Investigating the global and regional response of drought to idealized deforestation using multiple global climate models

Abstract. Land use change, particularly deforestation, significantly influences the global climate system. While various studies have explored how deforestation affects temperature and precipitation, its impact on drought remains less explored. Understanding these effects across different climate zones and time scales is crucial for crafting effective land use policies aimed at mitigating climate change. This study seeks to investigate how changes in forest cover affect drought across different time scales and climate zones using simulated deforestation scenarios, where forests are converted to grasslands. The study utilizes data from nine global climate models participating in the Land Use Model Intercomparison Project. Drought effects are assessed by examining changes in the Standardized Precipitation Evapotranspiration Index (SPEI). The results reveal that deforestation leads to negative shifts in global SPEIs, indicating increased dryness, particularly in tropical regions, while causing wetter conditions in dry regions. Moreover, the impact on drought indices becomes more pronounced with longer time scales, underscoring the lasting effects of deforestation on drought. Seasonally, deforestation exacerbates SPEI03 shifts during autumn and winter, especially affecting tropical and northern polar regions. Continental zones experience significant seasonal changes, becoming drier in winter and wetter in summer due to global deforestation, while the northern hemisphere's dry regions see increased wetter conditions, particularly in autumn. These findings deepen our understanding of the relationship between vegetation change and climate change, offering valuable insights for better resource management and mitigation strategies against future climate change impacts.