P2C2: Long-term Environmental Changes and Anthropogenic Impacts on Tropical African Landscapes

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Non-Technical AbstractThis award to Georgia State University will study the long-term history of climate change, vegetational changes and human impacts on tropical African environments. The investigator will analyze carbon and nitrogen isotopes, fossil pollen, diatoms, fungal spores, and charcoal in lake and swamp-sediment cores from East Africa. Understanding climate and vegetational change in East Africa is significant because it opens a window for studying the variability of tropical climate systems. This project will reconstruct East Africa's environment with the necessary time resolution and sufficient precision to reveal the causal mechanisms behind the climate changes during the last 10,000 years. An important scientific goal of the project is to investigate the interaction of human-induced impacts and the pattern of climate change in shaping East Africa's environment in the past. Specifically, the study seeks to answer the following questions: At what point during the the last 10,000 years does the evidence of human-induced impacts on the environment appear in the record? To what extent does variability in the solar cycle and long-distance climate events explain changes in East Africa's climate and environment through time? And lastly, does the human-induced imprint on the environment supplant natural climatic change trend in East Africa during the last 4,500 years? The project holds the promise of providing important data and a broader understanding of environmental change and its relation to climate, and provides a context for better understanding the interplay of humans and climate. The broader impacts of the project include supporting graduate students, contributing to local capacity building in Kenya, and international collaboration with scientists in Kenya through collaborative research and joint publications.Technical AbstractDiscerning the dynamics of human-climate interaction remains one of humanity's eminent unanswered questions. This project aims to study the history of climate change, vegetational changes, and human impacts on tropical African environments during the Holocene through the examination of a multi-proxy record of the lithostratigraphy, fossil pollen, diatoms, fungal spores, and microscopic charcoal in lake-sediment cores. Geochemical, biological, and sedimentary records preserved in lacustrine and palustrine environments provide an excellent archive of past changes in the environment resulting from both climate changes and anthropogenic impacts which could reveal how the natural environment may respond to human-related climate change in the future. Understanding climate and vegetational change in East Africa is significant because it opens a window for studying variability in tropical climate systems and their causal mechanisms which, to date, remain largely unresolved. This project will use a multi-proxy approach to reconstruct East Africa's paleoenvironment with the necessary time resolution and sufficient precision to reveal the causal mechanisms behind the climate changes during the late Holocene through analysis of cores from Lake Kanyaboli (a satellite of Lake Victoria) and Saiwa Swamp in western Kenya. The important goals of the project include: producing a high-temporal-resolution multi-proxy paleoenvironmental record of the late Holocene for the East African region based on analysis of sediment cores collected from lacustrine and palustrine environments; understanding the control mechanisms for the spatial and temporal variability of environmental changes in East Africa and their possible linkage to solar activity and teleconnection events; isolating human-induced changes in the East African landscapes from the changes due to climate variations by employing the multi-proxy approach involving geochemical species, pollen, mycological data, diatoms, and microscopic charcoal; and identifying and dating the onset of anthropogenic impacts on the environment and exploring their relationship with environmental changes in the tropical African region.The scientific issues that will be investigated are interdisciplinary in nature and will address questions which are important to understanding the impacts of human activities on geophysical processes and paleoenvironmental change. The research holds the promise of providing important data and a broader understanding of environmental change and its relation to climate, and provides a context for better understanding the interplay of humans and climate. The broader impacts of the project include supporting graduate students, contributing to local capacity building in Kenya, and international collaboration with scientists in Kenya through collaborative research and joint publications.