To make pesto, one of the great culinary achievements of the human race, you need large amounts of sweet basil or Ocimum basilicum L. And if you want lots of fresh basil you should hope for lots of CO2 because yet again, as the CO2Science archive shows, based on two studies in 2018 and 2020 an extra 300 ppm boosts dry weight biomass by an average of 41%. There was also one study in 1993 that looked at hydroponic systems with an extra 900 ppm of CO2 and it yielded a 21% boost. So the future of pesto is looking very green.