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

Abstract

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