| Description |
The Tigray Plateau of northern Ethiopia is most notable as the geographic cradle of humanity, a region that has experienced substantial climate and societal changes in the past, and likely will see more changes in the future. To understand the scale of present and future climate variability, this research provides a long-term, multimillennial perspective on climate dynamics since ~2500 cal year BP. Previous paleoecological research in the region suggests open shrub-grassland vegetation is associated with the intensification of human land use. The impact of recent human activities coupled with increased variability in seasonal precipitation are key variables for decreasing overall plant cover and increasing soil erosion in recent times. In the last 4 to 5 decades, severe and prolonged drought has become more common as exemplified by the impacts following a strong 2015-2016 El Niño. Although human activity is considered to play a significant role in landscape change in the Horn of Africa, questions remain regarding the past and present extent and specific drivers of human-landscape-climate linkages. This research explores evidence from sediment records from the Tigray Plateau in northern Ethiopia to explore these linkages through time. Elemental analysis of sediment sequences from the late Holocene suggest an overall decrease in precipitation towards present as indicated by elemental proxies. Sedimentary-charcoal-based fire reconstructions suggest fire events were dominated by natural climate forcing and corresponds to drought conditions between 1000- ~400 cal years BP. However, iv environmental change during the last millennia is likely linked to increased human activity. The role of climate variability, including El Niño Southern Oscillation and the Indian Ocean Dipole, are likely key processes that amplify and dampen human-landscape interactions. Evidence from sediment archives spanning the last two millennia suggests that as these climate oscillation modes intensify, the Tigray region will likely become more susceptible to extreme and frequent drought and disturbances like fires and flooding. |
