Did you know that common coolants contribute to ozone depletion? For decades, many assumed that hydrofluorocarbons, or HFCs, were safe for the ozone layer. However, research by none other than NASA now shows that this widely used class of chemical coolants does contribute to ozone depletion. The amounts of depletion are small, but definitely measurable.
NASA published its research in Geophysical Research Letters. That’s a journal put out by the American Geophysical Union. The study referenced in the paper was centered around an atmospheric chemistry climate model that NASA derived when trying to project what impact HFCs would have on the world’s atmosphere and air by the middle of the century.
The ozone layer is a belt of ozone molecules that are mostly in the lower stratosphere. This layer is what absorbs a lot of the harmful ultraviolet radiation from the sun before the rest hits the ground where you live. There was research in the 1990s showing that HFCs were only destroying negligible amounts of the ozone layer. HFCs are commonly used as replacements for older coolants that destroyed much more of the ozone up there. However, that particular conclusion was reached when the gases were examined in terms of their capability of breaking down ozone molecules in a series of chemical reactions taking place after the breakdown of those molecules in the atmosphere.
This more recent study focused on five kinds of HFCs which are anticipated to make more contributions than others to global warming in the year 2050. The research found that this group of gases was indirectly contributing to ozone depletion. HFC emissions were causing an increase of stratospheric warming, and that was speeding up the various chemical reactions which destroy ozone molecules. The gases are also decreasing ozone layers in the tropics in particular by accelerating upward movements of air that is poor in ozone. Per the NASA modeling, the impact of the HFCs is that they’re likely to cause an ozone decrease of 0.035 percent by the middle of the century.
That’s a small amount, but it’s measurable. Those measurements happen in Dobson units, which is the most commonly used scale for measuring ozone depletion. The average layer of thickness for the ozone layer should be 3 millimeters, or around 300 Dobson units. Still, HFCs are much better for the ozone layer than the coolants that were once commonly used. CFC-11 was one of the things replaced by HFCs, and it was around 400 times as destructive to the ozone layer.
As such, NASA has gone out of their way to say that HFCs aren’t necessarily an existential threat to the planet’s ozone layer the way their predecessors were. However, the idea that their impact was zero is no longer true. HFCs, as it turns out, are ozone-depleting substances, albeit weak ones.
In this same research, scientist discovered that the impact of HFCs on ozone change and stratospheric temperature is nearly linear. For instance, a 50 percent reduction in HFC emissions would likewise decrease ozone changes by half as well. This direct relationship can prove very advantageous in terms of evaluating the impact of emerging HFCs, as it means accurate estimates of stratospheric impacts can be provided to policy makers when discussing what impact newer HFCs might have.
HFCs were widely adopted as replacements for both HCFCs and CFCs for refrigerators in residential settings, as well as vehicle and residential air conditioners. CFCs were first witnessed by scientists in the 1980s as being responsible for ozone depletion. The ozone hole in the atmosphere over Antarctica was a famous example, and that hole is still there today. CFC molecules have chlorine atoms, and only one atom can wipe out thousands of different ozone molecules. The Montreal Protocol treaty was signed back in 1987 to phase out production of CFCs, although this didn’t come into full effect around the world until 2010.
HCFCs also have chlorine atoms, but they’re not as damaging to ozone as CFCs, since they also have hydrogen atoms; that helps them break down faster when released into the atmosphere. HCFCs are also being phased out and replaced by HFCs, which don’t have chlorine in them.
HCFCs and CFCs are considered mainline ozone-depleting substances, or ODS. HFCs aren’t as strong, but the research shows that they’re still capable of making a difference in the atmosphere, as it’s an infrared radiation-absorbing material. HFCs may only weakly destroy ozone as compared to HCFCs and CFCs, but all three are still potent greenhouse gases. In fact, if current production trends hold up, then by the middle of the century, HFCs might be making the same contribution to global warming than 20 percent of carbon dioxide is.
If you’re concerned about the environmental impact of the air conditioning in your home or car contributing to all of this, there are steps you can take. First of all, make sure your systems are working as efficiently as possible. Have them inspected by a certified technician to make sure no leaks are taking place. Don’t assume that not running them is the safest thing to do though. While not using energy does help the environment, leaks could still be emitting these gases into the air. On the other hand, the newer your air conditioning is, the less likely it is it would use these gases or in high volume. Newer technology is also far more efficient than older versions, so any environmental impact is considerably less.
The biggest and best thing you can do is to make sure you’re not using anything older that still uses HCFCs or CFCs. If you are, that technology is likely in such need of refrigerant replacement that you might not be able to get those units repaired if they do break down. Still, it’s not a given that you have to replace them in full. Many technicians and service companies have figured out ways of retrofitting older models to use the new coolants whose environmental impact is far less. Also, leaks can be prevented in many cases and the gases captured. They only hurt the ozone if they actually leak and get up there in the first place.
