Data-driven selection of optimal afforestation sites in Europe for drought adaptation

Future climate change is expected to exacerbate hydrological drought in many parts of Europe, making effective management of water resources more imperative to ensure groundwater sustainability. The EU biodiversity strategy for 2030 suggests a strategic target to turn at least 10% of the EU's agricultural areas into high-diversity landscape features like hedges and trees.

In this study, we investigate how afforestation would affect hydrological conditions in Europe under climate change, focusing on three scenarios: (1) a hypothetical extreme scenario transforming all agricultural land into forests under the current climate, (2) a more realistic scenario aligning with the EU biodiversity strategy which envisages converting 10% of the land under the current climate, and (3) a scenario involving the conversion of 10% of agricultural land into forests, but under a climate that is 2°C warmer.

We use the LISFLOOD hydrological model setup across Europe at a spatial resolution of ~2km forced by gridded observed precipitation and temperature over a period of 1991-2020 under current climate. The results were evaluated as changes in evapotranspiration, groundwater levels, and river discharge peaks against a benchmark run. The findings from the afforestation scenario indicated a rise in evapotranspiration, higher groundwater levels, and diminished river flow peaks, suggesting an improvement in water sustainability as well as increased resilience to flooding. This study highlights the hydrological benefits of strategic land use changes, offering key insights for European water resource management and policy formulation in the face of climate change. It also offers a potential toll for decision makers to tackle affects of climate change.