Antarctic Ice Floes
By Ayden Planker
While it’s common knowledge that as much as 71% of Earth’s surface is water, the substance is actually extremely rare across the universe. Of all water that exists, a vast majority is believed to be frozen, but on Earth, home to all of the universe’s known liquid water, ice takes up only 7% of the surface. Take away the ice that is directly connected to land, called fast ice, and the remaining drift ice of the world takes up an even smaller portion. Despite its small size, Antarctic Ice Floe is integral to the health of our planet as we know it.
Sea ice is formed when frost forms at the top layer of mostly-still seawater. This film isn’t enough to develop into ice on its own, but it is cold enough to form minute crystals similar to snowflakes, which break apart and congeal into a substance called frazil when waters become choppy. When the water returns to stillness, frazil becomes ice.
When this ice forms, it does so in very small portions. Only when these small pieces come into contact with each other do they begin to make pack ice, and when sufficiently large, at least 20 meters across, they form large, flat stretches of sea ice called ice floes. Ice floes expand through a similar process of rafting, in which they catch together and refreeze as one, or in a process called basal freezing, in which the ice is cold enough to freeze small portions of water at its base, thus growing from the bottom up.
When many ice floes collide, they can begin to move as singular bodies called ice packs. Most of the world’s sea ice can be found in two ice packs, those being the Arctic and Antarctic packs. The seasons affect the size of the ice packs greatly, but at their yearly peaks, the Antarctic pack is the larger of the two by a margin of 3 million square kilometers, or 11 and a half million square miles. The Antarctic ice pack is so large, at its peak in September, that it is estimated to occupy around 18 million square kilometers, which is nearly a million square kilometers larger than the surface area of Pluto, but in summer it is reduced to only one-sixth of that size.
Northern and southern ice differ in more than just quantity, however. Because the north pole tends to get more rain in the summer months than snow, the melting habits of northern and southern sea ice are actually opposite to one another. The year-round snow covering of the south pole means that its ice typically melts from the bottom up, rather than the top down, as sun-exposed ice normally would.
Because of how much southern sea ice melts throughout the year, most of its ice at any given time is less than a year old. What little persistent sea ice can be found on the continent is usually in the Weddell Sea, the sea within the crook of the Antarctic peninsula. Because of their young age, Antarctic Sea floes tend to be thinner and saltier, and thus more fragile, than their northern counterparts.
When sea ice melts, it forms a positive feedback loop. Ice has a significantly higher albedo than water, and when it melts, the water that takes its place absorbs much more radiation. This radiation causes it to grow hotter, which causes more ice to melt, and the cycle repeats itself. Greenhouse gases accelerate this cycle exponentially, and without the ability to regulate, our ice continues to vanish.
More directly than that, albedo is heavily reliant on color. The brighter a substance, the more radiation it reflects. The burning of hydrocarbons like coal, petroleum, and other natural gasses releases soot, which is one of the primary components of a substance called cryoconite, a black dust that accumulates on glaciers and in snow in both the north and south poles. Because of its dark color, cryoconite absorbs any radiation the ice might have reflected, causing the melting process to accelerate yet again.
Overconsumption endangers all of us. Ultimately, there is still time to protect the Antarctic, but our world’s attention must turn toward what we can do to fight climate change. Always remember what’s at stake, even if it seems insignificant, and remember to ask yourself what you can do to help.
Written by Ayden Planker
Photographs by wilderness photographer
Tom Murphy of Livingston, Montana
Be Conservation-Minded, People!
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