Mount Everest was once a pristine environment. However, due to increased tourism, waste is accumulating on the mountain, with a large proportion being made of plastic. This research aimed to identify ...and characterize microplastic (MP) pollution near the top of highest mountain on Earth and could illustrate the implications for the environment and the people living below. Stream water and snow were collected from multiple locations leading up to, and including, the Balcony (8,440 m.a.s.l). MPs were detected at an ~30 MP L−1 in snow and ~1 MP L−1 in stream water, and the majority were fibrous. Therefore, with increased tourism, deposition of MP near Mt. Everest is expected to rise. At a pivotal point in the exploration of remote areas, environmental stewardship should focus on technological and other advances toward minimizing sources of MP pollution.
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•Microplastics were found in snow and stream water samples on Mt. Everest•The highest microplastics were discovered in a sample from 8,440 m.a.s.l.•Most microplastics were polyester fibers, likely from clothing and equipment•Technological advances could minimize microplastic pollution from exploration
Plastic pollution is a key issue of our time, with the environmental impacts of this remarkable material increasingly the focus of interventions ranging from grassroots clean-up initiatives to product re-design and international policies. In this paper, we provide the first documentation of the likely presence of microplastics in snow and stream water on Mt. Everest, including near regions of high human presence, such as near climbing paths. These tiny plastic pieces (<5 mm) were mainly polyester fibers, likely coming from climber’s clothing and equipment. These findings highlight human impacts in Earth’s remotest areas, partly through the act of exploration of extreme environments. This creates a challenge and opportunity for manufacturers of performance clothing and equipment to develop designs that use more sustainable materials that are either natural or minimize shedding of microplastics. Climbers and trekkers should consider the full impact of exploration activities on the environment.
An analysis of snow and stream water on Mt. Everest up to 8,440 m.a.s.l. found microplastics (<5 mm) that were more concentrated near high human presence. Most of these microplastics were polyester fibers, likely to come from clothing and equipment. Exploration of extreme, remote environments requires appropriate stewardship, including progressing technological advances in gear design and minimising specific sources of plastic pollution.
On February 20, 1963, a team of nineteen Americans embarked on the first expedition that would combine high-altitude climbing with scientific research. The primary objective of the six scientists on ...the team-who procured funding by appealing to the military and political applications of their work-was to study how severe stress at high altitudes affected human behavior. The expedition would land the first American on the summit of Mount Everest nearly three years after a successful (though widely disputed) Chinese ascent. At the height of the Cold War, this struggle for the Himalaya turned Everest into both a contested political space and a remote, unpredictable laboratory. The US expedition promised to resurrect American heroism, embodied in a show of physical strength and skill that, when combined with scientific expertise, would dominate international rivals on the frontiers of territorial exploration. It propelled mountaineers, scientists, and their test subjects 29,029 feet above sea level, the highest point of Chinese-occupied Tibet. There they faced hostile conditions that challenged and ultimately compromised standard research protocols, yielding results that were too exceptional to be generalized to other environments. With this book, Philip W. Clements offers a nuanced exploration of the impact of extremity on the production of scientific knowledge and the role of masculinity and nationalism in scientific inquiry.
Mt. Everest, one of the most coveted climbing mountains on earth, also contains the highest altitude chemical contamination on land. For the first time, meltwater and snow samples from Mt. Everest's ...Khumbu Glacier were analyzed for “forever chemicals” per- and polyfluoroalkyl substances (PFAS). Our research team utilized solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify pollutants sampled from Everest Base Camp, Camp 1, Camp 2, and Everest Balcony. From the 14 PFAS compounds tested for, we found perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexanoic acid (PFHxA) in Mt. Everest snow and meltwater. The highest concentrations found were 26.14 ng/L and 10.34 ng/L PFOS at Base Camp and Camp 2, respectively. However, PFAS species were seen within 1–2 orders of magnitude in all sampling sites with detection, potentially suggesting a widespread presence on the mountain. Our samples are the highest altitude PFAS samples ever retrieved and indicate the need for further sampling both on Mt. Everest and in the below-glacier watershed.
