Abnormal atmospheric warming on the Tibetan Plateau has caused an imbalance in Asian Water Towers, leading to widespread and frequent cryospheric disasters such as ice avalanches and Glacial Lake Outburst Floods (GLOFs). These events pose a significant threat to life and infrastructure downstream, impacting regional socioeconomic development. Our recent studies, conducted during the Second Tibetan Plateau Scientific Expedition and Research Program, utilized field observations, remote sensing, and modeling to examine glacial lakes and GLOFs on the Tibetan Plateau. As of 2020, we had identified 14 310 glacial lakes on the Tibetan Plateau, covering an area of 1 148.3 km², along with a 20.4% increase in lake number and a 20.2% increase in lake area since 1990. Hazard and risk assessments revealed 1 256 glacial lakes with high or very high hazard levels, including 182 glacial lakes with high or very high-risk levels. These high-risk glacial lakes pose severe GLOF threats to communities and infrastructure downstream. At the regional scale, the eastern Himalayan and southeastern Tibetan regions exhibit the highest number of glacial lakes, the largest area expansion, the most destructive GLOF hazards, and the highest concentration of very high hazard level and very high-risk level glacial lakes on the Tibetan Plateau. In terms of administrative regions, Shigatse City, Nyingchi City, and Shannan City in the Tibet Autonomous Region have the highest distribution of very high-risk level glacial lakes. Future research should focus on precise GLOF assessments, the development of monitoring and early warning systems, and strategies for adapting to GLOF disaster chains and transboundary threats.

Groundwater-dependent vegetation is essential in arid ecosystems, where it maintains ecological balance and supports biodiversity. The health and functionality of this vegetation are closely linked to groundwater characteristics, including groundwater quality, distribution, and fluctuations. This review explores the relationship between vegetation and groundwater, methods for identifying groundwater-dependent vegetation, the impact of groundwater on the plants, adaptation mechanisms of these plants, and the nonlinear dependencies and thresholds of vegetation in groundwater environments. The objectives of the study are to provide a theoretical foundation for protecting and restoring arid ecosystems and to provide support for the sustainable development and utilization of groundwater resources. Future research should focus on plant responses to groundwater changes at the individual, population, and community scales; the effects of climate change and human activities on groundwater-dependent vegetation; innovative methods for studying ecosystem resilience and state-transition mechanisms for groundwater-dependent vegetation; and identifying stable water environment factors and catastrophic thresholds for typical groundwater-dependent vegetation.

Internal Solitary Waves (ISWs), which are characterized by large amplitudes and strong nonlinearity, are pivotal dynamic phenomena in oceanic processes. These waves contribute significantly to vertical mixing, cross-isopycnal transport of nutrients and sediments, and modulation of marine ecosystems, while posing substantial risks to subsea infrastructures, underwater navigation, and offshore operations. Therefore, a comprehensive understanding of their generation mechanisms, spatiotemporal evolution, and environmental impacts is critical for advancing oceanographic knowledge and ensuring maritime safety. The South China Sea (SCS) and its adjacent regions along the Maritime Silk Road, including the Sulu Sea (Sibutu Passage), Celebes Sea, Lombok Strait, and Andaman Sea, serve as global hotspots for ISW activity because of their complex bathymetry, intense tidal currents, and stratified water columns. This paper synthesizes multidisciplinary advances in ISW research across these regions, leveraging integrated methodologies such as multi-sensor satellite remote sensing (e.g., MODIS, VIIRS, and SAR), in situ observational networks, high-resolution numerical modeling (e.g., MITgcm, FVCOM), and emerging seismic oceanography techniques. Furthermore, the review identifies persistent gaps in knowledge, such as the role of mesoscale and submesoscale processes in wave–current interactions and interference effects between ISWs from multiple sources. Technical challenges, including the assimilation of multi-platform data into predictive models and the development of AI-driven forecast systems (e.g., physics-informed neural networks, convolutional neural networks), are critically assessed. The paper concludes by advocating for coordinated international observational campaigns and next-generation, non-hydrostatic models to unravel the multiscale complexity of ISWs, ultimately enhancing predictive capabilities for scientific and operational applications in these strategic waters.

Since 1958, China has conducted numerous artificial fog dissipation field experiments and research. This paper summarizes the classification and characteristics of fog as well as the mechanisms and methods of artificial fog dissipation. Fog areas in China are extensively distributed, with obvious seasonal differences. Land fog is mostly radiation fog, whereas sea fog is distributed in foggy areas along the coast, and its formation and dissipation are restricted by various conditions. The methods and technical approaches for artificial warm and cold fog dissipation were determined. The dissipation methods for warm fog include heating, dynamic mixing, thermodynamic methods, and hygroscopic particle seeding; whereas the dissipation methods for cold fog include seeding silver iodide of ice nucleating agents and spraying refrigerants. Other methods such as ultrasound are currently being researched and tested. The applicability, advantages, disadvantages, and uncertainties of these seeding methods were analyzed. The applicability of the fog dissipation methods varies. When applying these methods, it is necessary to comprehensively consider the technical approaches, implementation challenges, cost-effectiveness, and fog dissipation efficacy in field trials and operational applications. Aircraft-induced downdraft mixing is a simple, expensive, and operationally challenging process for warm fog. Thermal heating is universally applicable to all warm fog types but is cost-prohibitive and reserved for emergencies or critical infrastructure (e.g., major international airports and vital seaports), particularly for high-temperature fog. For cold fog, silver iodide seeding exhibits poor nucleation efficiency at temperatures around -5 ℃ (optimal below -8 ℃), necessitating cooling agents like liquid nitrogen, dry ice, and propane. Despite its high cost, liquid-nitrogen seeding is preferred operationally owing to its reliability and ease of deployment.All the current methods can dissipate local small-range warm or cold fog, but none can dissipate large-scale fog systems. A comprehensive analysis of fog dissipation provided ideas and references for artificial fog dissipation experiments, seeding operations, and future development in China. Future research should integrate numerical modeling, laboratory experiments, and field trials to validate and optimize seeding techniques and enhance the operational efficiency and cost-effectiveness.

