Mount Everest – Earth’s highest mountain, behemoth of the Hindu Kush Himalaya (HKH) – is a reminder of humanity’s subordination to the elemental forces of Earth’s systems. After all, it took us nine attempts to successfully ascend its 8,848 meters. At the outer edges of human endurance, thousands of mountaineers are now inspired to replicate that first feat every year, pitting themselves against the most hostile and unforgiving of Earth’s environments. But as visitor numbers have reached annual highs of more than 45,000, we humans now exercise far more power over the mountain than days of old.
The blessing of ‘Chomolungma’ – the Buddhist Sherpa name for the deified mountain – is said to have granted Nepali Tenzing Norgay and New Zealander Sir Edmund Hillary access to the summit in 1953. Permissions, since then, have ceded to the Nepali tourist board. In 2019, 772 climbing permits were issued in Nepal. Some 660 climbers reached the summit. Vast contributions have been made to the local economy – but it’s not without a cost. The mountain has accumulated old tents, fixed ropes, oxygen bottles, human waste, tins, glass, paper – even bodies – as visitor numbers have risen.
In February 2020, the Nepali government set out plans to clear 35,000 kg of rubbish from Everest and five other peaks in the HKH. The move drew criticism for its chosen workforce, however: unskilled army members were selected over nimble and experienced local Sherpas. In 2019, following the army’s clearance of 10,000 kg of rubbish, Kami Rita Sherpa told BBC Nepali: ‘They collected garbage from lower altitudes. They should instead mobilise Sherpas to clean up garbage from higher elevations.’
The Sagarmatha Pollution Control Committee, a Buddhist Sherpa-led operation, manage waste throughout the region, educating climbers and visitors on how to prevent pollution in respect of sacred tradition. Preventing waste is no easy feat, however. Expeditions require climbers to spend around two months acclimating to the altitude, during which time individuals are estimated to produce around nine kilograms of rubbish – much of it from life-saving provisions. Sherpas often risk their lives bringing down used oxygen tanks and tents.
Worryingly, new research has found that clean-up efforts will need to become more sophisticated. As part of a new research initiative from National Geographic and Rolex Perpetual Planet, 34 international researchers journeyed to Everest’s summit to address scientific questions about the effects of pollution, climate change and environmental degradation in the HKH. Published as a set of papers in the new journal One Earth, the team report the first documentation of microplastics discovered in snow and stream water in the Everest region.
During an expedition between April and May 2019, the team collected a series of snow, glacial melt water and river samples. Starting from base camp, their efforts stretched to the 8,440-metre elevation of ‘the Balcony’. They found that microplastic over 30 μm is ubiquitous throughout the Everest region, even at the summit. Polyester (56 per cent) was the most abundant polymer found, followed by acrylic (31 per cent), nylon (9 per cent) and polypropylene (5 per cent). They suspect that fibrous microplastics originated from high performance clothing used by climbers. This is likely, they say, given that a single kilogram of polyester clothing can shed up to 2.8 million microplastic fibres per day. The team are calling on performance clothing manufacturers – who make clothes designed to be used in remote and sensitive environments – to engineer materials that limit microplastic fibre shedding.
This is not the first time that microplastics have been recorded in remote environments. Earlier this year, US scientists showed that microplastic particles are ubiquitous throughout remote US conservation areas; 236,000 metric tonnes of microplastic are estimated to be floating on the sea surface; the depths of the Atlantic Ocean, Mediterranean Sea and Indian Ocean are accumulating microplastic that sink into deep-sea sediment.
As the numbers of climbers continue to rise, the authors are concerned that both visible conventional waste and invisible microplastic pollution are likely to contaminate the water tower throughout the HKH. Here, glacial melt water sustains the flow of South Asia’s largest rivers, including the Ganges, Indus and Brahmaputra. Some 230 million people in the catchment areas depend on glacial melt water; within the Khumbu Valley, this source provides 65 per cent of usable water. While the environmental contamination of microplastics is of broad concern for the HKH ecosystem, the potential consequences for human health is an emerging science. Microplastics have shown to ‘bioaccumulate’ in the tissues of marine mammals including dolphins and orcas – the direct effects on human health, however, remain unclear. We can expect that to change: earlier this year, scientists developed a new technique to extract and quantify microplastic contaminants in human tissues, adding a missing component to microplastic contamination research.
With so many reliant on melt water from Everest’s glaciers, scientists are hoping that the discovery of microplastics at the summit will spur public engagement with the region’s plastic pollution problem. ‘Currently, environmental stewardship is focused on reducing, reusing, and recycling larger items of waste,’ they write. ‘Although these actions are necessary and important, it is evident that solutions need to expand into deeper technological and novel advances with focus on microplastics.’
