Should I use the new IPCC GHG Inventory Guidelines?

Yes, you should use the new IPCC guidelines, with an awkward caveat. Technically speaking, there is every reason anyone engaged in estimating greenhouse gas (GHG) emissions or removals—from corporate, to facility, to project, to national scales — should use this updated guidance. Fully published late last year, it is the product of five years of rigorous scientific work by 280 experts from 47 countries (yours truly included).

As you hopefully know, the guidelines from the Intergovernmental Panel on Climate Change (IPCC), although created for national GHG inventory preparation, are the foundational reference for all GHG measurement, reporting, and verification (MRV) work. All modern-day GHG programs, methods, and policies have their roots in the IPCC Guidelines—including project methods from VCS, corporate reporting using the GHG Protocol, carbon-neutral claims, or Paris Agreement Nationally Determined Contribution (NDC) commitments.

Now for the caveat. To my displeasure, these new IPCC guidelines are going to be difficult for you to use. The reason relates to some complicated international diplomatic factors. The end result is that it is not politically acceptable to replace the previous guidelines (2006 IPCC Guidelines for National Greenhouse Gas Inventories). Instead, this new guidance is in the format of an elaborate corrigenda or amendment. And because the international climate negotiations feed on ever shifting terminology (its easier to agree on a new term because the previous language has too much baggage), the latest guidelines descriptor is “refinement” (having previously cycled through “revised” and “good practice”). As a practical matter, for some sections you will use this new 2019 Refinement, but there are many sections that the IPCC did not update, so you must still refer to the previous 2006 Guidelines (see Figure). You will need to have both documents open at the same time and frequently jump back and forth between them.

In sum, the ridiculous official title says it all: 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Here is the full description:

What was already a huge 5-volume reference has effectively been doubled in size. But, that doubling is sort of like the concept of the accumulation of junk DNA. A good portion of the old 2006 Guidelines should be replaced entirely by what is described within the 2019 Refinement. But given the nature of addendum, the only way to know which particular sections are overwritten is to first look up a section in the 2019 Refinement and then move back to the same section in the 2006 Guidelines to fully grasp the combined current good practice. And yes, there are additional refinements for the Wetlands Supplement as well. OK, now I’ll stop. The 2019 Refinement is awkward and will take more work to use, but nevertheless that shouldn’t stop us from utilizing them.

Technically the new guidelines are a substantive improvement and you should use them.

Since 2006, ample new scientific knowledge has become available in the literature to update the guidelines, particularly with respect to new emission factors and technologies. More specifically the 2019 Refinement:

• Provides updated methodologies, default emission factors, and other parameters based on the latest scientific information for GHG sources and sinks; and
• Adds wholly new guidance on select topics for which there was previously no guidance provided.

Ultimately, it is expected that all countries will use the 2019 Refinement for GHG reporting under the Enhanced Transparency Framework (ETF) of the Paris Agreement. For this to happen, the 2019 Refinement will have to be agreed upon through a decision of the Conference of the Parties serving as the Meeting of the Parties to the Paris Agreement. Amidst the unfortunate dumpster smolder that is the delayed UNFCCC negotiations process, who knows when this formal decision will be taken. Regardless, all countries and anyone else can voluntarily begin using them immediately.

So, what is in this new 2019 Refinement? Overall, there are hundreds of small technical updates. But, there are also a few broader improvements to highlight.

• A highly useful new section has been added that covers inventory systems and management, data gathering, compilation, and reporting, including inventory management tools (e.g., workplans, improvement plans, data management systems, quality systems, training and capacity building, and documentation procedures). [co-authored by yours truly]
• For fugitive CH₄ emissions from oil and natural gas systems, significant updates to methods and emission factors have been added to reflect the range of technologies and practices in use, including unconventional oil and gas exploration technology and abandoned wells. These are notable given the dramatic oil and gas production changes associated with fracking and other techniques (see this blog post on the topic).
• Biomass Tier 1 factors have been updated for Forest Land, Cropland and Settlements. Tier 1 carbon stock change factors have been updated for tillage management, grassland management to address impacts on soils.
• New guidance for CO₂ and non-CO₂ emissions from flooded lands.
• Includes more manufacturing sectors identified as sources of GHGs, including production of hydrogen, rare earth metals, and alumina, and waterproofing of circuit boards.
• Appendices have been added to address emission sources or removal sinks that are poorly understood and where there is insufficient scientific information to develop reliable guidance. But, others are encouraged to use the appendices as a basis for further methodological development.
• The definition of inventory “good practice” has effectively been better defined statistically. It was described as “a set of procedures intended to ensure that greenhouse gas inventories are accurate in the sense that they are systematically neither over- nor underestimates so far as can be judged, and that uncertainties are reduced so far as practicable”. A careful read of the 2019 Refinement now explains “good practice” as “a set of procedures intended to ensure that greenhouse gas inventories are accurate in the sense that they are systematically neither over- nor underestimates so far as can be judged, and that they are precise so far as practicable“. Get exited!

I am sure you agree that this detailed technical work on guidelines is enormously important and foundational to climate change policy at all levels.

I’ll conclude with a summary of the major improvements you will find in the 2019 Refinement (see below). This summary is itself a short version of a longer more detailed summary by the IPCC, which you can find here.