With the rapid accumulation of marine big data and the robust development of Artificial Intelligence (AI) technology, intelligent marine forecasting has shown greater precision and efficiency in this new era. Marine data can be categorized into point- and field-observation data based on the observation methods, providing foundational support for marine forecasting. Marine forecasting methods can be divided into three main types based on the characteristics of the dynamic marine processes and phenomena: point-to-point, field-to-point, and field-to-field forecasting. These forecasting approaches not only cover a variety of marine phenomena but also address different forecasting requirements. Through a case analysis, this study specifically introduces intelligent forecasting models and results for point-to-point internal solitary wave forecasting, field-to-point El Niño-Southern Oscillation (ENSO) forecasting, and field-to-field phenomena such as mesoscale eddies and sea ice. Finally, it explores the development directions for intelligent marine forecasting in the context of big data, suggesting that enhancing the integration of data-driven methods with physical mechanisms can improve forecast accuracy and real-time responsiveness, thereby providing technical support for marine environmental monitoring, disaster warning, and the sustainable use of marine resources.

As the largest desert in the world, the Sahara Desert emits dust aerosols, accounting for 50%~60% of the global total dust, exerting significant impacts on regional and even global climate, environment, and ecosystems. Previous domestic and international studies reported two primary transport pathways for Saharan dust: westward across the North Atlantic, reaching North America, or northward to the European continent. In recent years, studies have shown that Saharan dust can be transported across the Middle East and Central Asia, undergoing long-distance (nearly 10 000 km) to East Asia, which is the third transport pathway for Saharan dust. Therefore, this study primarily summarizes the research progress on the long-range transport of Saharan dust to East Asia and its impacts, including the physical and chemical properties of Saharan dust, dust emission mechanisms, transport processes, and climatic and environmental effects. Finally, we highlight the current challenges in the research on the eastward transport of Saharan dust and provide suggestions and ideas for future research.

A new framework for studying climate change projections and disaster risks oriented towards carbon neutrality was developed using a division method of positive emissions, net zero, and net negative periods. Focusing on the main Belt and Road regions, future mean and extreme climate change projections and disaster risks oriented towards carbon neutrality were systematically addressed under the SSP1-1.9 and SSP1-2.6 sustainable development pathways. Moreover, it is projected that over global carbon neutrality or net-zero periods, climate change will exhibit new characteristics and patterns, and disaster risks will undergo new changes over the main Belt and Road regions. The newly developed framework provides a new scheme for climate change projection and disaster risk assessment. The seventh assessment report of the Intergovernmental Panel on Climate Change and other future assessment reports on climate change should include climate change projections and disaster risk assessments oriented towards carbon neutrality, which can provide new scientific knowledge for jointly dealing with climate change and achieving sustainable development. Additionally, the role and application of Artificial Intelligence in future climate change projections and climate disaster risks assessments are discussed.

Short-duration heavy precipitation is one of the most substantial severe convective disasters in China and is prone to causing urban waterlogging and secondary geological disasters, such as mountain torrents, mudslides, and landslides. This paper reviews recent progress in short-duration heavy precipitation research in China and briefly compares relevant findings from the United States and Europe. It covers the spatiotemporal distribution characteristics and diurnal variation patterns of short-duration heavy precipitation, atmospheric circulation patterns and environmental conditions that influence its occurrence and development in major regions of China, radar echo characteristics and raindrop distributions, impact of topography and urbanization on its formation and development, and application of artificial intelligence in potential forecasting, short-term forecasting, and nowcasting of short-duration heavy precipitation in China. With global warming, the frequency and intensity of short-duration heavy precipitation events have increased. In the future, further research will be required to enhance understanding of the formation mechanisms and environmental conditions, improve the spatiotemporal resolution of observations, expand the use of new observation data, and enhance forecasting capabilities in high-resolution, rapid-update cycle assimilation numerical weather prediction models through the fusion and analysis of dense multisource observation data. Additionally, optimizing deep learning models and algorithms—particularly in the development of largescale deep learning models—will be crucial for improving forecasting and early warning capabilities for short-duration heavy precipitation.

Significant advances in the formation mechanism and forecasting methods of severe convective winds and related convective systems were reviewed to improve understanding of the formation mechanism and forecast accuracy of severe convective winds. First, the spatial and temporal distribution characteristics of severe convective winds worldwide are briefly described. Next, the relationship between the organizational types and structural features of the parent convective systems that generate severe convective winds is then summarized, as well as the impact of atmospheric environmental conditions and topography, and forecasting methods. Finally, the current issues and future research directions associated with severe convective winds are discussed.

Humanity’s current water problems range from local-scale issues such as water supply to regional- and global-scale issues including protecting ecosystems, responding to global changes, sustaining the earth system, etc. Water resources exploitation, land utilization and climate changes have intensified pressure on water cycle through water distribution, interconnection, and virtual flows. The impact of anthropogenic pressure on water cycle has extended beyond the catchment-scale, with human activities becoming the primary driving force behind changes in regional, continental and global water cycle. Estimations by planetary boundaries framework indicated that development of global blue water and green water is approaching or beyond water planetary boundaries posing increased rising risks to earth system stabilization. Current water governance, which is focused on catchment scale and water-centric approaches, struggles to address the complexity of these issues. Governance must shift to manage not only increasing water use for economic and societal development, but also the roles and functions of water cycle in sustaining biosphere and Earth systems. Moreover, it should consider the equitable distribution of ecological services provided by water cycle. Concepts of water resilience and the economics of water as a common good enhance the conventional understanding of the water cycle, highlighting its essential role in sustain Earth systems and the cross-scale effects of human activities. Future, water resources governance is likely to evolve in three directions: from blue water management to blue-green water management, from integrated water-centric management to integrated land-water-ecosystem management, and from integrated river basin management to multi-scale management. It is critical for promoting transformation of water governance to strengthen cooperation among scientists of different fields in research of basic theory of water cycle, management policies and governance institutions.

