Accounting for El Niño-Southern Oscillation influence becomes urgent for
predicting future East African ecosystem responses
Istem Fer1,2,3, Britta Tietjen4,5, Florian Jeltsch1,5, and Christian Wolff6,71Department of Plant Ecology and Nature Conservation, Institute of Biochemistry and Biology, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany 2DFG Graduate School Shaping the Earth's Surface in a Variable Environment, University of Potsdam, Karl-Liebknecht-Str. 24, 14476 Potsdam, Germany 3Department of Earth and Environment, Boston University, 675 Commonwealth Avenue, 02215 MA, USA 4Biodiversity and Ecological Modelling, Institute of Biology, Freie Universität Berlin, Altensteinstr. 6, 14195 Berlin, Germany 5Berlin-Brandenburg, Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany 6Climate Geochemistry Department, Max-Planck Institute for Chemistry, Hahn-Meitner Weg 1, 55128 Mainz, Germany 7International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawai’i at Manoa, Honolulu, 96822 HI, USA
Received: 15 Feb 2017 – Accepted for review: 07 Mar 2017 – Discussion started: 09 Mar 2017
Abstract. The El Niño Southern Oscillation (ENSO), is the main driver for the interannual variability in East African rainfall with significant impact on vegetation and agriculture, and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the East African rainfall variability to forecast future East African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using Empirical Orthogonal Teleconnections (EOT) analysis. Then, we simulated the vegetation under the historical climate without components related to ENSO teleconnections. We found ENSO driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific Sea Surface temperature-East African rainfall teleconnection from observed datasets. We further simulated East African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlight that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in East African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.
Fer, I., Tietjen, B., Jeltsch, F., and Wolff, C.: Accounting for El Niño-Southern Oscillation influence becomes urgent for
predicting future East African ecosystem responses, Biogeosciences Discuss., doi:10.5194/bg-2017-49, in review, 2017.