Warming of the climate system is unequivocal. It is evident from observations of increases in global average air and ocean temperatures, loss of ice in West Antarctica and in Greenland, and rising global sea levels. The magnitude of future ice loss, and consequent sea-level rise, is a major concern, but current projections of ice loss still have major uncertainties, in part due to our incomplete understanding of ice sheet and glacier dynamics. Crevasses – deep cracks or fractures found in an ice mass – are an important and often overlooked component of the cryosphere. A recent article published in Reviews of Geophysics summarizes research on how crevasses form and how they affect glaciers.
Crevasses have long been relegated to the periphery of glaciological research, but there is emerging evidence that they can accelerate the decay of large bodies of ice, providing a potentially significant contribution to contemporary and future sea level rise. In addition, the distribution of crevasses on a glacier varies both in space and time, making them good indicators of glacier and ice sheet dynamics. In response to increasing scientific interest in crevasse processes, and in their influence on glacier and ice sheet volumetric changes through time, William Colgan of York University in Canada and six team members have adopted a holistic view of crevasse processes and reviewed about 60 years of in situ and remote sensing studies of crevasses as well as the numerical models now employed to simulate crevasse fracture. Although there have been a number of recently published and highly cited papers expressly dealing with crevasses, this is the first synthesis to date of both the surface mass balance and ice dynamic influences of crevasses on glacier and ice sheet mass balance. Given the broad interest in potential sea level rise caused by changes in the cryosphere, Colgan and his team provide a timely synopsis of the numerous mechanisms by which crevasses can influence glacier and ice sheet mass balance.
Colgan, W., H. Rajaram, W. Abdalati, C. McCutchan, R. Mottram, M. S. Moussavi, and S. Grigsby (2016), Glacier crevasses: Observations, models, and mass balance implications, Rev. Geophys., 54, doi:10.1002/2015RG000504.
—Fabio Florindo, Editor, Reviews of Geophysics; email: [email protected]