Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 287

estimated that the extremely cold conditions maintained by the vortex caused two-thirds of
the ozone loss and that the remainder resulted from the vortex blocking the transport of less
ozone-depleted stratospheric air from lower latitudes.
It is still not understood exactly what caused these atmospheric conditions to be es-
tablished. However, could we see periodic erosion of the slow ozone recovery achieved
through implementation of the Montreal Protocol? The massive Arctic depletion event was
not repeated in the winters of 2011-2012 or 2012-2013, but the Arctic Messenger will be
watching carefully in the coming years.
Itturnsoutthattheremayalsobeotherlinksbetweenclimatechangeandstratospheric
ozone depletion. Before the age of CFCs, stratospheric ozone absorbed so much of the en-
ergy from incoming solar ultraviolet light that it warmed the stratosphere. Less of this very
energetic UV radiation managed to reach into the troposphere below. Ozone depletion has
changed this picture. Less ultraviolet radiation is now absorbed in the stratosphere. Conse-
quently, the stratosphere is cooling. This leaves more UV radiation to heat the troposphere
below.