Recently, the iceberg named A68a, which broke off from Antarctic glaciers in 2017, has been creating ripples in the news. The current location of the drifting iceberg, off the coast of South Georgia island, has ignited concerns regarding its potential effect on the region’s rich wildlife.
Understanding Icebergs
An iceberg is a large chunk of ice that has detached itself from glaciers or shelf ice and is adrift in open water. These massive bodies of ice are moved by ocean currents until they become ensnared in shallow waters or ground themselves. In the Antarctic, the US National Ice Center (USNIC) is the only organization that names and tracks these icebergs, which are named based on the quadrant in which they were first sighted.
About A68a
A68a, shaped like a closed hand with a finger pointing, broke off from the Larsen Ice Shelf located in the West Antarctic Peninsula in 2017. This region has witnessed a faster rate of warming than any other areas of Antarctica. During its voyage, A68a has calved multiple smaller icebergs, with the largest part, spanning approximately 2,600 sq. km, still bearing the name A68a. The USNIC recently named two of these offspring icebergs as A68e and A68f. These fragments are caught in a swift stream of water known as the Southern Antarctic Circumpolar Current Front.
The Antarctic Circumpolar Current (ACC)
The ACC is the primary current in the Southern Ocean, and it stands as the only current that flows around the globe unimpeded. As it circles the Antarctic continent, the ACC moves eastward through the southern regions of the Atlantic, Indian, and Pacific Oceans. Presently, it is carrying A68a towards the remote South Georgia island.
Potential Impact on Wildlife
South Georgia, a British Overseas Territory (BOT), is now gripped by fear. If A68a grounds itself near their island, it may disrupt the local wildlife that relies on the ocean for food. The penguins and seals of the region could be forced to travel further distances in search of sustenance. However, there are also potential benefits of an iceberg grounding itself in the open ocean, such as dust carried by the iceberg fertilizing ocean plankton which consequently reduces atmospheric carbon dioxide levels.
British Antarctic Survey’s Response
To investigate A68a’s impact on the ecosystem, the British Antarctic Survey (BAS) is set to launch a research mission. BAS, part of the Natural Environment Research Council (NERC), makes significant contributions to world-leading interdisciplinary research in the Polar Regions.
The Calving of Glaciers
Calving is the break-off of ice from a glacier margin. Often occurring when a glacier flows into a body of water, this process can also happen on dry land, referred to as dry calving. Through repetitive calving, smaller cracks in the glacier ice transform into larger crevasses, effectively dividing the ice into blocks that typically fall into an adjacent lake, forming icebergs.
What it Means for Global Warming
Global warming has led to an increase in the frequency of calving. Until the late 20th century, the Larsen Ice Shelf had remained stable for more than 10,000 years. However, starting from 1995, substantial chunks began breaking off, leading to the disintegration of the nearby Wilkins Ice Shelf in 2008 and 2009, and subsequently, A68a in 2017. Hydrofracturing, a process where water infiltrates surface cracks and splits the ice below, has played an instrumental role in these events. Originally developed for the oil and gas industry, hydrofracturing contributes to significant greenhouse gas emissions on a global scale, further contributing to global warming.
