Thwaites Glacier: are we skating on thin ice?

The impacts of climate change are all around us and can be observed in our everyday lives. A direct and progressively concerning consequence of climate change is the rise of global sea levels. Conservative trajectories predict that the sea level will rise 49-56 cm by 2100 (Kopp, et al., 2017). Worst-case scenarios predict increases of 79-146 cm by 2100. The latter prediction would mean land currently occupied by approximately 153 million people would be submerged (Kopp, et al., 2017). This exemplifies why monitoring sea-level rise is so essential. It can cause tremendous coastal erosion and force the migration of millions (Mimura, 2013).

This increase in sea level is predominantly caused by changes in water as seas warm and glaciers and ice sheets deposit into the sea (NASA, 2022). Some glaciers have bigger roles in sea level changes, Thwaites Glacier, located in western Antarctica, is a large contributor. This glacier is responsible for up to 4% of all global sea-level rise (Pettit, et al., 2021). Thwaites Glacier is made even more pivotal in sea level rise by its proximity to other ice structures (Scambos, et al., 2017). If this glacier were to retreat entirely, it would raise global sea levels upwards of 300 cm. This is because the glacier would sweep ice off of neighbouring structures into the sea as it began to flow faster, triggering the deglaciation of the West Antarctic Ice Sheet (Scambos, et al., 2017). In addition, temperature rises are causing increased melting of the base of the glacier through warm currents and a higher potential for fractures and cracks due to surface melting. These processes contribute to an accelerated collapse of the glacier ​(Scambos, et al., 2017).

Figure 1: Thwaites Glacier as seen by satellite images in 2015 and 2021. In 2021 the presence of rifts on the TEIS can be seen. The red line represents the boundary of the glacier (Pettit, et al., 2021).

The Thwaites Glacier is supported by the Thwaites Eastern Ice Shelf (TEIS). This shelf supports a significant portion of the structure and creates a more stable section of the glacier, is losing its grip on its pinning point. The pinning point prevents the movement of the shelf through its connection to a submerged bank. Recent satellite images have confirmed that the shelf’s cracks and fractures have started to form rifts through the ice. It is estimated the shelf could be completely shattered and separated within five years. This would lead to the accelerated flow of ice into the ocean as Thwaites became increasingly unstable (Pettit, et al., 2021). These features can be seen in Figure 1.

Figure 2: Schematic of potential aids to prevent ice loss from glaciers (Moore, et al., 2018).

There have been several efforts to help support this glacier and prevent its demise. For example, Moore, et al., 2018 suggested several possibilities in an attempt to stall the flow of significant glaciers. This involved pumps to freeze glacier base water, a barrier to block warm currents from reaching the glacier base, and “islands” to support the glacier and slow glacial flow (Moore, et al., 2018). The interventions are depicted in Figure 2. However, these solutions are costly, take time to plan and build, and could have unintended effects and accelerate ice loss (Moon, 2018). The aforementioned direct artificial methods ultimately do not address the root of the problem and are generally considered unfavourable (Moon, 2018).

The observed changes discovered at Thwaites Glacier demonstrates the urgency of addressing and preventing climate change. Action must be taken to prevent worst case scenarios and preparation must begin for high risk populations.

Sources

Kopp, R.E., DeConto, R.M., Bader, D.A., Hay, C.C., Horton, R.M., Kulp, S., Oppenheimer, M., Pollard, D. and Strauss, B.H., 2017. Evolving Understanding of Antarctic Ice‐Sheet Physics and Ambiguity in Probabilistic Sea‐Level Projections. Earth’s Future, 5(12), pp.1217–1233. https://doi.org/10.1002/2017EF000663.

Mimura, N., 2013. Sea-level rise caused by climate change and its implications for society. Proceedings of the Japan Academy, Series B, 89(7), pp.281–301. https://doi.org/10.2183/pjab.89.281.

Moon, T.A., 2018. Geoengineering might speed glacier melt. Nature, 556(7702), pp.436–436. https://doi.org/10.1038/d41586-018-04897-5.

Moore, J.C., Gladstone, R., Zwinger, T. and Wolovick, M., 2018. Geoengineer polar glaciers to slow sea-level rise. Nature, 555(7696), pp.303–305. https://doi.org/10.1038/d41586-018-03036-4.

NASA, 2022. Sea Level. [online] Global Climate Change and Global Warming: Vital Signs of the Planet. Available at: <https://climate.nasa.gov/vital-signs/sea-level/>.

Pettit, E.C., Wild, C., Alley, K., Muto, A., Truffer, M., Bevan, S.L., Bassis, J.N., Crawford, A., Scambos, T.A. and Benn, D., 2021. Collapse of Thwaites Eastern Ice Shelf by intersecting fractures. [online] American Geophysical Union annual meeting. Available at: <https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/978762>.

Scambos, T.A., Bell, R.E., Alley, R.B., Anandakrishnan, S., Bromwich, D.H., Brunt, K., Christianson, K., Creyts, T., Das, S.B., DeConto, R., Dutrieux, P., Fricker, H.A., Holland, D., MacGregor, J., Medley, B., Nicolas, J.P., Pollard, D., Siegfried, M.R., Smith, A.M., Steig, E.J., Trusel, L.D., Vaughan, D.G. and Yager, P.L., 2017. How much, how fast?: A science review and outlook for research on the instability of Antarctica’s Thwaites Glacier in the 21st century. Global and Planetary Change, 153, pp.16–34. https://doi.org/10.1016/j.gloplacha.2017.04.008.