In 2024 Ukraine lost 965,000 hectares to fire, more than all 27 EU member states combined in the same year (JRC EFFIS, Advance Report 2024). The worst fire season in the country’s history. Climate change or war?
Both. War ignites, climate supplies dry fuel and a longer season. Peatlands drained under Soviet reclamation feed the underground burn. The Kakhovka dam, destroyed in June 2023, removed the southern hydrological buffer.
Global context: what Nature and Science show
Andela et al. (Science 356:1356, 2017): global burned area declined by approximately 24% over 2000-2018, driven by savanna conversion to agriculture. In closed-canopy forests the picture reverses: Jones et al. (Science 386:eadl5889, 2024) report that carbon emissions from forest fires rose 60% over 2001-2023.
Canada 2023: 18.5 Mha, twice the 1989 record. Byrne et al. (Nature 633:835, 2024) estimated the emission from GOSAT inversion at 647 TgC, comparable to India’s annual fossil-fuel emissions.
Why a warmer sky means more fire: the VPD mechanism
The central mediator is vapour pressure deficit (VPD). The Clausius-Clapeyron relation raises the atmosphere’s maximum water-holding capacity by approximately 7% per degree Celsius of warming. A warmer atmosphere extracts more water from foliage, litter, and soil.
Zhuang et al. (PNAS 118:e2111875118, 2021): 68% of VPD increase over the western US during 1979-2020 is anthropogenic; CMIP6 attributes rise the share to 88%. Abatzoglou and Williams (PNAS 113:11770, 2016): anthropogenic warming doubled burned forest area in the western US during 1984-2015.
Lightning in a warmer world
Janssen et al. (Nature Geoscience 16:1136, 2023): lightning causes 77% of burned area in intact extratropical forests. Strike frequency rises by 11-31% per degree Celsius. In Ukraine lightning accounts for less than 5% of fires today, a shortfall of convective storms over dry fuel. CMIP6 projects a longer summer dry spell and more frequent thunderstorms over the Carpathians and the north.
The fire-danger season is lengthening
Jolly et al. (Nature Comm. 6:7537, 2015) from FWI 1979-2013: global mean fire-danger season length grew by +18.7%. Kelley et al. (Nature Comm. 16, State of Wildfires 2023-24, 2025): the odds of an extreme year on the scale of Canada 2023 are now 3-6x higher than under pre-industrial climate.
Ukraine before the war: 30-50 thousand hectares per year across three ecosystems
By EFFIS the pre-war baseline 2010-2021 stood at 30-50 thousand hectares burned per year, with peaks in 2015 and 2020. Three ecosystems concentrate risk: Polissia (the largest peatland complex in Europe, in Volyn, Rivne, Zhytomyr, and Chernihiv oblasts, shaped by Soviet drainage), the Steppe (Kherson, Zaporizhzhia, Mykolaiv, Odesa oblasts, dry grasslands and summer drought), and the Carpathians (historically wet, but increasingly fire-prone since 2018).
Almost all Ukrainian fires are anthropogenic. Stubble burning has been prohibited since 2015 (Article 77-1 of the Code of Administrative Offences); enforcement is weak.
The Chornobyl Exclusion Zone: 2015, 2020, 2022
April 2015: approximately 12,000 ha. April 2020, the largest fire since 1986: approximately 115,000 ha. Evangeliou et al. (Sci. Rep. 6:26062, 2016) and Masson et al. (Atmos. Environ. 291:119402, 2022) reconstructed an emission of 341 GBq of caesium-137 over 1-22 April, nine orders of magnitude below 1986, yet Kyiv recorded PM2.5 at 60-150 ug/m^3 over 3-5 days (KMDA/EcoCity). March-April 2022: Russian occupation of the Zone, >= 31 fires, armoured vehicles ploughed through the Red Forest.
