California SB 253 Carbon Reporting Software
About This Compliance Framework
SB 253 requires massive public and private companies doing business in California to publicly disclose their Scope 1, 2, and 3 greenhouse gas emissions.
California's Climate Corporate Data Accountability Act (SB 253) represents a seismic shift in US environmental regulation. Since the beginning of 2026, companies with over $1 billion in global revenue that "do business" in California—a deliberately broad definition—are required to publicly disclose their Scope 1 and Scope 2 greenhouse gas emissions. Moving into 2027, this expands to include the notoriously difficult Scope 3 (value chain) emissions. The data cannot be an estimate; it requires independent, third-party assurance, with penalties reaching $500,000 for non-filing or severe inaccuracies.
The ripple effect of SB 253 impacts companies of all sizes. Even if your company is well under the $1B threshold, if you supply a major retailer, tech giant, or manufacturer that operates in California, they must calculate *your* emissions to satisfy their Scope 3 obligations. Consequently, thousands of SMEs are now receiving urgent data requests from enterprise partners demanding verified carbon footprint data aligned with the GHG Protocol.
Sustalium provides the verifiable data architecture required for SB 253. For reporting enterprises, it serves as the central ledger to aggregate facility energy data, fleet usage, and supplier responses, directly linking raw data to the final carbon calculation for the assurance auditors. For suppliers, Sustalium allows you to calculate your product or corporate footprint once, attach your evidence, and securely share a standardized compliance pack with every California-bound client that requests it.
Why It Matters
First Major US Mandate
The strongest climate disclosure law in the United States
Scope 3 Inclusion
Requires calculation of complex value-chain emissions
Third-Party Assurance
Data must be independently verified by auditors
Severe Penalties
Up to $500,000 in administrative penalties per reporting year
Applicable Markets
- United States (California): Mandatory for public/private companies with $1B+ global revenue doing business in California.
What You'll Include
- Scope 1 emissions (direct operations)
- Scope 2 emissions (purchased electricity and energy)
- Scope 3 emissions (supply chain, product use, and disposal)
- GHG Protocol alignment documentation
- Independent third-party assurance reports
Who It's For
Large enterprises exceeding $1B in global revenue, and the SMEs within their supply chains being asked for emissions data.
Typical Inputs
- Facility energy consumption and utility bills
- Fleet fuel usage and logistics data
- Supplier carbon footprints and LCA data
- Purchased goods and services spend data
- Auditor verification statements
How We Help
- GHG Protocol aligned data collection
- Supplier Scope 3 surveying portal
- Audit-ready documentation linking
- Exportable SB 253 compliance reports
Implementation Steps
Define Boundaries
Map organizational and operational boundaries
Calculate S1 & S2
Aggregate direct and indirect energy emissions
Survey Supply Chain
Collect Scope 3 data from suppliers
Assure & Report
Attach auditor assurance and generate final disclosure
Ready to Get Certified?
Simplify your SB 253 emissions reporting and ensure penalty-free compliance in California.