The two prime ways in which the two differ are the type of GHG Emissions that have to be reported and the types of companies that have to do the reporting. California's regulation requires any US company operating in the state with annual revenue over $1B USD (including public and private companies) to report on Scope 1, 2 and 3 emissions while the SEC's regulation is limited to scope 1 and 2 and to all public companies. As per SEC, businesses would only have to report on scope 3 emissions if they have set scope 3 reduction targets or if scope 3 emissions are deemed material to their business.

The SB 253 is applicable to the public and private companies doing business in California with annual revenue in excess of $1 billion. These companies will have to disclose their scope 1, 2, and 3 emissions, beginning in 2026.While the SB 261 is applicable to US entities that do business in California with total annual revenue of at least $500M. These entities will have to submit climate-related financial risk reports that cover climate-related financial risks consistent with recommendations from the TCFD.

Calculating your GHG emissions can be a complex exercise with you requiring data from multiple stakeholders and all your operational locations. You can already start measure your company's scope 1 (direct emissions from their owned operations) and scope 2 (indirect emissions from purchasing electricity, steam, heating, and cooling) emissions. You can purchase a cutting-edge platform like the Oren Sustainability Hub to streamline your internal processes.