The ozone hole as a phenomenon is mostly associated with the Antarctic, but the Arctic also has one, much more variable in size than its Southern Hemisphere sibling. This winter the stratosphere over the Arctic has been extremely cold, causing a lot of ozone to be destroyed. If things keep up, even more ozone will be lost in spring and the hole could become larger than the 2011 record ozone hole. Read more about it in this press release by the Alfred Wegener Institute.
A good article on the subject was posted on the Science website a couple of days ago, explaining what it all means and what the role of climate change is:
Record ozone hole may open over Arctic
in the spring
Lingering atmospheric pollutants and a blast of frigid air have carved an unusually deep hole in Earth’s protective ozone layer over the Arctic, and it threatens to get deeper. Atmospheric scientists are analyzing data from weather balloons and satellites for clues to how the ozone will fare when sunlight—a third factor in ozone loss—returns to the Arctic in the spring. But they are already worrying about how extra ultraviolet light might affect humans and ecosystems below and wondering whether climate change will make such Arctic holes more common or severe.Record cold temperatures in the Arctic stratospheric ozone layer, 15 to 35 kilometers up, are the proximate cause for this year’s losses, because they help to unleash ozone-destroying chemicals. “This winter has been stunning,” says Markus Rex, an atmospheric chemist at the Alfred Wegener Institute in Potsdam, Germany. By next week, about 25% of the Arctic’s ozone will be destroyed, he says.
This time of year, the stratosphere tends to warm up with the breakdown of the polar vortex, a cyclone that traps cold air. But if a strong vortex persists another month as light returns to the Arctic after the dark winter, ozone losses will get much bigger, Rex says. Conditions are ripe for losses to surpass a record Arctic ozone hole observed in the spring of 2011, he adds.
At Earth’s surface, ozone is a caustic chemical and a health hazard. But in the stratosphere, it shields the planet from ultraviolet light. Scientists noticed in the 1980s that chlorine-containing chemicals commonly used in refrigerants were reacting to form compounds that ate away stratospheric ozone, especially over the poles. The 1989 Montreal Protocol led to the phaseout of those chemicals, but their long atmospheric lifetime means that seasonal ozone losses will persist well into this century. Every year, a major ozone hole opens up over Antarctica, where winters are colder and polar vortices are stronger and more stable than over the Arctic.
But this year, the Arctic could be the poster child. Cold temperatures have allowed nitric acid, mostly from natural sources, to condense and form the peculiar, iridescent clouds that have been spotted all over northern latitudes this winter. “They’re beautiful, but once I see them, I’m concerned—they’re dangerous,” Rex says. That’s because the clouds catalyze the reactions that mobilize chlorine into active chemicals that can react in the presence of sunlight to destroy ozone.
Read the rest of the article here.
Although it is said that the Antarctic ozone hole may be a factor in the sea ice increase of recent years, I'm not sure what effect this will have on Arctic sea ice, if any. But it's noteworthy nonetheless.