Alpine wetland is one of the important types of land cover on the Qinghai-Tibetan Plateau, which connects different geospheres of the plateau and plays an important role and value for maintaining the function of the plateau ecosystem. The inherent characteristics of wetland system and the special natural geographical environment of the plateau determine that the plateau wetland ecosystem is sensitive to climate change. Previous studies have shown that the types of wetlands in the Qinghai-Tibetan Plateau are diverse, but there are large discrepancies between studies, the response of wetlands to climate change shows significant temporal and spatial differences and typological differences, the comprehensive ecological functions of plateau wetlands need to be scientifically evaluated, and the lack of wetland-related thematic data products limit the in-depth research on wetlands, especially, in the fields of carbon cycle and biodiversity conservation. In the future, it is necessary to strengthen the synthesis of multi-source technology, interdisciplinary cross-research, and launch the simulation of environmental effects of wetland changes and quantitative assessment studies of ecological functions, and so on, which are suggesting to provide scientific support for the sustainable management of alpine wetlands.
This paper reviews the mechanisms of interaction between glaciers and glacial lakes (mainly proglacial lakes) on the Qinghai-Tibet Plateau (QTP) based on existing research. It aims to understand the processes and patterns of glacier retreat and proglacial lake expansion on the QTP and deepen the understanding of the interaction mechanisms between glaciers and proglacial lakes. Proglacial lakes on the QTP are mainly distributed in the southeastern region over QTP, particularly in the Himalayas and Nyainqentanglha Mountains. Of the recorded and identified reason of glacial lake outburst flood events, 55% are caused by glacier dynamics, predominantly in the southeastern QTP including the Himalayas and the Nyainqentanglha Mountains. The interaction pattern between glaciers and proglacial lakes includes the effects of glaciers on proglacial lakes and the feedback of proglacial lakes on contacted glaciers. The effects of glaciers on glacial lakes mainly include providing space for the development of glacial lakes through glacier retreat, supplying abundant water sources for the formation and expansion of glacial lakes through glacier meltwater, and causing glacial lake outburst floods due to extreme glacier events, e.g. ice surface/internal water system outbursts, glacier advances/movements, ice avalanches. The feedback mechanisms of proglacial lakes on glaciers involve thermal melting of glaciers by proglacial lakes, mass loss from ice calving on the terminal glacier caused by dynamic processes of proglacial lakes, and the local climate effects of the evolution of proglacial lakes on their parent glaciers. It is important to note that the interaction between the two is not isolated but mutually dependent and simultaneous. Future research on glacier and proglacial lake should focus on: (1) Establishing unified glacier observation standards and glacier-lake datasets; (2) Integrating a comprehensive observation system that encompasses “climate-glacier-glacial lake-disaster” and sharing those observation datasets; (3) Coupling glacier and glacial lake models to quantify interaction processes and understand their mechanisms; (4) Standardizing the evaluation system for glacial lake outburst flood disasters and improving early warning mechanisms. Besides, the theories of glacier and glacial lake changes are relatively mature, while the theoretical research on the interactions between glaciers and proglacial lakes is still insufficient and urgently needs further development.
In order to explore the impact of climate change on the changes in lakes in the southwest of Nagqu, Tibet, the characteristics of lake changes and their relationship with climate factors were analyzed based on the 1976-2022 Landsat series of remote sensing image data. The results showed that the total area of lakes in 1976-2022 showed a significant expansion trend, at a rate of 6.96 km2/a (P<0.001). Compared with 1976, the lake area increased by 234.29 km2 in 2022, with the largest expansion of 144.44 km2 in 2000-2010, accounting for 64.46% of the total expansion; and the smallest expansion of 7.98 km2 in 2010-2020, accounting for only 3.56% of the total expansion. Changes in lake water level and water volume are basically the same as the lake area. The lake area are very significantly correlated with temperature, maximum frozen soil depth of the research area (P<0.01). The increase in temperature has caused the thawing of permafrost and the continuous expansion of the lake area. The influence of precipitation on expansion is staged.
Vapor pressure deficit (VPD) reflects the atmospheric water demand, and clarifying the spatial and temporal characteristics of VPD is helpful to understand the response of regional atmospheric dryness and wetness to climate change. Based on the data of monthly sunshine duration, average temperature (Tm), average maximum temperature, average minimum temperature, precipitation (Pr), relative humidity, vapour pressure (e) and wind speed of 34 meteorological stations in the Yalung Zangbo River basin (YZRB) from 1981 to 2023, the spatio-temporal characteristics and influencing factors of VPD in YZRB during recent 43 years were analyzed by linear trend estimate, R/S analysis, Mann-Kendall method, Morlet wavelet analysis and stepwise regression method. The results show that: (1) The annual and seasonal VPD in YZRB were generally lower in the east and west, and higher in the middle. The monthly variation showed a bimodal pattern, with the 1st and 2nd peaks in June and October, respectively, and the minimum in January. VPD was the largest in summer, followed by spring, and the smallest in winter. (2) The annual VPD increased significantly with a rate of 0.030 kPa/(10 a), mainly in summer and autumn, especially in the last 23 years (2001-2023). The annual and seasonal VPD mutation occurred in the mid-to-late 2000s, and the possibility of continuous increase in the future is very high. The annual and seasonal VPD were lower in the 1980s and 1990s, especially in the 1990s. In the 2000s, due to the higher VPD in summer and winter, the annual VPD was higher. Annual and seasonal VPD were higher in the 2010s, mainly in summer and autumn. VPD had a significant 3-4 a cycle in spring, summer and autumn, 2-3 a cycle in winter, and annual VPD had no significant cycle. (3) Seasonal/annual VPD had no significant linear relationship with geographical factors, but there was a very significant quadratic curve relationship between them. (4) The increase of annual and seasonal Tm was the dominant factor causing the increase of VPD. After 2004, the contribution of annual Tm and e to VPD decreased, and the role of Pr increased significantly.
