This is being worked on. The problem is we are terrible at engineering biosystems, CRISPR currently works mainly to knockout genes rather than the kind of enhanced evolution you describe, and upscaling a solution to the point it can have a planetary impact is non-trivial.
Re: upscaling, I was reading another article on HN about a specific species of plant when grown in sufficiently large quantities (6x size of Texas I think) would basically bring us down to carbon neutral. We can probably scrounge up that land if the world works together but who knows.
Re: engineering biosystems, I imagine engineering native plants (if possible) has much fewer ecosystem wide chain effects) than using gene drives to eliminate mosquitoes or whatever.
Re: crispr, I see photos of glow in the dark monkeys and super muscular dogs, so as a layman it seems like cutting a gene and vaguely throwing the desired gene near the cut location seems to work. We don’t have as many ethical implications about rapidly iterating on plants as we do on animals, so it seems like if an experiment doesn’t work, just repeat 1000x until it works would do it. People talk about off-target effects etc. but you won’t really know unless you try I guess.
