Your AC could make jet fuel
One method of getting carbon out of the atmosphere is to build huge fan systems that operate like trees, sucking out the CO2, but running those fans would require energy and it’s hard to imagine building enough of them to make a difference. Some researchers are realizing our society already has huge fan systems...in buildings. What if they attached a filter that grabbed carbon as the HVAC systems circulated air throughout the buildings?
In the paper, the researchers calculated that one large office tower in Frankfurt, Germany could capture enough CO2 to produce more than 600,000 gallons of fuel in a year. Office buildings throughout the city could produce more than 120 million gallons. Large grocery chains in Germany could potentially capture 350 metric tons of CO2 per store each year. The same process could happen on buildings everywhere.
The proper thing to do with that carbon while we have too much in the air is to sequester it: bury it or put it into products where it couldn’t leak back out into the atmosphere. Instead, they’re talking about using the waste heat from air conditioning systems to turn the carbon into fuel like for airplanes. That would spew the carbon right back into the atmosphere. But that’s better than pumping new oil to make the fuel, adding ever more carbon into the atmosphere. All this is still theoretical; the engineers have to figure out how to scale this up.