Additional CDR Variables

[gidden]

For our SoCDR work, the MESSAGE model would like to explicitly report Biomass Burial and non-land-based Biochar applications. It sounds like this is also needed for UPTAKE. The current variable definitions do not support this. Further, there seems to be an inconsistency in the Carbon Removal Tree where the definition logic is Carbon Removal | {Where CO₂ is Stored or applied} | {Method} - but ERW in particular does not follow this (it is just Carbon Removal|ERW)

My suggestion would be to expand the Other category more explicitly, including:

• Carbon Removal|Land Use|ERW (erw on agricultural lands to enhance crop yields) [this is open for discussion, we can just use the Other version below if this is confusing/not helpful]
• Carbon Removal|Other|ERW (non-land-based ERW)
• Carbon Removal|Other|Biomass Burial
• Carbon Removal|Other|Biochar (non-land-based biochar)

@strefler @jayfuhrman @ywpratama @danielhuppmann @CandeBergero

[danielhuppmann]

Maybe naive comment, but as "not-a-CDR-expert", I find it strange to separate EWR into two subcategories when a lot of public discourse treats it as one.

I'm also skeptical of grouping several diverse (and potentially substantial) methods into an "Other" category.

[ywpratama]

In addition to those variables, I would also suggest to separate Direct Ocean Capture, which currently falls under Ocean (i.e., Carbon Removal|Ocean|Direct Ocean Capture) into two variables:

• Carbon Removal|Ocean|Direct Ocean Capture and
• Carbon Removal|Geological Storage|Direct Ocean Capture

[gidden]

Maybe naive comment, but as "not-a-CDR-expert", I find it strange to separate EWR into two subcategories when a lot of public discourse treats it as one.

I'm also skeptical of grouping several diverse (and potentially substantial) methods into an "Other" category.

There are different ways to deploy ERW. The most discussed is on agricultural fields. But there is also discussion of riverine ERW, etc. So it goes back to how we want to define the variables (is it by application like on land, etc.). Water-based ERW would not fit in "Carbon Removal|Land Use".