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In recent decades, the winter surface air temperature (SAT) anomaly in the Northern Hemisphere has exhibited a warm Arctic‐cold Eurasia (WACE) dipole pattern and this has undergone significant decadal variation. In this paper, the physical cause of the decadal variability of the WACE pattern is explored, and it is shown to be mediated by the phases of the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO). Although the negative PDO (PDO−) or positive AMO (AMO+) favors the WACE pattern, the meridional structure of the pattern is significantly influenced by whether PDO− or AMO+ dominates. During PDO− (AMO+) phase, the winter‐mean WACE pattern shows an asymmetric dipole with weak (strong) warm anomaly over the Barents‐Kara Seas or BKS and strong (weak) cold anomaly over central Eurasia or Siberia, which corresponds to Ural blocking (UB) concurring with the negative (positive) phase of North Atlantic Oscillation in a winter‐mean field. The winter asymmetric WACE pattern is more strongly related to PDO− than AMO+. It is further found that an asymmetric sub‐seasonal WACE dipole pattern with strong (weak) warm anomaly over BKS and weak (strong) cold anomaly over Siberia is usually formed during the UB episode due to favored (suppressed) sub‐seasonal downward infrared radiation and turbulent heat flux over BKS during AMO+ (PDO−), which leads to a strong asymmetric dipole of the winter WACE pattern. Plain Language Summary: The most prominent climate change in the Northern Hemispheric mid‐high latitudes in recent decades is that the winter surface air temperature anomaly has exhibited a warm Arctic‐cold Eurasia (WACE) dipole pattern. However, it is still unknown what causes the decadal variability of the winter WACE pattern and its meridional asymmetry. In this paper, we address this issue by examining the different effects of Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) on the winter WACE pattern. It is shown that PDO− (AMO+) plays an important role in the occurrence of the asymmetric WACE dipole with weak (strong) warm anomaly over the Barents‐Kara Seas and strong (weak) cold anomaly over central Eurasia or Siberia through modulating Ural blocking and associated sub‐seasonal cold anomaly. It is also found that the asymmetric WACE dipole is more strongly dependent on PDO− than AMO+. Our findings are of great significance for understanding the physical cause of the decadal variability of the WACE dipole pattern in spatial structure. Key Points: Ural Blocking plays an important role in the occurrence of the sub‐seasonal warm Arctic‐cold Eurasia (WACE) dipole pattern in winterUral blocking can amplify the winter‐mean Warm Arctic‐cold Eurasia (WACE) patternWarm Arctic‐cold Eurasia (WACE) is linked to the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) [ABSTRACT FROM AUTHOR]

This paper uses monthly surface air temperature (SAT) data from the Climatic Research Unit dataset and the Coupled Model Intercomparison Project phase 6 multimodel ensemble simulations to investigate the variations in the annual‐mean and four seasons SAT across the Eurasian and North Africa landmasses and the possible causes. The SAT over multiple timescales has significant seasonal and regional differences. The trend, variance of decadal variation (DV), and variance of interannual variability (IV) show that the differences between Siberia and mid‐low latitudes are much larger in winter and spring than in summer and autumn. The SAT exhibits a robust warming trend over Siberia in winter (0.21–0.42°C·decade−1) than over mid–low latitudes in summer (<0.07°C·decade−1). The cause is the combined diversity effects of greenhouse gases (GHG) and anthropogenic aerosols (AA) in four seasons over different regions. The warming trend of Siberia in winter is affected by the combination of strong warming effect by GHG and the weak cooling effect by AA, and the trend of mid–low latitudes in summer is opposite. The leading modes of the DV show a consistent spatial pattern over the whole Eurasia in four seasons while the IV show a meridional dipole pattern across 40°N except in summer. The internal climate variability is the main driver of the SAT IV and DV, but the effect of anthropogenic activity and natural forcing may reinforce the IV and DV in some regions. The combined role of GHG and AA forcings can significantly enlarge the DV in many parts of Eurasia, and the AA and natural forcing have significant effect on the IV in the high latitudes. [ABSTRACT FROM AUTHOR]

