Our presentation represents a brief overview of recent climatic and environmental changes over the Dry Lands of Northern Eurasia. The Dry Land Belt (DLB) in Northern Eurasia is the largest contiguous dryland on Earth. During the last century, changes here have included land use change (e.g., rapid virgin land development in the mid of the 1950s; cf. Figure 1), resource extraction, rapid institutional shifts (e.g., collapse of the Soviet Union), climatic changes, and natural disturbances. These factors intertwine, overlap, sometimes mitigate but sometimes feedback upon each other to exacerbate their synergistic and cumulative effects. Thus, it is important to document properly each of these external and internal factors and to characterize structural relationships among them in order to develop better approaches to alleviating negative consequences of these regional environmental changes. This paper addresses the climatic changes observed over the DLB in recent decades and outlines possible links of these changes (both impacts and feedbacks) with other external and internal factors of contemporary regional environmental change and human activities within the DLB.

River flow to the Arctic Ocean plays a significant role in the oceanic freshwater budget accounting for about 2/3 of the total freshwater flux to the Arctic Ocean. Ocean salinity and sea ice formation are critically affected by river input and changes in the freshwater and heat fluxes to the ocean can exert significant control over global ocean circulation via the North Atlantic deep water formation. There are mounting evidences that hydrological regime across the pan-Arctic is experiencing an unprecedented degree of change. However, the exact causes of such change are not immediately apparent, as they constitute a complex interplay between climate- and human-induced drivers. We used a new version of University of New Hampshire Water Balance Model (WBM) to quantify major sources of changes in river flux to the Arctic Ocean from Eurasian drainage basin. WBM is a grid based model which simulates the vertical water exchange between the land surface and the atmosphere and the horizontal water transport along a prescribed river networks for both natural and anthropogenic systems. The model accounts for sub-pixel land cover types, glacier and snow-pack accumulation/melt across sub-pixel elevation bands, permafrost dynamics, anthropogenic water use (e.g. domestic and industrial consumption, and irrigation for most of existing crop types), hydro-infrastructure for inter-basin water transfer and reservoir/dam regulations. To identify and quantify contributions of individual drivers/factors to river flow we used a new water source tracking capability recently developed in WBM. It allows “fingerprinting” of water at all steps in the water cycle such as in soils, groundwater pools, lakes, reservoirs, and fluxes such as originated from snowmelt, rain, glacier runoff, and baseflow. By comparing the difference in water component fractions in water storages and fluxes resulting from multiple historical runs we were able to quantify responses of each water source to the changes in climatic drivers and to characterize causes of observed changes in river flow to the Arctic Ocean. This work was mainly supported by Russian Foundation for Basic Research, grants: 18-05-60192 and 18-05-60240.

The instrumental data shows 7%-20% increase in annual discharge of the major Eurasian rivers like Ob, Yenisei and Lena between 1936 and 2018 (Wang et al. 2021). The trend has been attributed to increased precipitation and permafrost thawing due to the temperature warming (Walvoord, Kurylyk 2016). However, the instrumental data does not provide the longterm scope of the trend. We modeled seasonal discharge from tree rings for the Yenisei River upstream at Kyzyl gauge and found a remarkable 80% upsurge in winter ‘ow (Nov-Apr) over the last 25 years, which is unprecedented in the last 214 years since 1784 (Panyushkina et al. 2021). In contrast, the annual discharge (Oct-Sept) has only a 7% increase over the last 25 years and shows normal range of variability since 1700 (Fig. 1). Water balance modeling with CRU data at the Yenisei upstream indicates a significant discrepancy between decadal variability of the gauged ‘ow and climate data after 1960 (Fig. 1). The long-term buckhound of the changes in regional hydrology is successfully assessed with tree-ring methods. The tree-ring networks in Eurasian cold climates have a great potential to reconstruct spatial pattern of the seasonal runoff and quantify the long-term impact of permafrost degradation on the hydrological regimes in Siberia. We discuss the impact of melting permafrost on the base ‘ow and enrichment of the surface and groundwater interaction at the Yenisei River basin coupled with the warming temperature and, more importantly, forest fires. Recent increase in the frequency, size, and intensity of boreal fires scale s of its impact on hydrology and permafrost in Siberia. This study demonstrates the complexity of hydrological feedback in Siberia to the Arctic Ampli:cation (AA). The adverse impacts of AA have been and will remain the greatest for the health and socioeconomic of people living in the Pan-Arctic and the geopolitics and macroeconomics of the global society.