Oct 9, 2015

Past and future rainfall in the Horn of Africa

Jessica E. Tierney, Caroline C. Ummenhofer, Peter B. deMenocal
Science Advances
  • States that the recent decline in Horn of Africa rainfall during the March–May “long rains” season has provoked drought and famine, threatening food security in an already vulnerable region
  • Generates a detailed paleoclimate record in the eastern Horn of Africa region (Somalia, Djibouti, and eastern Ethiopia) over the last 2000 years
    • Reconstructs past changes in sea surface temperature using the TEX86 proxy and a Bayesian calibration
    • Reconstructs aridity by measuring the hydrogen isotopic composition of leaf waxes (δDwax)
  • Juxtaposes the paleoclimate information with climate simulations conducted as part of the recent Coupled Model Intercomparison Project 5
  • Shows that the rate of drying in the Horn of Africa during the 20th century is unusual in the context of the last 2000 years and is synchronous with recent global and regional warming
  • Concludes that the drying may have an anthropogenic component, though this needs to be confirmed by detection and attribution studies