Concerns about aviation emissions and climate change are shared internationally. The aviation industry plays a role in climate warming through its greenhouse gas and high-altitude particulate emissions. Conversely, climate warming alters flight conditions and increases extreme weather, impacts aviation operations and safety. The interaction creates a complex cycle of impacts, and research in this area is not only crucial for coordinating and adapting to climate changes in the aviation industry, but also holds scientific significance. An extensive literature review explores the relationship between aviation and climate warming, examining aviation’s CO₂ and non-CO₂ contributions to global warming and the phenomena and mechanisms by which climate warming in turn affects aviation (including changes in turbulence, flight time, aircraft performance degradation, and increased frequency of extreme events). The review also presents future research prospects. A deeper understanding of this interrelationship will help promote sustainable development of aviation and provide a scientific basis for addressing global climate challenges.

In recent years, flash droughts with rapid onset have occurred frequently worldwide, severely impacting society, economy, and the ecological environment. Major progress in the formation and evolution mechanisms of flash droughts has been reviewed. Concludingly, intense precipitation deficits cause flash droughts, whereas increased evapotranspiration accelerates drought onset, further triggering flash droughts. These abnormal meteorological factors are closely associated with sea surface temperature anomalies (such as the El Ni?o-Southern Oscillation, North Atlantic Tripole, and Indian Ocean Dipole) and their related atmospheric circulation anomalies. In addition, the roles of local and non-local land surface anomalies in the onset and maintenance of flash droughts are important. Moreover, the synergistic effects of climate and land-use change on land-atmosphere-ocean coupling processes make the development of flash droughts more complex and add considerable uncertainty to evolutionary trends. Therefore, future research needs to achieve breakthroughs in several areas, including the large-scale atmospheric circulation background of flash drought onset and maintenance, modulating roles of key land and ocean signals, flash drought-vegetation interactions, and response mechanisms of the variation of flash droughts to climate warming and land cover changes.

The recently published report “Earth System Science in China: The Development Strategy for 2035” identified three major areas for potential research breakthroughs: \mathrm{①} Revisiting the marine carbon pump, \mathrm{②} Hydrological cycle and orbital forcing, and \mathrm{③} Ocean-Continent connection between the Pacific and Asia. The strategy research group was jointly established in 2019 by the National Natural Science Foundation of China and the Chinese Academy of Sciences. Over the course of three years, the group organized 14 thematic workshops, involving over 500 experts from various research fields. This study provides a brief overview of these three major research areas.

With growing concerns about ecosystem functioning and the services provided by soil, the study of soil aggregates has increasingly become a central discipline of modern soil science, with ongoing updates to consensus and methodology. In this review, we provide a holistic overview of the understanding and characterization of the soil aggregate system that has emerged over the last two decades. The evolution of concepts related to soil aggregation, size fractionation, and structural characterization is presented, along with discussions on the separation and examination of the biophysical structure. Additionally, the final core scientific consensus on the soil hierarchy system is synthesized. The key points of understanding soil aggregates are as follows: \mathrm{①} Soil aggregates are considered the fundamental micro-architectural and functional units, composed of mineral particles, organic matter, and microbiomes through their interactions and co-occurrence, thus representing the basic functional particles of soil in nature; \mathrm{②} The micro-spatial distribution of soil aggregates at different hierarchical levels results in the heterogeneity and functional diversity of soil; \mathrm{③} The ultimate nature of soil aggregates can be envisioned as an embedded bio-pore system, created through the dual structure of aggregates and the associated pore system governed by the hierarchical aggregate system; \mathrm{④} A soil aggregate system is generally represented by three major hierarchical size fractions: macroaggregates, microaggregates, and the silt/clay fraction, with macroaggregates formed by binding microaggregates and/or silt-clay particles with coarse organic matter, resembling a pomegranate structure; \mathrm{⑤} Wet sieving of field-moist samples is recommended for the preparation of soil aggregate separates, although dry or moist sieving is often used for samples from drylands; \mathrm{⑥} μCT tomography technology is a powerful tool for quantifying and visualizing the pore system of soil aggregates, with the potential to link soil life processes to ecosystem services. Global cooperation is encouraged to develop a unified protocol for fractionating, quantifying, and visualizing the soil hierarchy system of aggregates across the world’s soils. With these developments, the complex soil system, particularly its biodiversity, can be explored at the aggregate scale. Based on the updated understanding and characterization of the soil aggregate system, nature-based solutions for global soil management policies and technical options will be provided, contributing to Earth’s sustainability.

Inter-ocean exchange between the tropical Pacific and the Indian Ocean, which relies on throughflow from the Pacific to the Indian Ocean, serves not only as a crucial conduit for the exchange of mass, momentum, and energy between the Indo-Pacific basins, but also as an oceanic channel for the propagation of climate anomalies between the Pacific and Indian Oceans. In addition, it plays a key role in the closure of the Great Ocean conveyor belt by facilitating the compensation of surface waters in the deep Atlantic. Therefore, interocean exchange is a pivotal component of global ocean and climate systems. It has been recognized as one of the most important academic hotspots for ocean circulation in interocean change regions and their related climates. Since the 1990s, international cooperative actions have been conducted, focusing on the observation of inter-ocean exchange. Starting in 2007, Chinese researchers have conducted observations in the main strait and channels of interocean exchange regions by collaborating with Indonesian researchers. Currently, they have established the largest on-site array for the synchronous observation of interocean exchange. The array covers the key inflow, throughflow, and outflow regions. This paper reviews the major progress and open issues of inter-ocean exchange from four aspects: \mathrm{①} multiscale variations of inter-ocean exchange, \mathrm{②} cross-scale and \mathrm{③} cross-basin interactions, and \mathrm{④} modulation of the primary climate modes of the Pacific and Indian Oceans. The prospects of the key research goals for the next five to ten years are also outlined.

