You have probably heard of the ozone layer. The ozone layer hole over the Antarctic was one of the major environmental issues of the last century, and also one of our biggest environmental triumphs given the Southern ozone layer hole is now repairing itself; a good thing, given that a weakened ozone layer results in more harmful UV rays from the sun reaching the surface, resulting in an increase in skin cancers and other unpleasant diseases caused by it damaging our bodies. However, I think it would be useful to do a deep dive into the ozone layer, discussing what it is, how we discovered it, and what the future of it may hold.
When trying to explain things like the ozone layer, aspects of the material world that are not immediately observable in our everyday lives and thus can’t be connected to them as an opening throughline, there are two main ways of approaching it. One is just to go straight into describing the physical phenomenon itself, and then using that as a springboard for discussing how it was discovered and what its implications are as needed. The other is to take a more historical approach to it, describing how we obtained our current understanding through the discoveries and mistakes that got us here. None of these paths are the wrong way of presenting scientific understanding, but they do have different focuses and different rhetorical devices available to the writer. They can almost be imagined as separate paths to the same destination; all reaching the same place, but travelling through different surroundings and people will find some paths easier to walk than others.
Presenting science by linking it to things people are likely to have already experienced allows you to show how it matters to them directly, and provides a clear point of interest to then expand upon and explain the underlying processes and research with it as a touchstone. However, as noted above this approach struggles to explain things that are difficult to observe normally, even if their effects are highly important. In the case of the ozone layer, this is due to it being several kilometers above us and not being examinable from the ground without specialist equipment. It can also find you working backwards from a position that might not be the easiest to explain physically, and particularly for large scale and complicated issues it may well be easiest to start with the overall system and work your way down.
Taking an approach focusing on the physical processes first has the clear advantage of, well, doing exactly what it says on the tin. Communicating things takes time, energy and focus, and it is often easiest to just drill down to the core of what you want to present. It is also often the approach that scientists are most happy with; while knowing the history of how things are discovered and by who is important, when it comes to modern day research scientists generally focus on the current understanding and attempt to move on from it. The drawback is that you need to meet the people you are trying to communicate at your level, both in terms of understanding and motivation. It’s no good trying to engage your audience if you don’t both give them a structured explanation of the issue explained in a way a layperson can understand, and also explain why they should care beyond “X is amazing!”, which can certainly grab some people but no topic can grab all people all the time. This kind of approach to science communication, where we only look at what we know, or in some cases what we think we know, can also feed into some of the less healthy mindsets towards science, treating it as an ultimate arbiter of truth rather than a system of collecting evidence and creating theories to try and explain what is observed.
This problem is one the third method, where not just the processes but the history of how these processes were discovered, is often good at handling. It provides a narrative style framework to explain why and how discoveries were made, what mistakes were made along the way, and how our knowledge and understanding of a topic have grown over time. However, this can also make the actual processes harder to explain, since the history of how we reached our modern day understanding of a topic can be very convoluted indeed and require explaining multiple additional fields of study or techniques. Additionally, one can run into the exact opposite issue as with the second method; while that might cover up the people behind the discoveries, you can also put too much attention on certain big name scientists, and ignore valuable work done in providing the evidence confirming a theory or indeed not go into the required detail on the physical process the piece was attempting to explain to the audience in the first place!
For the sake of this discussion, I will be mainly using the third method. The story of the discovery of the ozone layer and its depletion by human activities is refreshingly linear in many ways, and also provides us with a number of natural rest points in the narrative which I will use to dig in and explain some of the physical properties and mechanisms that might not be fully described during the historical sections. The ozone layer, as well as being important in itself, allows for some nice introductions for various other important ideas such as why the atmosphere is structured the way it is vertically, how we observe concentrations of chemicals whether in the lab, the atmosphere or indeed beyond it into the stars, why the South Pole is colder than the North, and the concept of atmospheric lifetimes which is important for understanding why certain greenhouse gases are more important than others and for understanding air pollution.
These articles will go from ozone’s first discoveries, to the discovery of the ozone layer high above us, to why the ozone layer depletion was focused around the frozen wastes of Antarctica, and at the denouement of the story, we have a political drama resulting in the Montreal Protocol, the most successful piece of environmental legislation ever created. Finally, we will look at what the situation stands at today, and how it may change in the future.
But our story begins next time in a laboratory in Germany, where a scientist smells a strange sweet odor, like that you might smell during a lightning storm…