Projecting Extreme Climate Impacts on Vegetation Dynamics in the Northwestern Ethiopian Highlands (Blue Nile Basin): A 2027 NDVI Assessment

Climate extremes are intensifying across the Horn of Africa, yet their near-term impacts on vegetation dynamics in the Northwestern Ethiopian Highlands remain inadequately quantified. This study projects the spatial-temporal impacts of extreme climate events on vegetation greenness by 2027 using a 25-year NDVI time series (2000–2024) from MODIS, coupled with CHIRPS precipitation and ERA5-Land temperature data. Extreme climate indices; Consecutive Dry Days (CDD), Very Wet Days (R95p), and Warm Spell Duration (WSDI) were computed following ETCCDI standards. Future scenarios (2027) were generated using CMIP6 GCMs (SSP2-4.5 and SSP5-8.5) and applied to a Random Forest regression model (R² = 0.82) to project NDVI anomalies. Results indicate a dominant browning trend affecting 52% of the study area under SSP5-8.5, driven by concurrent increases in CDD (+15–25 days) and WSDI (+10–25 days). The Lake Tana cultivation zone faces the most severe declines (NDVI -0.05 to -0.08), while only 28% of the region shows greening, confined to western highlands benefiting from increased R95p. Croplands exhibit a 13.3% reduction in vegetation productivity, with severe implications for rain-fed agriculture and food security. The projected vegetation dieback threatens Blue Nile baseflows, agro-pastoral livelihoods, and Afroalpine biodiversity. These findings underscore the urgent need for targeted restoration, drought-resistant crop varieties, and sustainable water-harvesting structures in vulnerable woredas. Dynamic land-use models and soil moisture integration are recommended to improve future projections.