Nature Reviews Earth & Environment | 2021
The impact of glaciers on mountain erosion
Abstract
Glaciers and ice sheets erode mountains and produce vast quantities of sediments that are delivered to rivers and oceans, impacting global sediment and biogeochemical balances. Therefore, understanding how the production of sediments by glacial erosion has evolved in the past, and will evolve in a changing climate, is increasingly important. In this Review, we examine the processes that control the magnitude and timing of glacial erosion of mountains, and how models can be used to reconstruct processes during the development of mountains. Field observations reveal the important role of sliding on the erosion rate, which provide an empirical basis to explain the glacial buzzsaw and the impact of late Cenozoic cooling on erosion rates. Glacial erosion is also expected to evolve in the context of anthropogenic climate warming, as both glacier sliding and the input of meltwater related to thinning and retreat of ice will change, with large effects on downstream ecosystems and global biogeochemical cycles. Thus, the mechanics and impacts of glaciers on sediment production warrant more research, especially in regions experiencing rapid warming. Above all, there is a need for better monitoring of how erosion rates changed over the last decades and will evolve in the future. How glaciers affect mountain height, and the links between climate and glacial erosion in mountains, are debated. This Review describes the erosion of mountains by glaciers and the broader impacts of these processes. Glacial erosion is primarily a result of glacial bedrock erosion through abrasion and plucking, and their interaction with subglacial hydrology. Observations suggest a simple relationship between sliding and glacial erosion, which can be used to make predictions about glacial erosion in mountainous environments. Models can be used to estimate the impact of climate on mountain development, and including the impact of Quaternary glaciations on the erosion rates and the glacial buzzsaw hypothesis. The cryosphere and, in turn, glacial erosion are being altered. Therefore, the mechanics and impacts of glaciers on sediment production deserve more attention in regions experiencing rapid warming. Glacial erosion is primarily a result of glacial bedrock erosion through abrasion and plucking, and their interaction with subglacial hydrology. Observations suggest a simple relationship between sliding and glacial erosion, which can be used to make predictions about glacial erosion in mountainous environments. Models can be used to estimate the impact of climate on mountain development, and including the impact of Quaternary glaciations on the erosion rates and the glacial buzzsaw hypothesis. The cryosphere and, in turn, glacial erosion are being altered. Therefore, the mechanics and impacts of glaciers on sediment production deserve more attention in regions experiencing rapid warming.