When we launched Carbon Accountable in 2020, we were driven by a simple but urgent realization: the voluntary, fragmented approach to corporate greenhouse gas (GHG) reporting was not enough to meet the scale of the climate crisis. With gridlock in Washington threatening any efforts for climate legislation, we asked: why not start in California? As the world’s fifth-largest economy and a state with a long history of bold climate leadership, California was uniquely positioned to set a precedent for mandatory, economy-wide corporate emissions disclosure.

That question sparked the journey that became the Corporate Climate Data Accountability Act (SB 253). Carbon Accountable drafted the initial policy framework, and Senator Scott Wiener agreed to author the first bill—SB 260—introduced in January 2021. What followed was a tough, three-year legislative effort marked by two bill introductions, 13 committee votes, four floor votes, facing fierce opposition the entire way.

Thanks to Senator Wiener’s leadership and the collective determination of our co-sponsors—California Environmental Voters, Ceres, and The Greenlining Institute—SB 253 was signed into law on October 7, 2023. The law now stands as a national precedent: the first in the United States to require large corporations to disclose their full greenhouse gas emissions across value chains.

For us, this has been more than a policy campaign. It has been a chance to help write a piece of climate history. Few opportunities in a career allow one to shape a law of this magnitude, and being there at every stage of its journey has been one of the great privileges of ours.

Now, the work continues. Passing the law was only the beginning—ensuring its successful implementation is the task ahead. We remain committed to building the data, policy, and accountability frameworks needed to make SB 253 a success and to help other jurisdictions follow California’s lead.

Catherine Atkin, Esq.

Michael Schmitz, Esq.
Co-founders Carbon Accountable