As record heat risks bleaching 73% of the world’s coral reefs, scientists ask ‘what do we do now?’

Start killing oil executives? It won't fix anything but at least they'll suffer the consequences of their actions for once

https://www.cracked.com/personal-experiences-1424-5-things-you-learn-about-rich-people-working-at-nice-hotel.html
Quite an old listicle I read more than 10 years ago, but I still remember #1; "The Armed Security is Terrifying"
First he details how massive security was for the vice president of the US. Then for another high-profile politician, with Secret Service.
But by far the most security we've ever had was for big oil executives. We shut down two entire floors for them that only a select few hotel employees were allowed on. I was not one of those employees. Unlike the Secret Service dudes, rich people private security is as twitchy and heavily armed as every single character in a Michael Bay movie.
It's not going to be easy, but I'm up for it.
Let's make the ultra wealthy people so afraid they'll start hiring tasters again.
- Until they are too afraid to leave their bunkers, we haven't done enough. As long as they HAVE bunkers, we haven't done enough.

It's more that we've walked into a minefield, and we're going to keep on losing ecoystems like this as we keep stepping forward. Makes it incredibly vital to stop burning fossil fuels as soon as we can.
- No
  It makes it incredibly vital that we get shareholders and the C suite more money.
  Anything else is optional and not very important

What do we do now?

Two things:

Make more money for share holders
Nothing
Die....

We'll do three things:

Accurate

Transition to renewable energy faster
Consider environmental pollution an act of war, because we really are getting to that point. Yes this will be seen as the west “pulling the ladder back up after themselves”; ask the corals if they give a shit
Those won’t be enough, maybe we can put some mirrors in orbit to cool the world down just a tiny tiny bit, then de-orbit it the mirrors.

Big fold out sun blocks in space?

How about we all stop pretending we don't know what tje answer is and stop allowing the ultra-rich to steal and ruin everything.

Well shit. I thought we were supposed to ask the scientists.

Well they told us what to do, and we aren't doing it. So they are asking what options are left to them now
- scientist reaches for a rifle

Ecoterrorism when?

Well, it's not good when the scientists are asking me for advice.

Ummm... Did y'all try painting them yet?

is it nothing? I bet it's nothing

The question is this: what are you doing to make it not be nothing?
- Are you implying there is something we can do? Ooh, ooh, I know! We can ban straws! And a few if us can shower a minute shorter, that will show those pesky reefs!
  Not that I'm saying that small steps don't help, I'm sure they do, but we do tiny shit like this and a single corporation takes us a marathon back by deciding it's cheaper to cause more pollution.
  The only thing that will help is a world wide effort to curb capitalist systems. Not saying "go communist!" I'm saying we need to apply a boat load of strict environment laws and uphold them, and help companies responsible both in civil court as in criminal court. Make them pay 25% of a years revenue, jail C suit level (and lower) execs that signed off on pollution decisions or were the ones in charge of whatever caused the pollution.
  Give companies good and real incentives to play nice with the environment.
  Things like that will help. The entire "what are you going to do about it?" question can be answered with two words: absolutely nothing. Because I can't, and because the real solution shouldn't have to rest on our shoulders, it has to rest on the shoulders of the companies causing this pollution.
- I think it's important to acknowledge that systemic change needs to happen. But for those of us in a position to have the space and means for it we should be actively supporting green efforts to the fullest extent of our resources. Personal responsibility adds up when you talk about millions of people

let's grab some ice from Halley's comet and dump it in the ocean.../s

Thus solving the problem once and for all!
- ...ONCE AND FOR ALL!!!..shutup...
Lets grab some water from the sea, freeze it, and launch it at Halleys Comet.
- Matt Groening has a talent for bringing together smart people to tell us how fucked we are.....
You have the highest IQ on the planet, don't you not sure?
Xkcd did a "what if" on this. It doesn't end well.
- did you not see the futurama? hahahahahhahaha

More like, "What else do we do, now?" They've already been working to propagate heat-tolerant corals, but the climate is changing faster than they can grow them, so many corals are likely going to die in the meantime.

Good thing we've since invented plant-based sponges, whew! Carry on!

Withdraw your support for the system, stop voting, become anarchists, cultivate local communities rather than global communities.

As an anarchist who would welcome other anarchists - sadly, I doubt if that's a reliable recipe to stop climate change.
Limiting (hopefully stopping) climate change can be done under almost any political system... except perhaps dictatorial petro-states. However, it takes years of work to tranform the economy. Transport, heating, food production - many things must change. Perhaps the simplest individual choices are:
going vegetarian (vegan if one knows enough to do the trick)
avoidance of using fossil fueled personal vehicles
improving home energy efficiency (especially in terms of heating)
avoidance of air travel
avoidance of heavy goods delivered from distant lands
The rest - creating infrastructure to produce energy cleanly and store sufficient quantities - are typically societal choices.
As for corals - I would start by preserving their biodiversity, sampling the genes of all coral and coral-related species and growing many of them in human-made habitats. If we're about to cause their extinction, it's our obligation to provide them life support until the environment has been fixed.
Also, I would consider genetically engineering corals to tolerate higher temperatures. Since I understand that this is their critical weakness, providing a solution could save ecosystems. If a solution is feasible, that is.
Corals reproduce sexually so a useful gene obtained from who knows where would spread among them (but slowly - because typical colonies grow bigger asexually). Also, I would keep in mind that this could have side effects.
As for tempeature - it will be rising for some time before things can be stopped. Short of geoengineering, nothing to be done but reduce emissions, adapt, and help others adapt. The predictable outcome - it will get worse for a long while before it starts getting any better.