Volume 1 (General Guidance and Reporting)

• National GHG inventory arrangements and management tools: Elaborates guidance on establishing GHG inventory systems including institutional arrangements (the interactions between institutions/organisations involved with GHG inventory inputs, compilation processes, and outputs) as well as inventory management tools (e.g., workplans, improvement plans, data management systems, quality systems, training and capacity building and documentation procedures).
• Data collection strategy: Elaborated guidance for collecting existing national/international data and new data, applicable to activity data, emission factors, and uncertainty data collection.
• Use of facility-level data in inventories: Detailed industrial facility-level data that are increasingly collected for various goals such as tracking the progress of emission trading programmes or climate change policies have the potential to be utilized in GHG inventories. The challenge is assessing how to integrate facility reported data to achieve improvements, especially if there are some outstanding coverage and completeness issues. New guidance is provided on how best to use facility-level data that are not originally designed for GHG inventories.
• Uncertainty analysis: Provides an update on uncertainties associated with activity data and guidance on how to derive uncertainty estimates from activity data generated based on random samples (e.g., for land use or forest cover surveys). Examples are added for using the error propagation and Monte-Carlo analysis approaches for combing uncertainties.
• Comparison of GHG emission estimates with atmospheric measurements: Guidance on comparison of GHG emission estimates with atmospheric measurement has been elaborated to reflect new atmospheric science and inverse modeling.
• Indirect GHG emissions: New guidance on non-biogenic sources of CO₂ from the atmospheric oxidation of methane (CH₄), carbon monoxide (CO), and non-methane volatile organic compounds (NMVOCs).

Volume 2 (Energy)

All methodological updates made in the 2019 Refinement are in the fugitive emissions categories. No methodological updates were made for stationary combustion or mobile combustion.

• Fugitive emissions from oil and natural gas systems: Updates to emission factors to reflect the range of technologies and practices in use, including for unconventional oil and gas exploration. It also includes methods and emission factors for abandoned wells. An annex provides data to disaggregate factors into venting, leak, and flaring sources.
• Fugitive CH₄ and CO₂ emissions from mining, processing, storage and transportation of coal: New guidance on fugitive CO₂ emissions from underground and surface mines including CO₂ from methane utilization or flaring from underground coal mines. it adds year-specific default input values for fugitive CH₄ emissions from abandoned underground mines.
• Fugitive emissions from fuel transformation: Includes a new section on fugitive emissions from fuel transformation, including methods for fugitive emissions from charcoal production, biochar production, coke production, (including flaring), gasification transformation processes (coal to liquids, and gas to liquids), and methods in Appendix (biomass to liquids, biomass to gas, and wood pellet production).

Volume 3 (Industrial Processes and Product Use)

• New categories and new gases: Includes more manufacturing sectors identified as sources of GHGs, such as production of hydrogen, rare earth metals, and alumina, and waterproofing of circuit boards. In addition, a basis for future methodological development is provided for fluorinated treatment of textiles, carpet, leather and paper. Additional GHGs identified by the IPCC are also included, for example, additional hydrofluorocarbons, perfluorocarbons, and halogenated ethers, such as PFPMIE (a perfluoropolyether widely used as a heat transfer fluid in electronics manufacturing).
• Updates: The guidance for several source categories has been updated, including production of nitric acid, fluorochemicals, iron and steel, aluminum, and electronics, and for the production and use of refrigeration and air-conditioning equipment.

Volume 4 (Agriculture, Forestry and Other Land Use)

• Interannual variability (IAV): A new option to disaggregate Managed Land Proxy (MLP) emissions and removals into those that result from human effects and those that are considered to result from natural disturbances. This section may be of interest to those with emissions that have high IAV due to natural disturbances.
• Biomass estimates: Biomass Tier 1 factors have been updated for Forest Land, Cropland and Settlements. Guidance on Tier 1 methods for Cropland and Settlements has been clarified.
• Soil carbon: Tier 1 carbon stock change factors have been updated for tillage management, grassland management and land use based on evolving understanding of management impacts on soils. Many of the updated factors reflect a smaller impact of anthropogenic activity on soil carbon. The Tier 2 and Tier 3 methods have been refined to estimate the impact of biochar amendments on soil carbon stocks in mineral soils for cropland and grassland.
• Rice cultivation: Tier 1 factors have been updated for the baseline emission factors, scaling factors for water management regimes, and conversion factors for organic amendments.
• Flooded Lands: New guidance is provided for CO₂ and non-CO₂ emissions from Land Converted to Flooded Lands and Flooded Land Remaining Flooded Land. The science has matured over the past decade and these sources are now included in the main guidance (instead of appendices).
• Livestock and manure management: Numerous emission factors and other parameters have been updated, such as to address differential high and low productivity systems.
• Soil N₂O: Emission factors are now disaggregated by climate region.
• Harvested wood products (HWPs): Updated methods and equations are provided.

Volume 5 (Waste)

• CH₄ emissions from landfills: Updates parameters used in the first order decay (FOD) method including waste generation rate and waste composition by countries and region. Guidance has been updated on the use of methane correction factor (MCF) in different solid waste disposal sites (SWDS) management conditions. New default values for the MCF to estimate CH₄ emissions from active aeration have been provided (poorly and well managed). Default values for the fraction of degradable organic carbon which decomposes (DOC_f) have been updated.
• Incineration and open burning: Guidance on emission estimation from new technologies including gasification and pyrolysis has been elaborated with provision of CH₄ and N₂O emission factors.
• CH₄ emissions from wastewater treatment: Updated guidance and emission factors for septic systems and centralised wastewater treatment plants. Updated emission factors are also provided for CH₄ emissions after disposal of untreated wastewater into aquatic environments.
• N₂O emissions from wastewater treatment: New guidance and emission factors for domestic and industrial wastewater treatment plants, and updated emission factors for wastewater disposal into aquatic environments.