An unprecedented journey into the future of the areas covered by glaciers on Earth

The amplification of anthropogenic climate change is disrupting our planet, in particular causing a rapid and worrying melting of glaciers worldwide. Published in the prestigious journal Nature, a recent study by an interdisciplinary team of French and Swiss glaciologists and ecologists (including OSUG laboratories [1]) takes us on an unprecedented journey into the future through modeling and exploration of the evolution of glaciers and deglaciated areas on Earth between 2020 and 2100. In future ice-free areas, the authors predict the formation of emerging terrestrial, freshwater and marine ecosystems. As part of the rare intact natural spaces on our planet, glaciers and post-glacial ecosystems play a fundamental role in addressing the challenges of climate change, access to freshwater and the collapse of life. As the UN has just declared 2025 the international year of glacier’s preservation, this study calls for immediate and drastic climate change mitigation and increasing in situ protection measures to protect as many glaciers and post-glacial ecosystems as possible.

The scientific community has made enormous progress in quantifying and anticipating the evolution of the Earth’s glacier volume. However, a worldwide detailed analysis of the future evolution of glacierized areas and the associated ecological consequences has not yet been carried out. Thanks to detailed glacier evolution modeling, a French and Swiss research team analyzed the evolution of the 210 000 glaciers on our planet (excluding the Antarctic and Greenland ice sheets) as well as the future ice-free topography and air temperatures that will appear and prevail in deglaciated areas until 2100. The main results of the study show that:

– The world’s glaciers covered 665 000 km2 in 2020 (approximately the surface of Afghanistan). Depending on the greenhouse gas emission scenarios, this area is projected to decrease by 22 ± 8 to 49 ± 15% until 2100. As a result, areas that become ice-free between 2020 and 2100 will cover from 149,000 ± 55,000 (the surface of Nepal) to 339,000 ± 99,000 km2 (the surface of Finland) and consist of terrestrial areas (78%) and submarine (14%) as well as terrestrial (8%) overdeepenings. This will lead to the emergence of large terrestrial (rocks and sediments, grasslands, shrublands, forests, etc.), marine (fjords, lagoons, coastlines) and freshwater (lakes, wetlands, rivers) ecosystems. Depending on climate projections, these post-glacial ecosystems will be either limited in size and mainly subject to extreme ecological conditions, offering refuges for an adapted biodiversity, or vast and characterized by more favorable ecological conditions that will allow the arrival of generalist species.

– Glaciers and post-glacial ecosystems play a major role in mitigation (albedo, landcover change) and adaptation to climate change, to guarantee access to fresh water in many regions, limit sea level rise and halt the decline in biodiversity. Despite their importance, these ecosystems are still little recognized in nature conservation policies and less than 50% of glacierized areas are located in protected areas. The authors show how immediate, drastic and unprecedented measures to mitigate climate change would save a significant portion of today’s glaciers on Earth by 2100, with various benefits well beyond their reach. Glaciers and post-glacial ecosystems are mainly located on public or community spaces. Together with local populations, the creation of protected areas on these common goods would guarantee the integrity and functionality of these key ecosystems and limit growing anthropogenic threats.

The results of this study echo international calls and commitments on the urgency and the need to jointly intensify the mitigation of climate change (6th IPCC synthesis report in 2023), the preservation of water resources (UN 2023 water conference) and nature protection (Kunming-Montreal Global Biodiversity Framework in 2022). In this context and on the eve of the international year of glacier’s preservation in 2025, the protection of glaciers and post-glacial ecosystems will make it possible to contribute simultaneously and decisively to these unprecedented challenges.

This study was carried out as part of the Ice&Life project. Developed by Jean-Baptiste Bosson at Asters - Conservatoire d’Espaces Naturels de Haute-Savoie (Annecy, France), it aims to bring together science and nature conservation, civil society, academia and public actors to better understand and protect glaciers and post-glacial ecosystems.

References

Bosson J.B., Huss M., Cauvy-Fraunié S., Clément J.C., Costes G., Fischer M., Poulenard J. & Arthaud F. (2023).
Future emergence of new ecosystems caused by glacial retreat. Nature 620 (7974).

Updated on 29 August 2023