From 52d3c256cef4465e2face008175647d68c68cc78 Mon Sep 17 00:00:00 2001 From: WesIngwersen Date: Sun, 25 Oct 2026 11:53:00 -0400 Subject: [PATCH 1/2] docs: split technical docs and user guide; add EF calculation and margin pages - Frame the emission factors as the primary data product of the 2026 release; rc.1 publishes the spend-based GHG factors and 2026-v1 adds the time series and model matrices (format TBD). - Reorganize the TOC and home page into a technical documentation track and a user guide track, with colored cards for each. - Add "Calculating the emission factors": M = B x L, N = C x M, Tier 3, regional/global averages, zero filling, price-year re-pricing with the BEA gross output price index, and the producer-to-purchaser conversion. - Add "Margin emission factors": formula, margin sectors, re-pricing, published columns and when to use them. - Add A_margin, phi and PI to the notation page and a glossary term; fix the glossary statement that factors are only at purchaser price. Co-Authored-By: Claude Opus 5.5 --- _parts/custom.css | 19 +++++ factors/calculation.md | 116 +++++++++++++++++++++++++++++ factors/margins.md | 104 ++++++++++++++++++++++++++ factors/user-guidance.md | 2 +- factors/whats-in-a-release.md | 4 +- faq.md | 2 +- figures/diagrams/ef-pipeline.svg | 68 +++++++++++++++++ figures/diagrams/margin-dollar.svg | 38 ++++++++++ index.md | 62 +++++++++++---- myst.yml | 42 ++++++----- reference/glossary.md | 5 +- reference/notation.md | 3 + releases/index.md | 24 +++++- releases/rc.md | 6 +- 14 files changed, 454 insertions(+), 41 deletions(-) create mode 100644 factors/calculation.md create mode 100644 factors/margins.md create mode 100644 figures/diagrams/ef-pipeline.svg create mode 100644 figures/diagrams/margin-dollar.svg diff --git a/_parts/custom.css b/_parts/custom.css index 0bc69c16..b4a98478 100644 --- a/_parts/custom.css +++ b/_parts/custom.css @@ -125,3 +125,22 @@ body { font-size: 0.8rem; opacity: 0.7; } + +/* Home page tracks: technical documentation (brand blue) and user guide (amber). + The card tint and top rule tell the two tracks apart. */ +.track-technical .myst-card { + background-color: #eaf6fb; + border-color: #9fd3e8; + border-top: 4px solid var(--cs-brand); +} +.track-technical .myst-card:hover { + border-color: var(--cs-brand); +} +.track-user .myst-card { + background-color: #fdf3e7; + border-color: #f0c99a; + border-top: 4px solid #e08a1e; +} +.track-user .myst-card:hover { + border-color: #e08a1e; +} diff --git a/factors/calculation.md b/factors/calculation.md new file mode 100644 index 00000000..47564c1c --- /dev/null +++ b/factors/calculation.md @@ -0,0 +1,116 @@ +--- +title: "Calculating the emission factors" +--- + +:::{tip} Summary +The emission factors are the model's total emission factors (`N`): the CO₂e emitted across the whole supply chain per dollar of each commodity, by the country that produces it. This page follows the calculation from the matrices of [the IO model](../io/index.md) and [the GHG extension](../ee/index.md) to the published producer-price (PRO) and purchaser-price (PUR) factors for each year. +::: + +:::{figure} ../figures/diagrams/ef-pipeline.svg +:label: fig-ef-pipeline +:alt: B and L feed step 1, total intensities M equals B times L. Step 2 weights by GWP, N equals C times M. Step 3 forms regional averages and fills gaps. Step 4 re-prices to each year, 2024, 2025 and 2026, giving the producer-price factors. Step 5 multiplies by phi, the producer share of the purchaser price, giving the purchaser-price factors. Notes say steps 1 to 3 are in 2024 U.S. dollars at producer price, step 4 uses U.S. price indexes, step 5 uses U.S. trade and transport margins, and margin emissions are published separately. +From the model matrices to the published factors. The base calculation is in 2024 dollars; each year's factors are re-priced from it. `φ` is the producer share of the purchaser price. +::: + +## From the model to total emission factors + +The IO model gives the total requirements `L`, the output needed from every sector in every country per dollar of final demand (see [](../io/index.md#total-requirements)). The GHG extension gives the direct emission intensities `B`, the kilograms of each gas a sector emits per dollar of its own output (see [](../ee/index.md)). The emission factors combine the two. + +1. **Total intensities by gas.** `M = B × L` traces each sector's direct emissions through every round of suppliers. A column of `M` gives, for \$1 of one commodity from one country, the emissions of each gas anywhere in its supply chain. +2. **CO₂-equivalent.** The characterization factors `C` weight each gas by its 100-year GWP from the IPCC AR6, so `N = C × M` gives the total emission factors in kg CO₂e per dollar (see [](../ee/index.md#gases-and-global-warming-potentials)). The gas columns of the release are the rows of `M` in CO₂e, and Total GHGs is their sum. + +For the 65 countries in Tiers 0 to 2 and the rest-of-world region, `L` is solved once for the whole multi-region table, so `M` follows supply chains across every border in the table. Each column of `N` is one commodity produced in one country, so a factor describes where a product is made, not where it is bought. + +The factors are per dollar of commodity output at producer price, in 2024 U.S. dollars, the model's base year. They include every upstream supplier, but not the trade and transport services between the producer and the buyer, which are handled in [](#purchaser-price) and [](margins.md). + +The direct emission factors `D = C × B`, which hold only what a sector emits itself, are part of the model but are not published as a separate table. + +## Tier 3 countries + +The 83 Tier 3 countries are not part of the multi-region table, so their factors are calculated one country at a time, from the template described in [](../io/country-tiers.md#tier-3-no-io-tables) and [](../ee/country-tiers.md#tier-3-template-emissions). Each country's domestic inputs carry its own direct emission intensities through its domestic total requirements, `(I − Adom)⁻¹`. Its imported inputs carry China's total emission factors from the multi-region table. The two parts are added to give the country's `M`. + +## Regional and global averages + +The release has a factor for each of 21 regions and one global average (`GLOB`). For each sector and each gas, a regional factor is the average of its member countries' factors, weighted by each country's output of that sector in 2024 dollars (`q`): + +`N_region = Σ (N_country × q_country) ÷ Σ q_country` + +Only countries in Tiers 0 to 2 have output data in the model, so Tier 3 countries are not included in the weighted average, even where they belong to the region. A region with no Tier 0 to 2 member uses the simple average of its members' factors instead. The global average is weighted the same way over every Tier 0 to 2 country. The rest-of-world region is used only inside the model and is not published. + +## Filling missing country factors + +A few country–sector combinations have a total factor of exactly zero, because the source tables have no output or no emissions for that sector in that country. A zero factor would understate emissions for anyone buying from that sector, so it is treated as missing: the country's factor is replaced by its region's factor, or by the global average where the regional factor is also zero. The replacement applies to every