While sea ice in the Arctic has been shrinking, at the planet’s southern pole, the ice sheets had been increasing in size for four decades. That is until just a few years ago.

According to NASA satellite images, gains in Antarctic sea ice were being made from 1979 until 2014, when the pattern shifted from record highs to record lows by 2017.

Publishing their study results Monday in the journal Proceedings of the National Academy of Sciences, researchers are struggling to find an answer as to the cause.

Scientists believe changing wind patterns, changes in ocean circulation, or the El Nino effect could be to blame, but there is no consensus.

Source: https://apnews.com/d449b411a3db4d8b8564b7f6d8968f2d