How do future land-use changes jointly influence summer land–atmosphere coupling and fire danger across Europe?

Land use/land cover changes (LUC) modify local land surface properties that control the land-atmosphere mass, energy, and momentum exchanges. Through soil moisture and vegetation exchanges, land-atmosphere coupling contributes significantly to the evolution of extreme events like heat waves and forest fires. However, these interactions are still unsatisfactorily explored at regional scales under future climate scenarios.

Here, we investigate these processes using newly performed Weather Research and Forecasting (WRF v4.5.1.4) simulations under the SSP3-7.0 scenario, conducted within the EURO-CORDEX and LUCAS Phase 2 regional climate simulation ensembles. Both simulations use the LANDMATE Plant Functional Type (PFT) land cover dataset for Europe, in the first the landcover is kept constant using the 2015 map, while in the second, the land-use evolves annually according to the Land Use Harmonization dataset protocol for SSP3-7.0 scenario.

The impact of temperature–evapotranspiration coupling is assessed using a coupling metric defined as the product of normalised variables, allowing differences across regions and simulations to be examined consistently. The analysis focuses on the coupling between extreme heat (TX90p) or heat waves (defined as TX90p persisting for at least five consecutive days) and evapotranspiration (LH) or soil moisture (SMOIS), expressed through the metrics TX90p×LH and TX90p×SMOIS. Values lower than −1 indicate concurrent deficits in LH (or SMOIS), corresponding to a decoupled land–atmosphere regime. Conversely, values greater than 1 indicate strong land–atmosphere coupling.

The compound effects of extreme coupled and uncoupled events on future meteorological fire danger indices (FWI and FWIe) are analysed for both simulations, enabling a quantitative assessment of the sensitivity of future fire danger to combined climate and land-use changes.

Acknowledgements

The authors wish to acknowledge the financial support from the Portuguese Fundação para a Ciência e Tecnologia (FCT, I.P./MCTES) through national funds (PIDDAC): LA/P/0068/2020 - https://doi.org/10.54499/LA/P/0068/2020, UID/50019/2025, https://doi.org/10.54499/UID/PRR/50019/2025, UID/PRR2/50019/2025.

L.C.S. and R.M.C. also acknowledge individual funding from FCT, I.P./MCTES grants https://doi.org/10.54499/UI/BD/154675/2023, and https://doi.org/10.54499/2021.01280.CEECIND/CP1650/CT0006.