gas. + +(reporting-years)= +## From the base year to each reporting year + +Every source in the model is first brought to 2024 dollars: values are converted to U.S. dollars at the data year's exchange rate and re-priced to 2024 with a U.S. price index (see [](../io/country-tiers.md)). The model therefore produces 2024 factors, per 2024 dollar. + +The factors for 2025 and 2026 are re-priced from the 2024 factors, sector by sector: + +`N_t = N_2024 × PI(2024) ÷ PI(t)` + +where `PI` is the sector's price index and `t` is the year. When a sector's prices rise, each dollar buys less of its output, so the factor per dollar falls. The emissions behind the factors are the same; only the dollar they are expressed in changes. Each year's factors are therefore in current dollars of that year. + +The price index is the U.S. Bureau of Economic Analysis chain-type price index for gross output by industry (2017 = 100), mapped to the 405 sectors. The 2026 value is the average of the quarters published at the time of the release. Sectors without their own index keep a constant price. The same U.S. index is applied to every country, region and the global average. + +(purchaser-price)= +## From producer to purchaser price + +A purchaser pays more than the producer receives: wholesale, retail and transport businesses add their margins on the way to the buyer. Each dollar at purchaser price therefore contains less of the product itself. The purchaser-price factor converts the producer-price factor to this larger dollar: + +`N_PUR = N_PRO × φ`, where `φ = 1 ÷ (1 + Σ A_margin)` + +Here `A_margin` holds the margins paid on each commodity, in dollars of margin per dollar of the commodity at producer price, one row per margin sector, and `φ` is the producer share of the purchaser price. + +- **Margins come from the U.S.** `A_margin` is built from U.S. margin data, on the industry-average margins paid by industries and business investment. The same `φ` is applied to every country, region and the global average (see the [key assumptions](../io/country-tiers.md#currency) for the IO tables). +- **Margins only.** The conversion covers trade and transport margins. Taxes and subsidies on products are not included. +- **Services and electricity have `φ = 1`.** They carry no trade margins, so their producer- and purchaser-price factors are the same. +- **Each year has its own `φ`.** The margin coefficients are re-priced to each year with the price indexes of the margin sector and of the commodity, so `φ` changes slightly from year to year. + +The purchaser-price factor covers the emissions of making the product only. The emissions of the margin services themselves, such as running warehouses, stores and trucks, are not added to it; they are prepared as separate [margin emission factors](margins.md). + +## Rounding + +Published factors are rounded to three significant figures. Total GHGs is rounded from the unrounded total, so it may not equal the sum of the rounded gas values. + +:::{important} Key assumptions +:class: dropdown +**2025 and 2026 factors reflect price changes only** + +- **Assumption:** The supply chains and emission intensities of the 2024 model also describe 2025 and 2026. The factors for those years differ from 2024 only by the change in each sector's price. +- **Why we make it:** Input-output tables and emissions data for 2025 and 2026 are not yet available for any country. +- **How it affects results:** Real changes after 2024, such as a cleaner electricity grid or a shift in where inputs are bought, are not captured in the 2025 and 2026 factors. + +**One U.S. price index for every country** + +- **Assumption:** Each sector's U.S. price change applies to that sector in every country. +- **Why we make it:** Consistent sector-level price indexes in U.S. dollars are not available for every country and year. +- **How it affects results:** Where prices in a country moved differently from U.S. prices, or its exchange rate against the dollar changed, its factors for 2025 and 2026 could be too high or too low. + +**U.S. margins and no product taxes in purchaser prices** + +- **Assumption:** The U.S. share of trade and transport margins in each commodity's purchaser price applies in every country, and product taxes are left out of the conversion. +- **Why we make it:** Margin and tax data comparable to the U.S. tables are not available for every country. +- **How it affects results:** Where a country's margins or product taxes differ from the U.S., its purchaser-price factors could be too high or too low. Producer-price factors are not affected. + +**Gross-output weights for regional averages** + +- **Assumption:** A region's factor for a sector is the average of its member countries' factors weighted by their output of that sector, using only countries in Tiers 0 to 2. +- **Why we make it:** Output is the best available measure of how much of a sector's supply each country provides, and it is available only for countries with IO tables. +- **How it affects results:** The regional factor reflects the region's largest producers. Where a region's Tier 3 members produce differently from its Tier 0 to 2 members, their purchases are better represented by their own country factors. +::: + +:::{seealso} Learn more +- Calculating total requirements and multipliers: the standard textbook on IO analysis [@millerInputoutputAnalysisFoundations2022] +- How BEA builds the U.S. IO accounts, including margins and price bases [@beaConceptsMethodsUS2009] +- How to choose between producer and purchaser price: [](user-guidance.md#choose-between-purchaser-and-producer-price) +- What each published table contains: [](whats-in-a-release.md) +::: + ++++ + +:::{div} +:class: page-status +Applies to: 2026-rc.1 · Last reviewed: 2026-rc.1 +::: diff --git a/factors/margins.md b/factors/margins.md new file mode 100644 index 00000000..56a947d0 --- /dev/null +++ b/factors/margins.md @@ -0,0 +1,104 @@ +--- +title: "Margin emission factors" +--- + +:::{tip} Summary +Margin emission factors give the emissions of the wholesale, retail and transportation services that deliver a good from its producer to its buyer, per dollar of purchaser price. They are prepared for U.S. commodities only, for each year, and can be added to the U.S. purchaser-price factors when those delivery emissions are not counted elsewhere in a footprint. They mainly serve former USEEIO users, whose factors had a margin component. +::: + +:::{figure} ../figures/diagrams/margin-dollar.svg +:label: fig-margin-dollar +:alt: A horizontal bar for one dollar spent at purchaser price on a good. The largest part, producer value phi, is what the producer receives. The rest is split into wholesale, retail and transport margins. A bracket under the producer value is labeled purchaser-price emission factor, the emissions of making the good per purchaser dollar. A bracket under the three margins is labeled margin emission factors, the emissions of the trade and transport services that deliver it. A note says services and electricity have no margins. +A purchaser dollar pays for the good and for the services that deliver it. The purchaser-price factor covers the first; the margin factors cover the second. +::: + +## What margins are + +Between the producer and the buyer, most goods pass through wholesalers, retailers and transport companies. Their charges are the trade and transport {term}`margins `, and they are part of what the buyer