Briefs: WMO-UNEP

The WMO-UNEP "Scientific Assessment of Ozone Depletion: 2010" launched on the International Day for the Preservation of the Ozone Layer (September 16) highlights Montreal Protocol contributions toward reducing global greenhouse gas emissions. It also assesses that "EESC" (equivalent effective stratospheric chlorine) at midlatitudes is projected to return to 1980 levels in 2046 for the baseline scenario, 2-3 years earlier than projected in the previous 2006 Assessment; this revision is primarily due to an improved understanding of lower stratospheric chlorine and bromine release from ozone-depleting substances (ODSs) along with contributions from smaller HCFC emissions. Moreover, " the sum of the HFCs currently used as ODS replacements contributes about 0.4 gigatonne of CO2-equivalent per year to total global CO2-equivalent emissions, while the HCFCs contribute about 0.7 gigatonne. CO2-equivalent emissions of HFCs are increasing by about 8% per year and this rate is expected to continue to grow, while the contribution from HCFCs is expected to start decreasing in the next decade." www.unep.ch/Ozone/Assessment_Panels/SAP/ExecutiveSummary_SAP_2010.pdf