Carbon accounting overhaul slips to 2027

The Greenhouse Gas Protocol is no longer setting its own clock. In Trellis's updated 2026 timeline of voluntary climate and nature standards, the public consultation draft for the Corporate Accounting and Reporting Standard has slipped to Q2 2027, pushed there by the decision to align the overhaul with the ISO 14064 series. First published in 2001 as one of the first comprehensive greenhouse-gas inventory methodologies, the standard underpins a suite that includes amendments for Scope 2 electricity and Scope 3 value-chain emissions; it is now under review by the GHG Protocol's independent standards board, and the new timeline points to a unified standard draft in Q2 2027.

That same quarter now holds the public consultation draft for the Actions and Market Instruments standard, which is meant to create accounting rules for climate investments beyond a company's direct operations — insets or value-chain interventions — that existing frameworks don't cover. Its first component, consequential accounting for electricity, ended public consultation on Jan. 31 with a white paper available, and the workstream is now aligned with the Scope 2 electricity rules changes. The Corporate Value Chain (Scope 3) Standard's public consultation draft is due slightly earlier, in the second half of 2026, though Trellis flags that the date could move with the ISO work.

Beyond the GHG Protocol, the timeline tracks a feedback deadline for the ISO net-zero standard, updated dates for Science Based Targets for Nature and the Task Force for Corporate Action Transparency, a new report from Carbon Measures, and safer chemistry recommendations from the Safer Chemistry Impact Fund. Trellis says the list is not comprehensive and will be updated as new drafts, standards, and consultations open, but the spread of items — from net-zero validation to nature targets — suggests the disclosure agenda is broadening well beyond the traditional carbon-inventory boundaries.

ISO alignment has made the corporate standard the pacing item, and the two Q2 2027 drafts will now arrive in the same quarter, which means the corporate and market-instruments standards will be negotiated in tandem. For companies, the delay is a reprieve with a price: more time before the new rulebook lands, but a rulebook that will likely demand a more integrated, and more complex, inventory. The wait buys time, not simplicity.