Biennial Transparency Report

The principal reporting document each Party to the Paris Agreement submits every two years under the Enhanced Transparency Framework. A BTR carries a national greenhouse gas inventory, information tracking progress towards the country’s NDC and, as applicable, information on climate impacts and adaptation and on support provided, needed or received. First BTRs were due by 31 December 2024; least developed countries and small island developing States may submit at their discretion.

Why it matters in the room

The BTR is where a claim becomes checkable: each report goes through a technical expert review and a facilitative, multilateral consideration of progress, and the reported data is the raw material for the Global Stocktake. As of October 2026, the first synthesis of BTRs (FCCC/PA/CMA/2025/16, 31 October 2025) drew on 101 reports received by 15 April 2025, and second BTRs are due by 31 December 2026.