Threat to Antarctic ice

HBS Guy

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Staff member
Abstract
The future surface mass balance (SMB) of Antarctic ice shelves has not been constrained with models of sufficient resolution and complexity. Here, we force the high‐resolution Modèle Atmosphérique Régional (MAR) with future simulations from four CMIP models to evaluate the likely effects on the SMB of warming of 1.5°C, 2°C and 4°C above pre‐industrial temperatures. We find non‐linear growth in melt and runoff which causes SMB to become less positive with more pronounced warming. Consequently, Antarctic ice shelves may be more likely to contribute indirectly to sea level rise via hydrofracturing‐induced collapse, which facilitates accelerated glacial discharge. Using runoff and melt as indicators of ice shelf stability, we find that several Antarctic ice shelves (Larsen C, Wilkins, Pine Island and Shackleton) are vulnerable to disintegration at 4°C. Limiting 21st century warming to 2°C will halve the ice shelf area susceptible to hydrofracturing‐induced collapse compared to 4°C.
Plain Language Summary
Whether Antarctic ice shelves are gaining or losing ice at the surface – their surface mass balance (SMB) – depends on many factors. To understand future Antarctic ice shelf SMB requires complex computer models, and until now, few studies using these models have been done. Here, we use the high‐resolution MAR model to explore how ice shelf SMB changes under warming scenarios of 1.5°C, 2°C and 4°C above pre‐industrial temperatures. Our results show that warming causes SMB to decrease because high temperatures produce meltwater, which then runs off the ice shelves, and that this effect is larger for greater levels of warming. Antarctic ice shelves may contribute to rising sea levels in future because larger amounts of melt and runoff increase their vulnerability to ‘hydrofracturing’, a process whereby ice shelves crack and disintegrate. Limiting future warming will reduce the number of ice shelves that will be susceptible to collapse via this mechanism.
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For plain language:
https://www.livescience.com/antarctic-ice-collapse.html

“A third of Antarctic ice shelves could collapse at current pace of warming
By Rafi Letzter - Staff Writer 7 days ago
The difference between 2 degrees and 4 degrees of warming is measured in millions of gigatons of ice.”
 

HBS Guy

Head Honcho
Staff member
West Antarctic ice sheet and CO2 greenhouse effect: a threat of disaster

Abstract
If the global consumption of fossil fuels continues to grow at its present rate, atmospheric CO2 content will double in about 50 years. Climatic models suggest that the resultant greenhouse-warming effect will be greatly magnified in high latitudes. The computed temperature rise at lat 80° S could start rapid deglaciation of West Antarctica, leading to a 5 m rise in sea level.
https://www.nature.com/articles/271321a0
 

HBS Guy

Head Honcho
Staff member
That is an old article—see the date—but still the WAIS is in trouble and it is due to AGW warming the oceans so warmer water reaches the ice sheet where it terminates in the sea.
 

HBS Guy

Head Honcho
Staff member
Yup, including the Himalayan ice sheet “the third pole” the melt water from which waters a quarter of the worlds population. The second nuclear war will be fought over that.
 

pinkeye

Wonder woman
No.. it'll be a brutal body on body fight.

Tech killing ? Drones etc ? Depends on the capability of the tech.

Imagine if the NBN was the only net/comp/sat network.??

The world would be a much better place.
We'd have to rely on our local resources.
 
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