pays: the purchaser price is the producer price plus the margins. + +The [purchaser-price factors](calculation.md#purchaser-price) spread the emissions of making a good over this larger purchaser dollar, but they do not add the emissions of the margin services themselves. Those emissions come from running warehouses, stores, trucks, trains, ships, aircraft and pipelines, and they are what the margin emission factors measure. + +## How they are calculated + +For each U.S. commodity `j` and each margin type, the margin emission factor adds up, over the margin sectors `i` of that type, the margin paid to each sector times that sector's total emission factor: + +`Margin EF[j] = φ[j] × Σ N[i] × A_margin[i, j]` + +- `A_margin[i, j]` is the margin paid to margin sector `i` per dollar of commodity `j` at producer price. +- `N[i]` is the U.S. total emission factor of margin sector `i` at producer price, the same factor published in the PRO table. It includes the margin sector's whole supply chain, such as the fuel a truck burns and the electricity a store uses. +- `φ[j]` is the producer share of the purchaser price of `j` (see [](calculation.md#purchaser-price)). It converts the result from per producer dollar to per purchaser dollar, so the margin factor is on the same basis as the purchaser-price factor it is added to. + +The margin sectors are grouped into three types: + +| Margin type | Margin sectors | +|---|---| +| Wholesale | The 10 wholesale trade sectors (423100, 423400, 423600, 423800, 423A00, 424200, 424400, 424700, 424A00, 425000) | +| Retail | The 9 retail trade sectors (441000, 444000, 445000, 446000, 447000, 448000, 452000, 454000, 4B0000) | +| Transportation | Air (481000), rail (482000), water (483000) and truck (484000) transportation, and pipelines (486000) | + +The total margin factor is the sum of the three types. Services and electricity pay no margins, so their margin factors are zero. + +### Margin data + +`A_margin` is built from U.S. margin data on the margins paid by industries and by business investment. Margins on household purchases and on changes in private inventories are not included. Because most retail margins are paid by households, the retail margin factors are close to zero for many goods. + +### Each year + +The margin factors are prepared for each year of the release, 2024 to 2026. Each margin coefficient is re-priced from 2024 with the price index of its margin sector and the price index of the commodity: + +`A_margin,t[i, j] = A_margin[i, j] × (PI_i(t) ÷ PI_i(2024)) ÷ (PI_j(t) ÷ PI_j(2024))` + +and the margin sectors' factors `N` for the same year are used, re-priced as described in [](calculation.md#reporting-years). Each margin sector is re-priced with its own index. + +## How they are published + +The margin emission factors are published in their own workbook, with one tab per year (`{YEAR}PUR`). Each row is one U.S. commodity, with the columns: + +| Column | Meaning | +|---|---| +| Code | Good or service code, as in the emission factor tabs. | +| Name | Name of the good or service. | +| Location | `USA`. | +| Location Name | United States. | +| Total Margin | Sum of the three margin types, in kg CO₂e per USD at purchaser price. | +| Wholesale | Wholesale margin emission factor, in kg CO₂e per USD at purchaser price. | +| Retail | Retail margin emission factor, in kg CO₂e per USD at purchaser price. | +| Transportation | Transportation margin emission factor, in kg CO₂e per USD at purchaser price. | + +## When to use them + +- **Add them only to purchaser-price factors.** A U.S. purchaser-price factor plus the total margin factor gives the emissions of making and delivering a good, per purchaser dollar. Producer-price factors are per producer dollar and exclude the margins, so margin factors should not be added to them. +- **Avoid double counting.** If you account for transport and distribution separately, for example in Scope 3 category 4 (upstream transportation and distribution), do not add the margin factors as well. +- **U.S. only.** Margin factors are prepared only for U.S. commodities, because margin data are available only for the U.S. + +### For former USEEIO users + +The USEEIO Supply Chain GHG Emission Factors were published per purchaser dollar, as factors without margins, margin factors, and factors with margins, the sum of the two [@ingwersen_supply_2024]. In Cornerstone EEIO, the U.S. purchaser-price factors correspond to the factors without margins, and adding the total margin factor corresponds to the factors with margins. + +:::{important} Key assumptions +:class: dropdown +**Industry-average margins** + +- **Assumption:** The margins on each commodity are the average margins paid by U.S. industries and business investment. +- **Why we make it:** The factors are designed for purchases by organizations, and household margins, mostly retail, are much higher than those businesses pay. +- **How it affects results:** Where an organization buys goods at retail, its actual margins are higher than those in the factors, and the margin factors, especially for retail, understate the emissions of delivery. + +**U.S. margin sectors and margins** + +- **Assumption:** The margin factors use U.S. margins and the U.S. factors of the margin sectors. +- **Why we make it:** Margin data comparable to the U.S. tables are not available for other countries. +- **How it affects results:** The margin factors describe delivery within the U.S. They are not prepared for other countries, whose distribution networks and transport modes can differ. +::: + +:::{seealso} Learn more +- How BEA measures trade and transport margins in the U.S. IO accounts [@beaConceptsMethodsUS2009] +- How the purchaser-price factors are calculated: [](calculation.md#purchaser-price) +- How to choose between producer and purchaser price: [](user-guidance.md#choose-between-purchaser-and-producer-price) +::: + ++++ + +:::{div} +:class: page-status +Applies to: 2026-rc.1 · Last reviewed: 2026-rc.1 +::: diff --git a/factors/user-guidance.md b/factors/user-guidance.md index f5f6e14b..b41f2f03 100644 --- a/factors/user-guidance.md +++ b/factors/user-guidance.md @@ -11,7 +11,7 @@ This user guidance covers two topics: 1. How to choose the right emission factor: the country, the year and the exchange rate. 2. How to choose between purchaser and producer price. -A separate guide explains how to think about the margin emission factors, relevant only for previous USEEIO users. +A separate page, [](margins.md), explains how the margin emission factors are prepared, which is mainly of interest to previous USEEIO users. ## Choose the right emission factor diff --git a/factors/whats-in-a-release.md b/factors/whats-in-a-release.md index 10f4c452..cf4910a1 100644 --- a/factors/whats-in-a-release.md +++ b/factors/whats-in-a-release.md @@ -3,12 +3,12 @@ title: "What's in a release" --- :::{tip} Summary -The Cornerstone EEIO model is updated annually and versioned with the year of the release, so Cornerstone EEIO 2026 is released in 2026 and the 2027 version will be released in 2027. Every year, the releases will be publicly available in October. Each release publishes emission factors covering 405 sectors across 148 countries, 21 regions and one global average. To download the latest version, check out [Zenodo](https://zenodo.org/doi/10.5281/zenodo.23396891). +The Cornerstone EEIO model is updated annually and versioned with the year of the