Capturing CO2 from air seems like a very difficult task. Its only 0.041% by volume, which means you need huge volumes of air, hence all the fans. One promisin

Capturing CO2 from air seems like a very difficult task. Its only 0.041% by volume, which means you need huge volumes of air, hence all the fans. One promising technology I've seen involves taking CO2 out of seawater, sequestering it as a mineral and producing H2 as a byproduct, called electrogeochemistry [0]. They claim it can be done relatively cheaply but are still lab scale. The other negative emissions technologies I've seen are biomass energy plus carbon capture and storage (BECCS). That involves using biomass for some energy purpose, say making ethanol or burning woods chips, and capturing and storing the resulting CO2. [0] https://news.ucsc.edu/2018/06/electrogeochemistry.html https://news.ucsc.edu/2018/06/electrogeochemistry.html