Published: Sun, September 23, 2018
Research | By Jody Lindsey

Moderate warming could melt Antarctica's 'sleeping giant' ice sheet

Moderate warming could melt Antarctica's 'sleeping giant' ice sheet

"We found that the most extreme changes in the ice sheet occurred during two interglacial periods 125,000 and 400,000 years ago, when global sea levels were several meters higher than they are today", Welsh said in a statement. However, the new study indicates that warming temperatures do affect the East Antarctic Ice Sheet, and that sustained warming of two degrees Celsius in Antarctica could lead to melting in parts of the Ice Sheet that are below sea level.

Instead of stopping the glaciers from melting further, the structure is meant to prevent warmer water from reaching the bases of them under the sea.

The ambitious projects, detailed Thursday in the European Geophysical Union journal The Cryosphere, reflect a gathering awareness that slashing planet-warming greenhouse gas emissions - while essential - may not happen quickly enough to avoid catastrophic climate change impacts.

If it does, the EAIS will cause sea levels to rise by 3.96 metres.

Option Two is a 100-metre tall underwater wall, or berm, running 80-100 kilometres beneath the ice shelf to block bottom-flowing warm water that erodes the glacier's underbelly, rendering it unstable.

This would be most effective at bigger glaciers, such as the Britain-sized Thwaites ice stream in West Antarctica, which is retreating fast. Moore added that such an "ice sheet intervention today would be at the edge of human capabilities".

Wolovick and Moore ran computer models to test their geoengineering schemes, taking into account the known variables influencing glacier-ocean dynamics.

Recent research has suggested that warm water beneath ice shelves was a contributor to ice loss in west Antarctica. Then a more simple design consists of constructing artificial mounds or columns on the seafloor, which wouldn't block warm water but could support and hold back the glacier, helping it regrow.

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In contrast, the EAIS mostly lies on land above sea level.

Dr Wilson, from Imperial's Department of Earth Science & Engineering, said: "Studying ice sheet behaviour in the geological past can inform us about future changes".

A larger initiative, which is beyond the size of existing large civil engineering projects, would have higher chances of success and could even cause ice sheets to regain mass, researchers said. Even the simple mounds would require significant engineering to work in the ocean. Nonetheless, the team wanted to see whether glacial geoengineering could work in theory, and wanted to get the scientific community to think about, and improve on, the designs.

Michael Wolovick, a geoscience researcher at Princeton and the other author of the study reveals that the collapse of the Thwaites Glacier could increase the global sea level by three meters.

"There are dishonest elements of society that will try to use our research to argue against the necessity of reducing emissions", said Wolovick. "Our research does not in any way support that interpretation", the authors note.

Engineering glaciers would only limit sea-level rise, while reducing emissions could also limit other harmful consequences of climate change, such as ocean acidification, floods, droughts and heat waves.

It sounds simple, but the walls would shore up a complex system of ocean floor and warm water flows to keep the glaciers from melting.

"The more carbon we emit, the less likely it becomes that the ice sheets will survive in the long term at anything close to their present volume", Wolovick concludes.

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