[shanxS]

Why so serious? /s

On a serious note, I hear you and agree with you to a certain extent.

Indulge me for a moment, in long run most likely universe will end up in heat death. So yes, we are screwed. But right now, it's time for action. We need to think of engineering solutions.

There are 2 key problems here:

1. amount of CO2 in atmosphere

2. heat added by sun every day.

Fix any one of them and we stand a chance. There are ways of fixing it from accelerating photosynthesis (chemically or by optimizing plant growth by controlling env. it's growing in etc.) or having a sun shade at L1 or just literally planting more trees.

I am assuming you are a techie, so you are well equipped with tools and you are certainly not happy, so you have a motivation.

We may not be able to solve it perfectly we can certainly make a huge dent.

[chr1]

A better alternative to a sunshade at L1 is a swarm of autonomous hot air balloons, which can change their reflectivity. A nice thing about this is that they do not need to be built all at once for the whole earth, but rich cities in north can use them to get more sunny days, and places like dubai would use them as artificial clouds.

[adrianN]

You'd need a lot more balloons inside the atmosphere than a good way away from Earth at L1.

[chr1]

But they are much cheaper, can be useful even when partially deployed, and allow fine grained control over weather instead of making everything uniformly colder.

[floatrock]

Blocking out the sun whether by a sunshade or light controlled nuclear winter/"artificial volcano" has the downside that it hurts agricultural production. And food production needs to increase anywhere by 25% to doubling by 2050, depending on which population growth hockey stick charts you look at.

[chr1]

That's assuming we block all the sunlight, but what we need to do is reduce sunlight in places like sahara, antarctica, middle of australia, and increase in places that are too cold. This can be achieved by satellites orbiting at lower level, or even stratospheric balloons. We do not need this to cover significant portion of earth surface, just enough to nudge winds in the right direction and change the humidity. Since the greenhouse effect from humidity and clouds is much larger than the effect from CO2, we can get much nicer climate even without reducing atmospheric CO2.