BASAL-CH4
Ecole polytechnique fédérale de Lausanne - EPFL
Lay summary
Recent research suggested that methane (CH4, a potent greenhouse gas) produced beneath glaciers, may be transported to the margins of the Greenland ice sheet via subglacial drainage systems. This mechanism could represent an overlooked pathway for methane release into the atmosphere.
The hypothesis is based on measurements of dissolved CH4 taken from a proglacial river on Greenland’s west coast. However, in many regions of Greenland, subglacial meltwater from the ice sheet drains directly into the ocean through marine-terminating glacier fjords. In these settings, rapid oxidation of CH4 in the water column may significantly limit the amount that ultimately reaches the atmosphere. As glaciers retreat inland due to climate change, these subglacial drainage systems may increasingly emerge on land, bypassing oceanic oxidation and allowing more methane to escape directly into the atmosphere. This transition could become a significant contributor to rising atmospheric CH4 levels in the future.
To better understand this potential source, we will conduct the first investigation of dissolved CH4 concentrations in subglacial outflows at the base of major fjord outlets in the central-western and northwestern sectors of the Greenland ice sheet, and at the time of maximum basal melt rates (July). Four fjords have been selected based on recent regional basal melt estimates: three are marine-terminated glaciers and one is land-terminating (included for comparison).
Our study will utilize a novel instrument called SubOcean, capable of conducting highly precise in-situ, real-time measurements of dissolved CH4. These measurements will be complemented by additional water properties recorded with a multi-sensor CTD. We will also track the spatial distribution of CH4 concentrations throughout the water column within each fjord to assess the extent of in-situ oxidation by microbial processes.
Details
| Regional focus | Arctic |
| Location | Greenland |
| Funded amount | 80,555 CHF |
| Project dates | 10th May 2025 – 31st August 2025 |
| Category | SPI Forel Grants |