Oh hey, another bad thing to worry about happening in 2020.
But it's a cool paper. It would be interesting to see if they can find more instances of this sort of damage over various, widely space geographic areas. And especially in other species/other external signs of UV damage.
Even though they do analysis to try to eliminate other possible explanations, I'm not sure I'm super on board with immediately accepting the UV/ozone explanation whole sale. I always like to see bets hedged with "lends further evidence to support...." language.
I'd also love to hear from anyone with domain knowledge that might be able to add their perspective on the paper.
I have searched for, but been unable to find, a chart of estimated UV levels at ground level over the past few hundred years.
I'm interested in it because suntans seem so much worse now than in the past, where people didn't have access to suncream, yet still spent lots of time outside.
"I got used to it by spending my whole life outside" doesn't seem to fully explain it.
I don't know if they even have that data for that length of time. You might find some info in literature regarding the difference in UV exposure in areas under the ozone hole vs areas of more normal exposure.
As an aside, don't get misled by nutters talking about ground level UVC levels. They don't know what they're talking about and are citing people who don't know how to use their UV-C meters (which are sensitive at wavelengths other than UVC and therefore require extensive filtering).
Further edit: I should mention total solar irradiance has remained relatively consistent over time (and continues to). I bring up these things because I've talked to some nutty people about this stuff in the past and those are common stepping off points into la-la land.
>I should mention total solar irradiance has remained relatively consistent over time (and continues to).
It should be noted that the 11-year solar cycle is much stronger in the shorter wavelengths, especially below 200nm. Since that is absorbed in the ozone layer there is a change of up to 2K max in the stratopause (~50km). It doesn't really appear to propagate down, and is rather on the level of a scientific curiosity, but still. [0] (Longer-term changes than the 11-year oscillation seem to be much lower, but this is hard to determine.)
If you want to have information about UV at ground level you can look at proxy data. [1][2][3]
Of course there are some complications with that as always though, and it's not that easy to interpret.
But it looks like while there is variation it is mainly along the 11-year cycle. (I can't say much about the strength of the change on ground level without further reading. It's in the low percent range on top of the atmosphere, but almost all of that will be stopped in the ozone layer.)
But it's a cool paper. It would be interesting to see if they can find more instances of this sort of damage over various, widely space geographic areas. And especially in other species/other external signs of UV damage.
Even though they do analysis to try to eliminate other possible explanations, I'm not sure I'm super on board with immediately accepting the UV/ozone explanation whole sale. I always like to see bets hedged with "lends further evidence to support...." language.
I'd also love to hear from anyone with domain knowledge that might be able to add their perspective on the paper.