This week, we’re responding to a listener who asked whether it’s true that sea ice in Antarctic waters has been generally increasing, while Arctic sea ice has seen dramatic declines.
“The short answer to the question is ‘yes,’” climatologist Brian Brettschneider said. “There’s been a trend in the last decade or so of increasing sea ice surrounding Antarctica. But from a climate point of view, that’s really far less significant than the decline that we’ve seen in the Arctic. And even if you add the two together, the overall trend is a reduction in global sea ice.”
It’s important to remember that it’s summer right now in the Southern Hemisphere, but still, Antarctica’s record low is for any day of the year since 1979 when they started keeping satellite records.
“So not only do we have record lows in the Arctic, but we’ve just set an all time record low in the Antarctic,” Brettschneider said. “So it’s bad all around.”
The overall trend in the Antarctic has been of increasing sea ice but this year is a different story.
“Remember that climate effects are vastly different,” said Brettschneider. “It’s not a zero sum game. You don’t just add Arctic and Antarctic sea ice and that’s your ice climate equation. Arctic sea ice is far more significant from a global climate perspective.”
Researchers are still trying to understand why there’s been an increase in sea ice in the last 10 to 15 years. Some theorize that glacial melt is flooding the ocean with more fresh water which freezes more easily than sea water.
“There’s also some discussion about the jet stream pattern, the circumpolar jet stream, at about 60 degrees south latitude and how that is preventing, at certain times of year, low pressure areas from generating large swells and kind of breaking up the ice, so it makes it (the sea ice) a little bit more resilient,” Brettschneider said.
Alaska’s Energy Desk is checking in with climatologist Brian Brettschneider each week as part of the segment, Ask a Climatologist. What do you want to ask?