Climate impact of the Montreal Protocol and its Kigali Amendment (Speaker: Guus J.M. Velders, Rijksinstituut voor Volksgezondheid en Milieu (RIVM), Universiteit Utrecht (UU/IMAU))

Speaker: Guus J.M. Velders, Rijksinstituut voor Volksgezondheid en Milieu (RIVM), Universiteit Utrecht (UU/IMAU)

The Montreal Protocol has reduced the use of ozone-depleting substances by more than 95% from its peak levels in the 1980s. As a direct result the use of hydrofluorocarbons (HFCs) as substitute compounds has increased significantly. National regulations to limit HFC use have been adopted recently in the European Union, Japan and USA to substantially reduce growth in HFC use. In October 2016 in Kigali, the parties to the Montreal Protocol agreed to amendment the protocol to include HFCs and phasedown their consumption and production in the coming decades. The effects of the national regulations and Kigali amendment on climate forcings and surface temperatures will be presented. Without global regulations the HFC emissions could reach 4.0-5.3 GtCO₂-eq yr^-1 in 2050, which corresponds to a projected growth from 2015 to 2050 which is 9% to 29% of that for CO₂ over the same time period. This yields a contribution of HFCs to the global average surface warming of 0.3-0.5 ^oC by 2100. With the Kigali amendment the emissions are reduced significantly and the surface warming from the HFCs is limited to less than 0.1 ^oC by 2100.