What are some ways that people in a culture where head shaving is common practice could protect themselves from sunburn and other natural elements?
They could wear a hat, or other head covering.
Hats are a nifty invention that can protect a head from the sun, or insulate it from the cold depending on construction and configuration. There are even specialized hats that can protect the head from falling debris or small arms fire.
A towel will work well enough in a pinch, which is why you should never leave home without one.
By having an appropriate amount of melanin in their skin they can greatly reduce their vulnerability to sunburns.
Most other exposure issues are solvable by having enough to eat and drink. If you are squeamish about huddling, shivering and sweating:
Have the sense to come in out of the rain
Houses are a common invention to limit natural elements' intrusion into human lives. When combined with clothes we can live comfortably pretty much anywhere on Earth.
You don't specify level of technology or anything useful about this culture, so I can really only give a few basic answers that all predate the era of modern sunscreens.
Hat. Preferably broad brimmed, as this will also shade the eyes. A tall stovepipe hat can also be used to keep a small flask or perhaps a derringer. Never know when those might come in handy!
Scarf / turban / kerchief. Easy to use, plus they can be put to other uses as well.
Wig. A must at court. Looks dandy on the town!
Sunscreen. Non-permanent, but does leave the shaved head visible so you can walk like an Egyptian.
Ancient resources. Speaking of Egyptians, we moderns aren't the first to worry about sun exposure! They apparently used some concoction of rice and jasmine. Zinc oxide has also long been known to medicine and protects against UVA & B.
tattoos paint. If you google for head tattoo, you will find many more
(and very beautiful) tattoos for the head. And yes,
if you use specific paint, the resistance against ultraviolet
radiation will increase drastically.
ADDITION: user151841 pointed out that tattoos cannot protect against sunburn because a sunburn burns only the epidermis, the topmost layer of the skin which is continually shed. So the other option is using paint directly on the skin, but this means it must be renewed each day. Metallic paint should give a very good protection.
You simply are most of the time out. The sun is normally not burning like fire from one day after another, but increases strength gradually. People get sunburn because they are inside buildings until the sun is really strong and then go out and wonder why their skin get burned.
Simply avoid being outside when the sun is the strongest.
Answer: the Oxygen molecule O3, known as Ozone.
I live in New Zealand and between us and the Australians we have a high level of UV compared to other places in the world. I get sunburned through my clothes, and I can get sunburned on a cloudy day.
Some of this is because of the Ozone hole over the antarctic, allowing more ulta-violet in sunlight to come though.
So your planet could have a naturally higher level of ozone, or could be actively adding ozone to the atmosphere somehow.
Perhaps there are a lot of shorelines, because Ozone is generated by wave action. Or a heap of electrical activity, again oxygen is converted to ozone in proximity of electrical discharges.
Ozone is damaged by chloroflorocarbons, aka CFCs, that were used in spray cans for years, as well as refrigerents like Freon and fire suppressent like Halon. Your planet should never have any of this.
- More on Ozone at Wikipedia
- ENZ website, specifically But How Pleasant Is The Sunshine?
- NZ has the highest skin cancer rates in the world and to quote "The strength of the UV radiation that New Zealand receives – our UV levels are 40% higher during summer than at corresponding latitudes in the northern hemisphere (NIWA research)." and "The low ozone levels – the ozone layer absorbs a good deal of UVB ultraviolet light from the Sun. Any decrease in the ozone layer (such as the ‘ozone hole’ over Antarctica) is expected to increase surface UVB levels. "
Well, you have many answers that say "hat" but it's silly to think that you didn't also come up with that one on your own. Nevertheless, those answers seem to be well received, huzzah! I'll put a hat on right now in celebration.
Provided below are a few more possibilities. These are a little more 'outside the box.' I will also include links, unlike many of the "hat" answers. I was previously advised to include links, after all, and am unsure if the hat answers are reliable as result.
I will warn you, it is possible that the links I provide may, some day, expire. I am not trying to go on and on, here, merely trying to find that perfect balance of an interesting answer, not too long, not too short, including links, but only the right kinds of links, and essential details.
With that said, finding the correct answer appears to be down to democracy and dealer's choice. Good thing you didn't ask about climate change. Here in the United States there is a 30% chance you would end up with something ridiculous.
On to the risk of sunburn (and skin cancer) for bald people.
Answer 1. They could evolve. This seems to be how many species have adapted to a lack of hats. Here is a link on how evolution is thought to protect us against the sun. You did not specify the time length required in your question. Hats will help in the immediate moment, but evolution is a better long term fix.
Answer 2. They could stay in the shade, or only go out at night. Here is a link showing that those who work the night shift have a 15% reduced risk of melanoma. Not bad. Make your race nocturnal and bald. This would protect against sunburn as well.
Answer 3. They could convince their government to geoengineer the planet to reflect UV rays. Here is a link describing geoengineering to reflect sunlight, a similar concept, but not tailored to bald people. Still, you can adapt it to your scenario.
Answer 4. They could decide to walk with their hands on their heads. Sound silly? Perhaps. But you may remember when the chicken dance was all the rage. If you can convince an auditorium full of human beings to do the chicken dance, I think you can convince bald human beings to walk with their hands on their heads. This particular answer also helps protect bald people's scalps from rain.
And lastly, please read the above as meant in good fun, and as a suggestion to not take anything on the internet too seriously.
Hardly a civilization-wide issue.
I have been shaving my head for many years. I am a Mediterranean white kind of person. My scalp enjoys some fresh air, but if the sun shines too brightly I put a hat on to prevent sunburn. Which is not a problem as I like hats very much and I live in an infamously sunlight-deprived country. Other people may have different preferences, or be blessed by lots of melanin in their skin.
Now, you know what could be interesting with reference to your world setting? What if hats were seen as immoral, sinful or illegal?
Update: TIL that ancient Egyptians used to shave their heads (beards) and put wigs on to cover their scalp (chin). This was a necessity in order to prevent lice infestations and a very common custom amongst the free, but not amongst the slaves, who were in fact forbidden from shaving.
Make the sun go out, or move the home planet away from the sun.
Or, hats. Am I just a grump today? This question seems pretty silly.
Or! A giant orbiting opaque structure that blocks sunlight (an "earth hat").
Ooo! Breed bats to hover over people who are out in the sun. Or hummingbirds. But then they'd need something to keep from getting covered with poo.
Ya know what rhymes with "bat"?
One answer not mentioned is to do what some animals do: roll through the mud, and protect your skin that way.
Whether that's going to be cultured acceptable in the world you're creating is up to you.
Im going to aggregate some here:
Hats: obviously, from ball caps to stetsons to rice farmer hats. Straightforward logic; if your head is getting burned by the sun put something on it.
Wraps: Heads getting burned, wrap it in cloth (turbens, hajibs, bandanas etc.)
Be Black: could be a natural evolution that they evolve their skin to protect itself naturally.
Sunblocks: either natural dirts/muds or concoctions of herbs and chemicals.
Dead Animal: Neolithic humanoids would wear animal hides to protect against exposure, same concept.
Wigs!: the ancient Egyptions actually did practice head shaving because of lice and would replace their hair with wigs which could be disposed of or cleansed of the lice.
Honestly its the unique environmental conditions that you didnt mention that would ultimately affect the outcome the most.
Like if it rains diamonds maybe a hard hat would be the outcome over say a scarf.
You don't mention what the setting is, but if you want to take it to an extreme everybody could live either underground or indoors in giant glass geodesic domes (like in Logan's Run) to give the feeling of being outside.
The glass should have UVA/UVB protection-- this is typical for any quality home window tint kit.