New satellite imagery has shown that the hole in the ozone layer over Antarctica is shrinking. In 2012, the hole was the smallest it has been in the past ten years.

The images were taken by the European Space Agency’s (ESA) MetOp satellite, which has a ozone sensor. The satellite monitors atmospheric ozone over the Antarctic.

Since the 1980s, the ozone layer over the Antarctic developed a hole – a decrease in ozone concentration of up to 70% – that stays from September to November. The depletion is noticeable in Antarctica because of high winds that cause a vortex of cold air, causing low temperatures. These conditions make it easier for chlorofluorocarbons (CFCs) to deplete the ozone. The arctic does not see this effect because the northern hemisphere’s landmasses prevent circumpolar winds.

Since the mid-1990s CFC concentrations have been falling as a result of international agreements. The ESA states, however, that it could take until the mid-21st century for the ozone to recover to 1960s levels.

“Unusual” weather and atmospheric conditions can also greatly affect the behavior of the ozone. ESA scientists are using data from satellites and other sensors, along with atmospheric models to predict the future of the ozone. The ESA Climate Change Initiative is generating ozone climate data records that have predicted the ozone layer hole could close “in the next decades.”