THE 21 GIGATONNE TIMEBOMB: Broadcast in May 2011 on BBC World News to 300 million homes this programme explores the much-neglected issue of what to do about the super-greenhouse gases?
Under the 1987 Montreal Protocol, CFCs and other so-called ozone-depleting chemicals are outlawed, but their Hydrofluorocarbon (HFC) replacements – while harmless to the ozone layer – are powerful greenhouse agents.
According to the Intergovernmental Panel on Climate Change fully one fifth of the greenhouse effect by midcentury will be ascribed to these ozone-friendly but "super greenhouse gases" used in refrigeration and air conditioning.
There are alternatives – principally hydrocarbons - commercially available now (but also ammonia, carbon dioxide and water), but in some countries, they are considered a fire hazard, and are restricted. Many countries allow their usage provided safety standards are followed.
Meanwhile companies such as Dupont are developing a new generation of refrigerants, such as R-1234yf, that they claim have an minimal impact on climate change and are only "mildly flammable" (overlooking extremely toxic combustion byproducts including the lethal hydrogen fluoride).
But they are not yet commercially available, and will be far more expensive than hydrocarbons and high GWP HFCs when they come to market. Different countries have different stances on how to deal with HFC issue. This documentary examines this interesting story from different perspectives.