Climate change and the global pattern of moraine-dammed glacial lake outburst floods

Abstract

Abstract. Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste. GLOFs can have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the rapid drainage of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and regularity – rather unexpectedly – have declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From an assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine-dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.

A Systematic, Regional Assessment of High Mountain Asia Glacier Mass Balance

“…Glaciers are sensitive climate indicators that primarily respond to interannual changes in temperature and precipitation (e.g., Bertrand et al, 2012;Harrison, 2013). They constitute important seasonal and long-term hydrologic reservoirs, providing water for hydropower, agriculture, and municipal use (Guido et al, 2016;Ragettli et al, 2016;Milner et al, 2017;Pritchard, 2019) Glaciers can also be a significant natural hazard, especially for regions subject to catastrophic glacier outburst floods (Harrison et al, 2017;Haritashya et al, 2018;Allen et al, 2019).…”

Mass Loss From Calving in Himalayan Proglacial Lakes

“…While the ice-cored moraine dam is in substantial direct contact with the lake, the system is metastable and some can be so unstable that a glacial lake outburst flood (GLOF) may occur due to dam breakup or overtopping and rapid erosional incision (Richardson and Reynolds, 2000a;ICIMOD, 2011;Rounce et al, 2017). GLOFs have large socioeconomic impacts in many regions of the world, including the Himalaya (Carrivick and Tweed, 2016), and are expected to increase in frequency in coming decades (Harrison et al, 2018), although GLOF reporting bias complicates historical trend analysis (Veh et al, 2019). Nonetheless, the physics and consequence of glacier-lake thermal and physical interactions are important to document and understand.…”

Characterizing neutral and adaptive genomic differentiation in a changing climate: The most northerly freshwater fish as a model

“…Further temperature increases will advance the break‐up of ice (Prowse et al, ), expanding the open period for some of the largest rivers in the world (Wrona et al, ). Accelerated glacial melting will also contribute to rising sea level and a higher frequency of landscape‐altering, glacial lake outburst floods (Harrison et al, ). Other stressors such as freshwater acidification, eutrophication, and ozone depletion will be exacerbated by climate change as well (Adrian et al, ; Heino, Virkkala, & Toivonen, ; Schindler & Smol, ; Woodward, Perkins, & Brown, ).…”