Mostly it's a question about cost, really. Arguably, we should rule out solar radiation management - in the models you get the weirdest side effects, for examp

Mostly it's a question about cost, really. Arguably, we should rule out solar radiation management - in the models you get the weirdest side effects, for example if you ramp up amount of stratospheric sulfur aerosol to the maximum effect (which doesn't even cover all of the warming we have already committed to btw), the jetstream collapses. Do you want to be the one to run that test for real? Also, they only combat a part of the problem, eg sea acidification is untouched. (Still, there is coffee talk about a sulfur test from the US soon.. the person they have in mind doesn't seem too stoked though. Not sure what the state is.) Carbon sequestration appears feasible. Options include increased biomass (limited effect and needs protection forever), direct removal (how to store safely and longterm?) and enhanced weathering. All of those cost more per ton of carbon in both energy and price compared to not burning fossil fuels. Techniques don't really exist yet to be deployed at scale either, plus the energy needs to come from somewhere. However, if you have a look at the 1.5°C IPCC report, all the pathways given there assume some kind of carbon capture. The most optimistic one just needs trees, the business-as-usual one needs a massive effort of capturing about half of our yearly emissions starting in 10 years. (!) [0] [0] https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3b.png https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3... edit: By the way, we have enough fossil fuels in the ground to reach 5000 ppm of CO2. At 1000 ppm humans already have measurable cognitive decline.