A paper published in nature on the 25th reported the relationship between the change of atmospheric circulation and the recovery of ozone layer in the southern hemisphere. The study of these changes shows that this effect is a direct result of the implementation of the Montreal Protocol.
Anthropogenic emissions of ozone depleting substances lead to the reduction of ozone, which changes the atmospheric circulation in the southern hemisphere. The main impacts include the polar movement of the mid latitude jet stream and the joint expansion of the tropical circulation and the subtropical dry area. These changes have been shown to affect precipitation and possibly ocean circulation and salinity in the southern hemisphere.
After reanalyzing the atmosphere (combined with data and modeling) from 1980 to 2017, antala Banaj, a scientist at NOAA / Earth Systems Research Laboratory, and his colleagues, point out that these trends have stopped or reversed since around 2000. For example, they found that the polar movement of Southern jet streams seems to have stopped around 2000. This point coincides with the recovery of the Antarctic ozone layer since about 2000, which indicates that the decrease of ozone depleting substances stipulated in the Montreal Protocol or the pause of circulation change rend.
The results show that the Montreal protocol may also have an impact on other aspects of the earth system. Since the entry into force of the Montreal Protocol in 1987, scientists have predicted that the Antarctic ozone hole will return to the level before 1980 in the early second half of the 21st century. However, the team also pointed out that with the increase of carbon dioxide emissions, it is not clear whether the pause in the trend of atmospheric circulation can be sustained.