Roundup: Ice-cliff Instability, Buffers, and Glacial Retreat

Future Acceleration of Antarctic Ice Sheet Retreat

From Nature: “Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 meters below sea level are lost. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to retreat only short distances before they reach extensive retrograde slopes. When grounding zones of glaciers retreat onto such slopes, theoretical considerations and modelling results indicate that the retreat becomes unstable (marine ice-sheet instability) and thus accelerates. It is thought that MICI is triggered when this retreat produces ice cliffs above the water line with heights approaching about 90 meters.”

Discover more about how marine ice-cliff instability could accelerate future retreat of the Antarctic Ice Sheet here.

A massive crack extends across the  Pine Island Glacier in 2011. (Source: NASA).

 

Glacier Melt Reduces Buffer Capacity

From Waters Resources Research: “Glaciers store large amounts of water in the form of ice. They grow and shrink dominantly in response to climatic conditions. In Central Asia, where rivers originate in the high mountains, glaciers are an important source for sustainable water availability. Thus, understanding the link between climate, hydrology, and glacier evolution is fundamental. Some instruments mounted on satellites are capable of monitoring glaciers. However, the potential of these sensors is limited by technical constraints that will affect the availability and precision of the products. In order to overcome these shortcomings and investigate glacier dynamics, we use a numerical model that represents the relevant processes of the hydrological cycle with a very fine spatial and temporal resolution. Our results show that glaciers buffer extreme weather conditions to provide sustainable river flow. This functionality is put in jeopardy due to the currently observed glacier retreat, in the Pamir Mountains.”

Read more about how glaciers buffer against river runnoff here.

Image of ice-covered mountains in the distanc
The Pamir Mountains are a mountain range in central Asia (Source: Allan Grey/Flickr).

How will Asia’s Glaciers React to Increases in Global Temperature?

From Nature: “Glaciers in the high mountains of Asia (HMA) make a substantial contribution to the water supply of millions of people, and they are retreating and losing mass as a result of anthropogenic climate change at similar rates to those seen elsewhere. In the Paris Agreement of 2015, 195 nations agreed on the aspiration to limit the level of global temperature rise to 1.5 degrees Celsius ( °C) above pre-industrial levels. However, it is not known what an increase of 1.5 °C would mean for the glaciers in HMA. Here we show that a global temperature rise of 1.5 °C will lead to a warming of 2.1 ± 0.1 °C in HMA, and that 64 ± 7 per cent of the present-day ice mass stored in the HMA glaciers will remain by the end of the century.”

Learn more about the impact of climate change and increasing temperature on Asia’s glaciers here.

Map showing glacial loss under a 1.5ºC increase in global average temperature
This map shows regional temperature increases and projected glacial area (Source: Kraaijenbrink et al. ).

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