Solarpunk

14-20 degrees C is ridiculous - not because it isn't possible, but 4 degrees C is already devastating for the survivability of very adaptable billions of humans. Anything past 6-8 degrees C is unimaginable for the layperson. There is nothing solarpunk about this.

Read the science.

Well last time the ice caps disappeared, we had 150m higher sea levels and we had tropical rainforests around the poles. So that's about the worst I expect.

And even if not a single plant survives on the surface of the earth due to heat, the planet would still be vastly more habitable than any other planetary body (including moons) in the solar system. Mostly because of the magnetic field, the atmosphere shielding us and abundant water and resources. The gigantic thermal mass of the oceans will keep temperatures survivable for a REALLY long time. Assuming we don't just move to space habitats then. I would expect most people to live in seasteading cities for the lower temperatures and cheap cooling. Probably using solar powered solid state magnetocaloric heat pumps. It would take millions of years for the oceans to boil off, so I wouldn't worry about a Venus scenario. But like, 99.99% life on earth would die out, humanity would be reduced to a couple of tens of millions maybe and we would only be surviving because of our technological competency.

By that point it would be a no brainer to build solar shade satelites at the L1 lagrange point to get temperatures back to normal levels. We could easily do that today if we really wanted. It would just take a couple of percent of current world GDP. It won't fix CO2, but it allows fine grained control over temperatures. IMO this option is way safer than any other geoengineering, because we can turn it off at any time by just turning the satelites by 90°.

You could even do things like making sure every spot on the planet is exactly the same ideal temperature to make it more habitable. But I doubt we would ever do that just for the conservation concerns alone. If we had that technology, we would probably try to revert the planet back to its pre-industrial state.

At the current 4% YoY growth in energy production, we would need to harvest ALL of the energy of the sun within 800-900 years. We will start cooking the planet from our energy prduction alone (as opposed to the GH effect) within the next few hundreds of years. So if growth is to continue, industry and energy production HAS TO move to space sooner or later.

I could easily see us moving most of everything into space some time between 2100 to 2200 and starting to turn Earth into a Garden Planet. We'll run out of space for solar panels and wind turbines some time 120-150 years from today at 4% energy growth rate. Unless we want to pave over the whole planet, then we have a couple more decades of solar... Compound growth is silly like that. You would have to start giant infrastructure to start pumping heat off the planet, like giant radiative cooling towers that glow a bright as the sun (higher temperatures are much more efficient at radiating away heat) or plastering the earth in panels emitting the infrared radiation our atmosphere is almost completely transparent to (think subambient cooling paint).

All of that seems like a giant hassle, so I think energy use on earth will remain low and probably be beamed down from space with solar or fission/fusion satelites instead of being produced on earth. Except for solar cells plastering everthing man-made. I believe the entire earth will be like a giant national park after space industry&energy has outgrown earth.

In my estimation, by 2100 we'll have "solved" the worst technological challeges of climate change and from then on we'll focus on restoring the planet and moving into space.

Why? Because solar technology is still in its infancy and already extremely cheap. With 100s of different energy storage technologies on the near term horizon potentially solving the storage problem in the next 10-20 years, we'll have cheap abundant clean energy. The fact that we don't have cheap abundant is the only reason why climate change is even a problem. If energy was clean and 10x cheaper, you could literally just suck all the CO2 out of the atmosphere we emit in excess. But we don't and that's why it doesn't work currently.

I don't expect drastic decreases to clean energy prices until 2100, but enough that the switch won't be painful, but actually increase overall prosperity. You can already be completely energy self sufficient for around 50k bucks, which is nothing compared to home prices today. And those costs will only come down as the renewable technologies and industries mature. We're basically entering the exponential part of the innovation curve of renewable technoliges. Progress up until now may have been slow, but it will be radical for the next 20 years or so.

I can easily see 90% of cars being replaced by EVs, e-bikes and anything in between. A large part of their fuel will come from solar panels on said vehicles. Short to mid range electric aircraft and drone taxis will become standard. Pretty much all homes will be energy self-sufficient for cheap. Solar panels will enter 30-40% efficiency ranges soon, which means solar EVs become a no brainer, pretty much guaranteeing the average person driving the average driving range will never have to charge them. I expect agriculture to become much more sustsinable, while many degraded areas of land will be rewilded. Both of these are already happening.

There are myriads of technologies to replace CO2 heavy concrete production, not sure how competitive they'll be but at least there's hope.

People will genuinely need less cars because getting around will become much more convenient with increasing walkability, public transport and soon robot taxis.

If cheap energy is sorted out, all the other most CO2 emitting industries will easily decarbonize. E.g. solar + energy storage becomes cheaper than coal, the incentive to build coal power plants will disappear for developing countries.

I'm rambling too much but you get the point, I am pretty optimistic about the future, even in the worst scenarios, I am confident we'll figure it out. After we achieved world wide net zero, the transistion period until the climate has stabilized again will be painful, with ecosystems shifting, farming experiencing issues, hundreds of millions of people potentially having to migrate, but I think we can manage.

Then after that, unless we blow ourselves up, the planet will only become healthier.

My biggest fear really is that fertility rates drop so low, that the world economy collapses, setting decarbonization back by decades. But there are potential technological solutions there as well, like AI.

i would expect lots of house boats with gardens on their roof and deployable floating solar farms. self sustainability is the name of the game. plus cost of living just went down, since you can relocate easier to escape high docking fees.

Sunburnt.

If all the fossil fuel in the world was burned then we would be dead already.

We probably should decide how much conflict we want to imagine happening here lol.

Wars from the 1700s-1800s (a couple hundred years ago from today) just aren't thought about much during my regular daily life, but none of those were global catastrophes right.

So if we can manage to avoid major nuclear destruction, then it could be pretty tame after 300 years!

Assuming we don't all destroy each other, then we mostly keep our knowledge base, so we don't need to restart from a basic agrarian culture lol. Someone saved wikipedia right??

There will still be an unbelievable amount of losses from starvation alone, so we're definitely restarting the population from small communities.

But 300 years of repopulation, and 300 years battery research might actually get us to something approaching the early 1900s again! (Around the 1930s is when about half of American households had electricity.) Cities are possible, we start getting back into shipping between countries or continents. If we add internet into this mix, we get even further!

Honestly, if we're talking about hundreds of years (and humans don't self-destruct) then I actually think we don't get set back too far on the grand scheme of things lol.