• Apple "strongly believes" that companies' corporate climate emissions disclosures should include the emissions that come from their supply chain, or what's called Scope 3 emissions.
• Mike Foulkes, Apple's director of state and local government affairs, sent the supportive letter to Scott Wiener, a California state senator and one of backers of the bill that would require business entities with annual revenues exceeding $1 billion to publicly disclose the greenhouse gas emissions associated with their operations.
• The tech giant's position on Scope 3 emissions in California, where Apple is headquartered, comes at a time when federal regulators are considering requiring some level of corporate climate disclosures.

Apple "strongly believes" that companies' corporate climate emissions disclosures should include the emissions that come from their supply chain, or what's called Scope 3 emissions.

That's according to a letter sent from Mike Foulkes, Apple's director of state and local government affairs, to Scott Wiener, one of the California state senators who introduced Senate Bill 253, which would require business entities with annual revenues exceeding $1 billion to publicly disclose the greenhouse gas emissions associated with their operations.

"To ensure accuracy and transparency, we strongly believe that companies' carbon emissions disclosures should include their Scope 3 emissions," Foulkes wrote.

"While these emissions can be challenging to measure, they are essential to understanding the full range of a company's climate impacts."

Scope 1 emissions are classified as those released from sources that are owned by an organization, including the emissions associated with burning fuel that goes into boilers, furnaces and vehicles. The Scope 2 grade are the indirect greenhouse gas emissions that a company incurs from such processes as buying electricity, heating and cooling buildings.

Scope 3 emissions come from a company's supply chain, or value chain, and are difficult to track. They tend to be the largest source of greenhouse gas emissions associated with a company.

Senate Bill 253 would require California to pass regulations by 2025 to require businesses with more than $1 billion in revenue to publicly disclose their Scope 1 and 2 emissions to a reporting organization starting in 2026. Affected companies would then be required to report their Scope 3 data starting in 2027. The bill also requires the state to review these rules in 2029 and update them "as necessary" by 2030.

In the letter, Apple acknowledges some amount of uncertainty in reporting Scope 3 emissions due to available data at this time.

"Scope 3 emissions, in particular, involve making educated assumptions and complex modeling," Foulkes wrote. "We believe, however, that our reports attest to the feasibility of reasonably modeling, measuring and reporting on all three scopes of emissions, including scope 3 emissions, which represent the overwhelming majority of most companies' carbon footprint and are therefore critical to include."

In a post on X, the platform formerly known as Twitter, Wiener thanked Apple for the vote of confidence.

Huge new endorsement — @Apple — of our groundbreaking climate bill to require large corporations to disclose their carbon footprint (SB 253).

Thank you, Apple, for making clear that this is doable & a critically important piece of climate action. pic.twitter.com/mntbWzXFDV

— Senator Scott Wiener (@Scott_Wiener) September 7, 2023

In the letter, Apple also backed third party oversight of the emissions reporting.

Apple's support of Scope 3 emissions in California, where the company is headquartered, comes at a time when federal regulators are considering requiring some level of corporate climate disclosures.

The U.S. Securities and Exchange Commission has proposed rules that would force disclosure of climate-related risks that could have a material affect on businesses. The SEC hasn't confirmed how the rule would be implemented or whether Scope 3 emissions, for example, would be included.

Apple said that with the expectation of forthcoming climate disclosures coming from other regulatory agencies besides the one in California, it would be helpful to have parallel standards.

"Given the likely proliferation of mandatory disclosures at the international, national, and sub-national level, we would appreciate the provisions for the state board to minimize the need for reporting entities to prepare duplicative reports or engage multiple assurance providers," Foulkes wrote. "We would welcome further efforts to promote convergence at a national and international level."

Apple did not immediately respond to CNBC's request for comment.