Chapter 06 · Governance & regulationRegulation & International Instruments
Biennial report / Biennial update report (BR / BUR)
Definition
Biennial reports (BRs) were submitted by developed country Parties and biennial update reports (BURs) by developing country (non-Annex I) Parties under the Convention's measurement, reporting and verification (MRV) framework established by the 2010 Cancun Agreements. BURs contained updated national GHG inventories, information on mitigation actions and their effects, and needs and support received; BRs covered developed countries' progress toward emission targets and support provided.
References
Supersession of BR review and BUR technical analysis by BTR technical expert review; transition rules (decision 1/CP.24).
BUR contents and frequency; Cancun Agreements origin; ICA process; LDC/SIDS flexibility.
Overview
What it means
The BR/BUR system embedded differentiation: different reports, review processes (international assessment and review for developed countries; international consultation and analysis for developing countries) and flexibility for least developed countries and small island states.
Under the Paris Agreement's enhanced transparency framework (ETF), both were superseded by the single biennial transparency report (BTR) format for all Parties, with flexibility for those that need it — the first BTRs were due by 31 December 2024.
How it is used
BRs and BURs remain historically important: they built developing-country reporting capacity (the first BURs were due December 2014), and their review processes created the expert-review culture the ETF now inherits. Final BURs/BRs marked the transition point to the ETF.
Why it matters
Understanding the BR/BUR era explains the design compromises of today's transparency system — and provides the archive of pre-Paris national climate reporting that long-term assessments still draw on.