Climate variability in southern Africa during the last  22, 000 years
by
Karin Holmgren
Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden
Coauthors: Julia Lee-Thorp (Department of Archaeology, University of Cape Town), Peter Tyson (Climate Research Group, University of the Witwatersrand), Tim Partridge(Climate Research Group, University of the Witwatersrand), Simon Gear(Climate Research Group, University of the Witwatersrand)

While climate of high latitudes, glaciated and marine environments are increasingly well documented, knowledge of climate variations in mid and low latitudes terrestrial areas is still patchy to poor. In order to understand natural variability and the interactions between climate, man and environment we need more knowledge on regional and temporal patterns in the late Quaternary climate and environment in the tropics and subtropics. Any improvement in understanding regional effects of global change and the forcing mechanisms for specific local changes has important consequences relating to future water resources and food provisions in low-latitude regions.

Detailed studies on suitable stalagmites from southern Africa have permitted high resolution (10-50 yrs), quantitative, estimates of past variations in regional temperature, precipitation and vegetation for the last 22,000 years. Information from stable isotopes, laminae and trace element patterns have been tied together within the framework of high precision U-series TIMS dating. Regional precipitation emanating from the Indian Ocean oscillated markedly and rapidly over the last ~22,000 years on centennial and multi-decadal scales. A sharp change at the glacial/interglacial boundary, a warm and wet early Holocene and a cold (about 1 degree colder than today) and dry so-called Little Ice Age period are distinct features of the record. Regional and global comparisons suggest both large-scale synchronuous changes implicating rapid global teleconnections and small-scale regional variations suggesting that rearrangements of the atmospheric circulation produce different weather situations in widely spread regions.

http://www.geo.su.se/naturgeo/klimat/index.htm

Date received: April 29, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahi-44.