Complex “human−vegetation−climate” interactions in the Late Holocene and their significance for paleotemperature reconstructions

Using 3,980 14C ages and 43,669 pollen data from 632 globally distributed lakes (∼88% of them in North America and Europe; Fig. 1 A ), Jenny et al. (1) demonstrate that increased soil erosion rates (Fig. 1 B ) and decreased tree coverage (Fig. 1 C ) have occurred in lake watersheds across a substantial portion of Earth’s surface since ∼4,000 y BP. Besides, using climate model results (Fig. 1 D ), they propose that the Late Holocene tree coverage decreases were caused mainly by anthropogenic deforestation (1). Notably, the model-deduced Late Holocene slight cooling trends in North America and Europe (1) (Fig. 1 D ) are the opposite of the slight global warming trends indicated by other models (2) (Fig. 1 E ); arguably, it is problematic to use model results to determine a “climate−vegetation” relationship. Moreover, the model-deduced slight cooling trends since ∼4,000 y BP (1) (Fig. 1 D ) are supported by a synthesized global mean temperature record (3) (Fig. 1 F ). However, only 4 out of the 73 selected records (Fig. 1 A ) comprising the synthesized record are terrestrial records (3). Fig. 1. ( A ) Locations of the study sites cited herein. The blue squares represent the … [↵][1]1To whom correspondence may be addressed. Email: raozhg{at}hunnu.edu.cn. [1]: #xref-corresp-1-1