Scottish Greenhouse Gas Emissions 2012

Section A - Introduction to Greenhouse Gases

Purpose of this Publication

The "Scottish Greenhouse Gas Emissions 2012" Official Statistics publication contains the results of the Scottish Greenhouse Gas Inventory for 1990-2012. 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 (Scotland) Act 2009.

Using the Statistics. Which measure to use and when?

The "Scottish Greenhouse Gas Emissions 2012" Official Statistics publication includes data on two categorisations of greenhouse gas emissions.

• Estimated net source emissions. These are sometimes referred to as "territorial" emissions, as they are produced within a country's territory or economic sphere. Section B contains results using this categorisation.
• Estimated net source emissions which have been adjusted to take into account of trading in the EU Emissions Trading System (EU ETS). Section C contains results using this categorisation.

The publication does not contain information on "consumption" estimates, with the spending of Scottish residents on goods and services, wherever in the world these emissions arise along the supply chain, and those which are directly generated by Scottish households through private motoring and heating. This information will be published as part of the Official Statistics publication: " Scotland's Carbon Footprint" later this year.

The table below shows how to use the different categorisations of statistics on greenhouse gas emissions.

	Estimated Source Emissions (Section B)	Estimated Source Emissions Adjusted to take into account of EU Emissions Trading System (Section C)
Adjusted for EU Emissions Trading System
Used for reporting progress against Scotland's Climate Change Targets 1
Can be compared with EU countries 2
Can be compared with UK 3
Includes International Aviation and Shipping
Includes Offshore Emissions
Data on individual greenhouse gases
Data on Scottish Government source sectors
Base Year	1990	Baseline (Variable)

¹ Further information on Scotland's Climate Change Targets can be found in Section C.

² Data for EU countries include figures offshore emissions which cannot be broken down at present, so are not directly comparable with Scottish estimates. Figures on offshore emissions are available at a UK level, but not for devolved administrations.

³ Direct comparisons between Scotland and the UK can be made by adding up the results for the four Devolved Administrations separately. The UK figure in this case would exclude offshore emissions.

Which greenhouse gases are reported on and how do they contribute to global warming?

The basket of greenhouse gases consists of carbon dioxide, methane, nitrous oxide, and the three F-gases (hydrofluorocarbons- HFCs, perfluorocarbons - PFCs and sulphur hexafluoride- SF₆). These gases are weighted by global warming potential (GWP), so that total greenhouse gas emissions can be reported on a consistent basis. The GWP for each gas is defined as its warming influence relative to that of carbon dioxide over a 100 year period. Greenhouse gas emissions are then presented in carbon dioxide equivalent (CO₂e) units. In the case of the F-gases, the global warming potential is listed as being within a range of values, due to the gases existing as a variety of isotopes with differing GWPs.

Table A1. List of Greenhouse Gases and their contribution to Scotland's net greenhouse gas emissions, 2012

Name of Greenhouse Gas	Chemical Formula	Global Warming Potential (GWP) (Conversion factor to carbon dioxide equivalent)	Contribution to Scotland's Net Greenhouse Gas Emissions in 2012 (in Mt CO2e)	Percentage of Scotland's Net Greenhouse Gas Emissions in 2012 (in Mt CO2e)	Examples of sources of gas
Carbon dioxide	CO2	1	39.8	75.2%	All other sources of greenhouse gases, including removals of emissions (carbon sinks)
Methane	CH4	21	6.8	12.9%	Waste management, enteric fermentation and animal waste
Nitrous oxide	N2O	310	5.1	9.6%	Agricultural soils
F-gases			1.2	2.3%	Industrial air conditioning, aluminium smelting, refrigeration, use as tracer gases
- Hydrofluorocarbons	HFC	140 - 11,700	1.1	2.1%
- Perfluorocarbons	PFC	6,500 - 9,200	0.1	0.1%
- Sulphur hexafluoride	SF6	23,900	0.0	0.1%
Total Net Greenhouse Gases			52.9	100.0%

The Global Warming Potentials (GWPs) are based on international reporting standards, as set by the Intergovernmental Panel on Climate Change (IPCC). The IPCC guidelines are being updated for the 1990-2013 inventory to reflect updates in scientific knowledge and these will be reflected in figures published in 2015. At this time, the GWP of methane will increase from 21 to 25. The GWP of Nitrous oxide will fall from 310 to 298.

