Originally a comment by iknklast on Consequences for marine life.

Sulfuric acid will fall as acid rain. Particulate matter of all sorts often leads to (temporary) cooling, but it doesn’t last as long as carbon dioxide. As the carbon increases in the air, the other pollutants remain the same, and eventually they get overwhelmed.

While the optimum trade off may be fewer stomata, it makes it foolish to say that plants will gain that much from increased carbon dioxide. Which is what I was saying earlier – unless the plant growth is limited by carbon dioxide, and ONLY carbon dioxide, you will not likely see great increases in plant growth. Since nitrogen and water are the two greatest limitations on plant growth, and there are only certain conditions where CO2 is limited, the overall increased growth of plants will likely be minimal. The death of plants from increased heat, and from increased insects (insects reproduces better when its warmer) will more than offset that.

The answer? At this point, I would say there isn’t one. Every answer has a downside, yes, even nuclear. But…the answer would be a combination of wind, solar, and nuclear, with limited use also of hydropower. The real answer is to reduce the population, because every single possible answer will be met with, yes, but it will hurt the poor. Yes, but we have to feed eight billion people. Yes, but….

There are excuses floating around in the ozone, and whenever something is suggested that might lead to a change in lifestyles, someone just grabs whichever one is floating by at that moment and deploys it…wham!…to smash your argument to smithereens. We really need to get off our buts.

The truly real answer, though, is the one NOT written on the front of the Hitchhiker’s Guide to the Galaxy – panic. But that won’t solve anything, so we say not to, and we still don’t solve anything, because no one thinks it’s worth panicking about. Both solutions are non-starters, and so we don’t start.

It’s sort of like peace in the Middle East.