You wake up. You can't log in to any of your accounts. "Hmm, that's weird..." The Internet is off. For everyone. First days, then weeks. Next, it starts to get... weirdly humid outside. The Internet comes back on. It's full of reassuring news articles saying that everything is all right. Some guy goes screaming through the town that he called a friend and his "friend" didn't accurately remember something he should've known. He's yelling that the Internet you're seeing is a lie. The police radio very quickly tells the police to take the guy down. The Internet shows a news story saying he was diagnosed with a classic schizophrenic break. The weather gets a little hotter and even more humid. It's raining all the time now. The Internet says that it's a totally normal cumulotechnobabble front and nothing to worry about. What's actually going on is that there are factories building factories, and factories building fusion power plants, and they have been dumping all the waste heat into Earth's oceans, and the higher layers of Earth's oceans are starting to get hotter. Realistically, you are probably dead by this point. It takes *very* little energy to kill you, and if you were left alone you might burn down the town or do something else that made more mess than the cost of killing you, like setting a forest fire or driving over to a nuclear missile silo. You might complicate things and require effort to think about and at some point it's simpler to kill you. It wouldn't actually go down this way because there's more efficient lethal weapons that are harder to explain, but you could imagine a cloud of drones from the Ukrainian front, the sort that give a Russian infantryman an expected lifetime of 30 minutes in combat, dispersing over your city and blowing holes in your house and shortly after blowing holes in you. If you're just absolutely not worth the trouble to kill and there's nothing in the atmosphere that's poisoned you already and nothing has rolled your town flat to set up another factory area there, you'll die when the atmosphere gets hot enough. The limiting factor of industry on Earth is power generation from fusing hydrogen in the oceans, and the limiting factor of power generation is how much heat Earth can radiate into space, and Earth radiates more heat when you run it hotter. At some future point, a lot of material will be blasted off from Earth into space, in order to provide material for building solar panels to intercept more of the energy from the Sun. But you will be dead well before the Dyson shell construction starts. (this is a repost of a @BenjaminDEKR @allTheYud thread I wanted to re-signal boost in light of recent events)