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•For the first time, PFAS were found in snow and meltwater on Mt. Everest from below the Base Camp to the Balcony.•Samples from the Base Camp to the Summit are the first to characterize chemical deposition on the mountain.•Combined atmospheric and local direct deposition elevate concentrations above other alpine regions.•Human pollution impacts on Mt. Everest are both visible and chemical.
Mt. Everest (Qomolangma or Sagarmatha), the highest mount on Earth and located in the central Himalayas between China and Nepal, is characterized by highly concentrated glaciers and diverse ...landscapes, and is considered to be one of the most sensitive area to climate change. In this paper, we comprehensively synthesized the climate and environmental changes in the Mt. Everest region, including changes in air temperature, precipitation, glaciers and glacial lakes, atmospheric environment, river and lake water quality, and vegetation phenology. Historical temperature reconstruction from ice cores and tree rings revealed the distinct features of 20th century warming in the Mt. Everest region. Meteorological observations further proved that the Mt. Everest region has been experiencing significant warming (approximately 0.33 °C/decade) but relatively stable precipitation during 1961−2018 AD. Projected results (during 2006−2099 AD) under different representative concentration pathway scenarios showed a general warming trend in the region, with larger warming occurring in winter than in summer. Meanwhile, the precipitation projections varied spatially with no significant trends over the region. Intensive glacier shrinkage was characterized by decreasing glacier areas, while glacier-fed river runoff increased. Glacial lakes expanded with increasing glacial lake areas and numbers. These findings indicated a clear regional hydrological response to climate warming. Owing to the remote location of Mt. Everest, the present atmospheric environment remained relatively clean; however, long-range transport of atmospheric pollutants from South Asia and West Asia may have substantially influenced the Mt. Everest region, resulting in increasing concentrations of pollutants since the Industrial Revolution. Anthropogenic activities have been shown to influence river and lake water quality in this remote region, especially in the downstream. The end of the vegetation growing season advanced in the northern slope and did not change in southern slope region of the Mt. Everest, and there was no significant change in start date of the growing season in the region. This review will enhance our understanding of climate and environmental changes in the Mt. Everest region under global warming.
•Climate and environmental changes were synthesized in the Mt. Everest region.•Glaciers have retreated significantly, posing impacts to river runoff and glacial lakes.•Transboundary transport of atmospheric pollutants influenced the region.•TThere was no significant change in start date of the growing season.
Reduction of ice masses concerning global warming is significantly changing geomorphology in high mountains. Formation of supraglacial lakes is one of such essential indications. Therefore, in the ...present study, we attempted to understand regional morphodynamics of supraglacial lakes, distributed in 17 glaciers within the Everest Himalaya. An average of 0.08 km2/yr lake expansion rate was noticed during the studied year. Decadal (2010–2019) lake morphodynamic study using high resolution satellite images revealed that only 161 out of total 2424 lakes were static, and mostly concentrated at the lower part of the ablation area with an alarming rate of surface area increase. We also found appearance of new cluster of lakes at higher elevations. We collected here statistical evidences of regional morphodynamics and key controlling factors to stabilize lakes. The parameters, viz., spatio-temporal distribution of lakes, their domain wise variation, multi-temporal (Seasonal to long-term) changes, lake density, and stability index were estimated and mapped. Finally, we concluded that new lake formations at higher elevation were triggered by gradual increase in temperature, decrease in glacier surface velocity, slope and ice thickness. The feature selection techniques indicated ice thickness as prior controlling factor followed by the surface velocity and slope to stabilize lakes at the lower part of ablation.
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•Higher resolution GeoEye images were used for the supraglacial lake dynamics study.•The constant and coalensing of supraglacial lakes were concentrated at the lower part of the ablation area.•Supraglacial lake dynamics were correlated with the glacier change.•Constant supraglacial lake and its change were monitored using feature selection techniques.
