Climate warming has impacted the sustainability of freshwater supply in the global water tower unit (WTU) zone. The rainfall infiltration process, a key component of WTUs supply, is affected by freeze-thaw cycles, yet it remains uncertain whether it has undergone corresponding changes. We propose a temperature-mediated infiltration model considering changes in soil water holding, water potential, and hydraulic conductivity due to varying degrees of freezing under negative temperature. Using this model, we calculate the infiltration of 78 WTUs globally from 1980 to 2023. Our results indicate that global WTUs have a multi-year average infiltration of 26 similar to 2359 mm/year. Notably, WTUs in the key latitudinal zone (24 degrees S-42 degrees N) contribute 54 % of the total infiltration volume, showing expanding differences in infiltration characteristics compared to other regions. While rainfall primarily influences infiltration and infiltration capacity, soil temperature and initial soil water content also significantly impact these characteristics. Enhanced infiltration capacity promotes vegetation growth, though the relationship is not linear. Variations in infiltration characteristics threaten the water resource buffering and the stability of downstream living ecological water supply of WTUs. This study provides crucial references for the integrated management of water resources and ecological conservation amid changing infiltration characteristics.

The thermal coupling between the atmosphere and the subsurface on the Qinghai-Tibetan Plateau (QTP) governs permafrost stability, surface energy balance, and ecosystem processes, yet its spatiotemporal dynamics under accelerated warming are poorly understood. This study quantifies soil-atmosphere thermal coupling ((3) at the critical 0.1 m root-zone depth using in-situ data from 99 sites (1980-2020) and a machine learning framework. Results show significantly weaker coupling in permafrost (PF) zones (mean (3 = 0.42) than in seasonal frost (SF) zones (mean (3 = 0.50), confirming the powerful thermal buffering of permafrost. Critically, we find a widespread trend of weakening coupling (decreasing (3) at 66.7 % of sites, a phenomenon most pronounced in SF zones. Our driver analysis reveals that the spatial patterns of (3 are primarily controlled by surface insulation from summer rainfall and soil moisture. The temporal trends, however, are driven by a complex and counter-intuitive interplay. Paradoxically, rapid atmospheric warming is the strongest driver of a strengthening of coupling, likely due to the loss of insulative snow cover, while trends toward wetter conditions drive a weakening of coupling by enhancing surface insulation. Spatially explicit maps derived from our models pinpoint hotspots of accelerated decoupling in the eastern and southern QTP, while also identifying high-elevation PF regions where coupling is strengthening, signaling a loss of protective insulation and increased vulnerability to degradation. These findings highlight a dynamic and non-uniform response of land-atmosphere interactions to climate change, with profound implications for the QTP's cryosphere, hydrology, and ecosystems.

Central and Eastern European geography, shaped by its entanglement of natural and social sciences, provides a distinctive lens for rethinking the unity of the discipline. Its historical and institutional hybridity makes the region particularly well positioned to foster integrative geographical perspectives. The objective of this study was to evaluate the present, post-transitional state of the discipline in Central and Eastern Europe (CEE), to identify its future trajectory and to uncover the significant role of CEE geography in addressing global environmental, social and economic challenges. To facilitate this process, four significant geographical topics have been identified as potentially providing a conducive environment for the partial reintegration of geography. The aforementioned themes encompass a range of topics, including migrations, the green transition, anthropogenic climate change, global tipping points, wetland disturbance, peatland carbon sequestration and cryosphere degradation. Furthermore, we have sought to assess the perspective and significance of geographical unity in addressing global crises that impact human life on Earth. This analysis has enabled the identification of critical issues that necessitate integrated approaches. The necessity for enhanced collaboration between physical and human geography, as well as between nature studies and social and economic explorations, is emphasised. In this regard, it is acknowledged that a more inclusive approach is employed in the field of CEE geography, with contributions from other disciplines such as biology, ecology, physics, sociology and economics being welcomed. These disciplines address processes that span from local to global scales, as well as those that study long-term phenomena, such as history and archaeology. The establishment of robust interdisciplinary networks has the potential to enhance the scientific standing of integrated geography and to strengthen innovative connections between human and physical geography.