Under the background of climate change, there have been increasing trends in both the amount and intensity of autumn rainfall in West China in recent years. To comprehensively understand the long-term variations and daily characteristics of hourly precipitation, hourly precipitation data from 342 stations in West China from 1981 to 2023 were analyzed. The spatial distribution and temporal changes of hourly average precipitation, frequency, intensity, and extreme precipitation were investigated. The results are as follows. Overall, there is a slight increasing trend in hourly average precipitation in West China from 1981 to 2023. The frequency of precipitation events show a slight decreasing trend in the entire region as well as in the northern and southern regions. However, intensity exhibits a slight increase in the entire region and southern region, with a marginal decrease in the northern region. Diurnal variations consistently show a unimodal pattern, but the peak times differ between the southern (04∶00-07∶00) and northern (around 08∶00, with low values from 16∶00 to 20∶00) regions. Spatially, hourly average precipitation exhibits a morning-dominant and afternoon-decreasing pattern, with rainfall moving from southwest to northeast and being more pronounced at night. However, there are significant spatial differences in intensity, with stronger nighttime precipitation in the southern region, whereas daytime precipitation is stronger in the northern region. The southeastern part of Gansu and southern part of Ningxia show relatively lower intensity with less pronounced diurnal variations. Extreme precipitation frequency shows an overall increasing trend, more significantly in the northern region. Diurnal variations in both the southern and northern regions exhibit a unimodal pattern, with nighttime peaks in the south and early morning peaks in the north. The contribution rate of extreme precipitation shows an overall increasing trend but a slight decreasing trend in the northern region. September exhibits the highest frequency and contribution rate of extreme precipitation, though the centers of maximum values do not coincide, the frequency peak is mainly in the junction area of Shaanxi, Sichuan, and Chongqing, while the contribution rate peak is in the western Sichuan basin.
Based on the daily precipitation data from 274 national meteorological stations in the west route of the South-to-North Water Transfer Project area from 1961 to 2022, the spatiotemporal distribution characteristics of annual and seasonal precipitation in the water source and receiving areas were analyzed, as well as the characteristics of the encounter between dryness and wetness in the two areas. The results show that in the past 62 years, the precipitation in the water source area of the west route of the South-to-North Water Transfer Project showed an increasing trend, while the trend of precipitation in the water receiving area was not significant. The seasonal precipitation of summer and winter in both water source area and receiving area increased. The precipitation of spring and autumn in water source area increased while that in water receiving area decreased. The frequency of dryness in water source area was lower than that in water receiving area in spring, summer, and autumn. The frequency of dryness in water source area showed a decreasing trend, while the frequency of wetness showed an increasing trend. The asynchronous frequency of annual and seasonal precipitation in the water source area and receiving area was above 60%, which was much higher than the synchronous frequency. The five types of dryness-wetness encountering favorable for water transfer occurred at a frequency of over 50% in spring, summer, and autumn. In general, the precipitation in water source and receiving areas of the west route of the South-to-North Water Transfer Project had a strong compensatory effect, and the frequency of dryness-wetness encountering favorable for water transfer increased after 1971, ensuring the possibility of water supply. However, the frequency of continuous dryness years in water source area was high. Therefore, it is necessary to consider climate changes of precipitation in water source and receiving areas in the planning, design, and operation scheduling of the west route of the South-to-North Water Transfer Project.
Comprehensive assessment of the carbon emission efficiency of Central and Eastern European countries is of great significance for promoting cooperation between China and Central and Eastern European countries, and for high-quality joint construction of the “Belt and Road”. In this paper, the carbon emission efficiency was measured for Central and Eastern European countries from 2010 to 2020 based on the Super-SBM model that considers undesired output, an in-depth analysis was conducted on the spatiotemporal distribution characteristics and dynamic evolution of carbon emission efficiency, and finally the Tobit model was used to explore its influencing factors. The results show that the low-carbon development level of Central and Eastern European countries showed an overall upward trend during the study period, and the average carbon emission efficiency increased from 0.57 in 2010 to 0.74 in 2020, but there were significant differences among countries. The carbon emission efficiency values of Greece, Lithuania and Slovenia were significantly higher than those of other countries, with the Baltic States and Slovenia showing the largest improvements in carbon emission efficiency. Different factors had different impacts on carbon emission efficiency of Central and Eastern European countries. Energy intensity and total population were the main reasons restricting the increase in carbon emission efficiency in countries such as the Czech Republic and North Macedonia. Net foreign direct investment inflows promoted the improvement of carbon emission efficiency in Lithuania, Romania, North Macedonia and Greece to varying degrees. The research results can provide scientific support for Central and Eastern European countries to formulate low-carbon development strategies and carry out international cooperation.
