These figures are compiled in line with the Code of Practice for Official Statistics. A restricted number of people are granted pre-release access for quality assurance and for briefing of these statistics.

The compilation of the inventory is governed by a rigorous quality assurance process and is subject to a great deal of third party scrutiny, such as annual reviews by the UNFCCC of the UK inventory. The Scottish Government is represented at the UK's National Inventory Steering Committee (NISC), where improvements to the Scottish and UK inventories are discussed. As part of the NISC, a major programme of work has been recently launched to review and improve the quality assurance and quality control processes within the models used in the greenhouse gas inventory. The UK Department for Energy and Climate Change (DECC) has published tools and guidance to help people with quality assurance of analytical models.

The greenhouse gas inventory covers a wide variety of all anthropogenic sources of greenhouse gas emissions and therefore a wide variety of emissions sources which require different approaches to their estimation. There are a large number of data sources used in its compilation, obtained from Government statistics, regulatory agencies, trade associations, individual companies, surveys and censuses. The methods used to compile the greenhouse gas inventory are consistent with international guidance on national inventory reporting from the Intergovernmental Panel on Climate Change. Most emission estimates are compiled by combining activity data (such as fuel use) with a suitable emission factor (such as amount of CO2 emitted per unit of fuel used). Estimates of emissions from the industrial sector are often compiled based on plant-specific emissions data. Emissions from some sectors are based on more complicated models - such as the model used to estimate emissions from landfill, and the model used to estimate the carbon dynamics in soils when trees are planted. Much of the data on net emissions from agriculture and related land use, land use change and forestry emissions are based on modelled data for Scotland, which are consistent with, but not constrained to, the UK totals and thus are known as "bottom up" estimates. Many of the remaining emissions sources within the inventory have been collated on a "top down" approach where estimates of emissions have been apportioned to Scotland using proportions of energy use in the Department of Energy and Climate Change (DECC) Publication "Digest of UK Energy Statistics (DUKES)". All estimates, by definition, are subject to a degree of statistical 'error' but in this context it relates to the uncertainty inherent in any process or calculation that uses sampling, estimation or modelling.

Estimates of greenhouse gases are compiled by a consortium of contractors. The source emissions are based upon a range of data sources, ranging from model based estimates to point source emission data. As a result, the estimates are subject to a degree of uncertainty. Full analyses of these uncertainties are provided on the National Atmospheric Emissions Inventory website.

The Scottish Government has commissioned research to overhaul and update the uncertainties model used for the Scottish greenhouse gas inventory. A detailed study was carried out in parallel with the compilation with the 1990-2013 Scottish greenhouse gas inventory to review and improve the uncertainty calculations. A link to this project and to the full report can be found in the Scottish Greenhouse Gas Inventory Uncertainties Project.

These uncertainty calculations have been updated for the 1990-2014 inventory. The outcome is a model that delivers more accurate and lower estimates of uncertainty for Scottish greenhouse gas emissions (9% uncertainty for 2014 emissions), and a narrower range of "Base year to latest year" Greenhouse Gas trends (-41%, within a -33% to -49% range). Note that these calculations exclude emissions from international aviation and shipping.

The Scottish Government has published a document titled "Scottish Greenhouse Gas Statistics 2021 - UK comparisons"

The data are published on the Scottish Government website in pdf and HTML format. Pivot Tables containing the entire Greenhouse Gas Inventory for Scotland in 1990-2021 can be found here

The Scottish Greenhouse Gas Inventory is the key tool for understanding the origins and magnitudes of the emissions and the assessment of policies designed to control or reduce emissions. The inventory is compiled in line with international guidance from the Intergovernmental Panel on Climate Change (IPCC). Data are reported by source sector (such as energy supply) and by greenhouse gas (such as carbon dioxide). The inventory is also used to report data against targets as required under the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019. Further information on how to use the inventory can be found in Section A of the Official Statistics bulletin: "Scottish Greenhouse Gas Emissions 2021"

The data are published every June and cover a calendar year's worth of emissions. This is just under 1.5 years after the end of the relevant calendar year; and 4 months after the publication of UK data, from which devolved administration data can be then calculated.

Each year the whole time series is revised to incorporate improved methods and data, so that data in the current inventory cannot be compared to previous inventories. Section D of the "Scottish Greenhouse Gas Emissions 2021" statistics release examines key revisions in estimated source emissions between the latest inventory (1990-2021) and the previous inventory (1990-2020) published in June 2022. It also provides a summary of the cumulative impact of revisions since the 1990-2008 inventory.

In the latest release, there was a change to the Global Warming Potential (GWP) of greenhouse gasses resulting in a slight increase in emissions estimates, along with other recalculations in various areas.