Polar Access Fund 2021

The Arctic Ocean plays an important role in the global carbon dioxide (CO2) and methane (CH4) cycles. Atmospheric concentrations of these gases have been rapidly increasing since pre-industrial times leading to warming of the global climate. While seas at high latitudes are a net annual sink of atmospheric CO2, the Arctic Ocean emits CH4. This region has been highly impacted by rising surface temperatures at a rate of about +0.4°C per decade, twice as fast as the global average warming rate. CH4 release and CO2 uptake in the Arctic Ocean are expected to increase but there are still large uncertainties due to complex feedbacks and the lack of field data.

The objective of the expedition is to collect data in and around Baffin Bay to estimate CH4 and CO2 emissions and identify areas as sources and sinks. For this reason, CH4 and CO2 concentrations and their stable carbon isotopes ratio will be measured in the air and surface waters. In addition, meteorological and oceanographic measurements will be carried out to characterise the surface water hydrodynamics that govern gas exchange with the atmosphere. The Arctic Change expedition will be performed on the sailing boat Mauritius in partnership with Fondation Pacifique. The sailboat Mauritius is an ideal platform for these measurements and provides the great opportunity to explore the shallow coastal regions around Baffin Bay with a minimal carbon footprint and contamination of the greenhouse gas measurements.

Increased glacier melt on the Greenland Ice Sheet will most certainly change the way that the glacier erodes its bed and transports sediment under the glacier. A record of sediment discharge
at the Watson River in Greenland exists since 2006 and offers the possibility to understand changes to sediment discharge from the ice sheet, and if the changes are large enough such that the river system captures the signal. This project aims to better understand landscape changes in Greenland by: 1) continuing this record of sediment leaving the ice sheet and being carried by the Watson River; and 2) installing other instruments along the river to better understand the sources of this sediment and the sediment transport processes. During the melt seasons of 2021 and 2022, we will install turbidity meters in select locations to record the amount of sediment leaving the catchment. This record of sediment discharge from the catchment will serve as a means to calibrate numerical models of sediment transport from the glacier and yield initial insights into the landscape changes in the region. This research remains part of a larger project to better understand the processes by which the Greenland Ice Sheet erodes its bed.

Volcanic eruptions are considered key natural drivers for changes in the global climate system, and evidence of these events (volcanic ash and sulphate aerosols) may be preserved in high-resolution archives such as the Greenland ice cores, allowing for reconstructions. Eruptions over the last 2000 years have been well characterised, however, gaps still remain. Notably, a period of increased volcanic activity, attributed to Icelandic volcanic systems, and coincident with short-term warming in the North Atlantic and Arctic regions (Medieval Climatic Anomaly), remains poorly understood. To resolve these complexities, correlations are required between the ice-core records and near-source (proximal) deposits, as this will provide better insight into the nature (magnitude and location) and climatic impacts of these events.

Therefore, within this project we will sample proximal volcanic material from two regions across Iceland and undertake geochemical and sulphur isotope analysis alongside existing ice-core records to 1) pinpoint the source volcano and, 2) determine the quantity of sulphur ejected into the atmosphere by these Icelandic eruptions.

In 1936 and 1939, the first Swiss expeditions to the Himalaya led by geographers and mountaineers explored the Garhwal range in Northern India, drawing the first maps of its glaciers and taking some of the earliest photographs of its high mountains towering above 7000 meters.

More than 80 years later, Himalayan glaciers are undergoing extreme changes caused by anthropogenic increase in global temperatures. In recent decades, scientists have witnessed and measured accelerated glacier thinning and retreat, and accumulation of rock debris on top of the glaciers, due to enhanced melt in several locations in High Mountain Asia.

This bears consequences for water resources as these glaciers provide water to several hundreds of millions of people, and the dwindling of glacier ice will increase the vulnerability of the region to droughts. On the other hand, the development of a supra-glacial debris layer could have a melt-reduction effect on the long-term, as rock debris shields the ice from incoming radiation.

Such measurements of debris expansion and glacier thinning were possible largely thanks to high-quality satellite products with ever-increasing spatial resolution. Using spy-satellite archives, our modern remote sensing datasets on Himalayan glaciers can take us back as far as the mid-1970s for some regions. This constrains our understanding of the evolution of these glaciers and their representation in modern glacio-hydrological models, especially regarding the expansion of supra-glacial debris, which occurs on time-scales of several decades.

This project will attempt to go back further in time to reconstruct more than 80 years of changes across four glaciers in the Garhwal Himalaya of India. To achieve this, we will use the maps produced by the early Swiss explorers and retrace the steps of these expeditions to repeat the photographs they took and quantify the changes that occurred across these debris-covered glaciers using modern photogrammetry techniques.

Glaciers and ice sheets are observed to rapidly change under the current global climate conditions. In Europe this is particular the case for Greenland. Yet, for future projection of glacial developments it is of key importance to provide a long-term, multimillennial perspective on changes of Greenland outlet glaciers and local glaciers. For example, the dating of glacial deposits (e.g. moraines, rock boulders etc.) provide an essential time component to the understanding of glacial retreat.

The project, “Origin and timing of erratic boulders on Disko Island, Greenland” focuses on glacial erratics, material deposited by glaciers that originated at a distance from its present position. Prominent erratics are found on Disko Island in Western Greenland, where pale granite blocks from the mainland rest on the dark basalt of the island. The goal is to identify the time of deposition and the source of these erratic boulders. The deposition ages of these granitic glacial erratic boulders will be determined with cosmogenic nuclide dating. Cosmogenic nuclides predictably form within minerals through the constant bombardment of galactic particles. By measuring the content of specific cosmogenic isotopes (e.g. 10Be), the time of exposure and thus deposition age, can be determined. The origin of the glacial deposits will be traced back by comparing the chemical signature of the erratic boulders with the various basement rocks of the Western Greenland basement.

The results on Disko Island will provide important constraints to determine the thinning and timing of deglaciation of the former ice stream covering Disko Bugt. It will further provide a firm basis for modelling of material transport and ice-flow direction, as well as a minimum age constraint for the rock glaciers that are researched by the RockDynDisko project.