A team of U.S. scientists simulated “two worlds” and found that nearly half of the Arctic warming between 1955 and 2005 was caused by ozone-depleting substances (ODS), according to a climate science report published Tuesday in the British journal Nature Climate Change. The findings point to an unidentified source of climate change in the Arctic in the 20th century.
Ozone is mainly present in the ozone layer in the lower stratosphere 20 kilometers from the Earth’s surface, which absorbs short-wave ultraviolet rays harmful to human stoics and prevents them from reaching the Earth to protect life on the Earth’s surface from ultraviolet rays.
The ozone-depleting substance is a class of halogen compounds that destroy the protective ozone layer in the upper atmosphere, which was used as a propellant, refrigerant and solvent in the 20th century. Since the adoption of the Montreal Protocol in 1987, emissions of ozone-depleting substances have been brought under control and the ozone layer has been slowly recovering. However, ozone-depleting substances are a powerful class of greenhouse gases that live longer in the atmosphere and can therefore significantly exacerbate the man-made greenhouse effect.
This time, Arrenzo Perfani, a researcher at Columbia University in the United States, and colleagues used a climate model to estimate how much warming could be attributed to such substances.
The team simulated “two worlds”: one based on natural and man-made emissions measured from 1955 to 2005, and the other excluding ozone-depleting substances and their effects on the ozone layer. The differences can reveal the net effects of ozone-depleting substances on the climate system. The team estimates that ozone-depleting substances may have contributed to nearly a third of the global average warming over the same period, and about half of the Arctic warming and sea ice melting.
The findings offer new perspectives on the climate impacts of ozone-depleting substances, noting that the phase-out of the Substance through the Montreal Protocol would help to slow future Arctic warming and sea ice melting.