Nuclear war is no closer now than it was during the cold war. Everything then was on a hair trigger. Now it'll just take a psychopath in charge, and no one willing to ignore the order in the command structure
We have plans for how one would modify the Sun. The physics is fine. The machines are enormous.
But over all we expect intelligent life to be able to spread to other planets, we expect them (and us) to capture more than their planet's share of their star's energy
But we see no evidence of it happening
So really there are two options
It's too hard to use enough energy to be seen; or
There aren't other intelligent species in the observable universe, at least none that can reach space
"republic" is opposite to "monarchy". It is unrelated to democracy or authoritarianism. Nazi Germany was a republic. France is a republic.
Your republic is flawed by design. Your founders didn't trust democracy so they weakened it, the country hasn't managed to improve the democracy since.
Australia is also a Federation, but a monarchy not a republic. Australia is quite a bit more democratic than America
My grandfather clock is correct* about once a week when I wind and correct it
*It must be correct as it's very slightly fast (less so than can be fixed with a quarter turn off the pendulum screw) and I set it slightly in the past
The exit bag uses nitrogen suffocation as a suicide method. It's a bag that encloses the person's head. If they felt a mask could have been used, they would have
The poor tropics are especially screwed. Also all the cities on the coast
And there's optimism in climate change, zeroing our carbon burn is straight forward. It wouldn't take a decade if we could agree on the sane path
But we have pushed so much CO2 into the air, and so much heat into the sea we need to do better than zero. I'm pretty pessimistic