Many Himalayan glaciers are characterised in their lower reaches by a rock debris layer. This debris insulates the glacier surface from atmospheric warming and complicates the response to climate ...change compared to glaciers with clean-ice surfaces. Debris-covered glaciers can persist well below the altitude that would be sustainable for clean-ice glaciers, resulting in much longer timescales of mass loss and meltwater production. The properties and evolution of supraglacial debris present a considerable challenge to understanding future glacier change. Existing approaches to predicting variations in glacier volume and meltwater production rely on numerical models that represent the processes governing glaciers with clean-ice surfaces, and yield conflicting results. We developed a numerical model that couples the flow of ice and debris and includes important feedbacks between debris accumulation and glacier mass balance. To investigate the impact of debris transport on the response of a glacier to recent and future climate change, we applied this model to a large debris-covered Himalayan glacier—Khumbu Glacier in Nepal. Our results demonstrate that supraglacial debris prolongs the response of the glacier to warming and causes lowering of the glacier surface in situ, concealing the magnitude of mass loss when compared with estimates based on glacierised area. Since the Little Ice Age, Khumbu Glacier has lost 34% of its volume while its area has reduced by only 6%. We predict a decrease in glacier volume of 8–10% by AD2100, accompanied by dynamic and physical detachment of the debris-covered tongue from the active glacier within the next 150 yr. This detachment will accelerate rates of glacier decay, and similar changes are likely for other debris-covered glaciers in the Himalaya.
•Debris-covered glaciers show a differing response to climate change to clean-ice glaciers.•Many glaciers in the Himalaya are debris-covered, particularly in the Everest region.•We present the first dynamic model of debris transport and feedbacks with mass balance.•Debris-covered Khumbu Glacier in Nepal will lose 8–10% volume by AD2100.•The glacier tongue will detach from the active glacier and accelerate glacier decay.
•The overall glacier elevation change was calculated based on DEMs.•The debris-covered ice thinned much more rapidly than the exposed ice.•Surface lowering rates varied significantly with glaciers ...and altitudes.•Glacier imbalance constitutes 40% of the Rongbuk runoff.•A continuous rising trend of air temperature explains glacier melting.
Elevation changes of glacier surfaces were investigated in Rongbuk Catchment (RC) on the northern slopes of Mt. Qomolangma in the central Himalayas, by comparing a digital elevation model (DEM) generated from the 2006 ALOS/PRISM imageries with the base DEM1974 derived from the 1:50,000 topographic maps. The average elevation change rate of glacier surfaces in RC was estimated at −0.47±0.23ma−1 between 1974 and 2006. Such surface lowering rates varied significantly with glaciers and altitudes. One of the notable results is that the debris-covered ice thinned much more rapidly than the exposed ice at higher altitudes. Overall, glaciers in RC have lost mass of −0.06±0.04Gta−1 during 1974–2006. Glacier imbalance constitutes about 50% or more of the Rongbuk runoff.
•UHT metamorphism is reported for the first time in the Himalaya.•The heat source was an over-thickened crust associated with lithospheric thinning.•Cold vs. granulitized eclogites formed during ...infant vs. mature collisional stages.•2.0–1.8 Ga eclogites have formed by a Himalaya-type global collisional network.
Modern-style plate tectonics, often characterised by subduction, is a fundamental dynamic process for planet Earth. Subduction related eclogites are widely used to indicate initiation of plate tectonics or whether different tectonic regimes dominated Earth history. However, such markers are commonly overprinted in ancient metamorphic terranes and rarely preserved even in most Phanerozoic mountain belts. This study tries to reveal the detailed burial and exhumation processes that formed granulitized eclogites in the Everest east region, central Himalaya, so as to explore the tectonic regimes recorded by similar rocks on early Earth. Robust Pressure-Temperature-time paths were achieved by studying the mineral relicts (Omp, Jd ∼29%), high-temperature mineral textures (Sil-Crd-Qz-Spl-Mesoperthite assemblage, rutile exsolution in biotite), and multiple thermobarometry and petrochronology of eclogites and metapelites. Results show that these eclogites underwent eclogitization at conditions of 730–770°C and ∼20 kbar (∼11°C/km) at ∼30 Ma and were overprinted by a heating and decompression path to ultrahigh temperature (UHT) conditions of 6–11 kbar and 900–970°C (∼40°C/km) during 25–15 Ma. The resulting exhumation rate (2–3 mm/yr) is slow and prolonged (10–15 Myr) (U)HT favoured re-equilibration of the eclogitic mineral assemblage and textures. The obtained UHT conditions, the first time ever reported for the Himalaya, were induced by combined effects of over-thickened (∼60 km) radioactive felsic crust and thinning of lithosphere to <90 km. This case study provides a critical example to understand the heat sources and timescale of UHT condition during continental collision. By comparing with the western Himalaya eclogites, we suggest that formation of cold vs. granulitized continental eclogites during the Himalayan orogeny is caused by different crustal thickness (normal ∼30 km vs. over-thickened ∼60 km) due to different collisional stages (infant vs. mature). In a wider perspective, ancient eclogites were commonly granulitized by stacking into the over-thickened orogenic crust during mature continental collision. According to similar granulitized eclogites preserved on early Earth, Himalaya-type continental subduction/collision should have become a global pattern during the Paleoproterozoic (2.0–1.8 Ga).