Aim: To determine the ecological processes and drivers of range collapse, population decline and eventual extinction of the steppe bison in Eurasia. Location: Siberia. Time period: Pleistocene and Holocene. Major taxa studied: Steppe bison (Bison priscus). Methods: We configured 110,000 spatially explicit population models (SEPMs) of climate–human–steppe bison interactions in Siberia, which we ran at generational time steps from 50,000 years before present. We used pattern‐oriented modelling (POM) and fossil‐based inferences of distribution and demographic change of steppe bison to identify which SEPMs adequately simulated important interactions between ecological processes and biological threats. These "best models" were then used to disentangle the mechanisms that were integral in the population decline and later extinction of the steppe bison in its last stronghold in Eurasia. Results: Our continuous reconstructions of the range and extinction dynamics of steppe bison were able to reconcile inferences of spatio‐temporal occurrence and the timing and location of extinction in Siberia based on hundreds of radiocarbon‐dated steppe bison fossils. We showed that simulating the ecological pathway to extinction for steppe bison in Siberia in the early Holocene required very specific ecological niche constraints, demographic processes and a constrained synergy of climate and human hunting dynamics during the Pleistocene–Holocene transition. Main conclusions: Ecological processes and drivers that caused ancient population declines of species can be reconstructed at high spatio‐temporal resolutions using SEPMs and POM. Using this approach, we found that climatic change and hunting by humans are likely to have interacted with key ecological processes to cause the extinction of the steppe bison in its last refuge in Eurasia. [ABSTRACT FROM AUTHOR]

In this study, the single value decomposition method was used to analyze the covariation between the winter (December, January, and February) North Atlantic sea surface temperature (SST) and spring (April and May) normalized difference vegetation index (NDVI) over mid‐high‐latitude Eurasia for the period 1982–2015. The results show that the first paired mode explains 32.8% of the total squared covariance, and the correlation of time coefficients is +0.67 (p < 0.01), suggesting that the meridional tripole structure of the winter North Atlantic SST is significantly associated with the three zonally anomalous centers of the spring mid‐high‐latitude Eurasian NDVI. Surface air temperature (T2m) is the most important factor related to spring NDVI changes. The tripole pattern of the winter North Atlantic SST can persist until the following spring, triggering an eastward anomalous Rossby wave train in the middle troposphere, which features two negative geopotential height anomalies centers near northwestern Europe and eastern Siberia and one positive center over central Eurasia. Surface temperature anomalies are well consistent with these anomalous pressure centers. This implies that the winter North Atlantic SST could be a robust driver and potential precursor for spring vegetation prediction over the mid‐high latitudes of Eurasia. Key Points: There is a significant covarying mode between the tripole pattern of the winter North Atlantic sea surface temperature (SST) and spring normalized difference vegetation index (NDVI) anomaly over EurasiaT2m is the main intermediate factor linking SST and large‐scale NDVIThe tripole pattern can persist until the following spring, which modulates T2m over Eurasia through a Rossby wave train [ABSTRACT FROM AUTHOR]

The ecosystems of Siberia provide valuable services to the human population and afford important climate feedback. However, they are subject to anthropogenic pressures leading to the transformation of ecosystem structure and functions such as deforestation; extraction and transportation of fossil hydrocarbons; mining, refining, and smelting industrial activities; damming of rivers by high‐pressure hydroelectric plants, and other activities. The articles in this special series deal with the monitoring of natural ecosystems of Siberia that are located on vast areas of Eurasia, many of which are hard to reach and sparsely populated. The results and approaches of environmental monitoring presented in this special series offer new opportunities for developing the strategy of intelligent management and conservation of vulnerable Siberian ecosystems to meet the challenges of global climate change and unsustainable use of natural resources. Integr Environ Assess Manag 2023;19:970–971. © 2023 SETAC Key Point: The approaches of environmental monitoring presented in this special series offer new opportunities for developing the strategy of intelligent management and conservation of Siberian ecosystems to meet the challenges of global climate change and unsustainable use of natural resources. [ABSTRACT FROM AUTHOR]