The chemicals, collectively known as hydrofluorocarbons (HFCs), are becoming popular as replacements for those phased out or being phased out to protect the ozone layer – Earth’s atmospheric shield that filters out dangerous levels of the sun’s ultraviolet rays.
The UNEP study projects that by 2050 HFCs could be responsible for emissions equivalent to 3.5 to 8.8 gigatonnes (Gt) of carbon dioxide, comparable to total current annual emissions from transport, estimated at around six to seven Gt annually.
“The more than 20 year-old international effort to save the ozone layer ranks among the most successful examples of cooperation and collaboration among nations – the original chemicals, known as CFCs [chlorofluorocarbons], were phased out globally in 2010 and countries are freezing [the use of] and then phasing out the replacements, HCFCs,” said Achim Steiner, the UNEP Executive Director.
“However a new challenge is rapidly emerging as countries move ahead on HCFCs and that is HFCs. While these ‘replacements for the replacement’ chemicals cause near zero damage to the ozone layer, they are powerful greenhouse gases in their own right.
“The good news is that alternatives exist alongside technological solutions, according to this international study. While assessing the absolute benefits from switching needs further scientific refinement, there is enough compelling evidence to begin moving away from the most powerful HFCs today,” he added.
HFCs are, along with carbon dioxide, methane and other gases, controlled under the UN’s Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. Measures to protect the ozone layer are carried out under the Montreal Protocol on Substances that Deplete the Ozone Layer.
“Cooperative action between these treaties may be the key to fast action on HFCs – assisting to maintain momentum on recovering the ozone layer while simultaneously reducing risks of accelerated climate change,” said Mr. Steiner.
The new report was launched in Bali, Indonesia, at the 23rd Meeting of the Parties to the Montreal Protocol.
It is the first of three being launched this week by UNEP in the run up to the UNFCCC conference which gets under way in Durban, South Africa, next week.
