Anthropogenic climate change and glacier lake outburst flood risk: local and global drivers and responsibilities for the case of Lake Palcacocha, Peru

Abstract

Abstract. Evidence of observed negative impacts on natural and human systems from anthropogenic climate change is increasing. However, human systems in particular are dynamic and influenced by multiple drivers, and hence identifying an anthropogenic climate signal is challenging. Here we analyze the case of lake Palcacocha in the Andes of Peru which offers a representative model for other glacier lakes and related risks around the world because it features a dynamic evolution of flood risk driven by physical and socio-economic factors and processes. Furthermore, it is the object of a prominent climate litigation case where a local Peruvian citizen sued a large German energy producer over risk of flooding from lake Palcacocha. Adopting a conceptual model of cascading impacts and multiple drivers of risk we first study climatic and other geophysical drivers of flood risk. We find that an anthropogenic signal related to greenhouse gas emissions is traceable. In parallel, flood risk has been strongly shaped (and increased) by interacting socio-economic, institutional and cultural processes over the past decades. The case raises important questions of responsibility for flood risk of global and local agents which, however, are difficult to address in cases like Palcacocha where we reveal a complex network of interlinked global, national and local drivers. Following from this we outline a normative framework with a differentiated perspective on responsibility, implying that global emitters commit to support strengthening capacities in affected regions and localities, and local institutions and societies engage in local risk reduction measures and policies.

Socio-environmental value of glacier lakes: assessment in the Aosta Valley (Western Italian Alps)

“…As mentioned 389 in similar studies (e.g. Emmer et al 2020), also for the Aosta Valley glacier lakes there is the evidence 390 of a transition from moraine-dammed lakes (dammed by the LIA moraines) already existing in the 391 oldest inventories (Viani et al 2016;, to bedrock-dammed lakes (impounded by fractured 392 bedrock or by bedrock overdeepenings). This last type of lake is becoming predominant, including also 393 -the total number of lakes doubled (about 19 lakes formed per year); 397 -the total area increased of ca.…”

“…Numerous are the studies on the hazards connected to the presence of glacier lakes, assessed mainly 101 by remote sensing techniques, topographic and geomorphometric analysis, and modelling approaches 102 (e.g. Huggel Emmer et al 2020). On the 104 other hand, there are few investigations on the services provided by glacier lakes (e.g.…”

Regime Shifts in Glacier and Ice Sheet Response to Climate Change: Examples From the Northern Hemisphere

“…In terrestrial environments, glacier retreat often exposes bedrock basins that have been over-deepened by glacial erosion, creating proglacial lakes in the wake of the retreating ice (e.g., Shugar et al, 2020). Proglacial lakes often pose a hazard, due to the risk of outburst floods (Carrivick and Tweed, 2016;Huggel et al, 2020), but they can also serve to moderate the hydrological impacts of diminished glacier ice, by acting as reservoirs to store water and release it slowly through the summer. Ice-marginal proglacial lakes also increase glacier mass loss through calving (Benn et al, 2007;Sakai et al, 2009;Maurer et al, 2016).…”

The need for stewardship of lands exposed by deglaciation from climate change

“…Disasters, from avalanches to rockfalls, show increasing trends (Deline et al, 2021; Dussaillant et al, 2019; Haeberli et al, 2017; McColl & Draebing, 2019), where exposure is the most important driver and vulnerability the great unknown (IPCC, 2019). For example, the Andes and the Himalayas are facing difficulties with water supplies, moraine erosion, and glacial lake formation that can result in glacial lake outburst floods (GLOF; Wells et al, in press; Clague & O'Connor, 2021; Huggel et al, 2015, 2020; Zheng et al, 2021). While in the Alps decision‐makers and civil society are concerned with increasing frequency and magnitude of mass wasting hazards like rock‐ice avalanches and rockfalls (Coe et al, 2018).…”