On the cause of abrupt vegetation collapse in North Africa during the Holocene: Climate variability vs. vegetation feedback
نویسندگان
چکیده
[1] The abrupt desertification over the northern Africa in the mid-Holocene is studied in both a complex and a simple coupled climate-vegetation model. In contrast to the previous mechanism that relies on strong positive vegetation-climate feedback and the resulted multiple equilibria, we propose a new mechanism in which the abrupt desertification is caused by low frequency climate variability, rather than a positive vegetation-climate feedback. The implication of this new mechanism to modelling and observation is also discussed. Citation: Liu, Z., Y. Wang, R. Gallimore, M. Notaro, and I. C. Prentice (2006), On the cause of abrupt vegetation collapse in North Africa during the Holocene: Climate variability vs. vegetation feedback, Geophys. Res. Lett., 33, L22709, doi:10.1029/ 2006GL028062.
منابع مشابه
Simulating the transient evolution and abrupt change of Northern Africa atmosphere–ocean–terrestrial ecosystem in the Holocene
We present the first synchronously coupled transient simulation of the evolution of the northern Africa climate-ecosystem for the last 6500 years in a global general circulation ocean–atmosphere–terrestrial ecosystem model. The model simulated the major abrupt vegetation collapse in the southern Sahara at about 5 ka, consistent with the proxy records. Local precipitation, however, shows a much ...
متن کاملQuantifying Regional Vegetation Cover Variability in North China during the Holocene: Implications for Climate Feedback
Validating model simulations of vegetation-climate feedback needs information not only on changes in past vegetation types as reconstructed by palynologists, but also on other proxies such as vegetation cover. We present here a quantitative regional vegetation cover reconstruction for North China during the Holocene. The reconstruction was based on 15 high-quality lake sediment profiles selecte...
متن کاملClimate-Human interaction over the Iranian Plateau during the Upper Pleistocene-Holocene: A review
During the past two decades an array of studies have shed light on potential links between the evolution of Hominids as well as Human dispersal out of Africa and episodes of abrupt climate change. Although archaeological evidences suggest that anatomically modified humans appeared in Africa between 200 and 150 ky ago, the timing of the early humans migration out of Africa remained unclear. Stra...
متن کاملDetecting vegetation-precipitation feedbacks in mid-Holocene North Africa from two climate models
Using two climate-vegetation model simulations from the Fast Ocean Atmosphere Model (FOAM) and the Community Climate System Model (CCSM, version 2), we investigate vegetation-precipitation feedbacks across North Africa during the mid-Holocene. From mid-Holocene snapshot runs of FOAM and CCSM2, we detect a negative feedback at the annual timescale with our statistical analysis. Using the Monte-C...
متن کاملOrbital- and millennial-scale changes in the hydrologic cycle and vegetation in the western African Sahel: insights from individual plant wax D and 13C
To reconstruct variability of the West African monsoon and associated vegetation changes on precessional and millennial time scales, we analyzed a marine sediment core from the continental slope off Senegal spanning the past 44,000 years (44 ka). We used the stable hydrogen isotopic composition (dD) of individual terrestrial plant wax n-alkanes as a proxy for past rainfall variability. The abun...
متن کامل