Scientists discover and create and down the years we learn that some 'inventions' are damaging.
Sometimes we make the necessary changes quickly; other times when jobs and business are at stake we do not until we have to.
But the damage goes on.
Look at the table below for just an idea of some of the harm caused by everyday products. In some cases they will affect generations to come for many years. And remember these are just the tip of the iceberg.
Gas Use Lifetime in atmosphere (half-life) Global warming potential
CFC-11 Early refrigerant (banned) 45 years 4,680x CO2
CFC-12 Car air conditioning (banned) 100 years 10,720x
CFC-113 Refrigerant, propellant (banned) 85 years 6,030x
HCFC-22 Refrigerant, propellant 1780 years 12x
HFC-23 Microchip etching, fire suppressant, by-product of
HCFC-22 production 270 years 14,310x
HFC-134a Fridges, car air conditioning 14 years 1,410x
HFO-1234yf Replacement for HFC-134a 11 days 4x Tetrafluoromethane
(CF4) Biproduct of aluminium smelting 50,000 years 5,820x Hexafluoroethane (C2F6)
Biproduct of aluminium smelting 10,000 years 12,010x
Nitrogen trifluoride (NF3) Etching silicon 740 years 17,200x
Sulphur hexafluoride (SF6) Anti-sparking in electricity
substations, magnesium production 3,200 years 22,800xBanning CFCs had real and positive change on our climate but the terrible legacy in some cases will live on for many years.
The ozone layer which protects people on Earth from excessive Sun damage is reportedly stabilising. Earlier use of CFCs in a range of products including deodrants had resulted in holes in the ozone layer and global warming.
But our dependence on motorised vehicles and white goods will not be abandoned.
Developers and scientists working or more environmentally friendly ways to refrigerate and power vehicles sometimes unwittingly add to the problem.
For each banned substance a replacement is found; in the long run that substance may be as bad or worse. It is trial and error with business and money too often the main priority. Once unleashed the resulting damage does not simply disappear.
"Consider toothpaste. It contains tiny amounts of those aggressive fluoride ions. But once in your mouth, the ions combine with calcium in your teeth to provide a protective coating of chemically resilient calcium fluoride."
Fluorine is an evil gas. And it is also used to manufacture a string of other artificial gases, some of which nearly left mankind exposed to burning ultraviolet light - and are even now warming the planet.