release, so Cornerstone EEIO 2026 is released in 2026 and the 2027 version will be released in 2027. Every year, the releases will be publicly available in October. The emission factors are the primary data product of each release, covering 405 sectors across 148 countries, 21 regions and one global average. This page describes the emission factor workbook; how the factors are calculated is in [](calculation.md). To download the latest version, check out [Zenodo](https://zenodo.org/doi/10.5281/zenodo.23396891). ::: ## The release -The release includes one Excel workbook that contains: a cover, a data dictionary, a producer-price tab and a purchaser-price tab for each year the data is available for, and five auxiliary tabs. +The 2026-rc.1 emission factors are published as one Excel workbook that contains: a cover, a data dictionary, a producer-price tab and a purchaser-price tab for each year the data is available for, and five auxiliary tabs. ### Cover diff --git a/faq.md b/faq.md index 8d7e3972..a44c6771 100644 --- a/faq.md +++ b/faq.md @@ -27,7 +27,7 @@ Both. Data updates reflect real-world change, such as new economic, trade and em ::: :::{dropdown} Why is it called a "release candidate"? -2026 is the first time CEDA and USEEIO are combined in one model, and the first time a time series is released. The two-phase release gives companies time to assess the impact on their most recent year of measurements while the time series is under development. The release candidate (2026-rc.1) is published on October 27, 2026. The final version (2026-v0.1), with the 2017–2026 time series, follows in early December 2026. See [](releases/rc.md). +2026 is the first time CEDA and USEEIO are combined in one model, and the first time a time series is released. The two-phase release gives companies time to assess the impact on their most recent year of measurements while the time series is under development. The release candidate (2026-rc.1) is published on October 27, 2026. The full release (2026-v1), with the 2017–2026 time series and the model matrices, follows in early December 2026. See [](releases/rc.md). ::: :::{dropdown} Will the 2024–2026 factors change between the release candidate and the final version? diff --git a/figures/diagrams/ef-pipeline.svg b/figures/diagrams/ef-pipeline.svg new file mode 100644 index 00000000..bdd8f96d --- /dev/null +++ b/figures/diagrams/ef-pipeline.svg @@ -0,0 +1,68 @@ + + + + + + + + + + + B + + L + from the IO model + and GHG extension + + + + 1 + Total + intensities + M = B × L + + + + 2 + Weight by + GWP + N = C × M + + + + 3 + Regional + averages + and gap filling + + + + 4 + Re-price to + each year + 2024, 2025, 2026 + + + + Producer price (PRO) + + + + Purchaser price (PUR) + 5 + × φ + + + + + + + + + + + + Steps 1 to 3 are in 2024 U.S. dollars at producer price, by country of production. + Step 4 uses U.S. price indexes; step 5 uses U.S. trade and transport margins. + Emissions of the margin services themselves are published separately as margin emission factors. + diff --git a/figures/diagrams/margin-dollar.svg b/figures/diagrams/margin-dollar.svg new file mode 100644 index 00000000..8e1da11f --- /dev/null +++ b/figures/diagrams/margin-dollar.svg @@ -0,0 +1,38 @@ + + + + $1 spent at purchaser price on a good + + + + Producer value (φ) + what the producer receives + + + Wholesale + margin + + + Retail + margin + + + Transport + margin + + + + + + Purchaser-price emission factor + emissions of making the good, per purchaser dollar + + + + + Margin emission factors + emissions of the trade and transport + services that deliver it + + Bar widths are illustrative. Services and electricity have no margins, so φ = 1 and their margin factors are zero. + diff --git a/index.md b/index.md index 26071394..94db3cfb 100644 --- a/index.md +++ b/index.md @@ -4,17 +4,24 @@ site: hide_outline: true --- -The Cornerstone EEIO model is a multi-regional environmentally-extended input-output model. It links countries' economies through international trade and attaches greenhouse gas emissions to every sector, producing emission factors per dollar of purchases. +The Cornerstone EEIO model is a multi-regional environmentally-extended input-output model. It links countries' economies through international trade and attaches greenhouse gas emissions to every sector. Cornerstone EEIO is the successor of the USEEIO and CEDA models; see [](intro/cornerstone-eeio-history.md). -The emission factors are available for 405 sectors across 149 countries and 21 regional averages. The model is built as a time series from 2017 up to 2026, with the time series release coming before the end of 2026. These emission factors are most commonly used for Scope 3 measurements in corporate inventories and for academic and policy research. Cornerstone EEIO is the successor of the USEEIO and CEDA models; see [](intro/cornerstone-eeio-history.md). +Cornerstone EEIO 2026 was developed to produce cradle-to-gate emission factors for the goods and services that organizations commonly buy. These **emission factors are the primary data product** of the 2026 release: spend-based factors, in kg CO₂e per USD, for 405 sectors across 148 countries, 21 regional averages and one global average. They are most commonly used for Scope 3 measurements in corporate inventories and for academic and policy research. -::::{grid} 1 2 2 3 +The [2026-rc.1 release](releases/rc.md) publishes the spend-based GHG emission factors. The full 2026-v1 release adds a 2017–2026 time series and will be accompanied by the model matrices, in a format still to be decided. :::{card} Understand EEIO :link: intro/what-is-eeio.md -A short, visual primer on how EEIO models work. +New to EEIO? Start with a short, visual primer on how EEIO models work and where Cornerstone EEIO comes from. ::: +## Technical documentation + +How the model is built, how the emission factors are calculated from it, and how both are checked. + +::::{grid} 1 2 2 3 +:class: track-technical + :::{card} The IO model :link: io/index.md How country tables are linked through trade into one global model. @@ -25,24 +32,53 @@ How country tables are linked through trade into one global model. Where the emissions data come from and how they reach each sector. ::: -:::{card} Look up a country -:link: reference/methods-by-country.md -The methods and data behind each country in the model. +:::{card} Calculating the emission factors +:link: factors/calculation.md +From the model matrices to published factors, including price-year and purchaser-price adjustments. ::: -:::{card} Emission factors -:link: factors/whats-in-a-release.md -What's in a release, and how to apply the factors correctly. +:::{card} Margin emission factors +:link: factors/margins.md +How the emission factors of trade and transport margins are prepared. ::: :::{card} How we validate :link: validation/index.md -The checks and benchmarks behind each release. +The checks behind each release. +::: + +:::{card} How we benchmark +:link: benchmarking/index.md +How the results compare with independent evidence. ::: -:::{card} Releases +:::{card} Look up a country +:link: reference/methods-by-country.md +The methods and data behind each country in the model. +::: + +:::{card} Release details :link: releases/index.md -Release notes and change logs. +Release notes, summaries of changes and change logs. +::: + +:::: + +## User guide + +How to get the emission factors and