Under protocol, assessments such as the one released on Monday are required to take place at least every four years. In addition to NOAA scientists, researchers from NASA, the World Meteorological Organization, the United Nations Environment Program and the European Commission were among the contributors.
The new assessment also looked, for the first time, at the effects on ozone of a possible type of climate intervention, or geoengineering. The method, known as stratospheric aerosol injection, aims to cool the atmosphere by using aircraft or other means of distributing sulfur aerosols to reflect some of the sun’s rays before they reach the surface.
The idea met fierce opposition. Among other objections, opponents say interfering with the climate in this way could have severe unintended consequences, potentially altering weather patterns around the world. But many scholars and others say that at least, Search is requiredbecause warming could reach a point where the world becomes desperate to try such a method of intervention, perhaps temporarily to buy time before cutting greenhouse gases has a significant impact.
NOAA’s Dr. Fahey said some studies showed an effect on ozone from sulfur spray, so the assessment team was given the task of looking into that.
He said the protocol “is in place to protect the ozone layer, and we’ve done a very good job dealing with ozone-depleting substances.” Looking at stratospheric aerosol injection “is in our wheelhouse,” he added.
Dr. Fahey said there is a lot of uncertainty in their findings, but the underlying message is that trying to cool the planet by 0.5 degrees Celsius (0.9 degrees Fahrenheit), for example, through the use of sulfur spray, will have some effect on ozone. But he said it “will not destroy the ozone layer and cause catastrophic consequences.”
“We already knew that because Mount Pinatubo did the experiment for us,” he said, referring to the massive volcanic eruption in the Philippines in 1991 that sent massive amounts of sulfur gas into the stratosphere, creating a haze that resembled geoengineering efforts.
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