Climate change in Africa, based on tree rings and stable isotope results, and its potential for climatic tele-connections

There is a growing need to develop long-term regional and sub-regional climate data for proactive adaptation management of climate-change risk. However in Africa long-term climate information is still sorely lacking. Tree rings and stable carbon isotopes ( d 13C) have the potential to provide empirical data regarding past climatic events. In this paper the potential of tree rings and d 13C as proxies for climate reconstructions in Africa is described. High correlations were found between the treering chronologies and precipitation data which demonstrates their potential to reconstruct precipitation in semi-arid tropics. When strong declines in tree-ring width were compared with past El Niño–Southern Oscillation (ENSO) events and drought/famine periods in Ethiopia they showed a remarkable relation. Spectral analysis of the master tree ring indicated occurrences of periodic drought events which fall within the spectral peak equivalent to 2–8 years. A declining trend with time was observed in d 13C series notably for Balanites aegyptiaca and could be attributed to anthropogenic increases in the concentration of CO2 in the atmosphere. The results demonstrate the potential of tree-ring width and d 13C to understand past and future climate changes

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