Ozone hole over Antarctica getting smaller
doi:10.1038/nindia.2018.167 Published online 17 December 2018
Researchers at Indian Institute of Technology (IIT) Kharagpur report that that the Antarctic ozone hole is shrinking1.
The ozone layer is a region of the stratosphere that shields the Earth from the most harmful ultraviolet rays. But industrial emissions of ozone depleting substances (ODSs) such as cholorofluorocarbons (CFCs) have led to the formation of a hole in the ozone layer above Antarctica in winter. Two years after the ozone hole was detected in 1985, most countries of the world signed the Montreal Protocol pledging to get rid of ODSs, mainly CFCs.
The IIT researchers collected data from 1979 to 2017 using high-resolution 'ozonesondes' and satellite measurements at various altitudes over decades from stations across Antarctica. These also included measurements from Maitri, the Indian research in Antarctica. They say the Montreal Protocol may have been instrumental in saving the ozone layer from depletion. According to their report, the ozone loss (at 12-21 km) has significantly reduced over the 2001-2017 period as compared to the period before that. The reduction, they say, is in the range of 20 to 60 per cent.
The report is the first detailed long-term analysis of Antarctic ozone loss. The analysis shows a clear reduction in the frequency of occurrence of ozone loss over 2001–2017, consistently throughout various data sets. “This reveals the emergence of an important milestone in ozone recovery,” the researchers note adding, however, that the ozone recovery process "is very slow and it will take a few decades to get back to the pre-ozone hole levels.”
1. Kuttippurath, J. et al. Emergence of ozone recovery evidenced by reduction in the occurrence of Antarctic ozone loss saturation. Npj Clim. Atmos. Sci. 1, 42 (2018) doi: 10.1038/s41612-018-0052-6