In areas of high relief, many glaciers have extensive covers of supraglacial debris in their ablation zones, which alters both rates and spatial patterns of melting, with important consequences for ...glacier response to climate change. Wastage of debris-covered glaciers can be associated with the formation of large moraine-dammed lakes, posing risk of glacier lake outburst floods (GLOFs). In this paper, we use observations of glaciers in the Mount Everest region to present an integrated view of debris-covered glacier response to climate change, which helps provide a long-term perspective on evolving GLOF risks.
In recent decades, debris-covered glaciers in the Everest region have been losing mass at a mean rate of ~0.32myr−1, although in most cases there has been little or no change in terminus position. Mass loss occurs by 4 main processes: (1) melting of clean ice close to glacier ELAs; (2) melting beneath surface debris; (3) melting of ice cliffs and calving around the margins of supraglacial ponds; and (4) calving into deep proglacial lakes. Modelling of processes (1) and (2) shows that Everest-region glaciers typically have an inverted ablation gradient in their lower reaches, due to the effects of a down-glacier increase in debris thickness. Mass loss is therefore focused in the mid parts of glacier ablation zones, causing localised surface lowering and a reduction in downglacier surface gradient, which in turn reduce driving stress and glacier velocity, so the lower ablation zones of many glaciers are now stagnant. Model results also indicate that increased summer temperatures have raised the altitude of the rain–snow transition during the summer monsoon period, reducing snow accumulation and ice flux to lower elevations.
As downwasting proceeds, formerly efficient supraglacial and englacial drainage networks are broken up, and supraglacial lakes form in hollows on the glacier surface. Ablation rates around supraglacial lakes are typically one or two orders of magnitude greater than sub-debris melt rates, so extensive lake formation accelerates overall rates of ice loss. Most supraglacial lakes are ‘perched’ above hydrological base level, and are susceptible to drainage if they become connected to the englacial drainage system. Speleological surveys of conduits show that large englacial voids can be created by drainage of warm lake waters along pre-existing weaknesses in the ice. Roof collapses can open these voids up to the surface, and commonly provide the nuclei of new lakes. Thus, by influencing both lake drainage and formation, englacial conduits exert a strong control on surface ablation rates.
An important threshold is crossed when downwasting glacier surfaces intersect the hydrological base level of the glacier. Base-level lakes formed behind intact moraine dams can grow monotonically, and in some cases can pose serious GLOF hazards. Glacier termini can evolve in different ways in response to the same climatic forcing, so that potentially hazardous lakes will form in some situations but not others. Additionally, the probability of a flood is not simply a function of lake volume, but depends on the geometry and structure of the dam, and possible trigger mechanisms such as ice- or rockfalls into the lake. Satellite-based measurements of glacier surface gradient and ice velocities allow probable future locations of base-level lakes to be identified. A base-level lake has begun to grow rapidly on Ngozumpa Glacier west of Mount Everest, and could attain a volume of ~108m3 within the next 2 or 3 decades. Unless mitigation efforts are undertaken, this lake could pose considerable GLOF hazard potential.
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