"upcasting" and "downcasting" scoped emissions #40
Description
In the wild we find various companies reporting emissions and/or targets with various scopes: S1 emissions only, S1+S2 emissions (with no breakdown as to S1 vs. S2), S1+S2+S3 netzero ambitions, etc.
The question to be settled in this issue is whether or how we should attempt to make data comparable between companies that report some, but not all, scoped emissions. For example, should it be possible or not possible to compare a company reporting only S1 emissions with another company that reports only S1+S2 emissions? Or should the tool provide temperature scores based only on specific scopings (such as S1+S2 requiring either a combined S1+S2 report or both S1 and S2 reports that can be combined)?
Presently the ITR code will allow S1-only emissions to be "upcasted" to become comparable with S1+S2 emissions. This could result in undercounting emissions if the firm's S2 emissions are actually material. Failing to do so could greatly reduce the number of companies that can be compared with one-another.
The answer to this question will decide how we compute projections in the function BaseCompanyDataProvider::_convert_projections_to_series