Please do not tamper with nature on this scale. One can only get this wrong once and we could end up back in the ice age. Global warming is bad however an ice age is exponentially worse. Humans would have to figure out how to grow all food indoors at scale in a hurry, something we are not even close to yet. Someone will mention we do have vertical indoor farming but that has not proven out to scale yet even for first world countries. All third world countries would certainly starve. Climate has far too many feedback loops for humans or computers to predict what such tampering would have on a long time scale. If a group of scientists or researchers confidently disagrees just ignore them as they are likely pursuing funding without regard for the safety of the people of Earth. Moving fast and breaking things is not an option here.