War years: a step change in scale
2022: Zibtsev et al. (Ukrainian Journal of Forest and Wood Science 15(1), 2024): 749,500 ha burned, emissions of 5.2 Mt CO2 plus 0.28 Mt of other greenhouse gases. 68.9% of burned area fell within 60 km of the front line; 42.5% within occupied territory.
2023: a comparable order of magnitude. Cluster analysis of Sentinel-2/MODIS (UWEC “Flames of War”): approximately 80% of burned area within 30 km of the front line, against 66% in 2022. A complementary assessment of Luhansk and Donetsk forest losses appears in Trees, Forests and People (DOI 10.1016/j.tfp.2024.100639).
2024: JRC EFFIS: 965,000 ha, 8,753 fires, 317 above 500 ha, 110 above 1,000 ha. Structure: other natural lands 39%, agricultural lands 33%, mixed forest 19%.
Ignition sources: six categories
Combat operations. Artillery, missiles, Grad, HIMARS, thermite-based incendiary munitions. Fragments ignite dry grass, reeds, and pine litter; the blast wave desiccates adjacent fuel.
Strikes on energy and chemical infrastructure. The Kremenchuk refinery: >= 8 strikes between February 2022 and September 2023, at least 15 fires (CEOBS). The Lysychansk refinery in 2022, the Drohobych refinery in 2025. Plumes are dark, combining black carbon with PAHs, SO2, benzene, and formaldehyde. Within the first 3 km of the source, PM2.5 can exceed 500 ug/m^3 — two orders of magnitude above the WHO 24-hour guideline (15 ug/m3) and EU ambient air-quality standards.
Agricultural burning and mined territory. Through autumn 2022 and 2023, Kyiv entered the IQAir global top ranks (AQI above 150, sometimes above 300) from stubble smoke and smoke generators. Approximately 170,000 ha of mined forest remain inaccessible to fire suppression.
Polissia peat fires. One hectare of peat 1 metre thick holds approximately 500 t of carbon (1,800 t CO2-eq). Polissia contains approximately 500,000 ha of drained peatlands. Moskalchuk et al. (Sustainability 17:2223, 2025): warming of +0.60 degC per decade over 1990-2021 and a 3-5% reduction in precipitation.
The Kakhovka aftermath. On 6 June 2023 the dam breach released approximately 18 km^3 of water over four days, exposed 1,870 km^2 of former lake bed, and removed 584,000 ha of the south from irrigation. Summer 2024: approximately 200,000 ha of steppe fires in Kherson oblast. PM2.5 in Kherson reached 80-300 ug/m^3, Mykolaiv 40-150, Odesa 30-100. Satellite plumes extended as far as Chisinau; back-trajectories for events of this scale are typically reconstructed with NOAA HYSPLIT.
The carbon footprint of the war
Zibtsev 2024: 5.2 Mt CO2 from landscape fires in 2022. The GHG Accounting of War Initiative (Korotkov et al., update February 2025): cumulative Ukrainian war emissions for 2022-2024 at approximately 230 Mt CO2-eq, of which 50-80 Mt come from landscape fires. The pre-war baseline was 0.5-2 Mt/year. 2022-2024 therefore represents a tenfold exceedance of the baseline. Climate widens the window within which a military ignition becomes a large fire.
What CMIP6 projects through 2050
CMIP6-FWI projections (Quilcaille et al., ESSD 15:2153, 2023; JRC GMD 16:3103, 2023) for Ukraine in 2050:
| Indicator | SSP2-4.5 (moderate) | SSP3-7.0 (high) |
|---|---|---|
| Summer mean FWI | +15-25% | +25-40% |
| Fire season length | +20 days | +35 days |
| Very high danger days (FWI >= 30), Kherson / Zaporizhzhia | doubling | more than doubling |
| Poltava / Cherkasy oblasts (FWI >= 30 days) | +50% | +80% |
The strongest season extension falls in Polissia (earlier snowmelt, faster peat drying) and in the south (longer drought). Moskalchuk 2025 for Polissia: the peat-fire return interval contracts from a historical 8 years to 3-5 years by 2040 absent rewetting. Rovira-Navarro et al. (npj Climate 7:63, 2024): a tenfold increase in “extreme” fire-danger days by the end of the century under a high-warming scenario, with eastern Europe among the regions of steepest growth.
