Temperature reconstructions for the last 1.74-Ma on the eastern Tibetan Plateau based on a novel pollen-based quantitative method

Environment of the Early Pleistocene Banshan Paleolithic Site in the Nihewan Basin, North China

“…The stage began with a change from weak to strong Northern Hemisphere insolation (Berger and Loutre, 1991) and summer monsoon index from Nihewan Basin (Ao et al, 2012b) with resulting rapid climatic warming. In addition, the results are roughly consistent with the variation trend of temperature reconstruction (MAT) on the eastern Tibetan Plateau (Zhao et al, 2021) (Figure 7). In the Chinese loesspaleosol stratigraphy, this period is roughly equivalent to S16, characterized by minor magnetic susceptibility variations, indicating a warm relatively stable climate (Ding et al, 2002;Sun et al, 2006;Sun et al, 2010).…”

Decoupled Land and Ocean Temperature Trends in the Early‐Middle Pleistocene

“…(b) Glycerol dialkyl glycerol tetraether‐derived Lake Malawi basin temperature record (Johnson et al., 2016). (c) Weighted‐average partial least squares‐based temperature reconstructions for Zoige Basin core ZB13‐C2 with modern pollen training‐set from across China and part of Mongolia (blue) and a smaller modern pollen training‐set within a distance of 500 km (red) (Zhao et al., 2021). (d) Tropical sea surface temperature (SST) stack (Herbert et al., 2010).…”

“…A 400‐Kyr running average of GDGT‐based land temperature data from the Malawi valley in Africa (Johnson et al., 2016) shows that the average temperature has increased by ∼2.0°C from 1.3 to 0.6 Ma in eastern Africa (Figure 3b) and the warming primarily occurred during glacial periods. Further, a pollen‐based temperature record over the last 1.74 Myr from the eastern Tibetan Plateau (Zhao et al., 2021) suggests that, when all modern pollen data from China and Mongolia were used in the training data set, the reconstructed mean annual temperature increased substantially between 1.74 and 0.6 Ma, especially between 1.5 and 0.6 Ma (Figure 3c), against the background of global cooling but consistent with our record (Figure 3a). Such high similarity, albeit based upon limited data sets, suggests that the decoupling trends of long‐term land and ocean temperatures may not be merely a local coincidence but representing a previously unrecognized long‐term regional climate phenomenon during the Pleistocene, particularly in low latitudes to midlatitudes or monsoon‐influenced regions.…”

Controls of precipitation and vegetation variability on the NE Tibetan Plateau during the late Pliocene warmth (~3.5–3.0 Ma)

“…The CA uses the presence and absence of taxa in the record, and limitations have been identified for sites with cold climates, longdistance transport of taxa and strong altitudinal gradients (e.g., Grimm and Denk, 2012;Mosbrugger and Utescher, 1997;Zhang et al, 2015). We therefore additionally applied WA-PLS regression, a method that has been successfully applied for Quaternary reconstructions and uses modern pollen-vegetation calibration datasets instead of presence-absence data of palynomorph taxa and their NLR (e.g., Cao et al 2014;Zhao et al, 2021). The WA-PLS has been classified as an approach most suitable for our region, showing a reliable predictive power (Cao et al, 2014).…”