Not sure if anyones really considered this, but it bugs me to see future nascent industrial applications that want to pull CO2 out of the air for products. We could very well get ourselves into an even worse situation with too little CO2.<p>Off the top of my head, if levels were to drop below 120 ppm, we would see mass plant die off. Pre-industrial levels were already around 180 to 200 ppm. So even if we can stabilize right now around 400 ppm with renewables, AND start to sequester back to pre-industrial levels, we would need to also make sure we can turn that sequestration OFF at some point. And what is that point exactly? Optimal ppm CO2 level is actually very debatable. The dirty secret is that plant growth is most optimal around 1200 - 1500 ppm CO2. Likely because plants evolved in epochs of much higher levels. Stabilizing at todays 400 ppm is probably optimal.<p>We could very well get into a situation in the future where we are begging industry to STOP pulling CO2 out of the atmosphere for fear or crop failure, instead of pumping it out. Industry in China and India that might be outside of our sovereignty. It may take 1000 years, but levels will come down naturally if we can stabilize at 400 ppm. That stability will only come from technological advances like electric cars, planes, trucks and lab grown meats.