No, I didn't. You missed, or skipped outta class, the part of science that denies extrapolation the status of demonstrable results.
The Earth could never achieve the Venus atmosphere of fuming sulfuric acid for elemental reasons. We don't have that excess of sulfate. In the planetary lottery of accumulations, Venus got a lot of heavy stuff, much more than Earth. We got the carbon dioxide. Our atmosphere was primordially mostly carbonic acid fumes, but most of it has since become layers of carbonate rock thousands, even tens of thousands of feet in some places, thick. Back in the day, when photosynthesis took root in the soup, Earth was indeed pretty hot. Life could not exist before the planet cooled down. Precambrian deposits of carbonate are pure crystalline carbonates, mostly Calcium but significant amounts of Magnesium as well, even some Lithium. After our seas spawned zillions of tons of carbonate-shelled life, and after photosynthetic life began, there was some oxygen released into the carbonic fog. Sometime after that, the atmosphere could sustain oxygen-based repiration. Before that, we had some Sulphur-based respiration.
We do have a lot of sulfate rock, mostly in form of gypsum, a resource for making wallboard that is indeed sufficient to last human housebuilders trillions of years of building.
Most..... I think 90% is a safe figure.... of Earth's atmospheric heat comes from the sun. Most of the remainder comes from nuclear processes within the Earth's core. We humans are really quite insignificant. Any impact we have is marginal. Maybe 1 degree C outta more than 200. Sure we can debate about the marginal effects of the extra heat, but we need to keep it in the real context.
So yes indeed, Hawking's rant is not based on real science.
Much more achievable than Alpha Centauri, we could invent robots, say maybe of acid-resistant metal such as Titanium, and send them to Venus to mine gold and all the other heavy elements, and build nuclear rockets that could bring it back here. All that uranium..... and gold.....
