Virtually all experts on climate change mitigation agree that, in order to do this rapidly enough to avoid really major repercussions (like many coastal areas under water, mainly from melting Greenland and Antarctic Ice Sheets), we need to actively remove greenhouse gasses from the atmosphere. The main key for developing a viable technology it to reduce the net cost of doing this below $100 per ton of CO2 removed. Within viable pathways to this goal there are at least two approaches. One relies on a boost from Mother Nature, and the other subsidizes the CO2-removal with a salable side-product. Those two approaches are examined in this post.
Also, there is a new innovative method for improved monitoring of greenhouse gasses described at the end of this paper.