Sucking carbon dioxide from air is cheaper than scientists thought
Bubblers and tubes of algae in the sun.  The bubbles stir the algae to maximize growth.  Add a few goldfish to help cycle nutrients[1].  You can get the algae so thick that a test stick (plastic spoon) can&#x27;t be seen beyond a centimeter deep.[2]<p>At this stage you can remove <i>half</i> of the algae each day and they&#x27;ll regenerate within twenty-four hours.[3]  The extracted algae biomass (mostly composed of atoms that used to be air or water) can be &quot;upcycled&quot; by feeding to higher organisms (fish, earthworms, etc.) or processed industrially for e.g. plastics, fuel, foodstuffs, whatever.<p>Ah, here we go, a few people are doing it already: <a href="http:&#x2F;&#x2F;www.iflscience.com&#x2F;environment&#x2F;urban-algae-farm-gobbles-highway-air-pollution&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.iflscience.com&#x2F;environment&#x2F;urban-algae-farm-gobbl...</a><p>The important thing is it&#x27;s cheap as heck and doesn&#x27;t require fancy technology.<p>[1] Goldfish eat algae.  Few in the tank makes it a simple aquaculture system.<p>[2] I looked for images of &quot;tubes of algae in the sun&quot; and most of them were transparent. If you can see through the tube you&#x27;re doing it wrong.<p>[3] If conditions are optimal, otherwise you might have to be happy with 35-40%.