Visible light would probably be a hazard. Would be pretty great for "beam in the sky" special effects though.
We'll never make enough food... we'll never have enough energy... we'll never get along...
Things are always bordering on the end of the world yet we survive.
Time and time again, cries of "Too many people!!!"... how will we feed 1 billion people?
Advances in farming, logistics, technology, etc...
What's being done now? More advances in farming, vertical farming, AI, etc...
Except for advances in vertical farming, green energy, advances in urban planning allowing people to live denser and more packed together...
We'll all be dead because earth can't handle the population... cira'1968:
https://www.nytimes.com/2015/06/01/us/the-unrealized-horrors...
"Dr. Ehrlich was so sure of himself that he warned in 1970 that “sometime in the next 15 years, the end will come.” By “the end,” he meant “an utter breakdown of the capacity of the planet to support humanity.”
So... by 1985, we will all be dead because DOOM!!!
Time and time again...
Now... can we all "get along"? Christians, Muslims, Chinese, Russians, etc? THAT isn't a technology problem - that's a humanity problem.
Can we feed everyone? We sure can... and advances in tech continue to push the envelope and there is no reason to believe that we can support many multiples of what we have now.
Is there an upper limit? Undoubtedly... are we near it? Hardly...
...all the ones we never heard of.