Question

Do these recent findings make you question whether the Montreal Protocol is effective?

Answer 1

Curbing damage to Earth’s protective ozone layer is widely viewed as one of the most important successes of the modern environmental era. Earlier this year, however, a study reported that ozone concentrations in the lower level of the stratosphere had been falling since the late 1990s — even though the Montreal Protocol, a global treaty to phase out ozone-depleting chemicals, had been in effect since 1989.

This raised questions about whether and how human activities still could be damaging the ozone layer. Atmospheric chemist A.R. Ravishankara, who co-chaired a United Nations/World Meteorological Organization Scientific Assessment panel on stratospheric ozone from 2007 to 2015, provides perspective.