California’s SB 253 — also known as the Climate Corporate Data Accountability Act — mandates one of the most comprehensive greenhouse gas (GHG) disclosure regimes in the world. If your company meets the $1B revenue threshold and operates in California, you’ll soon be required to report emissions across Scope 1, Scope 2, and Scope 3 — each representing different layers of your carbon footprint.
In this guide, we break down what each scope covers, what the law expects, how timelines differ, and what it takes to actually get your data ready.
Quick Overview: What Is SB 253?
SB 253 requires all companies with over $1 billion in annual revenue that do business in California to report full-scope emissions — Scope 1, 2, and 3 — starting as early as 2026.
The bill emphasizes standardized, verified data and mandates public disclosure via a central platform. It also requires third-party assurance for Scope 1 and 2 starting in 2026, with Scope 3 assurance to be phased in later.
Learn more: What is California’s SB 253?
What Are Scope 1, 2, and 3 Emissions?
Scope
Description
Examples
Scope 1
Direct emissions from assets your company owns or controls
Fuel burned in company vehicles, on-site manufacturing processes
Scope 2
Indirect emissions from purchased electricity, heating, cooling
Electricity from the grid powering offices or data centers
Scope 3
All other indirect emissions in your value chain
Purchased goods and services, employee commuting, upstream freight, product use-phase
Scope 3 often accounts for more than 70% of a company’s total emissions, making it the most challenging part of SB 253 reporting and a critical focus for compliance.
What SB 253 Requires for Each Scope
Scope 1 and 2:
Must be reported annually starting 2026
Must be publicly disclosed through a state-contracted platform
Must follow the GHG Protocol Corporate Standard
Require limited assurance by an accredited third party
Scope 3:
Reporting starts in 2027, 180 days after Scope 1 and 2 disclosures
Must follow the GHG Protocol Corporate Value Chain Standard
Third-party assurance isn’t required yet, but the law allows for future updates
Primary and secondary data sources — including proxy data — are allowed for Scope 3, but must be clearly documented.
Reporting Timelines You Need to Know
Emissions Scope
First Reporting Year
Deadline
Assurance Requirement
Scope 1 & 2
FY2025 data → due in 2026
TBD by CARB
Yes, limited assurance
Scope 3
FY2026 data → due in 2027
180 days after Scope 1/2
Not required yet
How to Prepare: Data Sources, GHG Protocol, and Tools
Start With These Steps:
Conduct a data inventory: List all assets and activities across business units that produce emissions.
Map emission sources to Scope 1, 2, or 3
Align with GHG Protocol:
Use the Corporate Standard for Scope 1 & 2
Use the Value Chain Standard for Scope 3
Choose the right calculation methods:
Direct measurement (e.g., fuel logs, meter data)
Emission factors (e.g., EPA, DEFRA databases)
Spend-based or hybrid models for Scope 3
Document methodologies: Transparency matters. CARB expects clear disclosure of assumptions and sources.
Prepare for assurance: Align your internal process with limited assurance frameworks (like ISAE 3000 or equivalent).
Common Pitfalls in Scope Reporting
Incomplete Scope 3 value chain mapping
Inconsistent emission factors across business units
Overreliance on proxy data without explanation
Misaligned fiscal year vs reporting year
No audit trail for changes or data overrides
How Sprih Supports Scope 1, 2, and 3 Disclosures
Sprih’s platform was built with SB 253 in mind. Here’s how we help:
Automated data collection across Scope 1, 2, and 3
GHG Protocol-compliant calculators and emission factor libraries
Integrated workflows to collaborate across teams and business units
Audit-ready exports for third-party assurance
Dynamic Scope 3 modeling for complex supply chains
Support for multiple reporting frameworks (SB 253, CSRD, SEC)
You don’t have to build your emissions process from scratch — Sprih plugs into your current systems and evolves with your compliance needs.
FAQs
What counts as a Scope 1 emission under SB 253 and when must those emissions be reported?
Scope 1 emissions are direct greenhouse‑gas emissions from sources a company owns or controls, such as fuel burned in company vehicles or on‑site boilers. These must be reported annually starting in 2026 using fiscal year 2025 data. The data must follow the GHG Protocol Corporate Standard and undergo limited third‑party assurance.
How are Scope 2 emissions defined and what are the reporting expectations under SB 253?
Scope 2 emissions are indirect emissions from purchased energy (electricity, steam, heating, or cooling). Companies must report these annually beginning in 2026, align calculations with the GHG Protocol, publicly disclose via CARB’s reporting platform, and obtain limited assurance for these emissions.
What falls under Scope 3 emissions in SB 253 and when do they need to be reported?
Scope 3 includes all other indirect emissions from the value chain, such as purchased goods and services, upstream and downstream transportation, business travel, and product use. These disclosures begin in 2027, specifically within 180 days of filing the Scope 1 and 2 report.
Is third‑party assurance required for all three Scope categories, and how does it phase in over time?
From 2026, Scope 1 and 2 emissions require limited assurance by an independent verifier. Reasonable assurance for these emissions becomes required by 2030. Scope 3 assurance is voluntary at first and becomes mandatory for limited assurance by 2030.
What methods and protocols must companies use when calculating emissions across Scopes 1, 2, and 3?
All reporting must align with the Greenhouse Gas Protocol. The GHG Protocol Corporate Standard applies to Scope 1 and 2, while the Scope 3 Standard applies to supply chain and other indirect emissions. Assumptions, methodologies, proxy data, and emission factor sources must be transparently documented.
What are common challenges in preparing Scope 3 disclosures under SB 253?
Scope 3 emissions often account for 70–90% of total corporate emissions and are the most difficult to map. Challenges include incomplete supplier information, inconsistent use of emission factors, lack of activity-level data, and reliance on proxy estimates without proper documentation.
How should companies prepare internally for SB 253’s scope-based reporting requirements?
Companies should inventory all emissions sources across assets, operations, and value chains; map them to Scope 1, 2, or 3; collect data through measurement or proxies; use platforms that generate audit-ready records; align calculations with GHG Protocol standards; and structure data for third‑party assurance readiness.
