In the run-up to the Paris Agreement’s creation, over 180 countries submitted their first climate plans, known as intended nationally determined contributions (INDCs) which become nationally determined contributions (NDCs) once countries formally joined the Agreement. However, the end-dates of these plans are different: some cover the period through 2025, while others run through 2030. Most NDCs also did not specify the beginning date that they were covering. As part of the Paris Rulebook negotiations, countries grappled with three key questions: 1) whether future NDCs should all cover the same time frame, 2) if so, starting when, and 3) the length of the common time frame.

Read an overview below or our deep dive on Common Time Frames.

Key Rulebook Decisions from COP24

Ultimately, in Katowice countries were only able to decide whether and from when common time frames should apply. Countries agreed that the NDCs implemented beginning in 2031 should have common time frames.

Remaining Negotiating Mandates

Countries could not agree on the length of the common time frame. This means that we still do not know whether an NDC submitted in 2025 would have an end date in 2035 or 2040, or whether one submitted in 2030 would have an end date in 2040 or 2045, etc. Negotiations have focused on three main options: a five-year implementing period, a 10-year implementing period, and a compromise option known as 5+5.

The five-year implementing period requires that countries update their targets regularly and ensures that countries re-evaluate their contributions every five years. The 10-year time frame may allow more time for planning and implementation but could also lock in high-emitting infrastructure that would make it more challenging to limit global temperatures in the long term. The 5+5 approach would require countries to use a five-year time frame but would also encourage them to communicate tentative 10-year targets so that the necessary planning processes can prepare for their implementation.

Countries have decided to continue negotiating on this issue but did not set a deadline for a decision. As other components of how the Paris Agreement will work — such as reporting on achievement of NDCs — must be built on this decision, countries should decide as soon as possible.

Figure 3, showing options for NDC planning and implementation periods.


Read Common Time Frames Deeper Dive