Amid the rising calamity of climate change, Antarctic sea ice has hit an all-time high—but why? Well, scientists aren't quite sure, the Smithsonian reports. "It's really not surprising to people in the climate field that not every location on the face of Earth is acting as expected—it would be amazing if everything did," says senior NASA scientist Claire Parkinson. The mystery is that Antarctic sea ice reached 7.78 million square miles last month, the most since scientists began tracking it in 1979. A few theories, as per NASA:
- The Antarctic continent's edges could be melting, creating "just-above-freezing water," which can easily refreeze into sea ice.
- Snow falling on thin ice can push it underwater; cold water then moves up into the ice and snow, creating a slush that freezes and forms ice that's thicker and less prone to melting.
- A more complex theory involves a low-pressure system that could be blowing cold Antarctic air over the Ross Sea and creating more ice. "The winds really play a big role," a scientist says.
At the same time, scientists note that Antarctica's mainland ice is diminishing quickly, and the sea ice may only be increasing in area, not overall mass; we could be walking on thin ice here, in other words. (See how Louisiana crippled a vast environmental lawsuit.)