with potential to influence global fire patterns.

Looking ahead, the report provides a sobering outlook on the future of wildfires under various climate scenarios. The projections indicate that extreme wildfire events, currently considered rare, may become more common by the end of the century. This potential increase underscores the necessity for robust fire management strategies and policies aimed at mitigating the impacts of these increasingly severe events.

The "State of Wildfires 2023-24" report represents a landmark effort in the systematic documentation and analysis of extreme wildfire events on a global scale. It provides invaluable insights for policymakers, disaster management services, firefighting agencies, and land managers, aiming to enhance society's resilience to wildfires. The contributions of CAMS in providing high-quality data and analyses were instrumental in shaping the findings of this report, underscoring the critical role of scientific data in understanding and mitigating the impacts of climate change on wildfire activity.

As the climate continues to change, the insights from this report will be crucial in guiding future research, policy, and action to protect communities and ecosystems from the escalating threat of wildfires.

*CAMS is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) with funding from the European Commission

Source: Copernicus