Publié le 27 février 2020
One of the earliest climate model predictions of how human-made climate change would affect our planet showed that the Arctic would warm about two to three times more than the global average. Forty years later, this “Arctic amplification” has been observed first-hand.
Record-breaking Arctic warming and the dramatic decline of sea ice are having severe consequences on sensitive ecosystems in the region. But why has the Arctic warmed more than the tropics and the mid-latitudes? We now know that this is due, in part, to tiny concentrations of very powerful greenhouse gases, including ozone-depleting substances such as chlorofluorocarbons (CFCs).
The Ozone Hole over Antarctica during its 2019 maximum—the smallest maximum on record since its discovery. Source: NASA
A wonder gas?
The ozone layer is the protective layer in the stratosphere, roughly 20-50 kilometres above the Earth, that absorbs harmful ultraviolet radiation from the sun. Ozone-depleting substances are potent greenhouse gases, but they are more commonly known for their devastating effect on the ozone layer.
These chemicals were invented in the 1920s. They were touted as “wonder gases” and used as refrigerants, solvents and propellants in refrigerators, air conditioners and packing materials. It wasn’t until the 1980s when scientists discovered a hole in the ozone layer above Antarctica that they realized the full extent of the ozone-depleting nature of these chemicals.