We already are performing our own unintentional form of geo-engineering with our relentless pumping of CO2 into the air. That said, not sure blocking the sun is our best plan right now for avoiding the worst of climate change. Instead of trying to have our cake and eat it too, we need to accelerate our focus on reducing carbon output, decarbonize electricity and transportation, and invest in massive amounts of energy production to the point where energy is so cheap we can use it to pull carbon from the air.