The IPCC Task Force on National Greenhouse Gas Inventories (TFI) plays a quiet but critical role in global climate policy. This body develops methodologies that countries use to estimate and report the greenhouse gas emissions and removals that happen within their borders. Those national inventories provide the basis for national climate policies and for reporting progress toward Nationally Determined Contributions (NDCs) under the Paris Agreement.
We just returned home from Copenhagen, where the TFI gathered around 100 experts to develop a table of contents for an upcoming methodology report on carbon dioxide removal (CDR), carbon capture and utilization (CCU), and carbon capture and storage (CCS). This meeting was just one step in a long process. The scope and timetable will need to be approved by governments in the IPCC plenary in early 2025, authors will be recruited next summer, and the report will likely be published in the second half of 2027.
Although this process might feel removed from the day-to-day work of scientists and practitioners working on CDR, it will likely shape the field for a long time to come. Today's national inventories, for instance, follow guidelines established in 2006, which have only been tweaked a couple of times since. In other words, don’t expect the TFI to look at CDR again for several more years. Although countries always have the freedom to report on emissions and removals for which the TFI does not provide guidance, the methodology report will send an important signal about which CDR approaches countries should take seriously and provide a clear path for countries to take credit for those activities.
Some CDR approaches are already addressed by TFI methodologies. These include forest and soil-based methods, bioenergy with carbon capture and storage, and biochar. But existing methodologies will likely be updated, and new methodologies may be developed for other approaches such as direct air capture, enhanced weathering, ocean alkalinity enhancement, and direct ocean removal. During the writing process, authors will evaluate if there is sufficient scientific evidence to develop a methodology for each CDR approach under consideration. Only literature made public before July 2026 will be considered. Although published scientific papers will be given precedence, it appears that preprints and other reports made public by the deadline may be taken into consideration.
If you are working on CDR — especially on these newer technologies — this is an important window in which to publicly share the data and methods you have to demonstrate the efficacy of your approach. Keep an eye on the IPCC TFI website for public outputs from the scoping meeting and more details on the process to come.