The recently reported ice wedge δ 18O winter temperature record from the Siberian Arctic ( 5) ( Fig. 1 A) are less affected by direct human impacts. Unlike North America and Europe, which were profoundly impacted by human activities, the remote mid–high latitudes of Eurasia ( Fig. Therefore, it may be unreasonable to use the minor Late Holocene cooling trend for a “climate−vegetation” relationship analysis. If this is the case, and given that the tree pollen decrease is proposed to be largely a signal of anthropogenic deforestation ( 1), then the pollen-based minor cooling trend in the Late Holocene is arguably not a genuine climatic signal. Notably, it is unclear whether the pollen-based minor Late Holocene cooling trend is the result of the decrease in tree pollen. 1 G), which largely replicates the tree pollen changes ( 1) ( Fig. 1 A), the reconstructed regional record shows an overall warming trend during the Holocene, with a slight cooling trend in the last ∼4,000 y ( 4) ( Fig. Interestingly, using pollen data from 642 sites in North America and Europe ( Fig. The vertical bars indicate the last ∼4,000 y (the Late Holocene). ( K) GHG radiative forcing record ( 3, 10). ( J) Peat α-cellulose δ 13C summer temperature record from the southern Altai Mountains in central Asia VPDB, versus the Vienna Pee Dee Belemnite ( 7). ( I) Stalagmite δ 18O winter temperature record from the southern Ural Mountains in western continental Eurasia VPDB, versus the Vienna Pee Dee Belemnite ( 6). ( H) Ice wedge δ 18O winter temperature record from the Lena River Delta in the Siberian Arctic VSMOW, versus the Vienna standard mean ocean water ( 5). ( G) Pollen-based regional temperature record for North America and Europe ( 4). ( F) Synthesized global mean temperature record ( 3). ( E) Global mean temperature anomalies from different climatic models (FAMOUS, LOVECLIM, and CCSM3 ) ( 2). ( D) Normalized mean annual air temperature results from the Max Planck Institute Earth System Model (ECHAM6) for North America and Europe ( 1). ( C) Record of changes in tree pollen percentages ( 1). ( B) Record of changes in sedimentation accumulation rate (SAR) as an indicator of soil erosion rates in lake watersheds ( 1). The blue squares represent the 632 globally distributed lakes ( 1) the red dots represent the 642 pollen study sites in North America and Europe ( 4) the black triangles represent the 73 globally distributed sites ( 3) and the black dots represent 3 sites in the mid–high latitudes of continental Eurasia, including the Lena River Delta in the Siberian Arctic ( 5), the southern Ural Mountains in western continental Eurasia ( 6), and the southern Altai Mountains in central Asia ( 7). ( A) Locations of the study sites cited herein. 1 A) comprising the synthesized record are terrestrial records ( 3). However, only 4 out of the 73 selected records ( Fig. 1 D) are supported by a synthesized global mean temperature record ( 3) ( Fig. Moreover, the model-deduced slight cooling trends since ∼4,000 y BP ( 1) ( Fig. 1 E) arguably, it is problematic to use model results to determine a “climate−vegetation” relationship. 1 D) are the opposite of the slight global warming trends indicated by other models ( 2) ( Fig. Notably, the model-deduced Late Holocene slight cooling trends in North America and Europe ( 1) ( Fig. 1 D), they propose that the Late Holocene tree coverage decreases were caused mainly by anthropogenic deforestation ( 1). Besides, using climate model results ( Fig. 1 C) have occurred in lake watersheds across a substantial portion of Earth’s surface since ∼4,000 y BP. ( 1) demonstrate that increased soil erosion rates ( Fig. Using 3,980 14C ages and 43,669 pollen data from 632 globally distributed lakes (∼88% of them in North America and Europe Fig.
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