This paper summarizes recent progress in the observation, mechanism, and modeling of land-atmosphere interactions, and demonstrates that existing observational studies have not considered the effects of changes in terrestrial ecophysiology and the atmospheric boundary layer on land-atmosphere fluxes. Consequently, they restrict the parameterization of land surface processes, parameter inversion from satellite remote sensing, and the operational application of the land surface process model. To gain a comprehensive understanding of land-atmosphere interactions and the development of land surface process models, studies on the effects of changes in terrestrial ecophysiology and atmospheric boundary layers on land-atmosphere interactions and the operational application of land-surface process models need to be emphasized in the future. The main tasks to be considered include: \mathrm{①} three-dimensional observation of the land-atmosphere interactions across the boundary layer, \mathrm{②} application of multi-source data in the land-atmosphere interactions across the boundary layer, and \mathrm{③} development and operational application of land surface process models.

The island arc and oceanic plateau models of a mantle plume are two popular models for the origin of the crust. In contrast to the island arc model, the oceanic plateau model can account for most of the features of the Archean crust but meets the fundamental challenge of explaining the water-rich features of the magma source for the Archean crust. The recent water-induced mantle overturn model accounts for not only water-rich features but also several puzzling phenomena in the Archean. The whole-mantle Magma Ocean (MO) separated into outer and basal MO because the crystallized mantle floated in the middle mantle. The water-induced mantle overturn model shows that with crystallization, basal MO became increasingly enriched in water because lower-mantle minerals can only contain a limited amount of water. Water reduced the density of basal MO. The basal MO eventually became less dense than the overlying solid mantle and became gravitationally unstable because of water enrichment. The triggered mantle overturned transport a large amount of water to the shallow part of the Earth and resulted in large pulses of crust and thick subcontinental lithospheric mantle (SCLM) generation. Therefore, the Archean crust was the result of the evolution of the basal MO. Once the mantle overturned from the basal MO, Archean-type crust no longer formed. Thus, the water-induced mantle overturn model can account for global change at the end of the Archean and other puzzling phenomena. For example, why were Tonalite-Trondhjemite-Granodiorite (TTG) and thick SCLM rare in the Hadean, why does the source of Archean basalts remain the primitive mantle from ca 4.0 to 2.5 Ga, and why does only Earth have continental crust?

Sea-Level Rise (SLR) directly changes the hydrology and salinity of estuarine tidal wetlands and is one of the primary drivers of global change that significantly impacts ecosystem processes. Herein, various methodologies and experimental facilities (marsh organs, weirs, and flow-through mesocosms) for manipulating SLR are systematically reviewed. This study provides a comprehensive summary of the effects and mechanisms associated with SLR regarding the fluxes and production rates of CH₄ and CO₂, and the pathways and rates of soil organic carbon mineralization from the perspectives of SLR-saltwater intrusion and inundation increase. Saltwater intrusion due to SLR notably decreases CH₄ production rates and fluxes. It induces a shift in the pathways of soil organic carbon mineralization, transitioning from CH₄ production to microbial SO{}_{\mathrm{4}}^{\mathrm{2}-} reduction in tidal freshwater marshes. The main mechanism reducing saltwater intrusion-induced CH₄ flux is the increased presence of the electron acceptor SO{}_{\mathrm{4}}^{\mathrm{2}-}, which hinders soil CH₄ production. The impact of SLR through saltwater intrusion on CO₂ emissions in tidal freshwater marshes exhibits distinct uncertainty. Owing to the inherent challenges in experimentally manipulating SLR in situ, few reports concerning the effects of SLR-related inundation on CH₄ and CO₂ fluxes and production rates exist. However, some studies have suggested that an increase in inundation height leads to a reduction in CO₂ emissions. Additionally, this study consolidates information surrounding electron acceptors and microbial mechanisms associated with SLR that influence the pathways and rates of soil organic carbon mineralization in coastal tidal wetlands. Finally, this study outlines the specific domains that warrant further exploration in future research on the impact of SLR on the production and emission of carbon greenhouse gases in estuarine tidal marshes.

As computing power continues to improve, the horizontal grid resolution of numerical weather prediction models has reached the kilometer-to-sub-kilometer scale. This grid scale is comparable to the characteristic turbulent scales in the convective boundary layer, allowing the numerical models to resolve the organized convective structures. The assumptions of traditional one-dimensional boundary layer parameterization schemes (suitable for horizontal resolutions of several kilometers or coarser) and large eddy simulation three-dimensional turbulent closure schemes (suitable for horizontal resolutions below several tens of meters) do not hold at this scale, which is referred to as the gray zone. This study discusses the applicability and limitations of traditional parameterization methods and introduces the gray zone of the convective boundary layer from three perspectives: theory, methodological approaches, and impact. It summarizes the characteristics of the simulation methods at the CBL gray zone scale developed over the past two decades and explores the impact of the boundary layer process simulation at this scale on other physical processes (e.g., shallow/deep convection) in numerical models. Further, we anticipate future research directions and approaches.

The Anthropocene Working Group (AWG) of the International Commission on Stratigraphy voted that the Anthropocene should be defined by a Global boundary Stratotype Section and Point (GSSP or ‘golden spike’) as a formal chronostratigraphic unit. Increasing evidence has shown that human activities have drastically intensified since the mid-twentieth century, altering the original rate and direction of Earth’s evolution, triggering a profound impact on Earth’s environment, and leaving their imprint on geological records through physical, chemical, and biological markers. Consequently, the 1950s was assumed to be the ideal onset of the Anthropocene. Currently, 12 candidate sites for the GSSP of the Anthropocene have been proposed for consideration by the AWG. Chinese researchers have made outstanding progress in recent years regarding the establishment of a system of proxies for human activities and the global comparison of the candidate sites for the GSSP of the Anthropocene. These proxies, including anthropogenic radioactive isotopes, microplastics, δ¹³C, δ¹⁵N, and diatoms, have great potential as markers of human activities. These proxies recorded in the sediments of Sihailongwan Maar Lake, which is far away from cities and less affected by human activities, indicate that this site is sensitive to global change. The concentrations of ^{239, 240}Pu have drastically increased since 1953 CE in the sediment profile collected from Sihailongwan Maar Lake. as Additionally, other proxies such as PAHs, ¹²⁹I, soot ¹⁴C, SCP (spheroidal carbonaceous particles), DNA, δ¹³C, and Pb exhibit synchronous changes near 1953 CE, indicating the onset of Anthropocene. Two sediment stratotype profiles collected from Sihailongwan Maar Lake and Beppu Bay, Japan, were selected by the AWG as auxiliary sections for the GSSP of the Anthropocene. The ultimate goal of Anthropocene science should be to deepen the theory and technological innovation of sustainable development of the Earth-humans system and adaptation based on clarifying the impact of human activities on the Earth system.