Increasing Arctic warming rates drive significant environmental change, including permafrost thaw and new groundwater pathway development, thereby increasing groundwater vulnerability to contaminant transport at the thousands of unremediated sites in the circumpolar north. As a first step in assessing hydrogeological controls of Arctic contaminant transport, this study uses numerical modelling to disentangle the impacts of increasing precipitation and air temperature on groundwater flow within the active layer at a high arctic site (63 degrees 30 ' N). The study uses the numerical model SUTRA 4.0 to simulate groundwater flow and energy transport, including dynamic freeze-thaw processes, across an Arctic hillslope under current and future air temperatures due to climate warming. The model domain represents a two-dimensional hillslope terminating in a lake. Two layers implemented in the model represent unconsolidated glacial till and underlying crystalline bedrock. Four simulation cases are examined based on downscaled CMIP5 projections under the high-emissions business as usual scenario: Baseline Conditions (1981-2010), Near-Projections (2011-2040), Mid-Projections (2041-2070), and Far Projections (2071-2100). Climate projections indicate increasing mean annual air temperatures, reducing annual air temperature amplitude, and increasing precipitation. Further, model results show that groundwater flow dynamics are primarily influenced by the coupling of both increased mean annual temperatures and precipitation, with the consequent deepening and prolonged thawing of the active layer allowing for increased groundwater exfiltration to the lake. Sensitivity analysis identifies overburden permeability, overburden residual liquid freezing temperature, and model base temperature as significant parameters that affect model outcomes. Finally, a variable transmissivity assessment provides new insight into active layer groundwater flows.

Permafrost is a crucial part of the Earth's cryosphere. These millennia-old frozen soils not only are significant carbon reservoirs but also store a variety of chemicals. Accelerated permafrost thaw due to global warming leads to profound consequences such as infrastructure damage, hydrological changes, and, notably, environmental concerns from the release of various chemicals. In this perspective, we metaphorically term long-preserved substances as dormant chemicals that experience an awakening during permafrost thaw. We begin by providing a comprehensive overview and categorization of these chemicals and their potential transformations, utilizing a combination of field observations, laboratory studies, and modeling approaches to assess their environmental impacts. Following this, we put forward several perspectives on how to enhance the scientific understanding of their ensuing environmental impacts in the context of climate change. Ultimately, we advocate for broader research engagement in permafrost exploration and emphasize the need for extensive environmental chemical studies. This will significantly enhance our understanding of the consequences of permafrost thaw and its broader impact on other ecosystems under rapid climate warming.

It is increasingly recognized that light-absorbing impurities (LAI) deposited on snow and ice affect their albedo and facilitate melting processes leading to various feedback loops, such as the ice albedo feedback mechanism. Black carbon (BC) is often considered the most important LAI, but some areas can be more impacted by high dust emissions. Iceland is one of the most important high latitude sources for the Arctic due to high emissions and the volcanic nature of the dust. We studied optical properties of volcanic dust from Iceland and Chile to understand how it interacts with the Sun's radiation and affects areas of deposition as LAI. Optical properties of dust samples were measured at the laboratory of the Finnish Geospatial Research Institute (FGI) using the latest setup of the FGI's goniospectrometer. We found that, depending on the particle size, the albedo of dry volcanic dust on the visible spectrum is as low as 0.03, similar to that of BC, and the albedo decreases with increasing particle size. Wet dust reduces its albedo by 66% compared to dry sample. This supports the comparability of their albedo reducing effects to BC as LAIs, and highlights their significant role in albedo reduction of snow and ice areas. The potential use of the results from our measurements is diverse, including their use as a ground truth reference for Earth Observation and remote sensing studies, estimating climate change over time, as well as measuring other ecological effects caused by changes in atmospheric composition or land cover.

