Holocene hydro-climatic variability in the Mediterranean: A synthetic multi-proxy reconstruction

Abstract

Here we identify and analyze proxy data interpreted to reflect hydro-climatic variability over the last 10000 years from the Mediterranean region to: 1) outline millennial and multicentennial scale trends and 2) identify regional patterns of hydro-climatic variability. A total of 47 lake, cave and marine records were transformed to z-scores to allow direct comparisons between sites, put on a common timescale and binned into 200-year time slices. Six different regions were identified based on numerical and spatial analyzes of z-scores: S Iberia and Maghreb, N Iberia, Italy, the Balkans, Turkey, and the Levant, and the overall hydro-climate history of each region was reconstructed. N Iberia is largely decoupled from the five other regions throughout the Holocene. Wetter conditions occur in the five other regions between 8500 to 6100 yrs BP. After 6000 yrs BP climate oscillated until around 3000±300 yrs BP, which seems to have been the overall driest period in the Eastern Mediterranean and North Africa. In contrast, Italy and N Iberia seem to have remained wetter during this period. In addition, non-metric multidimensional scaling (nMDS) was applied to 18 long, continuous climate z-score records that span the majority of the Holocene. nMDS axes 1 and 2 illustrate the main trends in the z-score data. The first axis captures a long-term development of drier condition in the Mediterranean from 7900 to 3700 yrs BP. Rapid shifts occur in nMDS axis 2 at 6700 to 6300 BP, 4500 to 4300 BP, and 3500 to 3300 BP indicating centennial-scale climate change. Our synthesis highlights a dominant south/east vs north/west Mediterranean hydro-climate dipole throughout the Holocene and therefore confirms that there was no single climate trajectory characterizing the whole Mediterranean basin during the last ten millennia.

Emergence and Evolution of Anthropogenic Landscapes in the Western Mediterranean and Adjacent Atlantic Regions

“…Matching trends in biomass burning and tree abundance inferred from climate-driven models and proxy data suggest that fires and extensive forest cover prior to 7000 cal yr BP at the regional scale can be explained by the long, warm growing seasons prevailing in southwestern Europe (with the exception of southeastern Iberia and southwestern Italy; Figure 2). Pronounced seasonal and inter-annual precipitation variability [66,67] likely led to frequent floods [68]. Additionally, cyclical oscillations in moisture availability would also have favored fire spread by allowing fuel accumulation during humid periods and fuel desiccation in under drier conditions [69].…”

Meta-Analysis of Geomorphodynamics in the Western Lower Bakırçay Plain (Aegean Region, Turkey)

“…8.5 ka BP [103]. [104]; b, c: [105]; d: [104]; e: [106]; f, g, h: [105]; i, j: [106]; k: [107]; l: [41], interpolated; m: [7]; n, o: [99]; p: [7]; q: [8]; r-u: this study.…”

“…Highest climatic erosion susceptibility in the eastern Mediterranean region after the Pleistocene presumably occurred during Early Holocene peaking around 10 ka BP (Figure 5m) [7], coinciding with an Early Holocene wet period in the Balkans and Anatolia (Figure 5n,o) [99]. During this period, rainfall erosivity was relatively high.…”

“…For the eastern Mediterranean region, the Middle Holocene can be characterized as a phase of more or less continuous decline or stability of the climatic erosion sensitivity [7]. In the Balkans, reconstructed hydroclimate followed a trend of continuous aridization from the wettest Holocene period around 8.0 ka BP [99] (Figure 5n) until ca. 4.9 ka BP.…”

Mediterranean Geoscience Reviews: a Mediterranean perspective to geosciences

“…On the other hand, during the current Holocene interglacial, the evidence does not support a common pattern of climate change across the whole Mediterranean basin. During the last millennium, there seems to have been an east-west climate see-saw (Roberts et al 2012), while, over the last 10 millennia, the dominant pattern seems to have been a contrast between the southeast and the northwest (e.g., Iberia) (Finné et al 2019). We, therefore, need to understand the reasons behind this contrast.…”