Hi Masha,
Thanks for reaching out. I think there is a way to do this, but you'd likely have to introduce a new table and constraint. I would suggest trying to replicate the EmissionsLimit constraint, but changing the sign of the inequality. EmissionsLimit currently specifies the maximum allowable emissions in a period, and if I'm understanding you correctly, you'd essentially like to specify a minimum allowable emissions. Once you implement the constraint, you can run a baseline net-zero scenario to document emissions in the first time period. From there, you can manually calculate a percent change in emissions. Then you could populate a new table, formatted similarly to EmissionsLimit, where you entered this calculated minimum emissions level for that time period.
Best,
Katie