How do you ensure that the CO2 offsets you sell are additional and not just shifting emissions?

To ensure that CO2 offsets are additional, project developers use established methodologies and baseline scenarios to calculate the emissions reductions or removals generated by the project.

Additionality is a crucial concept in carbon offsetting, ensuring that the emissions reductions achieved by a project are above and beyond what would have occurred in the absence of the project. In other words, the project must provide a net positive impact on reducing greenhouse gas emissions. 

Each standard has specific tests to assess additionality. Generally, these tests involve demonstrating that the project:

1. Faces barriers (e.g., financial, technological, or institutional) that prevent it from being implemented under a "business as usual" scenario.
2. Is not required by regulations or laws.
3. Has emissions reductions that are above and beyond any that would have occurred in the baseline scenario.
   These scenarios must be conservative and take into account any factors that could lead to emissions leakage.