evidence: Antarctic sea ice has grown somewhat over the past 10 years. Between 2012 to 2014, it reached record-high extents each year during the winter. It topped 7.78 million square miles in September 2014, the largest extent since satellites started keeping accurate measurements in 1979. [...] The Antarctic freezing trend has not been captured well by climate models. So scientists have been trying to understand why planetary warming has not melted Antarctic sea ice like it has in the Arctic. In the new study, Son Nghiem, a researcher with NASA’s Jet Propulsion Laboratory, evaluated satellite data to zero in on an answer. [...] As the Antarctic sea ice reached record levels, scientists floated several hypotheses, including possible changes in the ozone hole over Antarctica, or increased amounts of fresh water—which freezes more easily—on the surface of the ocean around Antarctica. At the same time, they said it’s important to remember the big differences between the poles. Assessing sea ice dynamics at opposite ends of the Earth is not an apples-to-apples proposition.