apply them to your own data. + +::::{grid} 1 2 2 3 +:class: track-user + +:::{card} What's in a release +:link: factors/whats-in-a-release.md +The emission factor workbook, tab by tab. +::: + +:::{card} Applying the factors +:link: factors/user-guidance.md +Choosing the sector, country, year, currency and price basis. ::: :::{card} FAQs diff --git a/myst.yml b/myst.yml index 188485a0..035ac9ed 100644 --- a/myst.yml +++ b/myst.yml @@ -24,34 +24,40 @@ project: - file: intro/what-is-eeio.md children: - file: intro/cornerstone-eeio-history.md - - title: The IO model + - title: Technical documentation children: - - file: io/index.md - - file: io/country-tiers.md - - title: The GHG extension - children: - - file: ee/index.md - - file: ee/country-tiers.md - - title: Emission factors + - title: The IO model + children: + - file: io/index.md + - file: io/country-tiers.md + - title: The GHG extension + children: + - file: ee/index.md + - file: ee/country-tiers.md + - title: Emission factor calculation + children: + - file: factors/calculation.md + - file: factors/margins.md + - file: validation/index.md + - file: benchmarking/index.md + - file: releases/index.md + children: + - file: releases/rc.md + children: + - file: releases/summary-useeio.md + - file: releases/summary-ceda.md + - file: releases/change-log.md + - title: User guide children: - file: factors/whats-in-a-release.md - file: factors/user-guidance.md - - file: validation/index.md - - file: benchmarking/index.md + - file: faq.md - title: Reference children: - file: reference/glossary.md - file: reference/notation.md - file: reference/methods-by-country.md - file: reference/data-sources.md - - file: releases/index.md - children: - - file: releases/rc.md - children: - - file: releases/summary-useeio.md - - file: releases/summary-ceda.md - - file: releases/change-log.md - - file: faq.md site: template: book-theme nav: diff --git a/reference/glossary.md b/reference/glossary.md index f5466887..f7ae42e3 100644 --- a/reference/glossary.md +++ b/reference/glossary.md @@ -41,6 +41,9 @@ GWP Make/Use framework : IO tables that record which industries make which commodities (Make, or supply) and which commodities each industry and final user buys (Use). +Margin emission factor +: The emissions of the wholesale, retail, and transportation services that deliver a good to its buyer, per dollar of purchaser price. Prepared for U.S. commodities only. + Margins : The trade and transport costs added between the producer and the buyer: transport, wholesale, and retail. @@ -54,7 +57,7 @@ Producer price : The basic price plus taxes on products, less subsidies on products, excluding margins. Purchaser price -: The price the buyer pays: the producer price plus trade and transport margins. The published factors are per dollar of purchaser price. +: The price the buyer pays: the producer price plus trade and transport margins. The emission factors are published per dollar of both producer price and purchaser price. RAS : An iterative method that scales the rows and columns of a table until it matches known row and column totals. diff --git a/reference/notation.md b/reference/notation.md index 30b61d4a..750dac92 100644 --- a/reference/notation.md +++ b/reference/notation.md @@ -24,6 +24,9 @@ In the multi-regional model, every row and column is a country–sector pair. `D | `M` | Total emission intensities by gas | `B × L`: emissions of each gas across the supply chain per dollar | kg gas / \$ | | **`D`** | **Direct emission factors** | `C × B`: CO₂e emitted by the sector itself per dollar of output | kg CO₂e / \$ | | **`N`** | **Total emission factors** | `C × M` = `C × B × L`: CO₂e across the whole supply chain per dollar of purchases | kg CO₂e / \$ | +| `A_margin` | Margin coefficients | Trade and transport margins paid to each margin sector per dollar of a commodity at producer price | \$ / \$ | +| `φ` | Producer share of purchaser price | `1 ÷ (1 + Σ A_margin)`: converts producer-price factors to purchaser price | \$ / \$ | +| `PI` | Price index | U.S. BEA chain-type price index for gross output, by sector (2017 = 100) | index | :::{note} Draft :class: dropdown diff --git a/releases/index.md b/releases/index.md index 7b3213bc..a83a3362 100644 --- a/releases/index.md +++ b/releases/index.md @@ -1,7 +1,27 @@ --- -title: Releases +title: Release details --- -This is where the release note and change log for every Cornerstone EEIO release will live. For direct download of the data, check out [Zenodo](https://zenodo.org/doi/10.5281/zenodo.23396891). +:::{tip} Summary +Each Cornerstone EEIO release is a version of the model together with the data products published from it. For Cornerstone EEIO 2026, the primary data product is the set of spend-based GHG emission factors. This page lists each release, the data products it publishes, and its release note and change log. Download the data from [Zenodo](https://zenodo.org/doi/10.5281/zenodo.23396891). +::: + +## The model and its data products + +The **Cornerstone EEIO model** is the multi-regional input-output model described in [the IO model](../io/index.md) and [the GHG extension](../ee/index.md). A **data product** is something published from the model for others to use. Cornerstone EEIO 2026 was developed to produce cradle-to-gate emission factors for the goods and services that organizations commonly buy, so the emission factors are its primary data product. How they are calculated from the model is described in [](../factors/calculation.md). + +| Release | Status | Data products | +|---|---|---| +| [2026-rc.1](rc.md) | Release candidate, October 27, 2026 | Spend-based GHG emission factors for 2024, 2025 and 2026, at producer and purchaser price (see [](../factors/whats-in-a-release.md)) | +| 2026-v1 | Planned, December 2026 | Spend-based GHG emission factors for 2017 to 2026, accompanied by the model matrices (format to be decided) | + +## Release notes - [](rc.md) + ++++ + +:::{div} +:class: page-status +Applies to: 2026-rc.1 · Last reviewed: 2026-rc.1 +::: diff --git a/releases/rc.md b/releases/rc.md index 89dfa349..afd52ca1 100644 --- a/releases/rc.md +++ b/releases/rc.md @@ -4,9 +4,9 @@ subtitle: "Release note · Release date: October 27, 2026" --- :::{tip} Summary -The 2026-rc.1 (Release Candidate) is the first stage of a phased approach to releasing the Cornerstone EEIO 2026 model, the successor of USEEIO and CEDA. It is a global environmentally-extended input-output (EEIO) model that produces spend-based emission factors, in kg CO₂e per USD for 405 sectors across 148 countries, plus 21 regional averages and one global average. It uses 2024 as the base year and is available to use for 2024, 2025 and 2026 measurements. +The 2026-rc.1 (Release Candidate) is the first stage of a phased approach to releasing Cornerstone EEIO 2026, the successor of USEEIO and CEDA. It publishes the model's primary data product: spend-based GHG emission factors, in kg CO₂e per USD, for 405 sectors across 148 countries, plus 21 regional averages and one global average. The factors are cradle-to-gate, use 2024 as the base year, and are available for 2024, 2025 and 2026 measurements. -This release candidate will be superseded in December by the release of the 2026-v0.1 (final version), which will include a time series from 2017 to 2026. +This release candidate will be superseded in December by the full 2026-v1 release, which will include a time series of emission