Glacial and periglacial processes in a changing climate

Glacial and periglacial environments globally host reservoirs of glacier ice, frozen ground, and snowpacks, all of which are highly vulnerable to climate change and are experiencing unprecedentedly rapid changes. Since the 1950s, warming-intensified glacier retreat and permafrost degradation have substantially reshaped proglacial systems, altered hydrogeomorphic processes, enhanced erosion and carbon release and increased fluvially transported sediment, triggering cascading social-ecological impacts and climatic feedbacks. For example, erosion by glacial meltwater and permafrost thaw can mobilize large amounts of sediment and form distinct proglacial and paraglacial landscapes, subsequently delivering organic carbon, nutrients, and contaminants downstream and releasing greenhouse gases into the atmosphere. Development of glacial and thermokarst lakes can regulate hydrological and ecological processes via impacting capture of eroded sediment and carbon emissions, respectively. This chapter identifies these landscape changes and hydrogeomorphic responses within glacial and periglacial environments and discusses the broad implications for riverine and ecological sustainability, and for the security of infrastructure and local communities.