N₂O is an important greenhouse gas that also damages the ozone layer. N₂O emissions have been observed during microalgae cultivation and in microalgae-based ecosystems, such as eutrophic lakes. However, little has been reported on the important role of the N₂O balance in algae and the potential algal N₂O production pathways. A review of recent relevant studies on N₂O synthesis and fixation by algae shows that the studies mainly focus on the relationship between algae and N₂O emissions, several possible pathways of N₂O production and consumption in algae, the influence of the algal microenvironment on the distribution pattern of N₂O, and the potential impacts on global climate change. However, the Intergovernmental Panel on Climate Change currently does not consider the possible N₂O emissions during algal blooms or algal aquaculture; hence, it is necessary to intensify experimental studies related to algal N₂O production globally to take important steps towards a comprehensive clarification of the important roles of algae in N₂O emission and fixation and a comprehensive assessment of greenhouse gas emissions from aquatic ecosystems.

Global warming caused by human activities has resulted in significant changes in the climate system, including changes in the regional climate, extreme events, snow, ice, vegetation, air quality, water cycle, and responses and feedbacks among various components of the climate system. The land surface is where water, energy, and geochemical transports to and from the atmosphere occur, hydrological processes occur, and vegetation grows. Hence, the land surface is sensitive to climate change. Climate change affects the hydrological processes not only directly but also indirectly by affecting the vegetation structure and physiology. Land surface models are useful for studying climate change and its impacts on the land surface by modeling the relevant responses and feedbacks. There are three types of land surface models that simulate the mass and energy exchange between the land surface and atmosphere: the global land surface process model, global hydrological model, and global dynamic vegetation model. These three types of models focus on different specific components of the land surface. Since the 1990s, various land surface comparison projects have revealed many problems and shortcomings in land surface models and have furthered their development. However, various issues with these models still need to be addressed. For example, one major problem with the global hydrological model is that it does not incorporate dynamic vegetation growth; hence, it cannot project long-term vegetation change impacts on the hydrological processes—let alone extreme hydrological events such as flooding and drought—and cannot be useful with respect to future water resource management. Incorporating dynamic vegetation growth into hydrological models is a frontline research topic in hydrology. Moreover, many land surface models represent soil textures and heat exchanges among soil liquids, solids, and gases on the Tibetan Plateau insufficiently. This aspect requires improvement by enhancing the observations, understanding the relevant mechanisms, and realizing the mechanisms and processes in the land surface models. The Tibetan Plateau provides fresh water to the surrounding regions and forms and modulates climate and weather both regionally and globally; thus, it is dubbed the Asian Water Tower. Improving the land surface model capability of the plateau will improve the understanding of climate change and its impacts, both regionally and globally.

Ozone is among the most important trace gases in Earth’s atmosphere and plays a crucial role in both climate change and ecology. Tropospheric ozone is an important component of photochemical smog, and its variations are closely related to human activity. Monitoring of tropospheric ozone based on satellite remote sensing can help us better understand and quantitatively explain the characteristics of tropospheric ozone changes in different seasons, times, and regions, and explore the mechanism of ozone generation in the troposphere. With the comprehensive development of satellite remote sensing techniques, ozone remote sensing products (e.g., total ozone, profiles, etc.) have improved significantly in terms of accuracy and spatiotemporal resolution. However, the accuracy of tropospheric ozone products is still not sufficient for the current scientific application of the atmospheric composition of the troposphere due to the weak satellite signals and complexity of the subsurface. This review focuses on satellite remote sensing of tropospheric ozone. It outlines and analyzes the development history and current status of ozone satellite remote sensing payloads and discusses the characteristics and applicability of remote sensing retrieval algorithms based on different technologies (direct and indirect retrieval, multiband joint retrieval, collaborated nadir-limb retrieval, and innovative algorithms based on machine learning techniques). It further discusses the application of satellite remote sensing for the provision of reliable tropospheric ozone observation data at the global and regional scales. Overall, this review envisions the application of satellite remote sensing for providing reliable tropospheric ozone observations at the global and regional scales.

The matching of water and land resources often directly affects food production in various regions and is the basis for high-quality economic and social development and modernization of agricultural production. Using nine provinces along the Yellow River as examples, based on the cross-coupling of four elements, such as the natural background of water resources and water resources for total water consumption control, this study constructed a ternary synergistic model of water-cultivated land-grain by cross-coupling. The matching coefficients of water and soil resources from 2010 to 2020 under each scenario were calculated, and the temporal and spatial evolution characteristics of water and soil resources matching along the “province-city” scale of the nine provinces along the Yellow River and the contribution degree of each element were analyzed. The results showed that: \mathrm{①} The matching degree of binary water and soil resources based on the natural background of water resources in the nine provinces was improved as a whole, and the matching pattern of water and soil resources was relatively stable; however, the regional differences are notable and manifested as “high in the west and low in the east.” \mathrm{②} Along the three-way coordinated matching pattern of water-arable land and grain in the nine provinces, from the perspective of the total amount of cultivated land and the amount of irrigated arable land in the natural background of water resources, roughly three distribution patterns were presented: the western and northeastern regions were severely water-deficient areas, the northern and north-central regions typically had varying degrees of water shortage, and the central and eastern regions exhibited a diversified distribution pattern; from the perspective of total water consumption control, a remarkable difference is observed between the total amount of cultivated land and the three-way cooperative matching pattern of irrigated cultivated ground. \mathrm{③} Under the four scenarios, the average contribution rate of water resources were >50%, and the sum of the effective utilization coefficient of irrigation water and the contribution rate of the irrigation quota were >30%, indicating that increasing the effective utilization coefficient and setting a reasonable irrigation quota had a decisive impact on the change in water and soil resource matching. These results improve our understanding of the relationship between water resources and exploitation, cultivated land production capacity, and reclamation, as well as the interdependence and constraints of the grain planting structure.

