Pin or inspect the session snapshot date

Call once at the top of an analysis script to declare the vintage of CER data you intend to use. Every subsequent cer_* fetch records this date in the cer_tbl provenance header, in cer_manifest() entries, and in cer_cite() output.

Usage

cer_snapshot(date)

Arguments

date

ISO "YYYY-MM-DD" character, Date, or POSIXct. Pass NULL to clear.

Value

Invisibly, the new pinned date (as Date), or NULL.

Details

This matters more for CER data than for most government data: projects relinquish ACCUs retroactively, the CER transfers projects between proponents, methods are reclassified (e.g. post-Chubb-Review status changes), and the Quarterly Carbon Market Report occasionally restates prior quarters. A snapshot pin is the minimum evidence a reviewer needs to verify a published carbon-market claim.

See also

Other reproducibility: cer_cite(), cer_deposit_zenodo(), cer_legislative_instrument(), cer_manifest(), cer_manifest_clear(), cer_manifest_write(), cer_sha256()

Examples

cer_snapshot("2026-04-24")
cer_snapshot()
cer_snapshot(NULL)