As the second largest greenhouse gas after CO2 and the most important short-lived greenhouse gas, methane emission reduction has gradually become a consensus from scientific cognition to action, becoming the focus of global climate negotiations and the key area of international climate cooperation. In order to support China’s methane emission reduction work, firstly, the global and China’s methane emission trends, characteristics and existing emission reduction actions were compared and analyzed. Then, a methane model (SPAMC-Methane) on the basis of Strategy and Planning Assessment Model for Climate Change in China was established to analyze the methane emission trend, reduction potential and path of China from 2022 to 2060 under the baseline scenario, energy transformation scenario and methane low-emission scenario, with 2022 as the benchmark. The results show that the methane emission is expected to peak in 2032 at 75.80 Mt under the energy transformation scenario, and before 2025 at 70.60 Mt under the methane low-emission scenario. Under the methane low-emission scenario, the methane emission will decrease by 12.3% in 2035 and 53.7% in 2060 from the peak level. Compared with the baseline scenario, the emission reduction contribution of the energy transition and technology enhancement in 2060 are about 62.9% and 37.1%, respectively under the methane low-emission scenario, and about 77% of the emission reduction will come from the coal mining and solid waste treatment sectors.
Responding to global climate change, selecting appropriate transition technologies and pathways based on regional development differences is crucial for advancing high-quality development through coordinated pollution reduction and carbon mitigation efforts. The Low Emissions Analysis Platform (LEAP), which is constructed in a bottom-up manner, is widely used for assessing energy transition pathways and supporting coordinated pollution reduction and carbon mitigation goals due to its high flexibility, detailed technical capabilities, and features such as energy system modeling, optimization, and scenario analysis. This paper systematically analyzes the structure and function of LEAP, compares and analyzes the application of LEAP in evaluating the energy consumption levels, emission reduction costs, and environmental impact of different transformation paths and emission reduction policies in different fields since 2017. In the context of climate change, LEAP should enhance its functional expansion on key issues such as water resources, land use, and health effects. It should also address challenges related to urban-level transitions, new economic pillar sectors, and carbon reduction. This will promote the best balance between pollution and carbon reduction synergy and economic development in various regions, thereby promoting the formulation and implementation of more effective climate policies and action plans.
It is very important and urgent to conduct a study on climate adaptation planning for power systems considering the impacts of climate risks on power supply and demand. In this study, a study was carried out on power system climate adaptation from a planning perspective: a medium and long term power resource planning model that considers the coupled impacts of climate risks was constructed to enhance the level of power system climate adaptation through the optimal allocation of power resources. The results show that the proportion of renewable energy generation in the planning scheme that considers the long-term climate change trend would increase despite the reduction of installed capacity, and the utilization level of renewable energy increases. The average annual construction investment would reduce. Under the planning scenario that considers the climate risk of extreme weather, the average annual installed capacity and generation capacity of controllable power sources would increase to support the integration of renewable energy and the safe and stable operation of power system, and the average annual generation capacity of renewable energy slightly decreases. And the average annual construction investment of the system would increase. The power planning scheme that takes into account the coupled impacts of climate risk can improve the utilization of renewable energy and system security in an integrated manner, and promote the high-quality development of renewable energy.
In order to cope with increasingly serious climate change, various countries are actively formulating climate policies to promote green transformation and sustainable development. Frequent changes in climate policies bring new risks to business operations. As a strategic resource for enterprises, green innovation is an important way to boost the green transformation of the economy, which is inevitably affected by climate policy uncertainty (CPU). Based on the data of Chinese listed enterprises from 2010 to 2022, this paper investigates the impact of climate policy uncertainty on corporate green innovation and its mechanism through Tobit modeling. The results show that CPU has a significant inhibitory effect on enterprises’ green innovation, which is more pronounced among non-state-owned enterprises, non-energy enterprises and enterprises with high analyst attention. Rising CPU weakens enterprises’ willingness to innovate by increasing financing constraints and lowering risk-taking levels, with the indirect effect of risk-taking levels manifesting itself as a “masking effect”. The moderating mechanism test finds that enterprises’ digital transformation can significantly counteract the negative impacts of CPU on green innovation, and in particular helps to improve the ability of enterprises’ substantive green innovation to cope with climate policy changes. This paper not only deepens previous research but also provides richer empirical evidence for understanding the impact of CPU in developing countries. The findings are conducive to inspiring the formulation and adjustment of CPU and provide practical evidence for companies engaged in green innovation to mitigate climate-related risks.
