31
How much it costs to cut 1 metric ton of carbon emission with various methods for different global carbon emission levels
(www.edf.org)
As you reduce the amount of carbon emissions (the y axis) the methods to keep reducing carbon cost more (the x axis.)
This great graph came to my attention from this video from vlogbrothers. It also has some good explanations of what it means.
Note that carbon capture doesn't really make sense till you've exhausted all the other emission minimizing methods.
Source: https://www.edf.org/revamped-cost-curve-reaching-net-zero-emissions
Does the graph starting below $0 indicate some of this is negative cost?
Yes, it's cost savings to install solar over continue with coal for example.