Recent and past freshwater systems reaction to environmental change and the challenge of cultural sustainability
by
Daniel Ariztegui
Institute Forel and Dept. of Geology and Paleontology, U. of Geneva, Switzerland

Recent environmental changes have shown the impact that sudden and often unexpected events can have on freshwater systems. Flooding or drought episodes in highly populated areas can have devastating effects on the population. Thus, a good understanding of the causes and processes behind environmental degradation is critical to develop strategies that guarantee future sustainability. To date, the length of the instrumental record is not sufficient to fully appreciate the ranges of natural climate variability making critical the development and calibration of new proxies. Modern lakes are ideal to calibrate a broad range of indicators and to study recent and past environmental changes.

The combination of geophysical, sedimentological and geochemical data in lacustrine basins can provide extraordinary datasets. Comprehensive studies allow assessing both human- and climate- induced processes such as recent biodiversity changes in Lake Geneva, Switzerland, and ENSO frequency during the Little Ice Age in Lago Frias, northern Patagonia, Argentina, respectively. Furthermore, lakes are also exceptionally receptive systems to changes in the evaporation/precipitation balance. Lake sediments from Lago Cardiel, Argentina, in concert with well-constrained archeological data provide unique information on human migration during intervals of known relatively lower effective moisture. Analogously, lacustrine evidence from the Guatemalan lake district show that although the ancient Maya dramatically altered their surroundings, natural changes in climate may have played a substantial role in their development and collapse.

All these examples show that lacustrine records hold vital information to resolve cause and effect relationships for the natural and human- induced processes that have previously driven the climate system. Hence, they provide new insights that can be use for planning future strategies leading to sustainable development.

Date received: January 11, 2005

Copyright © 2005 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 # caod-67.