European emissions of the powerful greenhouse gases hydrofluorocarbons inferred from atmospheric measurements and their comparison with annual national reports to UNFCCC

摘要

Hydrofluorocarbons are powerful greenhouse gases developed by industry after the phase-out of the\udozone depleting chlorofluorocarbons and hydrochlorofluorocarbons required by the Montreal Protocol.\udThe climate benefit of reducing the emissions of hydrofluorocarbons has been widely recognised, leading\udto an amendment of the Montreal Protocol (Kigali Amendment) calling for developed countries to start\udto phase-down hydrofluorocarbons by 2019 and in developing countries to follow with a freeze between\ud2024 and 2028. In this way, nearly half a degree Celsius of warming would be avoided by the end of the\udcentury. Hydrofluorocarbons are also included in the basket of gases controlled under the Kyoto Protocol\udof the United Nations Framework Convention on Climate Change. Annex I parties to the Convention\udsubmit annual national greenhouse gas inventories based on a bottom-up approach, which relies on\uddeclared anthropogenic activities. Top-down methodologies, based on atmospheric measurements and\udmodelling, can be used in support to the inventory compilation. In this study we used atmospheric data\udfrom four European sites combined with the FLEXPART dispersion model and a Bayesian inversion\udmethod, in order to derive emissions of nine individual hydrofluorocarbons from the whole European\udGeographic Domain and from twelve regions within it, then comparing our results with the annual\udemissions that the European countries submit every year to the United Nations Framework Convention\udon Climate Change, as well as with the bottom-up Emissions Database for Global Atmospheric Research.\udWe found several discrepancies when considering the specific compounds and on the country level.\udHowever, an overall agreement is found when comparing European aggregated data, which between\ud2008 and 2014 are on average 84.2 ± 28.0 Tg-CO2-eq$yr1 against the 95.1 Tg-CO2-eq$yr1 reported by UNFCCC in the same period. Therefore, in agreement with other studies, the gap on the global level\udbetween bottom-up estimates of Annex I countries and total global top-down emissions should be\udessentially due to emissions from non-reporting countries (non-Annex I).