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John P. Smol – 2005

May 25, 2005 @ 2:30 pm – 4:00 pm
Senate Chamber, N940, Ross Building, York University

Title: Warnings from Lake Mud: Long-term perspectives on climatic and environmental change.

Abstract: Interest in climate change research has taken on new relevance with the realization that human activities, such as the accelerated release of the so-called greenhouse gases, may be altering the thermal properties of our atmosphere. Important social, economic, and scientific questions include the following. Is climate changing? If so, can these changes be related to human activities? Are episodes of extreme weather, such as droughts or hurricanes, increasing in frequency? Long-term meteorological data, on broad spatial and temporal scales, are needed to answer these questions. Unfortunately, such data were never gathered; therefore, indirect proxy methods must be used to infer past climatic trends. Fortunately, aquatic systems archive a tremendously important library of information of past changes in their sediments. For example, a large number of organisms leave fossils in lake muds, which paleolimnologists can then use to track past environmental conditions.  These studies have provided important insights into the natural modes of climate change, have determined the frequency of extreme climatic events, and have tracked the influence of human activities on our planet’s ecosystems. This lecture will summarize some recent studies that have documented marked climatic variability that is outside the range captured by the instrumental record, and other proxy data that have a strong bearing on sustainability of human societies. As arctic ecosystems are often the first to show signs of environmental change, and do so to the greatest degree, examples from polar regions will be highlighted. Only with such long-term perspective can we understand natural climatic variability and the potential influences of human activities on climate, and thereby increase our ability to understand future climate. Brochure - Y-File Article

Updated on August 7th, 2014.