factors from 2017 to 2026 and will be accompanied by the model matrices, in a format still to be decided. Download this release on [Zenodo](https://zenodo.org/doi/10.5281/zenodo.23396891) here. ::: @@ -27,7 +27,7 @@ The time series (2017-2026) will use the same methodology for all years and only This is the first time that either USEEIO or CEDA releases a time series built this way. In the past CEDA has released a time series built with inflation adjustments for years prior and after the base year. Moving forward the Cornerstone EEIO will only apply inflation adjustments to the years after the base year, for which there is no reported data (e.g. 2025 and 2026 are inflation adjusted from the 2024 base year). -To learn more about the methodology behind Cornerstone EEIO refer to [the IO model](../io/index.md) and [the GHG extension](../ee/index.md). +To learn more about the methodology behind Cornerstone EEIO refer to [the IO model](../io/index.md), [the GHG extension](../ee/index.md) and [](../factors/calculation.md). ::: ## What changed From 83d76ad6c608dbb9f2a7a65839bd2a5cf7dd8889 Mon Sep 17 00:00:00 2001 From: WesIngwersen Date: Sun, 25 Oct 2026 20:09:29 -0400 Subject: [PATCH 2/2] docs: describe B in CO2e and drop the separate GWP step GWPs are applied inline as emissions enter the model (ceda _apply_gwp_conversion_to_ceds_ghg_data; bedrock B is kg CO2e/USD and derive_C_usa is a row-summer), so B and E are in CO2e by gas, D is B summed over gases and N = D x L (= M summed over gases). - Notation: drop C; E, B, M in kg CO2e; D and N redefined. - GHG extension, intro primer and diagrams updated to match. - Calculation page: total factors in one step from D/B and L. - Drop the product-tax statements from the purchaser-price section; taxes less subsidies are already in the producer price. Co-Authored-By: Claude Opus 5.5 --- ee/index.md | 14 ++-- factors/calculation.md | 21 +++--- figures/diagrams/ef-pipeline.svg | 102 ++++++++++++++---------------- figures/diagrams/ghg-pipeline.svg | 10 +-- intro/emission-factors.md | 4 +- intro/what-is-eeio.md | 4 +- reference/notation.md | 11 ++-- 7 files changed, 81 insertions(+), 85 deletions(-) diff --git a/ee/index.md b/ee/index.md index 0b93d080..cea248ec 100644 --- a/ee/index.md +++ b/ee/index.md @@ -3,12 +3,12 @@ title: "The GHG extension: overview" --- :::{tip} Summary -The GHG extension attaches each sector's own greenhouse gas emissions to the IO model, as emissions of each gas per dollar of output (`B`). Every country follows the same steps, but the emissions data behind them, and how much detail they carry, depend on the country's tier. +The GHG extension attaches each sector's own greenhouse gas emissions to the IO model, as CO₂-equivalent emissions of each gas per dollar of output (`B`). Every country follows the same steps, but the emissions data behind them, and how much detail they carry, depend on the country's tier. ::: :::{figure} ../figures/diagrams/ghg-pipeline.svg :label: fig-ghg-pipeline -:alt: Seven boxes in a row joined by arrows: 1, source emissions by source sector; 2, split broad sectors; 3, allocate to the 405 common sectors; 4, fill in gas detail where needed, drawn dashed, with a note that it is not needed for the U.S., China, Japan, or the UK; 5, convert to AR6; 6, divide by output, first industry output x and then per commodity output q. The result is B, kilograms of each gas per dollar. A bracket under steps 2 to 4 notes that each country's source totals are kept through them. +:alt: Seven boxes in a row joined by arrows: 1, source emissions by source sector; 2, split broad sectors; 3, allocate to the 405 common sectors; 4, fill in gas detail where needed, drawn dashed, with a note that it is not needed for the U.S., China, Japan, or the UK; 5, convert to CO₂-equivalent with AR6 GWPs; 6, divide by output, first industry output x and then per commodity output q. The result is B, kilograms of CO₂-equivalent of each gas per dollar. A bracket under steps 2 to 4 notes that each country's source totals are kept through them. From source emissions to direct emission intensities (`B`). Every country follows the same steps; step 4 is needed only where a source does not separate every gas. ::: @@ -16,18 +16,18 @@ From source emissions to direct emission intensities (`B`). Every country follow The IO model traces the dollars that flow through supply chains. The GHG extension adds what each sector emits while making its output. For each country and sector it records: -- **Emissions** (`E`): kilograms of each gas emitted by the sector in a year. -- **Direct emission intensities** (`B`): those emissions divided by output, so kilograms of each gas per dollar of output. +- **Emissions** (`E`): the emissions of each gas by the sector in a year, in kilograms of CO₂-equivalent. +- **Direct emission intensities** (`B`): those emissions divided by output, so kilograms of CO₂-equivalent of each gas per dollar of output. `B` holds direct emissions only: what the sector emits from its own fuel use, processes, and other activities. Emissions from the sector's suppliers come in through the supply chain ([`L`](../io/index.md#total-requirements)), not through `B`. For example, the emissions from generating electricity stay with the power sector, and other sectors' purchased electricity reaches them through `L`. -Characterization factors (`C`) then weight each gas by its global warming potential, which gives the direct emission factors `D = C × B` (see [](../reference/notation.md)). +Each gas is weighted by its global warming potential as its emissions enter the model, so `E` and `B` are already in CO₂-equivalent and no separate weighting step is needed. Adding up the gases in `B` gives the direct emission factors `D` (see [](../reference/notation.md)). ## Gases and global warming potentials `B` has a row for each of seven gases or gas groups: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and nitrogen trifluoride (NF₃). -They are combined into CO₂-equivalent with 100-year {term}`GWPs ` from the IPCC's Sixth Assessment Report (AR6) [@forsterEarthsEnergyBudget2021]. Methane is valued two ways: fossil methane, from fuel production and use, at 29.8, and non-fossil methane, from farming and waste, at 27.0. Fossil methane is valued higher because, once it breaks down, it leaves CO₂ that was not already in the atmosphere. +Each gas is converted to CO₂-equivalent as its emissions are loaded, with 100-year {term}`GWPs ` from the IPCC's Sixth Assessment Report (AR6) [@forsterEarthsEnergyBudget2021]. Methane is valued two ways: fossil methane, from fuel production and use, at 29.8, and non-fossil methane, from farming and waste, at 27.0. Fossil methane is valued higher because, once it breaks down, it leaves CO₂ that was not already in the atmosphere. Several sources report emissions as CO₂-equivalent using older GWPs from the Fifth Assessment Report (AR5) [@myhreAnthropogenicNaturalRadiative2013]. These are converted to AR6, gas by gas. @@ -55,7 +55,7 @@ Every country's emissions go through the same steps: 2. **Split broad sectors where better data exist.** Some sources lump together sectors with very different emissions, such as electricity, gas, and heat, or all of farming. Where other data can separate them, the broad sector is split first, keeping its total. 3. **Allocate to the common sectors.