Quantitative assessments of progress towards Sustainable Development Goals (SDGs) and the complex interactions of indicators are critical for monitoring the achievement of SDGs and guiding policymaking and implementation. Based on Big Earth Data and the SDGs global indicator framework, an index system for evaluating progress towards SDGs in frontier, multi-ethnic underdeveloped areas was developed from the perspective of social, economic, and environmental dimensions and included 70 indicators. The study area was the National Innovation Demonstration Zone (Lincang) for the 2030 Agenda for Sustainable Development. The model incorporated regional characteristics and data acquisitioned from Lincang in 2015-2020 through field research. Consequently, we calculated the social, economic, and environmental sub-indices and integrated index of sustainable development of Lincang City from 2015 to 2020, evaluated the progress trend of SDGs and indicators, and proposed key challenges and solutions for the sustainable development of Lincang City. Research shows that the integrated index and the social, economic, and environmental sub-indices of sustainable development have shown an increasing trend from 2015 to 2020. In terms of the SDGs, progress was achieved with respect to all 16 SDGs. The average annual growth rate of SDG 5 was the highest, whereas that of SDG 13 remained unchanged. In addition, 81% of indicators showed acceptable progress. This study provides a reference for sustainable development planning in other typical demonstration areas and underdeveloped mountainous areas in China and worldwide.

The Diurnal Cycle of Precipitation (DCP) is the result of various dynamic and thermodynamic processes in the climate system and is closely related to the water cycle and land-atmosphere interactions. In North China, the DCP is influenced by factors such as valley wind circulation, boundary layer inertial oscillations, and sea-land breeze circulation, exhibiting two peaks during the early morning and afternoon. In addition, the DCP in North China is influenced by anthropogenic aerosol emissions. This study introduces the fundamental characteristics and factors influencing the DCP in North China and summarizes recent research on the connection between the DCP and land-atmosphere coupling in North China, the modeling of the DCP, and the influence of aerosols on the DCP. The existing scientific knowledge is synthesized, and its shortcomings and challenges are outlined. Overall, investigating the DCP and its influencing factors can help us better understand the mechanisms of precipitation formation and evolution. This provides scientific support for enhancing the accuracy of fine-scale precipitation forecasting.

Climate extremes threaten human health, economic stability, and the safety of both natural and built environments. Compound extreme events are combinations of multiple climate drivers and/or hazards that contribute to societal or environmental risks, and their impacts on human society and natural ecosystems are often more serious and destructive than those of a single extreme event. Understanding the changes in compound extreme events is important for adaptation, mitigation strategies, and disaster risk management. Here, the definitions and connotations of compound extreme events are briefly discussed, including preconditioned, multivariate, temporal, and spatial compounding events. Subsequently, the progress in compound extreme event research is discussed in terms of temporal and spatial evolution characteristics, influencing factors, and future scenario projections. Given the problems in current research, we suggest that future studies should focus on studying compound extreme events regarding variable/index selection and threshold determination, dependence and interaction analysis among drivers and/or hazards, simulation performance evaluation and future projections, and their dynamic processes and disaster-causing mechanisms. Compound extreme events are expected to increase in frequency and intensity in a warming world, and many regions are projected to experience an increase in the probability of compound events with greater global warming. Therefore, we must improve our understanding of the causes and drivers of compound and cascade events.

The Northwest region of China is a major battlefield and an important ecological and environmental security barrier to China’s western development. Flourishing the Belt and Road Initiative, climate change in this region has a direct impact on water resources, ecology, and environmental security. In the context of global climate change, Northwest China has shown an obvious and rapidly developing warming-wetting trend, which has resulted in increasingly prominent environmental and public security risks that are seriously affecting the sustainable development of the regional economy and society. This poses new challenges for climate change responses, water resource management, and disaster prevention and mitigation in this region. Research on the evolution characteristics, causes, and physical mechanisms of warming-wetting as well as its future trends and possible risks were reviewed. It further summarizes the current scientific consensus and existing problems, and finally looks forward to the key directions of future scientific research. A systematic review of the trend, causes, and future projection of climate warming-wetting in Northwest China will have important scientific implications for further research on this issue.

Data-driven methods with deep learning as their core have been gradually applied in Earth science; however, challenges remain regarding the interpretability of models and physical consistency. With the background of remote sensing big data, combining deep learning and data assimilation methods to develop new techniques for the simulation and prediction of terrestrial water cycle processes has become an important research direction in Earth science. Τhe progress in deep learning in recent years combines improving the quality of observation data of terrestrial water cycle components and reducing the uncertainty of physical models. Furthermore, the key scientific issues regarding data assimilation in terrestrial hydrology based on deep learning fusing remote sensing big data are classified according to the observations, physical models, and system integration: \mathrm{①} How can the temporal and spatial representativeness of samples be enhanced when deep learning inverts remote sensing products? \mathrm{②} How can a new physics-guided deep learning method be developed within the framework of data assimilation? \mathrm{③} How can the predictability of the terrestrial water cycle be improved through the “data-model” dual drive? Relevant research and exploration should help promote the in-depth application of the “data-model” hybrid modeling method in the field of hydrology and improve the simulation and prediction capacity of the terrestrial water cycle process.

