The calving of a 5,800 square-kilometre section of the Larsen C ice shelf has been recorded. Although it is only half the size of the largest ever recorded iceberg (B15 broke off from Antarctica’s Ross Ice Shelf in 2000, measuring 11,007 square-kilometres), it nonetheless represents yet another loss of ice – not just in Antarctica, but globally.
Calving is a natural geographic event and this is no exception. The difference here is that the process was potentially accelerated by oceanic and atmospheric warming. The iceberg itself presents very little threat to sea levels, as these had already been displaced since the iceberg consists of floating ice. What is of concern is the land ice that was effectively being held into place and protected by the ice shelf. With that ice shelf now gone, warmer waters and atmospherics will now be able to access the land ice and begin the process of slowly heating up and destabilising that ice. It is this ice, should it be affected and begin to enter the surrounding waters, that will have severe consequences for sea levels around the world.
The Larsen C Ice Shelf was attached to the Northern side of the Antarctic Peninsula. It is now detached, and will be lost. Image credit: Wikipedia Commons.
While the appearance of rifts in, and the eventual calving of, an area of ice is part of a natural cycle, the increase in rifts (such as in the Antarctic Peninsula and the Pine Glacier Ice Shelf) are not. A warmer atmosphere increases the pooling of water on the surface of an ice mass, which in turn, slowly begins to disintegrate the ice beneath. Meanwhile, warmer waters below the ice slowly erode it. Combined, these processes destabilise a whole section of ice. Although natural weather patterns do participate in the ebbing and flowing of ice shelves and glaciers, the rate at which they grow back becomes severely weakened, until growth can no longer be sustained and the ice shelf breaks away or the glacier no longer forms.
There will undoubtedly be some who will point to studies like that by NASA (Mass Gains of Antarctic Ice Sheet Greater than Losses) to demonstrate a lack of climate change and any affects it might have on Antarctica. Some will say that the calving at Larsen C Ice Shelf remains a natural event in itself and so should be given no particular scientific weight in terms of climate change. But this is to not look at the bigger picture. While Antarctica has indeed gained ice at a rate of 18,906 square-kilometres a year since the late 1970s, the Arctic has been losing ice at a rate of 53,872 square-kilometres per year over the same time period. Ice gain in the south doesn’t cancel out ice loss in the north. There is one particular area in which this is of most importance: the albedo effect.
As this graph of Arctic sea ice extent by the NSID shows, the world’s ice caps are melting alarmingly fast. Image credit: Wikipedia Commons.
The albedo effect is most simply explained as the rate at which the Earth’s surface is able to reflect the solar energy from the Sun. It measures how reflective the Earth’s surface is. Ice has the highest albedo and so, with less ice, the Earth’s surface is unable to reflect back as much of the Sun’s energy, thereby increasing the Earth’s temperature. This is why buildings in the hottest parts of the world are painted white.
The gain in ice in Antarctica might seem like a good thing, but there are other factors to take into account. Much of this gain has come from an increase in snow, a climate change factor in that warmer air carries more moisture and therefore more precipitation which takes the form of snow in Antarctica. The aforementioned NASA study concluded that snow has compacted, creating more ice. The problem with increased snowfall is that snow steepens surface gradients, increasing the stress on an ice flow, increasing the rate at which icebergs will then disperse into the ocean.
The iceberg is the call of the canary in the coal mine. Politicians can no longer say they weren’t warned.
The political will to face up to climate change has long been a thorn in the sides of scientists, scientific institutions and indeed many in the public. The White House Office of Science and Technology Policy is virtually empty. Proposed budget cuts will risk NASA losing its Carbon Monitoring System while the US Environmental Protection Agency’s budget may be cut by 31%. Meanwhile, Russian interest in Antarctica may well trigger competition between high-energy use nations to begin searching for resources, threatening the Antarctic Treaty System (ATS). Rough estimates have suggested up to 203 billion barrels of oil and 106 trillion cubic feet of natural gas. The potential of militarised competition over a continent that seven nations lay claim to (while Russia might intend to claim the whole lot) leaves open the possibility of a new theatre of war and political tensions.
Antarctica holds 27 million square-kilometres of ice, which, if melted, could potentially make sea levels rise by 58 metres, a truly catastrophic event on a global scale. Of course, such a large quantity of ice will not melt all in the same instance, but this is precisely why the problem of ice loss doesn’t get the attention that it deserves on a political and economic level. The problem is seen as happening slowly, which it is, and won’t affect many people for many years to come, which it won’t. But the truth of the matter is that it is happening. So often environmental issues are invisible to the naked eye, as was the case the Larsen C ice shelf, until now. The iceberg is the call of the canary in the coal mine. Politicians can no longer say they weren’t warned. How they react now could have a very real effect for many people for many years to come.
Featured image credit: Antarctica Bound, Flickr
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