Abundant shallow underground brackish water resources could help in alleviating the shortage of fresh water resources and the crisis concerning agricultural water resources in the North China Plain. Improper brackish water irrigation will increase soil salinity and decrease the final yield due to salt stress affecting the crops. Therefore, it is urgent to develop a practical and low-cost method to monitor the soil salinity of brackish irrigation systems. Remotely sensed spectral vegetation indices (SVIs) of crops are promising proxies for indicating the salinity of the surface soil layer. However, there is still a challenge concerning quantitatively correlating SVIs with the salinity of deeper soil layers, in which crop roots are mainly distributed. In this study, a field experiment was conducted to investigate the relationship between SVIs and salinity measurements at four soil depths within six winter wheat plots irrigated using three salinity levels at the Yucheng Comprehensive Experimental Station of the Chinese Academy of Sciences during 2017–2019. The hyperspectral reflectance was measured during the grain-filling stage of winter wheat, since it is more sensitive to soil salinity during this period. The SVIs derived from the observed hyperspectral data of winter wheat were compared with the salinity at four soil depths. The results showed that the optimized SVIs, involving soil salt-sensitive blue, red-edge, and near-infrared wavebands, performed better when retrieving the soil salinity (R² ≥ 0.58, root mean square error (RMSE) ≤ 0.62 g/L), especially at the 30-cm depth (R² = 0.81, RMSE = 0.36 g/L). For practical applications, linear or quadratic models based on the screened SVIs in the form of normalized differential vegetation indices (NDVIs) could be used to retrieve soil salinity (R² ≥ 0.63, RMSE ≤ 0.62 g/L) at all soil depths and then diagnose salt stress in winter wheat. This could provide a practical technique for evaluating regional brackish water irrigation systems.

Somatosensory comfort is mainly determined by the Temperature and Humidity Index (THI) with Wind Efficiency Index (WEI), but this conventional usage of these indicators does not capture the age-related differentials. Here we resolved this gap with a modification of the climatic comfort definition and method in a national standard, denoted as the Relative Climate Sensitive Index (RCSI), which incorporated the age-related vulnerability scores determined through online questionnaires with a scoring method, for each of the age-related and adaptive climatic comfort responses to changes in residence with Beijing-Tianjin-Hebei (BTH) region as an example. First, the result showed that the human comfort of living environment decreased with age in the BTH region, implicating age obviously impacted comfort, and weak adaptability made the elderly the relatively most high-risk group – their suitable region was less than a quarter of the whole study region. Second the adverse effects of persistent hot weather on comfort, indicating global warming as the leading driver of dwindling comfort over recent years. As the warming was more significant in the southeastern part, all these forces combined had there a hotspot, appealing for extra attention. Last this improved evaluation accorded with actual situation to captured high-risk groups with their distributions.

In order to effectively address the issue of severe soil salinization in the coastal area of the Yellow River Delta, which has led to a significant number of medium and low-yield fields in this region, and to satisfy the rising demand for feed grain in China in recent years, a highly effective solution is to replace conventional crops by cultivating a specialized type of forage grass that can withstand high salinity levels and is well adapted to the local climate. This study proposed a spatial layout scheme for planting salt-tolerant forages, with the aim of providing a foundation for enhancing saline-alkali land and increasing resource utilization efficiency. The results showed that the climate conditions in the Yellow River Delta were suitable for planting sweet sorghum. With respect to soil salt content, the suitable planting regions for sweet sorghum can be classified into four categories: Suitable, moderately suitable, less suitable, and unsuitable, with soil salt concentrations of 2.62–5.25‰, 5.25–7.88‰, respectively. Concerning economic benefits, sweet sorghum’s input-output ratio (74.4%) surpasses that of cotton in high saline-alkali zones, providing a significant advantage in comparison with traditional crops. In non-saline-alkali and light saline-alkali areas, the traditional winter wheat-summer maize planting system offers higher economic benefits and nitrogen use efficiency, so it is recommended to maintain this system as the dominant agricultural model. In moderately and severe saline-alkali zones, although one-season maize exhibits greater nitrogen efficiency, its economic benefits are lower than those of sweet sorghum. Hence, it is advisable to promote one-season maize in suitable regions and introduce salt-tolerant forage, such as sweet sorghum in other areas. This approach offers novel ideas and methods for crop spatial layout planning and addresses potential feed grain shortages in the region.