From 2015 to 2017, the Western Cape province in South Africa suffered a severe drought, resulting in an extreme shortage of water resources in the city, making its capital, Cape Town, the first modern city in human history to face the threat of a “Day Zero” disaster (i.e., the day when the city’s water taps are turned off). However, the interaction mechanisms and processes of various disaster-causing factors remain unclear, and how to scientifically cope with the natural precipitation variation mode by man-made water-supply management needs to be further explored. Therefore, this paper explores the key stages, spatial distribution, and management benefits from the three dimensions of meteorological drought, hydrological drought, and urban water supply management. The results show the following: \mathrm{①} The Western Cape experienced a significant increase in the area and intensity of meteorological drought from 2015 to 2017, with the most severe drought conditions occurring in May 2017. Compared with the Standardized Precipitation Index (SPI), the drought detected by Standardized Precipitation Evapotranspiration Index (SPEI) was more significant. \mathrm{②} The hydrological drought conditions in the Western Cape in May 2017 were the most severe. This is broadly consistent with the pattern of spatial and temporal characteristics of meteorological drought, reflecting the rapid spread of meteorological-hydrological drought. Both the Standardized Runoff Index (SRI) results and the change in reservoir water volume reflect water scarcity in the region, indicating that the drought event had a serious impact on the Western Cape, which relies heavily on rainfall and reservoir water supply. \mathrm{③} The Western Cape government adopted different levels of water restrictions and management policies in response to the evolution of this drought, effectively delaying and avoiding a “Day Zero” disaster; however, addressing the political and economic aspects of water inequality is still debatable and worth improving. This paper shows that urban drought problems involve multiple systems and interactions among the meteorology, hydrology, and water supply, and need to be monitored, understood, and mitigated in terms of the spatial and temporal processes.

Heavy metal migration and enrichment in areas affected by mining and smelting cause severe soil contamination. A thorough understanding of the sources and migration of heavy metals in the soil is the scientific basis for the efficient treatment of soil pollution. In recent years, metal stable isotopes have shown great advantages in identifying sources of soil heavy metal contamination and analyzing heavy metal migration processes, thus acting as powerful tools to trace the environmental behavior of heavy metals. In this paper, we reviewed the analysis technology, tracing principles, and tracing models of metal stable isotopes, determined the isotope fractionations caused by mineral mining and smelting processes (high-temperature smelting, electrochemical processes, and tailing weathering), and discussed the representative applications of metal stable isotopes in the traceability of soil pollution in mining- and smelting-affected areas. The V isotope system is in the initial stages of investigation, and its applications in heavy metal soil source analysis are relatively lacking. Zn, Cd, and Hg isotopes are advantageous for identifying heavy metal contamination sources associated with high-temperature smelting processes. Cu, Tl, and Ni isotopes can directly indicate the ore content of the soil. However, some problems remain, such as the difficulty in analyzing certain systems of metallic stable isotopes, limitations in the application of tracer models, and source uncertainties due to isotope fractionation. Therefore, in the future, it will be necessary to further explore and optimize metal isotope analysis methods, establish more metal stable isotope fingerprints, develop traceability models with stronger applicability and more accurate results, comprehend the characteristics and mechanisms of isotope fractionation in complex interfacial processes and reactions, and strengthen the practical application of metal stable isotopes to trace the history of soil heavy metal pollution.

The inconsistency between the supply and demand of lithium carbonate is becoming increasingly serious. Scientific prediction of the future lithium carbonate demand is of great significance for China’s lithium resource production, import and export arrangements, and national energy policy formulation. Based on a combined model of grey correlation analysis and the ARIMA-GM-BP neural network, data on the driving variables of China’s per capita GDP, industrial structure, urbanization level, grease production, ceramic production, glass production, air conditioning production, lithium-ion battery production, and new energy vehicle production in 2002-2021 were selected to predict China’s lithium carbonate resource demand between 2025 and 2035. The results show that the selected driving variables are highly correlated with China's lithium carbonate resource demand, and the combined model is more accurate than a single model. The predicted average quantity demand for lithium carbonate in 2025, 2030, and 2035 is 0.42 million tons, 0.69 million tons, and 1.03 million tons, respectively. Accordingly, some policy suggestions have been proposed.

Lakes play an essential role in the evolution of regional water cycles and ecosystems. In previous studies on lake evolution, most lake sediment proxy indicators have been used to reconstruct lake and climate change processes. However, there is a lack of quantitative research on the lake water cycle characteristics. Based on the water balance model for watersheds and lakes in distinct periods and the lake energy balance model based on the simulation of the transient climate, water balance calculations and lake evolution simulations for six typical lakes in the Qinghai-Tibet Plateau and its surrounding areas were carried out in this study. The results showed that the precipitation and evaporation variabilities in Xiao Qaidam Lake and Lop Nur were relatively small during the Holocene. The precipitation and evaporation variabilities in Selinco and Namco were relatively large during the early-middle Holocene, mainly controlled by temperature and net radiation changes. The precipitation and evaporation variabilities in Qinghai Lake and Zhuyeze were close during the early and mid-late Holocene. This study systematically analyzed and calculated the evolution of lake water cycle elements in different climatic regions of the Qinghai-Tibet Plateau during the Holocene, which will help to understand the paleoclimatic mechanism of lake evolution in this region.

The aim of this study is to scientifically implement water diversion projects and effectively provide water security for high-quality development and environmental protection. The research progress of water diversion projects is reviewed in terms of industry standards, specifications, and related studies. It was found that water demand prediction tends to be overly high, the integrity of comprehensive benefit evaluation needs to be improved, the standard of ecological compensation mechanism remains incomplete, and post-evaluation and tracking work is insufficient. To support the spatial equilibrium of water resource allocation and the construction of national water networks, future water diversion projects need to strengthen environmental protection and whole-stage follow-up evaluation, perform full cost pricing, perfect the investment and financing system, and improve information and intelligent management.

