Organizing Emissions
Disclosures for Assurance
California’s Climate Corporate Data Accountability Act (SB 253) establishes statutory greenhouse gas reporting for large organizations that do business in California. The law applies to companies with more than $1 billion in annual revenue and requires public emissions disclosures to be examined by an independent assurance provider, beginning with limited assurance over Scope 1 and Scope 2 and moving toward reasonable assurance and Scope 3 coverage on a later timeline.
For insurers subject to SB 253, compliance means producing emissions disclosures that can be traced to underlying systems and vendors, explaining how figures were calculated, and assigning clear ownership for controls and evidence so results can be tested and defended.
Johnson Lambert issues independent opinions under AICPA attestation standards for SB 253 emissions disclosures. We also provide attestation readiness services that focus on documentation, controls, and evidence ownership while emissions calculations and methodology design remain with your internal teams and greenhouse gas specialists.
What to Expect
in an SB 253 Engagement
Our SB 253 attestation engagements follow a phased methodology tailored to your organization’s structure and reporting needs ahead of statutory filing deadlines. We focus on confirming scope, understanding emissions data flows and related controls, performing assurance procedures over your disclosures, and sharing observations you can use to strengthen future reporting cycles.
SB 253 Independent Attestation
We perform limited assurance engagements over Scope 1 and Scope 2 greenhouse gas emissions disclosures under AICPA attestation standards, with an eye toward future reasonable assurance and planned limited assurance for Scope 3 requirements.
SB 253 Readiness Support (Non-Attest)
We provide readiness services that address how documentation is organized, how key controls operate, and who owns supporting evidence, while emissions calculations and methodology design remain with your internal teams and greenhouse gas specialists.
Documentation & Evidence Review
We review emissions disclosures and supporting files and identify gaps in support or organization that could affect future SB 253 assurance work.
Controls & Ownership Advisory
We advise on control design and clear ownership for key steps in your emissions reporting process so management can clearly describe both the figures and how related controls operate.
Vendor & Climate Reporting Alignment
We coordinate with software and sustainability partners involved in emissions reporting and consider how SB 253 disclosures align with related climate risk reporting so roles are clear and public information remains consistent.
SB 253
Engagement Design
Planning & Scoping
We confirm in-scope entities, review reporting boundaries, and align on the systems, data sources, and controls that will support SB 253 disclosures and assurance procedures.
Walkthroughs & Controls Evaluation
We assess data flows, control design, ownership, and evidence to evaluate whether your emissions disclosures are positioned for limited assurance.
Testing & Review
Our team performs assurance procedures over emissions disclosures and underlying data, methodologies, and supporting documentation to assess consistency, traceability, and overall readiness for assurance.
Reporting & Observations
We share assurance results and highlight refinements that can strengthen future reporting cycles to prepare your organization for evolving requirements.
Integration with SB 261
We identify connections between your Climate-Related Financial Risk Act (SB 261) narrative and SB 253 emissions disclosures to support coherent, well-aligned climate reporting.
Climate Disclosure Insights
Keep Pace with SB 253
December 2025
From Voluntary to Verifiable: Adapting to California’s New Climate Disclosure Standards
California’s passage of the Climate Corporate Data Accountability Act (SB 253) and the Climate-Related Financial Risk Act (SB 261) marks a turning point in U.S. climate reporting. For the first time, large companies, including many insurers, must prepare climate-related disclosures […]
California’s new climate disclosure rules—the Climate Corporate Data Accountability Act (SB 253) and the Climate-Related Financial Risk Act (SB 261)—are shaping planning discussions for many insurance organizations. Together, they introduce statutory climate reporting and emissions disclosures. SB 253, in particular, […]
California’s SB 253 and SB 261 statutes introduce a new era of climate disclosure, requiring unprecedented rigor for emissions data and climate-risk management. For insurers, this mandates clear, coordinated processes across finance, risk, IT, and operations. Our practical, insurer-focused playbook […]
Climate Disclosure Assurance
Tailored to Insurers
Johnson Lambert has devoted nearly 40 years to the insurance industry. We understand carrier, MGA, captive, and reinsurer structures; how data moves through underwriting, claims, finance, and risk functions; and how regulatory requirements shape reporting.
We serve more than 750 insurance organizations and are recognized by A.M. Best as the 5th largest auditor of property and casualty insurers. That experience allows us to bring proven assurance methodology, industry-specific insight, and practical recommendations to SB 253 emissions engagements.
Need a Plan for SB 253 Emissions Assurance?