The SCATSAT-1 (Scatterometer Satellite) was launched by ISRO (Indian Space Research Organisation) on September 26, 2016 from the Satish Dhawan Space Centre, Sriharikota, India. With nearly five years of its journey, the Ku-band (13.5 GHz) based SCATSAT-1 made a profound impact on many scientific domains such as ocean-atmosphere dynamics, soil moisture and vegetation dynamics, climate change, hydrology and polar sea-ice and snowmelt studies. As a successor of the Oceansat-2 Scatterometer (OSCAT), the SCATSAT-1 supports the long-term analysis in climate studies, crop yield prediction, and forecasting analysis. In addition, the SCATSAT-1 provides the four different levels of data products at an enhanced resolution to improve the scope of the scatterometer in different applications. Recently the SCATSAT-1 has been explored in many emerging applications apart from oceanography e.g., crop growth, snow cover analysis, jute crop detection and river level estimation with advanced algorithms i.e., machine learning-based classification, information fusion, and super-resolution mapping. Therefore, it is desired to summarise all operational SCATSAT-1 products, applications, and their emerging trends at the global level in the various scientific domains. This paper has summarized the progress made by SCATSAT-1 in different scientific domains since its launch. A meta-analysis has also been conducted in this paper (using the SCOPUS database) to analyse the current research status of SCATSAT-1 in terms of study area targets. This study highlights the features, challenges, and future directions for the scatterometer improvements.

High Mountain Asia (HMA) shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological extremes. The rapid thawing of the HMA cryosphere may alter the magnitude and frequency of nature hazards. We reviewed the influence of climate change on various types of nature hazards in HMA region, including their phenomena, mechanisms and impacts. It reveals that: 1) the occurrences of extreme rainfall, heavy snowfall, and drifting snow hazards are escalating; accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods; 2) due to elevating trigger factors, such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface, the mass flow hazards including bedrock landslide, snow avalanche, ice-rock avalanches or glacier detachment, and debris flow will become more severe; 3) increased active-layer detachment and retrogressive thaw slumps slope failures, thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region; 4) multi-hazards cascading hazard in HMA, such as the glacial lake outburst flood (GLOF) and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume, mobility, and impact force; and 5) enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions, and threat hydropower security and future water shortage. In future, ongoing thawing of HMA will profoundly weaken the multiple-phase material of bedrock, ice, water, and soil, and enhance activities of nature hazards. Compounding and cascading hazards of high magnitude will prevail in HMA. As the glacier runoff overpasses the peak water, low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and severe. Addressing escalating hazards in the HMA region requires tackling scientific challenges, including understanding multiscale evolution and formation mechanism of HMA hazard-prone systems, coupling thermo-hydro-mechanical processes in multi-phase flows, predicting catastrophes arising from extreme weather and climate events, and comprehending how highland hazards propagate to lowlands due to climate change.

Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.

The seasonal movement of the zero-degree isotherm across the Southern Ocean and Antarctic Peninsula drives major changes in the physical and biological processes around maritime Antarctica. These include spatial and temporal shifts in precipitation phase, snow accumulation and melt, thawing and freezing of the active layer of the permafrost, glacier mass balance variations, sea ice mass balance and changes in physiological processes of biodiversity. Here, we characterize the historical seasonal southward movement of the monthly near-surface zero-degree isotherm latitude (ZIL), and quantify the velocity of migration in the context of climate change using climate reanalyses and projections. From 1957 to 2020, the ZIL exhibited a significant southward shift of 16.8 km decade(-1) around Antarctica and of 23.8 km decade(-1) in the Antarctic Peninsula, substantially faster than the global mean velocity of temperature change of 4.2 km decade(-1), with only a small fraction being attributed to the Southern Annular Mode (SAM). CMIP6 models reproduce the trends observed from 1957 to 2014 and predict a further southward migration around Antarctica of 24 +/- 12 km decade(-1) and 50 +/- 19 km decade(-1) under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. The southward migration of the ZIL is expected to have major impacts on the cryosphere, especially on the precipitation phase, snow accumulation and in peripheral glaciers of the Antarctic Peninsula, with more uncertain changes on permafrost, ice sheets and shelves, and sea ice. Longer periods of temperatures above 0 degrees C threshold will extend active biological periods in terrestrial ecosystems and will reduce the extent of oceanic ice cover, changing phenologies as well as areas of productivity in marine ecosystems, especially those located on the sea ice edge.