PartagerLes émissions croissantes de HFC pourraient compromettre les bénéfices climatiques du Protocole de Montréal (en anglais)
Un rapport OMM-PNUE souligne que les bénéfices du Protocole de Montréal en termes de réduction des changements climatiques pourraient être remis en cause par les émissions croissantes de HFC utilisés pour remplacer les substances appauvrissant l'ozone.
The Scientific Assessment of Ozone Depletion 2014, published by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP), has found that the ozone layer is expected to recover to 1980 benchmark levels, the time before significant ozone layer depletion, before the middle of the century in mid-latitudes and the Arctic, and somewhat later in the Antarctic.
However, the report stresses that climate benefits of the Montreal Protocol could be offset significantly by projected emissions of HFCs used to replace ozone depleting substances.
HFCs currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year. These emissions are growing at a rate of about 7% per year and are projected to grow. If the current mix of these substances is unchanged, increasing demand could result in HFC emissions of up to 8.8 gigatonnes CO2-equivalent per year by 2050, nearly as high as the peak emission of CFCs of about 9.5 gigatonnes CO2-equivalent per year in the late 1980s.
Replacements of the current mix of high-GWP HFCs with low-GWP compounds or not-in-kind technologies would essentially avoid these CO2-equivalent emissions.
The report also mentions that one of the candidate’s low-GWP compounds (HFO-1234yf) yields the persistent degradation product trifluoroacetic acid (TFA) upon atmospheric oxidation. While the environmental effects of TFA are considered to be negligible over the next few decades, potential longer-term impacts could require future evaluations due to the environmental persistence of TFA and uncertainty in future uses of HFOs.
However, the report stresses that climate benefits of the Montreal Protocol could be offset significantly by projected emissions of HFCs used to replace ozone depleting substances.
HFCs currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year. These emissions are growing at a rate of about 7% per year and are projected to grow. If the current mix of these substances is unchanged, increasing demand could result in HFC emissions of up to 8.8 gigatonnes CO2-equivalent per year by 2050, nearly as high as the peak emission of CFCs of about 9.5 gigatonnes CO2-equivalent per year in the late 1980s.
Replacements of the current mix of high-GWP HFCs with low-GWP compounds or not-in-kind technologies would essentially avoid these CO2-equivalent emissions.
The report also mentions that one of the candidate’s low-GWP compounds (HFO-1234yf) yields the persistent degradation product trifluoroacetic acid (TFA) upon atmospheric oxidation. While the environmental effects of TFA are considered to be negligible over the next few decades, potential longer-term impacts could require future evaluations due to the environmental persistence of TFA and uncertainty in future uses of HFOs.