Glaciers and postglacial ecosystems: common goods to protect in the Anthropocene

Abstract Glacier shrinking and the development of postglacial ecosystems related to anthropogenic climate change is one of the fastest ongoing ecosystem shifts, with paramount ecological and societal cascading consequences globally (Huss et al., 2017; Milner et al., 2017; Cauvy and Dangles, 2019; IPCC, 2021). Yet, no complete spatial analysis exists to quantify or anticipate this major changeover (Ficetola et al., 2021; Zimmer et al., 2022). Here we model glacier responses to climate projections until 2100 and subglacial terrain to explore the ecological trajectory of all glaciated areas, outside the Antarctica and Greenland ice sheets. Depending on climate change magnitude, glaciers could lose less than one quarter to half of their area by 2100. Mainly composed of terrestrial, then marine and freshwater areas, deglaciated areas could range from the equivalent surface of Nepal to Finland. Ecological conditions in deglaciated areas will remain extreme in some regions, offering refuges for cold-adapted species, but become mild in others, favouring biogeochemical processes, primary productivity and generalist species. This unprecedented travel into the future of cold regions shows that glaciers and postglacial ecosystems have key roles to play to face climate change, biodiversity loss and freshwater scarcity. Less than a third of these vulnerable common goods, barely considered in nature conservation policies (IPBES, 2019), are located within protected areas. We therefore call to urgently enhance both climate change mitigation and the in-situ protection of these key ecosystems to secure their existence, functioning and values.