EverDrill: Accessing the interior and bed of a Himalayan debris-covered glacier to forecast future mass loss

The Hindu-Kush Himalaya is a region that is commonly known as the 'third pole' given the volume of glacier ice that is stored in the mountains - more than anywhere on earth outside the Arctic and Antarctic. Crucially, many millions of people living in the foothills and further downstream rely on the meltwater from these glaciers for their daily drinking, sanitation and irrigation needs. The region as a whole is known to be extremely sensitive to climate change, and the speed at which warming is taking place is greatest at high-elevation - where the glacier ice is located. It is still largely unknown, however, how climate is likely to change across the region in the future, and the impact this will have on melting glacier ice and those that rely on it in their everyday lives.

It is difficult to predict the impacts of future climate change in the region, because we know so little about the glaciers other than what we can measure at the surface. Many glacier models that are designed to predict glacier evolution therefore assume many of the parameters that are unknown, but these parameters are also very important to their functioning - for example the temperature of the ice, the thickness of the ice, and the existence or otherwise of sediment at the ice-bedrock interface. In this project we aim to collect real measurements of these subsurface properties and thus make much more robust predictions of how these glaciers may chance with climate.

We will drill six boreholes at four locations into the Khumbu Glacier, Nepal, which descends from Mount Everest and is one of the largest in the Himalayan region. It is debris-covered for its lowermost eight kilometres but pocked with clean-ice exposures that we can exploit with a hot-water drill. We will gather visual footage of each borehole interior and install a multi-sensor array at the bed at each of the four locations. The arrays will log water pressure, temperature, electrical conductivity and turbidity and how each of these parameters changes through the seasons. At two additional boreholes we will install englacial temperature and tilt strings to determine the thermal and deformation profiles of the glacier.

Existing glacier models are poorly tested to their sensitivity of variability in the input data. It is important to know how the model responds to small changes in the predicted climate for example, compared with small changes in basal water pressure or temperature. These sensitivity tests tell us about the uncertainty in our predictions as well as how the whole climate-glacier system works. We aim to test the sensitivity of the glacier model that we are using to a range of different parameters by adjusting them individually and analysing the change in prediction in each case. Ultimately, we will include our real-world data in the model and make robust predictions of debris-covered glacier evolution under a warming climate.

This work will inform regional policy makers concerned with future water supply, local humanitarian aid agencies who will work with foothill dwellers in periods of flood and drought, the Intergovernmental Panel on Climate Change (IPCC) which will inform future climate summits on the world stage, and local people who are dependent on glacier runoff for irrigation, hydro-electric power production and sanitation.

This research will yield: the first spatially distributed measurements of englacial structure and temperature, basal dynamics and hydrology for a Himalayan debris-covered glacier, a quantitative assessment of the sensitivity of glacier mass balance and ice flow models to their parameterisation and what this informs us about the processes driving climate-glacier interactions, and robust predictions of Himalayan glacier evolution under a warming climate and the impact of this evolution on glacier meltwater contribution to river flow. These data will be of specific interest to those working in the Himalayan region as well as informative for scientists working in other glacierised mountain regions of the world. Methodological advances from this research will be of interest to the technical climate and cryospheric communities, and field glaciologists will be able to use the principles of our methods in their own applications elsewhere.

The main non-academic beneficiary of the research will be policy makers in Nepal concerned both with securing future water availability and energy production from hydro-electric schemes being fed by glacier melt. Local humanitarian aid agencies will also benefit from the impact of our research, through an enhanced understanding of how continued changes in climate are likely to impact on populations that are, in places, entirely dependent on glacier meltwater runoff for drinking, irrigation and sanitation needs. This will clearly benefit the health of local people, and will reduce the requirements for UK-based organisations such as DFID to fund emergency response activities as a result of unexpected changes in water supply.

Our Nepali project partner will benefit from being exposed to new glaciological field techniques (e.g. hot-water drilling) as well as the transfer and discussion of more general climatological and glaciological knowledge. They will also take ownership of the hot-water drill following our final field season so that they have the capability to carry out related research in future projects. Through their teaching and student supervision this knowledge will be to the benefit of future generations of scientists graduating from Nepali universities in environmental disciplines. Second, our partner will benefit from enhanced profile through joint publications and press releases pertaining to our research outputs as they progress. Third, and most importantly, they will benefit from the findings of our research - enhanced knowledge of glacier-climate interactions that will feed into regional management plans and provision of information to the public.

The attached Pathways to Impact document provides full details of the methods we will employ to maximise the benefits of this research to end users. Briefly, they include a workshop for local stakeholders and authorities in Kathmandu, the provision of information summaries to academic and non-academic organisations in the region, and the publication of all data on a University of Leeds project website for access by the academic community as well as the general public. Such forms of information dissemination can be implemented very quickly, so the timescales for the delivery of end user benefits are short (during the lifetime of the project for some, and within a month of the project termination for the remainder). To ensure the impact of our research continues for some years beyond the lifetime of the project we aim to establish partnerships with both Tribhuvan and Kathmandu Universities to promote knowledge-exchange, capacity-building and potential joint PhD projects and staff exchanges.