The Beijing–Tianjin–Hebei region in China is experiencing a serious ecological water scarcity problem in the context of climate warming and drying. There is an urgent need for practical adaptation measures to cope with the adverse impacts of climate change and provide a scientific basis for urban water supply planning, water resource management, and policy formulation. Urban ecological water can maintain the structure and function of urban ecosystems, both as an environmental element and as a resource. Current research lacks quantitative analysis of the impact of regional meteorological factors on ecological water use at the small and medium scales. Based on the meteorological data and statistical data of water resources in the Beijing–Tianjin–Hebei (BTH) region, this paper analyzed the trend of climate change and established an ecological climatic water model using gray correlation analysis, polynomial simulation, and singular spectrum analysis to predict the ecological water consumption. And, we assessed the climatic sensitivity of ecological water use and estimated the future ecological climatic water use in the BTH region based on four climate scenarios’ data. The results showed that the average multi-year temperature was 13.2 °C with a clear upward trend from 1991 to 2020 in the BTH region. The multi-year average precipitation was 517.1 mm, with a clear shift in the period of abundance and desiccation. Ecological climatic water modeling showed that a 1 °C increase in temperature will increase ecological water use by 0.73 × 10⁸ m³~1.09 × 10⁸ m³ in the BTH region; for a 100 mm increase in precipitation, ecological water use will decrease by 0.49 × 10⁸ m³~0.88 × 10⁸ m³; under the four climate scenarios of SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5, the regional ecological climatic water use will be 5.14 × 10⁸ m³, 6.64 × 10⁸ m³, 7.82 × 10⁸ m³, and 9.06 × 10⁸ m³ in 2035, respectively; and in 2050, the ecological climatic water use will be 8.16 × 10⁸ m³, 9.75 × 10⁸ m³, 10.71 × 10⁸ m³, and 12.41 × 10⁸ m³, respectively. The methodology and results of this study will support the quantification of climate change impacts on ecological water use in the BTH region and serve as a theoretical basis for future research on ecological water use adaptation to climate change. This study can provide a basis for the development of the overall planning of urban ecological water supply, and at the same time, it can lay a foundation for the study of measures to adapt to climate change by ecological water use.

Beijing, a megacity in northern China, has been long facing the challenge of water scarcity, and the problem of domestic water scarcity has been becoming more serious in recent years due to climate change and global warming. To cope with the adverse effects of climate change, it is urgent to build a prediction model for water consumption in Beijing under the background of climate change. Here, a climate domestic water use model was established based on the historical meteorological data and domestic water use data, and the future domestic water demand in Beijing and the response of domestic water use to climate change were projected. The results showed that the climatic water consumption in Beijing will increase with climate warming by 177.23 million m³/°C, and the per capita annual water consumption will increase by 8.1 m³/°C. Combined with the CMIP6 multi-model climate change scenario data, the climate domestic water consumption in Beijing in 2035 under the four scenarios of SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 will be 169 million m³, 189 million m³, 208 million m³, and 235 million m³ respectively; by 2050, the climate domestic water consumption in Beijing will reach 338 million m³, 382 million m³, 395 million m³, and 398 million m³, respectively. Under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, if all the increased climate domestic water consumptions are supplemented by groundwater, compared with 2019, the groundwater depth will decrease by 0.18 m, 0.22 m, 0.27 m, and 0.32 m in 2035, respectively, and the area of funnel area will increase by 6.84 km², 8.48 km², 10.11 km², 12.34 km² respectively. Compared with 2035, the groundwater depth in 2050 will decrease by 0.37 m, 0.43 m, 0.41 m and 0.36 m, respectively, the area of funnel area will increase by 14.13 km², 16.21 km², 15.61 km², and 13.68 km², respectively. If the increased climatic water consumption in Beijing is supplemented by external water transfer, the cost of external water transfer in 2035 will increase by CNY 391 million, CNY 485 million, CNY 578 million, and CNY 706 million, respectively, compared with that in 2019 under the four scenarios. Compared with 2035, the cost of external water transfer in 2050 will increase by CNY 808 million, CNY 927 million, CNY 893 million, and CNY 783 million, respectively.

The extent to which the anthropogenic heat release (AHR) affects the energy balance of the land–atmosphere system remains one of the focus issues in climate change. This paper estimated the global AHR from 1965 to 2017 based on consumption of non-renewable energy and bioenergy, assessed its climate forcing, and found out its impact on the energy balance of land–atmosphere system based on the radiation balance model. The results showed that the climate forcing of AHR increased from about 0.050 W·m-2 in 1965 to 0.167 W·m-2 in 2017, and the contribution rate of bioenergy was about 1/3. In 2017, AHR increased the average temperature of land surface and atmosphere by 0.0284 K and 0.0506 K, respectively. The contribution rate of AHR to global warming during the 15-year period from 1995, 1996 and 1997 was 3.77%, 3.64%, and 7.57%, respectively. AHR plays an important role in global climate change.