Huge crack in Antarctic Ice Shelf threatens to break off into the sea

Science has warned us over and over again: climate change is real. It is happening now, and with every passing year, we can witness the slow, inevitable approaching change that glares over us. Make no mistake, I am not referring to some obscure Hollywood apocalyptic scenario; no… The change is much more subtle but no less terrifying.

Climate data from the past decades indicate that ice shelves are retreating rapidly. Here is a view of the changes in the Larsen ice shelves [2]

Unfortunately, there is no longer ground for climate skepticism. Last month, news media from all over the world reported observations of an immense 100km-long rift in the Larsen C ice shelve, one of the largest in the Antarctic peninsula [1]. The crack was 100m wide and 500m deep, unprecedented in Antarctica, where more and more cracks appear every year.  The colossal crack abruptly grew by 18 km during the second half of December 2016. Members of Project MIDAS, an Antarctic research group, reported this dramatic growth on January 5 [2]. This separating ice is now only about 20 kilometers from the edge of the Larsen C ice shelf. If this crack expands further, an iceberg the size of the state of Delaware could break off from the Antarctic peninsula and disappear into the sea.

 

The current state of melting in Antarctica is unprecedented in human history: Larsen C has been stable for nearly 12,000 years, according to ice caps data [3]. Climate change in the last decades has caused warming of the Antarctic climate, leading to unprecedented rates of melting during summer –  the ice shelf thinned by about 4m across its entire surface between 1998 and 2012!

 

Joe MacGregor, deputy project scientist for IceBridge and glaciologist at NASA Goddard Space Flight Center, commented that “The growth of this rift likely indicates that the portion of the ice shelf downstream of the rift is no longer holding back any grounded ice”.

 

 

Ice shelves typically float on water and are continually fed by glacial and continental streams of ice. Though cracks are common, and icebergs split off constantly during summer months, the loss of an iceberg of this mass could have devastating consequences on sea level rise and the global oceanic circulation. Larsen C isn’t the typical ice shelf: it holds back an enormous mass of land ice. Once the shelf detaches into the sea, this land ice will no longer have a buffer and will rapidly melt, and here lies the real danger.

 

Why is this melting so alarming? We have all heard of sea-level rise, but many think that it would only be a threat to low-lying archipelagos and coastal cities (which are home to a significant portion of the world population). Whilst it may not seem so dramatic to people living further inland, the effects of melting are far more wide-ranging. But sea-level rise is only one of many impacts that will result from the melting of ice caps and glaciers. As large amounts of freshwater are released into the ocean, scientists fear this inflow will result in huge disturbances in oceanic currents worldwide [4]. Ocean currents regulate climate stability and seasons, such disturbances could result in climatic anomalies, and increase the occurrence of extreme climate events like droughts, floods and typhoons. Such climate instability could be disastrous for agricultural production and increase the existing strain of global food security, causing widespread famine.

Still think global warming is not a threat? Think again…

 

References:

[1] https://www.nasa.gov/image-feature/rift-in-antarcticas-larsen-c-ice-shelf/

[2]http://www.ecowatch.com/nasa-antartica-larsen-c-2144755963.html

[3] http://www.nature.com/nclimate/journal/v6/n5/fig_tab/nclimate2912_F2.html

[4] https://www.scientificamerican.com/article/earth-talk-getting-fresh/

 

Image credits:

http://earthobservatory.nasa.gov/IOTD/view.php?id=89257

 

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