** For the U.S., each inventory activity is allocated to the industries that emit it. For other countries, each source sector's emissions are allocated to the matching common sectors with {term}`ABSR`, weighted by U.S. emission intensities. The country's total for each source sector is kept. 4. **Fill in missing gas detail.** Where a source does not separate every gas, the missing split is taken from the U.S. mix for the same sector. This is not needed for the U.S., China, Japan, or the UK, whose sources cover all seven gases. -5. **Convert to AR6** where the source used other GWPs. +5. **Convert to CO₂-equivalent** with AR6 GWPs. Sources reported in CO₂-equivalent with other GWPs are converted to AR6. 6. **Divide by output.** Each industry's emissions are divided by its output (`x`), then converted to commodities using market shares (who makes each commodity), giving `B` per dollar of commodity output (`q`). Emissions data years differ by country; see [](country-tiers.md#ghg-data-years). [](country-tiers.md) gives the sources and how each step is done for each tier. diff --git a/factors/calculation.md b/factors/calculation.md index 47564c1c..db3bf0da 100644 --- a/factors/calculation.md +++ b/factors/calculation.md @@ -8,22 +8,24 @@ The emission factors are the model's total emission factors (`N`): the CO₂e em :::{figure} ../figures/diagrams/ef-pipeline.svg :label: fig-ef-pipeline -:alt: B and L feed step 1, total intensities M equals B times L. Step 2 weights by GWP, N equals C times M. Step 3 forms regional averages and fills gaps. Step 4 re-prices to each year, 2024, 2025 and 2026, giving the producer-price factors. Step 5 multiplies by phi, the producer share of the purchaser price, giving the purchaser-price factors. Notes say steps 1 to 3 are in 2024 U.S. dollars at producer price, step 4 uses U.S. price indexes, step 5 uses U.S. trade and transport margins, and margin emissions are published separately. +:alt: D and B, in CO2e, and L feed step 1. Step 1 calculates the total emission factors, M equals B times L by gas and N equals D times L in total. Step 2 forms regional averages and fills gaps. Step 3 re-prices to each year, 2024, 2025 and 2026, giving the producer-price factors. Step 4 multiplies by phi, the producer share of the purchaser price, giving the purchaser-price factors. Notes say steps 1 and 2 are in 2024 U.S. dollars at producer price, step 3 uses U.S. price indexes, step 4 uses U.S. trade and transport margins, and margin emissions are published separately. From the model matrices to the published factors. The base calculation is in 2024 dollars; each year's factors are re-priced from it. `φ` is the producer share of the purchaser price. ::: ## From the model to total emission factors -The IO model gives the total requirements `L`, the output needed from every sector in every country per dollar of final demand (see [](../io/index.md#total-requirements)). The GHG extension gives the direct emission intensities `B`, the kilograms of each gas a sector emits per dollar of its own output (see [](../ee/index.md)). The emission factors combine the two. +The IO model gives the total requirements `L`, the output needed from every sector in every country per dollar of final demand (see [](../io/index.md#total-requirements)). The GHG extension gives the direct emission intensities `B`, the emissions of each gas a sector emits per dollar of its own output (see [](../ee/index.md)). Each gas is weighted by its 100-year GWP from the IPCC AR6 as its emissions enter the model, so `B` is already in kg CO₂e per dollar, one row per gas (see [](../ee/index.md#gases-and-global-warming-potentials)). Adding up its rows gives the direct emission factors `D`, what a sector emits itself per dollar. -1. **Total intensities by gas.** `M = B × L` traces each sector's direct emissions through every round of suppliers. A column of `M` gives, for \$1 of one commodity from one country, the emissions of each gas anywhere in its supply chain. -2. **CO₂-equivalent.** The characterization factors `C` weight each gas by its 100-year GWP from the IPCC AR6, so `N = C × M` gives the total emission factors in kg CO₂e per dollar (see [](../ee/index.md#gases-and-global-warming-potentials)). The gas columns of the release are the rows of `M` in CO₂e, and Total GHGs is their sum. +The total emission factors take one step: multiplying by `L` traces each sector's direct emissions through every round of suppliers. + +- `M = B × L` gives the total emission factors by gas. A column of `M` gives, for \$1 of one commodity from one country, the CO₂e of each gas emitted anywhere in its supply chain. These are the gas columns of the release. +- `N = D × L`, which equals the sum of the rows of `M`, gives the total emission factors. This is the Total GHGs column of the release. For the 65 countries in Tiers 0 to 2 and the rest-of-world region, `L` is solved once for the whole multi-region table, so `M` follows supply chains across every border in the table. Each column of `N` is one commodity produced in one country, so a factor describes where a product is made, not where it is bought. The factors are per dollar of commodity output at producer price, in 2024 U.S. dollars, the model's base year. They include every upstream supplier, but not the trade and transport services between the producer and the buyer, which are handled in [](#purchaser-price) and [](margins.md). -The direct emission factors `D = C × B`, which hold only what a sector emits itself, are part of the model but are not published as a separate table. +The direct emission factors `D` are part of the model but are not published as a separate table. ## Tier 3 countries @@ -64,7 +66,6 @@ A purchaser pays more than the producer receives: wholesale, retail and transpor Here `A_margin` holds the margins paid on each commodity, in dollars of margin per dollar of the commodity at producer price, one row per margin sector, and `φ` is the producer share of the purchaser price. - **Margins come from the U.S.** `A_margin` is built from U.S. margin data, on the industry-average margins paid by industries and business investment. The same `φ` is applied to every country, region and the global average (see the [key assumptions](../io/country-tiers.md#currency) for the IO tables). -- **Margins only.** The conversion covers trade and transport margins. Taxes and subsidies on products are not included. - **Services and electricity have `φ = 1`.** They carry no trade margins, so their producer- and purchaser-price factors are the same. - **Each year has its own `φ`.