A study published in Proceedings of the National Academy of Sciences updates estimates of the amount of warming that will be caused by hydrofluorocarbons (HFCs) between now and 2050, in a scenario where specific policies to address them are not implemented. These gasses were created as replacements for chlorofluorocarbons (CFCs), which were used as refrigerants and propellants before they were found to destroy stratospheric ozone. The study estimates that without preventative action, HFCs will cause 9-19% as much warming as carbon dioxide (CO2), by 2050. In a scenario where the concentration of CO2 is kept below 450 parts per million (ppm), unmitigated HFC emissions would be the cause of between 28% and 45% of warming.
While CO2 is the most important gas that needs to be managed to produce a stable climate, other powerful gasses like HFCs need to be dealt with, as well. This is being brought about to some extent through the operation of carbon markets, but care must be taken to avoid designing markets that can be exploited, as well as design systems where both CO2 emissions and emissions of powerful trace gasses are effectively discouraged.
One other element illustrated by all of this is how virtually any new technology that gets widely adopted has some sort of negative environmental consequences. This should be borne in mind when hoping that technological progress alone can produce a sustainable world. The technologies of the past always created problems along with new capabilities and benefits. Those of the future will inevitably do likewise.