A progressively wetter climate in southern East Africa over the past 1.3 million years
Johnson, T.C.; Werne, J.P.; Brown, E.T.; Abbott, A.; Berke, M.; Steinman, B.E.; Halbur, J.; Contreras, S.; Grosshuesch, S.; Deino, A.; Lyons, R.P.; Scholz, C.A.; Schouten, S.; Sinninghe Damsté, J.S. (2016). A progressively wetter climate in southern East Africa over the past 1.3 million years. Nature (Lond.) 537(7619): 220-224. dx.doi.org/10.1038/nature19065
In: Nature: International Weekly Journal of Science. Nature Publishing Group: London. ISSN 0028-0836; e-ISSN 1476-4687, meer
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| Auteurs | | Top |
- Johnson, T.C.
- Werne, J.P.
- Brown, E.T.
- Abbott, A.
- Berke, M.
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- Steinman, B.E.
- Halbur, J.
- Contreras, S.
- Grosshuesch, S.
- Deino, A.
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- Lyons, R.P.
- Scholz, C.A.
- Schouten, S., meer
- Sinninghe Damsté, J.S., meer
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| Abstract |
African climate is generally considered to have evolved towardsprogressively drier conditions over the past few million years,with increased variability as glacial–interglacial change intensifiedworldwide1–3. Palaeoclimate records derived mainly from northernAfrica exhibit a 100,000-year (eccentricity) cycle overprinted on apronounced 20,000-year (precession) beat, driven by orbital forcingof summer insolation, global ice volume and long-lived atmosphericgreenhouse gases4. Here we present a 1.3-million-year-longclimate history from the Lake Malawi basin (10°–14° S in easternAfrica), which displays strong 100,000-year (eccentricity) cycles oftemperature and rainfall following the Mid-Pleistocene Transitionaround 900,000 years ago. Interglacial periods were relativelywarm and moist, while ice ages were cool and dry. The Malawirecord shows limited evidence for precessional variability, whichwe attribute to the opposing effects of austral summer insolation andthe temporal/spatial pattern of sea surface temperature in the IndianOcean. The temperature history of the Malawi basin, at least for thepast 500,000 years, strongly resembles past changes in atmosphericcarbon dioxide and terrigenous dust flux in the tropical PacificOcean, but not in global ice volume. Climate in this sector of easternAfrica (unlike northern Africa) evolved from a predominantly aridenvironment with high-frequency variability to generally wetterconditions with more prolonged wet and dry intervals. |
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