Title: Uncovering Climate Tipping Points in East African Climate History: A Case Study of the Chew Bahir Basin
Researchers have recently shed light on the climate history of East Africa by analyzing sediment cores from the Chew Bahir Basin in southern Ethiopia. The study, published in Nature Communications, reveals that the end of the African Humid Period (AHP) was marked by a series of intense dry and wet events that occurred over a period of around 1,000 years before a dry climate prevailed around 5,000 years ago.
The transition from the AHP to dry conditions in North Africa is a prime example of climate tipping points in recent geological history. Climate tipping points occur when small perturbations trigger a large, non-linear response in the system and shift the climate to a different future state, usually with dramatic consequences for the biosphere.
The researchers identified two main types of tipping points. The first type is characterized by a slowdown in processes, leading to a decrease in variability, autocorrelation, and skewness. The second type is marked by a flickering between stable humid and dry climates that occurs shortly before the transition.
The study of the Chew Bahir Basin sediment cores revealed that at the end of the AHP, at least 14 dry events occurred, each lasting 20-80 years and recurring at intervals of 160±40 years. Later in the transitional phase, seven wet events occurred, which were of a similar duration and frequency. These high-frequency, extreme wet-dry events represent a pronounced ‘climate flickering’ that can be simulated in climate models and can also be observed in earlier climate transitions in the environmental records from Chew Bahir.
The research has significant implications for predicting future climate tipping points caused by humans. Better understanding the early warning signals of climate tipping points can help predict and prepare for possible future climate tipping points.
The study also highlights the importance of studying natural climate transitions, such as the one that occurred around 379,000 years ago, when human influence on the environment was negligible. The findings suggest that there are many arguments against human activity leading to an accelerated end of the AHP, as proposed by some researchers.
Overall, the study of the Chew Bahir Basin sediment cores provides valuable insights into the complex nature of climate tipping points and their early warning signals. The findings can help improve climate change research and modeling and inform strategies for addressing the impacts of climate change on human societies.
