The new Arctic ozone hole

An interesting and very informative paper was published by the American Geophysical Union this past Saturday, entitled “Arctic winter 2010/2011 at the brink of an ozone hole.” The first paragraph of the introduction essentially summed up the paper’s key points:

Large losses of Arctic stratospheric ozone have been observed during winter 2010/2011, exceeding observed losses during cold winters over the past decades, characterized as the first Arctic Ozone Hole. Although in general Arctic ozone is expected to recover because of the reductions in ozone depleting substances as a result of the Montreal Protocol and its amendments, the observation that apparently the cold Arctic winters in the stratosphere have been getting colder over the past decades raises some concern that Arctic ozone depletion may worsen over the next decades if the cooling trend continues while concentrations of ozone depleting substances remain sufficiently high. [emphasis mine]

Two important take-aways:
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