A region under the influence
The environmental contamination of water towers is just one of the effects of climate change and globalisation on the HKH.
As drought intensity and duration increases, more people will come to rely on the contributions of glacial melt water to the Asian water tower. But this lifeline is becoming more susceptible to environmental and climatic change; the Indus has recently been designated the world’s most vulnerable water tower. It’s therefore vital that we have an accurate understanding of how Himalayan glaciers are responding to climate change, and how variations in their mass might affect the contributions of glacial melt water.
To reach this goal, a separate team of scientists working with the National Geographic and Rolex Perpetual Planet expedition generated a time series that measured the changes in ice mass of 79 glaciers surrounding Everest over six decades. They found that Everest’s glaciers have shown a persistent and accelerating loss of ice mass every decade from the 1960s. In that time, Everest’s glaciers have thinned by more than 100 meters. They cite a number of reasons for this: elevated temperatures are causing thinning rates to increase; large proglacial lakes are expanding; and ice losses are occurring at higher elevation rates as higher temperatures have crept up the mountain range.
The team correlate the accelerating ice loss with an average regional temperature increase of up to 1.4 degrees Celsius between 2000 and 2016, relative to the period between 1975 and 2000. With little signs of slowing, the ice loss is likely to continue over the coming decades. The scientists are concerned that the shrinkage of Everest’s glaciers means that the supply of melt water to the Asian water tower will become unsustainable in the future. Glacier researcher and author of the study, Owen King, explains this phenomenon: ‘The amount of meltwater released from glaciers is constant if climatic conditions remain constant. As the temperature rises, glaciers melt more and the runoff contributes more to the water tower.’ Beyond certain temperatures however, each glacier has a ‘tipping point’, he says. ‘At a certain point the glacier would have lost so much mass that the amount of meltwater reaches a peak and then begins to reduce with further temperature increase.’ When this point is reached, researchers conclude that the contributions of glacial meltwater to Asian water towers will become unreliable and restricted.
‘Outside of the monsoon season, local communities rely greatly on that meltwater for everyday use. Further downstream, the meltwater feeds into the large rivers like the Ganges, the Indus and the Brahmaputra. Populations along these rivers continue to increase, but the contribution of the glaciers to the water tower is becoming more unsustainable with climate change,’ says King. Researchers Matthias Huss and Regine Hock used similar data looking at glacial mass loss over time to demonstrate that, under current trajectories of temperature increases, meltwater from the High Mountain Asia glaciers in the Himalayas will peak by around 2050. In fact, they find that peak melt water for the Brahmaputra in the Himalayan interior has already been reached.
Another pressing concern is the increased risk of glacial hazards, which can follow glacial melts. As temperatures rise, meltwater forms more glacial lakes in the valleys, increasing the possibility of glacial outburst floods occurring.
The recent results from Everest’s glaciers confirm the findings of other surveys in the region. One analysis from researchers at the University of Columbia and University of Utah identifies that the HKH has experienced broad-scale ice loss over the past 40 years. Perhaps unsurprisingly, the rate of ice loss has doubled in the 21st century relative to the 20th. This has implications for everyone. The International Panel on Climate Change estimate that mass loss from glaciers contributed more to global sea-level rise than ice sheets between 1993 and 2010.
Responding to the future
The National Geographic and Rolex Perpetual Planet research expedition has further highlighted the vulnerabilities of the Everest region to the effects of climate change and globalisation. With this come important questions about the nature of tourism in the HKH. Queues of climbers shuffling up the north and southeast ridges bring with them prosperity for many local Sherpas and communities, but leave waste and microplastic fibres in their wake. As atmospheric temperatures rise and glacial melts accelerate, both the safety and water supply of HKH communities will add to the region’s environmental concerns. In a sensitive and remote region – where grasslands have declined by 25 per cent, wetlands by five per cent, and where deforestation continues to occur – the Nepali government is facing pressure to forge a more sustainable relationship with the tourists that sustain their economy.
There are signs of progress: the government’s ban of single-use plastic in the HKH came into effect in 2020; its costly deposit system for waste control is regarded as a step in the right direction. Moreover, awareness is building. Studies working in consultation with local people in the Khumbu region reveal their increasing knowledge of environmental changes related to climate change, the impact on their daily lives, and that NGO-driven climate campaigns are offering help and advice for the future. More than three quarters of surveyed people in the Khumbu Valley have already noticed the decrease in the intensity and frequency of snowfalls, and increases in temperature and drought. Fifty one per cent of respondents to one recent survey were ‘alarmed’ about climate change in the HKH. As awareness grows that the tourism industry, which sustains so many local livelihoods, will be impacted by climate change, pressure will mount on the government to enforce a sustainable transition.