Declining sea ice in Antarctica and how it affects us all

The extent of sea ice surrounding Antarctica during the summer of 2022/23 was at its lowest level ever over its 45 years of being recorded through satellite data. The previous recorded low was set the previous summer. Antarctica is showing dramatic signs of a changing climate, with parts of the Antarctic Peninsula having already warmed five times faster than the global average. While sea ice extent might not seem significant, animals such as the Emperor Penguin breed on the sea ice and according to the Argentine Antarctic Institute could become extinct within the next 30-40 years if this trend continues. While the icy continent seems distant from our everyday lives, what happens in Antarctica matters, and can affect what happens to us locally as well.

Let's explore what's happening to sea ice in Antarctica under a warming climate. If we think about white snow on a sunny day, the reason it is so bright is that over 90% of the sun's radiation that hits the surface of the snow gets reflected. In contrast, if we think of the open ocean, less than 10% of solar radiation that reaches the ocean surface is reflected, meaning over 90% is absorbed into the ocean. Under a warming climate, snow and ice melt, and in Antarctica, melting sea ice reveals the darker ocean beneath it. This means as more ocean is being exposed under an ever-warming atmosphere, more of the sun's energy remains within our Earth's system rather than being reflected into space.

Differences in the reflectivity of the sun's rays when it hits snow and ice, compared with open water. Credit: Sam Carana for

So how does this process affect us here in Australia? Well, there are a couple of ways that melting sea ice has its effects felt globally. Firstly, with an additional amount of the sun's energy remaining here on Earth rather than being reflected back into space, it encourages further warming, which facilitates further sea ice melt, which leads to even more of the sun's energy remaining here. This process is known as a positive feedback loop as it feeds back on itself and amplifies over time. The additional solar energy now remaining within the Earth's system is what enables extreme weather events (such as floods, bushfires ,and tropical cyclones) here in Australia and across the world to become more extreme and more frequent.

Another major effect is that melting sea ice can also lead to a disruption in the regular global ocean circulation. As sea ice forms over the winter months from freezing surface ocean water, it expunges most of the salt into the ocean beneath, resulting in a higher concentration of salt in the water there. This water is more dense than regular ocean water so it sinks deeper into the water column where it gets caught up in the Antarctic Circumpolar current, which is part of the global ocean circulation. Without this dense salt water resulting from the formation of sea ice, there will be a slowing down in this ocean current, which can in turn see a slowdown in the global ocean circulation. Ocean currents, among other things, influence where weather systems form. Changes in the ocean currents could see a radical shift in rainfall patterns around the world

Simplified depiction of global ocean currents. Credit: NASA/JPL

Now that we can see the importance of sea ice to the functioning of our planet, the only way to stop sea ice melting in Antarctica is to reduce greenhouse gas emissions. While there isn't much time left to act to keep warming below 2C, the important thing is there's still time. The solutions to our crisis require action on all fronts. It demands not just a top-down approach that public policy provides, but also a bottom-up approach where individuals do their part in adjusting their lifestyles.

Looking over Vincennes Bay in West Antarctica. Credit: Louise Carroll (Author)

So what can we actually do?

Here are 3 things each of us can do as individuals to help alleviate the risks of climate change.

1. Reduce meat consumption

According to the United Nations Food and Agriculture Organisation, beef production contributes 14.5% to human-induced greenhouse gases, and is thus one of the biggest generators of greenhouse gases. Not only does cattle farming emit large volumes of greenhouse gases (methane and nitrous oxide) into the atmosphere, but the clearing of land required for our increasing global demand for beef is contributing to habitat destruction and a decline in biodiversity. By reducing our consumption of meat products and moving toward a more plant-based diet, we can reduce our demand for this industry and thus reduce the amount of greenhouse gases it emits into our atmosphere.

2. Reduce food waste

Generating less food waste can be a great contribution to a more sustainable lifestyle. According to Foodbank Australia, 2.46 million tonnes of food is lost or wasted in Australian households each year, the equivalent of $2000 to $2500 per household per year. Food scraps and other uneaten food ends up in landfill where it emits methane and contributes to the climate crisis. Having a greater awareness of what volume of food your household requires can go a long way to reducing food waste. Furthermore, if you have space, setting up a compost bin in your backyard, or a worm farm if you have an apartment with a balcony, can be a fantastic way of keeping food scraps and uneaten food out of landfill altogether. It is also a great way to get the kids excited about living sustainably.

3. Start a conversation

One of the simplest, yet most impactful, things you can do as an individual to address the global climate crisis is to start a conversation with friends and family. Most of us have a certain level of anxiety surrounding our changing climate, which can hinder our efforts to overcome the issues. Talking through our climate anxieties with those around us can help alleviate our emotions and help us feel empowered to make positive changes in our lives and communities. Getting outside our echo chambers and conversing with those around us who may not fully understand the impacts of climate change to them personally could enable them to become motivated to make changes themselves. Many studies in human behaviour have shown that it takes only 25% of the population to affect social changes in the greater population.

Together we can start to reduce to the effects of climate change for the betterment of future generations.

Written by Louise Carroll. Louise Carroll has a Bachelor of Science (Hons) in Atmospheric Science, extensive experience working as a Meteorologist for both the Australian Government and private sector, and has been part of five Antarctic expeditions with the Australian Antarctic Program. Louise is also part of the Homeward Bound program, which facilitates a global network of women leaders with a STEMM background to collaborate and drive change for our planet.

Header Image is provided by author.

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