Middle East climate response to the Saharan vegetation collapse during the mid-Holocene

Abstract:

Understanding the Middle East climate change is crucial as the people’s lives depend on the rain-fed crop systems. It is still unclear the ME climate response to the Saharan vegetation collapse at the end of the mid-Holocene (MH). Some proxy data suggest a transition from humid to more arid ME conditions during the period of 6.5-5 kyr BP. Using a set of idealized sensitivity experiments, we infer that the desertification of Saharan vegetation plays a role in this wet-to-dry transition over the ME. The experimental results show that the Saharan vegetation can significantly increase the late winter and early spring precipitation over the ME, which is caused by the vegetation-induced conspicuous and ubiquitous warming in North Africa, generating a local anomalous cyclone, transporting abundant moisture to the ME, and enhancing precipitation over the Tigris-Euphrates delta and Zagros Mountains. The crop model simulation further shows a substantial decrease in wheat yield in Mesopotamia at the termination of Saharan vegetation, which is consistent with the reconstructions. These results imply that future changes in Saharan land cover may have a potential impact on the water-stressed ME.