Agricultural expansion is one of the primary land use changes on the Earth’s surface. The Songnen Plain in Northeast China is renowned for its Black Soil and is one of the most important agricultural regions of this country. In the last century, its population increased 20-fold and excessive areas of grassland were cultivated. Based on a series of decadal land use/land cover data sets in the plain (1910s–2010s), this study simulated the water balance in each decade using the Weather Research and Forecasting (WRF) model and assessed the water effects of centurial agricultural expansion. Six variables were simulated to explain the land-atmosphere interaction: precipitation, total evapotranspiration, canopy transpiration, canopy interception evaporation, land evaporation and land surface runoff and infiltration. Agreeing with historical climate reanalysis data, the simulated precipitation in the plain did not have a significant trend. However, the total evapotranspiration significantly increased in the study region. The canopy transpiration and interception evaporation increased and the runoff and infiltration decreased, both indicating a drought effect in soil. The drying trend varied spatially with the strongest pattern in the central plain where large areas of wetlands remain. As a consequence of agricultural expansion, the centurial drying process in the fertile Black Soil may put strong pressure on the crop productivity and food safety of this important agricultural region.

In the context of global warming, a key scientific question for the sustainable development of the Arctic tourism industry is whether the region’s climate is becoming more suitable for tourism. Based on the ERA5-HEAT (Human thErmAl comforT) dataset from the European Center for Medium-range Weather Forecasts (ECMWF), this study used statistical methods such as climatic tendency rate and RAPS to analyze the spatial-temporal changes in Arctic summer climate comfort zones from 1979 to 2019 and to explore the influence of changes in climate comfort on Arctic tourism. The results showed the following: (1) With the increase in the Arctic summer temperature, the universal thermal climate index (UTCI) rose significantly from 1979 to 2019 at a rate of 0.457 °C/10a. There was an abrupt change in 2001, when the climate comfort changed from “colder” to “cool”, and the climate comfort has remained cool over the past decade (2010–2019). (2) With the increase in Arctic summer temperatures, the area assessed as “comfortable” increased significantly from 1979 to 2019 at a rate of 2.114 × 10⁵ km²/10a. Compared with the comfortable area in the 1980s, the comfortable area increased by 6.353 × 10⁵ km² over the past 10 years and expanded to high-latitude and high-altitude areas, mainly in Kola Peninsula, Putorana Plateau, and Verkhoyansk Mountains in Russia, as well as the Brooks Mountains in Alaska. (3) With the increase in Arctic summer temperatures, the number of days rated comfortable on 30% of the grid increased significantly from 1979 to 2019 (maximum increase: 31 days). The spatial range of the area with a low level of comfortable days narrowed and the spatial range of the area with a high level of such days expanded. The area with 60–70 comfortable days increased the most (4.57 × 10⁵ km²). The results of this study suggest that global warming exerts a significant influence on the Arctic summer climate comfort level and provides favorable conditions for further development of regional tourism resources.