** The margin coefficients are re-priced to each year with the price indexes of the margin sector and of the commodity, so `φ` changes slightly from year to year. @@ -88,11 +89,11 @@ Published factors are rounded to three significant figures. Total GHGs is rounde - **Why we make it:** Consistent sector-level price indexes in U.S. dollars are not available for every country and year. - **How it affects results:** Where prices in a country moved differently from U.S. prices, or its exchange rate against the dollar changed, its factors for 2025 and 2026 could be too high or too low. -**U.S. margins and no product taxes in purchaser prices** +**U.S. margins in purchaser prices** -- **Assumption:** The U.S. share of trade and transport margins in each commodity's purchaser price applies in every country, and product taxes are left out of the conversion. -- **Why we make it:** Margin and tax data comparable to the U.S. tables are not available for every country. -- **How it affects results:** Where a country's margins or product taxes differ from the U.S., its purchaser-price factors could be too high or too low. Producer-price factors are not affected. +- **Assumption:** The U.S. share of trade and transport margins in each commodity's purchaser price applies in every country. +- **Why we make it:** Margin data comparable to the U.S. tables are not available for every country. +- **How it affects results:** Where a country's margins differ from the U.S., its purchaser-price factors could be too high or too low. Producer-price factors are not affected. **Gross-output weights for regional averages** diff --git a/figures/diagrams/ef-pipeline.svg b/figures/diagrams/ef-pipeline.svg index bdd8f96d..0c9b3f46 100644 --- a/figures/diagrams/ef-pipeline.svg +++ b/figures/diagrams/ef-pipeline.svg @@ -6,63 +6,57 @@ - - - B - - L - from the IO model - and GHG extension - - - - 1 - Total - intensities - M = B × L - - - - 2 - Weight by - GWP - N = C × M - - - - 3 - Regional - averages - and gap filling - - - - 4 - Re-price to - each year - 2024, 2025, 2026 + + + D and B + kg CO₂e per $ + + L + from the GHG extension + and the IO model + + + + 1 + Total emission + factors + N = D × L + by gas, M = B × L + + + + 2 + Regional + averages + and gap filling + + + + 3 + Re-price to + each year + 2024, 2025, 2026 - - Producer price (PRO) + + Producer price (PRO) - - - Purchaser price (PUR) - 5 - × φ + + + Purchaser price (PUR) + 4 + × φ - - - - - - - - - - Steps 1 to 3 are in 2024 U.S. dollars at producer price, by country of production. - Step 4 uses U.S. price indexes; step 5 uses U.S. trade and transport margins. - Emissions of the margin services themselves are published separately as margin emission factors. + + + + + + + + + Steps 1 and 2 are in 2024 U.S. dollars at producer price, by country of production. + Step 3 uses U.S. price indexes; step 4 uses U.S. trade and transport margins. + Emissions of the margin services themselves are published separately as margin emission factors. diff --git a/figures/diagrams/ghg-pipeline.svg b/figures/diagrams/ghg-pipeline.svg index 154036f1..f3f42eac 100644 --- a/figures/diagrams/ghg-pipeline.svg +++ b/figures/diagrams/ghg-pipeline.svg @@ -35,8 +35,9 @@ 5 - Convert - to AR6 + Convert to + CO₂e + AR6 GWPs @@ -47,8 +48,9 @@ - B - kg gas per $ + B + kg CO₂e per $ + by gas diff --git a/intro/emission-factors.md b/intro/emission-factors.md index 46030ce3..794e7e6e 100644 --- a/intro/emission-factors.md +++ b/intro/emission-factors.md @@ -13,12 +13,12 @@ Plan §3.1.5 · target: **RC (Oct 27)** **Planned content** -- Introduce the key variables by name: `D = C × B` (direct emission factors) and `N = C × B × L` (total emission factors), where `C` converts each gas to CO₂e +- Introduce the key variables by name: `D`, the gases in `B` (already in CO₂e) added up (direct emission factors), and `N = D × L` (total emission factors) - Worked toy example with real-looking numbers you can follow by hand **Key visuals** -- 🖼 Matrix "shape" diagram (C × B × L = N), color-coded +- 🖼 Matrix "shape" diagram (D × L = N), color-coded - 🖼 Stacked bar for one real sector: direct, domestic supply chain, imported supply chain by region ::: diff --git a/intro/what-is-eeio.md b/intro/what-is-eeio.md index 3915ec2d..c3308b7b 100644 --- a/intro/what-is-eeio.md +++ b/intro/what-is-eeio.md @@ -21,8 +21,8 @@ EEIO grew out of economic input-output analysis when economist Wassily Leontief Each data component is put into a matrix, named by a letter that is common in input-output analysis and used throughout these docs (see [](../reference/notation.md)). Input-output analysis then combines the matrices with matrix algebra. - **Input-output tables.** The supply (`V`) and use (`U`) tables record which sectors produce which products, and which products each sector and final user buys. From them come the direct requirements (`A`), the inputs a sector buys per dollar of its output, and the total requirements (`L`, the Leontief inverse), which add up the purchases through every round of suppliers. See [](../io/index.md). -- **Environmental extension.** Emissions of each gas by each sector (`E`), divided by the sector's output, give the direct emission intensities (`B`). Characterization factors (`C`) convert each gas to CO₂-equivalent. See [](../ee/index.md). -- **Emission factors.** Combining the two gives the direct emission factors, `D = C × B`, for what a sector emits itself, and the total emission factors, `N = C × B × L`, for what is emitted across its whole supply chain. +- **Environmental extension.** Emissions of each gas by each sector (`E`), weighted by each gas's global warming potential to give CO₂-equivalent and divided by the sector's output, give the direct emission intensities (`B`). See [](../ee/index.md). +- **Emission factors.** Adding up the gases in `B` gives the direct emission factors (`D`), for what a sector emits itself. Combining them with the IO tables gives the total emission factors, `N = D × L`, for what is emitted across its whole supply chain. ## EEIO and life cycle assessment diff --git a/reference/notation.md b/reference/notation.md index 750dac92..046122fa 100644 --- a/reference/notation.md +++ b/reference/notation.md @@ -18,12 +18,11 @@ In the multi-regional model, every row and column is a country–sector pair. `D | `q` | Commodity output | Total domestic output of each commodity: the column sums of `V` | \$ | | `y` (`ydom`, `yimp`) | Final demand | Purchases by households, government, investment, and exports, split into domestic and imported | \$ | | `ynab` | Final demand for the national accounting balance | Final demand for domestic production: `ydom` plus exports | \$ | -| `E` | Emissions | Emissions of each gas by each sector | kg gas | -| `B` | Direct emission intensities | Emissions of each gas per dollar of a sector's own output | kg gas / \$ | -| `C` | Characterization factors | Global warming potentials that convert each gas to CO₂e | kg CO₂e / kg gas | -| `M` | Total emission intensities by gas | `B × L`: emissions of each gas across the supply chain per dollar | kg gas / \$ | -| **`D`** | **Direct emission factors** | `C × B`: CO₂e emitted by the sector itself per dollar of output | kg CO₂e / \$ | -| **`N`** | **Total emission factors** | `C × M` = `C × B × L`: CO₂e across the whole supply chain per dollar of purchases | kg CO₂e / \$ | +| `E` | Emissions | Emissions of each gas by each sector, weighted by AR6 GWPs | kg CO₂e | +| `B` | Direct emission intensities | Emissions of each gas per dollar of a sector's own output, in CO₂e | kg CO₂e / \$ | +| `M` | Total emission intensities by gas | `B × L`: emissions of each gas across the supply chain per dollar, in CO₂e | kg CO₂e / \$ | +| **`D`** | **Direct emission factors** | `B` summed over gases: CO₂e emitted by the sector itself per dollar of output | kg CO₂e / \$ | +| **`N`** | **Total emission factors** | `D × L`, or `M` summed over gases: CO₂e across the whole supply chain per dollar of purchases | kg CO₂e / \$ | | `A_margin` | Margin coefficients | Trade and transport margins paid to each margin sector per dollar of a commodity at producer price | \$ / \$ | | `φ` | Producer share of purchaser price | `1 ÷ (1 + Σ A_margin)`: converts producer-price factors to purchaser price | \$ / \$ | | `PI` | Price index | U.S. BEA chain-type price index for gross output, by sector (2017 = 100) | index |