While Arctic ice is melting at a record pace, a team of NASA-led researchers say they can explain why Antarctic sea ice has been edging in the opposite direction. That paradox has puzzled scientists for years and given climate-change deniers fodder to dispute global warming.
The group found that the icy winds blowing off Antarctica, as well as a powerful ocean current that circles the frozen continent, are much larger factors in the formation and persistence of Antarctic sea ice than changes in temperature.
The mighty Southern Ocean Circumpolar Current prevents warmer ocean water from reaching the Antarctic sea ice zone, helping to isolate the continent. The winds within that ice zone keep the water extremely cold, enabling the sea ice cover to grow in recent years even as global temperatures have risen markedly.
The findings are based on satellite readings of Antarctic sea ice movement and thickness, as well as new, detailed interpretations of charts showing the shape of the sea bottom around Antarctica. They were published online this month in the journal Remote Sensing of Environment.