The basket of greenhouse gases is determined by international reporting standards, as set by the Intergovernmental Panel on Climate Change (IPCC). The IPCC guidelines are being updated for the 1990-2013 inventory to reflect updates in scientific knowledge and this will incorporate a new greenhouse gas, nitrogen trifluoride (NF₃), which will be reported on in 2015.

Section B contains further data on the individual greenhouse gases.

Reporting of the Baseline and 1990

In this publication, a single 1990 Base Year is used for all estimated source emissions (Section B). This year is referred to as "1990" in charts, tables and text.

A different baseline is used for reporting progress against Scotland's Climate Change Targets only. This is referred to as "Baseline" in charts, tables and text.

The Baseline in for reporting against Climate Change Targets is:

• 1990 for carbon dioxide carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O)
• 1995 for Fluorinated gases (F gases): hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF₆)

Within this publication, data are estimated for the Baseline; and the years 1990, 1995 and 1998 to 2012.

What are net emissions and carbon sinks?

The emissions reported are the combination of emissions minus removals from the atmosphere by carbon sinks. Carbon sinks are incorporated within the three sectors of agriculture and related land use, development, and forestry, which include emissions as well as removals resulting from afforestation, reforestation, deforestation and forest management together with changes in land use.

Sectors

The sector breakdowns used in this report are primarily based on the National Communication (NC) sectors, which are used in the UK Greenhouse Gas Inventory. However, in order to associate emissions from conversion of grassland to and from cropland, and liming of agricultural land with other agricultural activities, we have generated three new sectors from the previous two sectors Land Use, Land Use Change and Forestry (LULUCF) and Agriculture. The first new sector, Agriculture and related land use, includes all emissions in the NC sector Agriculture together with those LULUCF emissions associated with agricultural practices. The remaining LULUCF emissions are grouped into Forestry (changes in emissions relating mainly to stock changes resulting from afforestation, deforestation and harvested wood products) and Development (changes in emissions resulting from land use change to settlements). These new sectors are the same as those that were reported in the Scottish Government publication "Low Carbon Scotland - Meeting the Emissions Reductions Targets 2013-2027". A detailed mapping between the sectors used in this report and the NC sectors and Intergovernmental Panel on Climate Change (IPCC) sectors is given in Section E.

This publication provides the latest estimates of Scotland's greenhouse gas emissions by source from 1990-2012. For the purposes of reporting, greenhouse gas emissions are allocated into sectors as follows:

Energy supply

Emissions from fuel combustion for electricity and other energy production sources.

Business and industrial processes

Emissions from industry and from those in combustion in industrial/commercial sectors, industrial off-road machinery and refrigeration and air conditioning

Transport

Emissions from domestic aviation, road transport, railways, domestic navigation, fishing and aircraft support vehicles.

Public

Emissions from combustion of fuel in public sector buildings.

Residential

Emissions from fuel combustion for heating/cooking, garden machinery and fluorinated gases released from aerosols/metered dose inhalers.

Agriculture and Related Land Use

Net emissions from cropland, grassland livestock, agricultural soils, stationary combustion sources and off-road machinery

Development

Net emissions from settlements and from land converted to settlements

Forestry

Changes in emissions relating mainly to stock changes, resulting from afforestation, deforestation and harvested wood products

Waste management

Emissions from waste disposed of to landfill sites, waste incineration, and the treatment of waste water

When emissions are reported by source, emissions are attributed to the sector that emits them directly. These high-level sectors are made up of a number of more detailed sectors, which follow the definitions set out by the Intergovernmental Panel on Climate Change (IPCC), and which are used in international reporting tables which are submitted to the United Nations Framework Convention on Climate Change (UNFCCC) every year. Section E contains a more detailed mapping of what is included in each source.