Global synthesis of subglacial lakes and their changing role in a warming climate

Abstract

<p>Subglacial lakes provide habitats for life and can modulate ice flow, basal hydrology, biogeochemical fluxes and geomorphic activity. They have been identified widely beneath the ice sheets of Antarctica and Greenland, and detected beneath the ice caps on Devon Island and Iceland, and beneath small valley glaciers. Past investigations focussed on lakes beneath individual ice masses. A scientific synthesis of different lake populations has not been made, so a unified understanding of the mechanisms controlling subglacial lake formation, dynamics, and interaction with other parts of the Earth system is lacking. Here, we integrate existing, often disparate data into a global database of subglacial lakes, enabling subglacial lake characteristics and dynamics to be classified. We use this assessment to evaluate how subglacial lakes shape microbial ecosystems and influence ice flow, subglacial drainage, sediment transport and biogeochemical fluxes. Through our global perspective, we examine how subglacial lake characteristics and function depend on the hydrologic, dynamic and mass balance regime of the ice mass beneath which they are located. By applying this synoptic understanding and perspective, we propose a conceptual model for how subglacial lakes and their impacts on the broader environment will change in a warming world. </p>

Surface outburst of a subglacial flood from the Greenland Ice Sheet

“…This equates to a mean rate of water discharge of 101 m 3 s −1 during the 10-day period between satellite acquisitions (22 nd July -1 st August 2014); albeit the drainage duration may have been much shorter, and the peak discharge higher. Nevertheless, this mean discharge rate is still approximately 2 orders of magnitude greater than that of an Antarctic subglacial lake of the same volume 43 . This newly identified active subglacial lake represents the largest such event recorded beneath the mainland Greenland Ice Sheet, albeit smaller than the 4×10 8 m 3 subglacial lake drainage under the neighbouring Flade Isblink Ice Cap 35 .…”

Chapter 2: Consequences of climate change for the cryosphere in the Hindu Kush Himalaya

“…Glacial lakes form on the surface of glaciers (generally, debris-covered glaciers) as supraglacial lakes (Miles et al, 2017), behind moraines as proglacial lakes (Carrivick & Tweed, 2013), and beneath glaciers as subglacial lakes or englacial lakes (Livingstone et al, 2022). Some lakes formed during previous glacial recessions since the Little Ice Age from the early 14 th to the mid-19th century but are now completely disconnected from the glacial source (Cook & Quincey, 2015).…”