The low temperatures recorded this year in the upper layers of the atmosphere have allowed for this phenomenon. In fact, low temperatures favor the formation of clouds in the stratosphere. Around these clouds, and with the help of sunlight, some chemical compounds that contain chlorine or bromine produce reactions that damage the ozone layer.

The phenomenon is common in Antarctica, where low temperatures are accompanied by major changes. However, the Montreal Protocol, which prevented the production of CFCs, has greatly weakened the ozone hole. In the case of the Arctic, temperatures are usually more variable and extreme temperatures that can damage the ozone layer are not maintained for a long time. This year, however, polar violence has been particularly strong, that is, the western wind system circulating through the North Pole. According to experts, these winds isolating the Arctic from the rest of the world ' s meteorological systems have contributed to maintaining low temperatures in the stratosphere, creating the right conditions for the formation of the ozone layer.