Growth in Antarctic sea ice
Now, now Lewis, you know that's a red herring.
Left as it is in your article a casual reader might think the growth in seasonal sea ice around Antarctica is due to a cooling ocean. In fact, it's quite the opposite; the ocean around Antarctica has warmed by about 0.5C in the last thirty years.
Warmer water evaporates more and produces more precipitation around the margins of the continent which dilutes the cool surface water and produces a highly stratified ocean. Heat can't circulate up from deeper, warmer, more saline water, encouraging the growth of a thin layer of ice. Antarctic sea ice is also much less important to the Earth's energy balance than that in the Arctic. Since we have been exploring the region around Antarctica, there have been almost no years where sea ice has not melted in early summer allowing the Sun to warm the surface of the ocean.