Antarctica is a rocky continent that is nearly twice the size of Australia and is mostly covered in ice averaging two kilometres in depth. This ice mass holds about 70% of the world’s fresh water and 90% of the world’s ice. It’s now missing a negligible amount as I had a couple of rum and cokes last night. Each winter the sea around it freezes to about 80k’s off shore. It apparently grows about 100,000 square kilometres a day and adds an extra two Australia’s to the size of the continent each winter. I read this on the internet so it must be true. I live in East Antarctica which I’m guessing must be classier than West Antarctica and our sea started freezing in May. It’s pretty cool to watch and happens over a relatively short time frame. It needs to be at least minus 10 and not too windy. We were getting into the minus 20’s when the edges of the sea started to freeze. It seems to freeze different ways in different spots according to depth and currents and locations. In a couple of spots we had these cool ice cake pancakes form and they eventually all connect up to each other and the shore.

There are so many types of ice and ice connections. Fast ice, new ice, grease ice, frasil ice, pack ice, drift ice and the ice you put in drinks. From our window and high vantage point in the Redshed we were able to watch the ice form in what just seemed a week or two. It started to form a grease ice or greyish looking ice and it was sort of rippled so it made it hard to tell if it was frozen or just the wind blowing across it. One morning it looked like ocean and next morning I could see some penguins walking across what I thought was the sea but I guess unless they were clever penguins then it must have been frozen. A few days later I got to walk in a similar location on similar looking ice. But, maybe I can walk on water? I was wearing a rope harness and on a device that resembled a waterborne version of a Zimmer frame. I also was wearing a dry suit and walked lightly.

One of our scientific tasks down here is to measure the sea ice depth in set locations around the base. We all get a go at doing it.  The day I got to drill the new grease looking ice it was only 100mm thick or possibly 100mm thin depending on your weight. If I thumped my foot down I would have gone through it. Other spots were over 2oomm thick. It seems to grow about 60mm thicker each week. We have a 2 4 6 rule down here. 200mm is walkable, 400 quad bikes and 600 vehicles. There’s a lot of paperwork and training involved before you can head out on the ice. It is pretty amazing though.

Our ice grew really well and was over 700mm thick when we headed off on various trips east and west to check ice depths on the way to the emperor penguin rookeries. One group almost made it to the Auster rookery but had to turn back due to the weather turning bad. It didn’t just turn bad it ended up being the biggest blow that Mawson has ever recorded in May. Locked up snuggly in our warm Redshed we endured the winds which reached a max of 214 kilometres an hour. It all seemed pretty cool until the blizzard subsided and the morning came and the sea was blue again. All our sea ice was gone. It was sad for us but then we thought about the thousands of penguins who lay and incubate their eggs and raise their chicks on the sea ice. Had they survived?
The salt water apparently need to be minus 2.8 degrees to freeze but I guess you don’t care and you’d rather know if all those baby penguins survived.

When all the sea ice melts it becomes the ocean again with no negligible difference to the sea level. It normally melts some time after Xmas when it gets hot down here. I guess the rest of the time it gets hot up in Broome and sucks up all the moisture and sends it down here where it becomes snow, falls down, eventually becomes ice, makes it way to the coast, breaks off as an iceberg and floats of into the ocean. Probably takes a few thousand years but its nice to think it’s all passively recycled again and again. Hopefully the cycle doesn’t speed up too much because if it melted all the ice down here then the sea level would rise by about sixty metres. Bye, Bye Broome, and all the Capitals except Canberra I guess. Maybe the politicians are smarter than we think! Speaking of smart. The penguins survived. They must have known it was going to be a crap ice year so they found a safe spot to lay their eggs and raise their chics. It took several trips to find them but they are lovely and cute and amazing and maybe I’ll write about them next.