Ozone "Hole" and Global Warming ... it's probably not what you think ... it's complicated

First - the "hole" is the ozone layer isn't really a hole but a zone of exceptional depletion that forms over the Antarctic during southern hemisphere Spring (August to October). A much smaller zone forms over the Arctic during northern hemisphere spring. It is caused by some extraordinary conditions and human release of synthetic compounds, most notably CFCs.  Soooo - a toupee won't help.

The key thing about this slow burning environmental disaster is that the world cooperated to find a solution. The Montreal Protocol was an International Treaty, which was initially signed by 24 countries in 1987, though now all UN countries are signatories to the original protocol. It entered into force in 1989, setting a timetable for a mandatory phase out of ozone depleting substances (richer nations first, poorer nations later) and creating a fund to help less developed countries pay for the change.

Embedded Video Player: The Hole - A film on the Montreal Protocol, narrated by Sir David Attenborough

And it worked! Now, on the whole, the ozone layer is improving and the "holes" have gotten smaller. This year marks the 30th anniversary of the Montreal Protocol. As part of the anniversary celebrations, the Ozone Secretariat launched a communication campaign ahead of World Ozone Day to be marked on 16 September 2017. (With all the hurricanes and other events, I am not sure many people in the US noticed).


This is a far cry from what would have happened if we didn't phase out use of CFCs - the conditions that create the "hole" break down at the end of spring and the depleted zone mixes in with the rest of the stratosphere - decreasing the total amount of ozone each time - thus that "hole" - really a depletion of ozone - would have expanded to cover most of the planet. Take a look at this NASA visualization below which presents the two cases: the 'world avoided' case, where the rate of CFC emission into the atmosphere is assumed to be that of the period before regulation, and the 'projected' case, which assumes the current rate of emission, post-regulation. Things start off the same but start to diverge radically as you pass the point at which the Montreal Protocol goes into effect. Both cases extrapolate to the year 2065. (You can see the whole article at https://svs.gsfc.nasa.gov//vis/a000000/a003500/a003586/index.html)

So this is more or less where we are now ...

You can check the state of the ozone hole at NASA's Ozone Hole Watch (https://ozonewatch.gsfc.nasa.gov) which is exceptionally cool and has tons of information and visualizations of what is going on there right now!

It is also very important to understand that global warming and the ozone hole are not directly linked and the relationship between the two is complex. The extra ultraviolet radiation that reaches the Earth due to the reduction of ozone in the stratosphere does not heat up the Earth because overall UV radiation makes up only a very small percentage of the incoming solar radiation. The purple line represents inbound solar radiation - you can see that UV makes up only a mall portion of that radiation. The red line is the rebounding black body radiation from the Earth - incident visible range solar radiation is absorbed and re-released at a longer wavelength, the infrared range that we can't see but experience as heat. (This is why a blacktop parking lot can still be burning hot on a sunny day where the air temperature isn't really that high)

UV radiation is also the wrong wavelength to bounce around and be absorbed by the atmosphere like IR (infrared radiation) does. The problem with increased UV radiation is that it harmful to animal and plant cells - high levels destroy cells - you have probably experienced this in the form of sun burn. This is why in regions of the planet near the south (and to a lesser extent north) polar region are experiencing higher levels of skin cancer and damage to crops.

However, the enhanced greenhouse effect is acting to warm the troposphere and cool the stratosphere, acting to further deplete ozone. Cooling in the stratosphere exacerbates the conditions that lead to the destruction of ozone, and as the amount of ozone decreases in the stratosphere, the temperature in the layer cools down even more (i.e. less ozone to absorb UV radiation means the layer cools down even more - what would be a small amount of energy in the troposphere is very significant in the stratosphere), which in turn leads to more ozone depletion. This is what's called a "positive feedback loop." So even though the ozone "hole" is healing, though things could potentially get worse or be delayed by increased global warming (which happens in the troposphere.)

You can read more about this at http://www.ucsusa.org/global_warming/science_and_impacts/science/ozone-hole-and-gw-faq.html#bf-toc-0