The importance of the Montreal Protocol in protecting climate

TLDR

The 1987 Montreal Protocol has successfully cut global production, consumption, and emissions of ozone‑depleting substances, which are also greenhouse gases that contribute to climate radiative forcing. The study proposes that further climate benefits beyond Kyoto’s target could be achieved by regulating substitute fluorocarbon emissions and adopting lower‑GWP alternatives under the Montreal Protocol. Historical data show that without the 1974 ozone‑depletion link, ODS radiative forcing would have been much higher, and the Montreal Protocol’s climate protection alone already surpasses Kyoto’s first‑period reduction goal.

Abstract

The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark agreement that has successfully reduced the global production, consumption, and emissions of ozone-depleting substances (ODSs). ODSs are also greenhouse gases that contribute to the radiative forcing of climate change. Using historical ODSs emissions and scenarios of potential emissions, we show that the ODS contribution to radiative forcing most likely would have been much larger if the ODS link to stratospheric ozone depletion had not been recognized in 1974 and followed by a series of regulations. The climate protection already achieved by the Montreal Protocol alone is far larger than the reduction target of the first commitment period of the Kyoto Protocol. Additional climate benefits that are significant compared with the Kyoto Protocol reduction target could be achieved by actions under the Montreal Protocol, by managing the emissions of substitute fluorocarbon gases and/or implementing alternative gases with lower global warming potentials.