Respuesta :
Answer:The reduction of ODS emissions is not a uniformly positive story. In fact it has indirectly led to new problems. Fluorinated gases (F-gases) have been introduced as substitutes for ODS in many sectors such as refrigeration and air conditioning applications. F-gases include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). These gases do not deplete the ozone layer, but they are greenhouse gases. This means that these new gases also contribute to climate change. And to make matters worse, these F-gases often have a far larger impact on the climate than 'traditional' greenhouse gases such as carbon dioxide (CO2). For example, some F-gases have a greenhouse effect that is up to 23 000 times more powerful than the same amount of carbon dioxide. Fortunately, the emissions of F-gases are far smaller than those of CO2, but the use of F-gases and their presence in the atmosphere have increased since the 1990s. As a result, the significant contribution of the Montreal Protocol to fighting climate change is in danger of being wiped out by the growing importance of F-gas emissions.
study estimated that properly disposing of old refrigerants, rather than letting them leak into the air, would be equivalent to preventing nearly 90 gigatons of carbon dioxide from reaching the atmosphere. That’s more than 17 years of U.S. CO2 emissions.
Explanation:
So the science is clear: cleaning up the world’s legacy CFCs would help prevent additional greenhouse gases from further changing the climate. Yet actually doing this, particularly in developing countries, is still being worked out, thanks to financial and logistical challenges. Still, a new wave of entrepreneurs think they have found solutions that work both for the climate and companies
In 2009, the Vienna Convention and the Montreal Protocol became the first treaties in the history of the United Nations to achieve universal ratification. Substances covered by the protocol are referred to as 'controlled substances'. The main substances include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, methyl chloroform and methyl bromide. The damage to the ozone layer caused by each of these substances is expressed as their ozone depletion potential (ODP).
HFCs account for 98% of F-gas emissions, and their use continues to increase even though environmentally-friendly alternatives to HFCs exist. Measures that further limit the use and emissions of HFCs are therefore needed.
Within the EU, ensuring a full implementation of the new F-gas Regulation (and in particular the phasing down of HFCs that it envisages) is critically important.
And even though most ODS are being phased out, the Montreal Protocol still allows some quantities of ODS to be produced and used for certain niche applications (e.g. feedstock use). Cost-effective alternatives in these niche applications should be developed.
In addition, large quantities of ODS are still contained in old equipment (refrigeration systems and air conditioners) and buildings (foams) and will be released in to the atmosphere if not properly reclaimed and destroyed. Measures enabling the safe recovery of remaining ODS are therefore also essential.