The upper Yellow River is the most important water conservation area as well as the runoff and confluence area in the Yellow River Basin, and accounts for more than half of the runoff of the entire basin. Therefore, it is of great significance to the ecological protection, water resource security, and food security of the entire Yellow River Basin. Scientifically understanding the change characteristics of natural environmental factors and deeply exploring the coordination problem of natural environmental factors can promote ecological protection and high-quality development of the Yellow River Basin. Based on the macro understanding of the six important characteristics of natural environmental elements, such as climate, hydrology, and ecology, in the upper Yellow River under the background of global warming and the implementation of national ecological protection projects and water resource management policies, this study describes the natural disharmony among hydrology, soil, climate, and ecology in the upper Yellow River. Moreover, from the perspective of the coordination of natural environmental elements, this study puts forward five scientific ideas on how to eliminate the traditional thinking and misunderstanding of ecology and development problems in the upper Yellow River, as well as six scientific suggestions on how to build an ecological protection and high-quality development model with regional characteristics. This study has important guiding significance for the promotion of ecological protection and high-quality development of the upper Yellow River.

Severe convective weather systems often cause rainstorms, lightning, gales, hail, and other disasters owing to their small spatial scale and rapid and violent development. Accurate forecasting has always been a difficult and bottleneck problem in the international meteorological field, and it is the focus of disaster prevention and mitigation in Shanghai. This research introduces key technologies developed by the Shanghai Meteorological Department in recent years, such as self-adaptive networking observation of strong convection targets, intelligent identification and prediction of strong convection abrupt structural features, machine learning correction of numerical prediction errors, and system integration. Based on this, an intelligent monitoring and early warning system that can simulate the three-dimensional structure and evolution of a strong convective system is established and applied, which has significantly improved the early warning capability fo severe convection in Shanghai. Relevant technical achievements have provided support for major services such as the China International Import Expo (CIIE) and have been promoted for application in urban disaster prevention and mitigation.

The ecologically fragile region in China and Mongolia is among the regions with the largest distribution area, the largest type of fragile ecology, and the most evident ecological vulnerability. The ecological environment condition in the ecologically fragile areas of China and Mongolia restricts the sustainable development of regional ecology and social economy, and is crucial to the ecological security of China and Mongolia. Thus, it is urgently necessary to thoroughly explore the characteristics of ecologically fragile ecosystems in China and Mongolia and their response mechanisms to global changes, which can provide a scientific basis for regional ecological environmental restoration. Based on the carbon and nitrogen cycles of fragile ecosystems affected by global change, this study presents and summarizes the following key research topics: fragile ecosystem carbon and nitrogen cycles and coupling mechanisms, the influence of global change on fragile ecosystems, fragile ecosystem safety threshold identification and risk assessment under the background of global change, and the adaptive management of fragile ecosystems to global change. In view of the national major needs of ecological safety, researches in the following aspects are urgently needed: analyzing the annual, seasonal, and diurnal characteristics of nitrogen turnover pathways, transformation form, and flux in water-soil-gas-biomass systematically to reveal the carbon and nitrogen cycling process, spatio-temporal law, and coupling mechanism of fragile ecosystems and determine the primary mechanism of the carbon and nitrogen sink function in fragile ecosystems. Building a carbon and nitrogen coupling model in fragile ecosystems, quantifying the influence strength of different intensities of climate change on fragile ecosystem safety and the influence of human disturbance on the carbon and nitrogen cycle and its ecological system, assessing the effect of fragile ecological systems on the carbon and nitrogen cycle in the Earth system and its carbon and nitrogen source-sink effect, and proposing management countermeasures and measures of fragile ecosystems to global change.

Mesoscale eddies play an important role in phenomena such as general circulation, momentum budgets, ocean water mass distribution, and water and nutrient transport. Based on the vertical structure of the density and current core, mesoscale eddies are classified into two categories: surface- and subsurface-intensified. The utilization of remote sensing has provided considerable information on surface-intensified eddies. However, little is known about subsurface eddies due to the lack of in-situ observations, although they have been found occasionally in the global ocean. Currently, subsurface eddies are a trending topic within the scientific community. This study reviews the scientific background and research progress on subsurface eddies, with a focus on the northwestern Pacific Ocean. The vertical structure, evolutionary process, and possible formation mechanism of subsurface eddies are summarized based on observational and modelling results. Their influence on marine biogeochemistry, marine sound propagation, and possible important scientific issues are also discussed.

Cretaceous Oceanic Anoxic Events (OAEs) have recorded significant changes in the climatic and paleoceanographic states of the planet and represent major carbon cycle perturbations. In the past two decades, analytical techniques for stable metal isotopes, such as molybdenum, zinc, uranium, chromium, cadmium, and calcium isotopes, have been developed to study OAEs. By systematically summarizing the geochemical characteristics of molybdenum isotopes (δ⁹⁸Mo), zinc isotopes (δ⁶⁶Zn), and uranium isotopes (δ²³⁸U), and research advances on Cretaceous OAEs, we found that molybdenum isotopes mainly reflect the transformation between sulfide and non-sulfide in the regional marine environment during OAEs. Zinc isotopes can reflect different responses of regional marine environments to different processes, such as primary productivity, continental weathering, and sediment burial/decomposition. Uranium isotopes can be used to estimate the global extent of seafloor euxinia. The coupled global C-P-U cycle model can simulate the response mechanism of the global ocean to different processes, such as the formation of large igneous provinces, continental weathering, and biological activities. However, the cyclic fractionation mechanism of these isotopes in marine systems is still in progress, and most research has only focused on the deposition record of OAE2. In the future, it will be necessary to conduct more systematic research on OAEs.

The atmospheric boundary layer connects the land surface to the atmosphere through the turbulent exchange of heat, momentum, and trace gases. In addition, it plays an important role in the formation and evolution of weather and climate. The characteristics and formation mechanisms of the deep atmospheric boundary layer have been key focus areas in atmospheric boundary layer research. Focusing on extremely arid regions and special geographical locations, the observational facts and influencing factors of the deep atmospheric boundary layer were reviewed and summarized. Furthermore, a physical description of turbulent motion in the development of the deep atmospheric boundary layer was provided. Using the Taklimakan Desert as an example, the effects of the interactions between the deep atmospheric boundary layer and dust stagnation on weather and climate were discussed. In order to provide a roadmap for future research, this study identified and outlined four key scientific problems related to deep atmospheric boundary layer research.