A progressively wetter climate in southern East Africa over the past 1.3 million years

T. C. Johnson*, J. P. Werne, E. T. Brown, A. Abbott, M. Berke, B. A. Steinman, J. Halbur, Sergio Contreras, S. Grosshuesch, A. Deino, C. A. Scholz, R. P. Lyons, S. Schouten, J. S.Sinninghe Damsté

*Corresponding author for this work

    Research output: Contribution to journalArticle

    39 Citations (Scopus)

    Abstract

    African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide. Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases. Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10°-14° S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals.

    Original languageEnglish
    Pages (from-to)220-224
    Number of pages5
    JournalNature
    Volume537
    Issue number7619
    DOIs
    Publication statusPublished - 8 Sep 2016

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