Warming-driven erosion and sediment transport in cold regions

We synthesized a global inventory of cryosphere degradation-driven increases in erosion and sediment yield, e.g., suspended load, bedload, particulate organic carbon, and riverbank/slope erosion. This inventory includes 76 locations from the high Arctic, European mountains, High Mountain Asia and Andes, and 18 Arctic permafrost-coastal sites, and they were collected from ~80 studies

Variations in sediment yield over the advance and retreat of a calving glacier, Laguna San Rafael, North Patagonian Icefield

Bathymetric and sub-bottom acoustic data were collected in Laguna San Rafael, Chile, to determine sediment yields during the Little Ice Age advance and subsequent retreat of San Rafael Glacier. The sediment volumes and subaqueous landforms imaged are used to interpret the proglacial dynamics and estimate erosion rates from a temperate tidewater glacier over a complete advance–retreat cycle. Sediment yields from San Rafael Glacier averaged 2.7×107 m3/a since the end of the Little Ice Age, circa AD 1898, corresponding to average basin-wide erosion rates of 23±9 mm/a; the highest erosion rates, 68±23 mm/a, occurred at the start of the retreat phase, and have since been steadily decreasing. Erosion rates were much lower during glacial advance, averaging at most 7 mm/a, than during retreat. Such large glacial sediment yields over two centuries of advance and retreat suggest that the contribution of sediments stored subglacially cannot account for much of the sediment being delivered to the terminus today. The detailed sub-bottom information of a proglacial lagoon yields important clues as to the timing of erosion, deposition and transfer of glacigenic sediments from orogens to the continental shelves, and the influence of glacier dynamics on this process

High Mountain Asia hydropower systems threatened by climate-driven landscape instability

Global warming-induced melting and thawing of the cryosphere are severely altering the volume and timing of water supplied from High Mountain Asia, adversely affecting downstream food and energy systems that are relied on by billions of people. The construction of more reservoirs designed to regulate streamflow and produce hydropower is a critical part of strategies for adapting to these changes. However, these projects are vulnerable to a complex set of interacting processes that are destabilizing landscapes throughout the region. Ranging in severity and the pace of change, these processes include glacial retreat and detachments, permafrost thaw and associated landslides, rock–ice avalanches, debris flows and outburst floods from glacial lakes and landslide-dammed lakes. The result is large amounts of sediment being mobilized that can fill up reservoirs, cause dam failure and degrade power turbines. Here we recommend forward-looking design and maintenance measures and sustainable sediment management solutions that can help transition towards climate change-resilient dams and reservoirs in High Mountain Asia, in large part based on improved monitoring and prediction of compound and cascading hazards