Forest recovery and breaking the feedback loop
The “Green Country” initiative of 2021 committed to 1 billion trees in three years. Through January-November 2024, approximately 5,000 ha were planted (Ukrinform, December 2024). Structural obstacles: 170,000 ha of mined forest; approximately 776,000 ha under occupation or direct combat impact. Zibtsev and Soshenskyi (Ambio 54:2263, 2025) propose a “forest socio-ecological system” framework that couples reforestation with peatland rewetting and the selection of fire-resistant species.
The cycle can be broken locally through four parallel actions. Peatland rewetting in Polissia (EUR 10-50 thousand per hectare * 500,000 ha = EUR 5-25 billion over a decade, aligned with EU Regulation 2024/1991). Enforcement of the stubble-burning ban. De-mining at industrial scale. An FWI-based early warning system tied into the DSNS dispatch loop. The key word is parallel: not “after the war”, but alongside its end.
FAQ
Why did 2024 become the worst year when the war has run since 2022? Accumulated effects: Kakhovka 2023 removed the southern hydrological buffer; FWI in summer 2024 showed anomalies over the east and south; minefields had accumulated over three years; Polissia peatlands had not recovered their water balance for a third consecutive year.
Will the end of the war change the climate picture? Not fundamentally. The military ignition source will disappear, but the climate-driven season lengthened by 20-35 days by 2050 will remain. Without rewetting and early warning, Ukraine may transition from a wartime to a climate-driven fire regime at a comparable annual magnitude.
What is FWI and where can it be tracked? Fire Weather Index, a Canadian composite of temperature, humidity, wind, and precipitation. >= 30, very high danger; >= 50, extreme. Our forecast map displays FWI-derived products alongside air-quality forecasts. More in our coverage of wildfires and on the monitoring system page.
References
- Andela N. et al., Science 356:1356 (2017); Jones M. W. et al., Science 386:eadl5889 (2024); Byrne B. et al., Nature 633:835 (2024).
- Zhuang Y. et al., PNAS 118:e2111875118 (2021); Abatzoglou J. T., Williams A. P., PNAS 113:11770 (2016).
- Janssen T. A. J. et al., Nature Geoscience 16:1136 (2023); Jolly W. M. et al., Nature Comm. 6:7537 (2015); Jones M. W., Rev. Geophys. 60:e2020RG000726 (2022); Kelley D. et al., Nature Comm. 16 (2025).
- Evangeliou N. et al., Sci. Rep. 6:26062 (2016); Masson O. et al., Atmos. Environ. 291:119402 (2022).
- Zibtsev S. et al., Ukr. Journal of Forest and Wood Science 15(1) (2024); Zibtsev S., Soshenskyi O., Ambio 54:2263 (2025); Moskalchuk N. et al., Sustainability 17:2223 (2025).
- Quilcaille Y. et al., ESSD 15:2153 (2023); JRC GMD 16:3103 (2023); Rovira-Navarro M. et al., npj Climate 7:63 (2024).
- IPCC AR6 WG1 Ch. 11-12 (2021); JRC EFFIS Advance Report 2024; CEOBS dossiers (Kremenchuk, Lysychansk, Kakhovka).
- Post-invasion wildfire impacts in Luhansk and Donetsk regions. Trees, Forests and People 18:100639 (2024). DOI 10.1016/j.tfp.2024.100639
- WHO global air-quality guidelines (PM, O3, NO2, SO2 and CO). who.int/publications/i/item/9789240034228
- European Commission — Ambient Air Quality policy. environment.ec.europa.eu/topics/air_en
- NOAA Air Resources Laboratory. HYSPLIT trajectory and dispersion model. arl.noaa.gov/hysplit
- Wildfire Today — Ukraine news archive. wildfiretoday.com/tag/ukraine