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Measuring UK greenhouse gas emissions

The UK is required to report its estimated greenhouse gas (GHG) emissions on a range of different bases (territorial, residence and footprint) to fulfil a wide range of international agreements as well as for domestic policy making purposes. The three key official measures of UK GHG emissions, territorial, residence and footprint, are explored and defined below.

One of these, territorial, is used to inform progress on UK-wide emissions targets. These include a target of net zero for UK greenhouse gas (GHG) emissions by 2050 compared with 1990 levels, adopted by the UK Government in 2019 following a Committee on Climate Change recommendation. More recently, UK government announced the sixth Carbon Budget target to reduce emissions by approximately 78% by 2035 compared with 1990 levels.

‘Net zero’ means that any GHG emissions would be the same as, or less, than those removed from the atmosphere, which can be achieved through a combination of reduction and removal of emissions.

Measuring UK progress towards net zero

The UK emissions estimates published by the Department for Business, Energy and Industrial Strategy (BEIS), are used to monitor net zero and other UK-wide targets.

These estimates include emissions produced within the UK’s geographical borders, also known as territorial. They take into account emissions and removals from:

  • UK-based businesses no matter where they are registered in the world;
  • the activities of people living in the UK as well as visitors from outside the UK; and
  • land, including forests and crop or grazing land.

They currently exclude emissions or removals from:

  • international aviation and shipping;1
  • UK residents and UK registered businesses abroad; and
  • production of goods and services the UK imports from other countries;
  • burning biomass – wood, straw, biogases and poultry litter – for energy production.2

In 2020 on a provisional basis and following the early impacts of the coronavirus pandemic, UK emissions were 414 million tonnes of carbon dioxide equivalent (Mt CO2e) — a measure covering the seven main GHGs3, weighting each gas based on its potential to cause global warming. As CO2 accounts for the majority of emissions (80% on average over the years 2016 to 2020), changes in CO2 tend to be reflected in changes in GHG emissions overall. Total emissions were down 49% compared with 809 Mt CO2e in 1990 (Figure 1).

Net greenhouse gas emissions on a territorial basis, UK, 1990 to 2019 and provisional 2020 (Mt CO2e)

Net greenhouse gas emissions on a Net Zero (Climate Change Act) basis, UK, 1990 to 2020

Source: Department for Business, Energy & Industrial Strategy

  1. (p) = these estimates give an early indication of emissions in 2020 and are subject to revision when final estimates are published in February 2022. There are uncertainties associated with all estimates of greenhouse gas emissions. Trends over time are more reliable, as considerable uncertainties may surround the emissions estimates for any given year. The estimates are provisional, so more uncertain than figures for earlier years, while the impact of the Covid-19 pandemic means they are more uncertain than usual for this year. For more information on uncertainties in emissions estimates see the annex published alongside the 2019 final UK greenhouse gas emissions statistics.

  2. Emissions from international aviation and shipping are currently excluded from these estimates.

Emissions tend to vary depending on average temperatures and weather conditions: for example, cold periods lead to more household heating. Temperature adjusted UK emissions have tended to track unadjusted emissions in recent years (Figure 2). More information is available here.

Emissions estimates comparable with economic data

Emissions estimates are also available on a UK residence basis. These cover emissions by UK residents and UK-registered businesses, whether they happen in the UK or overseas.

The Office for National Statistics produces these as part of the UK’s Environmental Accounts. These estimates provide additional useful information to complement the UK’s national accounts.

Total provisional GHG emissions in 2020 on a residence basis were 480 million tonnes of carbon dioxide equivalent (Mt CO2e), slightly higher than on the territorial measure. This difference is mainly due to the Environmental Accounts measure of emissions including emissions from international travel and emissions from burning biomass2.

A key use of this measure is that it enables direct comparison of emissions by sector of UK industry and households with key economic indicators including gross domestic product (GDP) and Gross Value Added (GVA).

In 2020, the industries contributing the most emissions were similar to previous years: energy supply, manufacturing and transport (Figure 3). Household emissions, from heating homes and travelling, for commuting, social, domestic or leisure purposes, has been the largest contributor since 2015. These three industries and households together accounted for 70% of emissions in 2020.

Greenhouse gas emissions for the three highest-emitting industries, and households, UK, 1990 to 2019 and provisional 2020 (Mt CO2e)

Source: Office for National Statistics

  1. Industry aggregations are based on the UK Standard Industrial Classification (SIC) 2007. ‘Households’ here includes the headings “consumer expenditure” and “activities of households as employers; undifferentiated goods and services – producing activities of households for own use” (for example, employing a cleaner and growing vegetables for your own consumption). The electricity, gas, steam and air conditioning supply sector is referred to as the energy supply sector. The transport and storage sector is referred to as the transport sector.

  2. For more information that explains the differences between estimates of emissions on a residence and territorial basis see bridging tables.

The reductions in GHG emissions seen from 1990 to 2020 (on both a territorial and residence basis) were driven largely by a switch from using coal and heavy-emitting fuels in the energy supply and manufacturing industries to lower emission fuels such as natural gas and, more recently, renewable sources.

When used for electricity generation, coal produces more carbon dioxide (CO2) than natural gas per unit of electricity produced, hence the reduction in CO2 emissions from the switch away from coal.

More detailed breakdowns are currently only available up to 2019. From 1990 to 2019, fossil fuel use fell in the energy supply industries by 57% and in the manufacturing industries by 44%. By contrast fossil fuel use by households fell by around 3%, while its use in transport and storage increased by 20% (Figure 4).

These four sectors accounted for 82% of all fossil fuel energy use in the UK in 2019. Agriculture accounted for 1% of fossil fuel energy use in the UK in 2019 but 9% of GHG emissions (residence basis). Emissions from agriculture are dominated by non-CO2 emissions such as Methane (CH4), mainly from enteric fermentation, which occurs in the digestive system of ruminant animals or Nitrous oxide (N2O) which largely arises from the use of nitrogen fertiliser.

More information on energy use (from fossil fuels and renewables) and energy intensity in the UK can be found in the article The UK’s climate is changing. What is driving this? How is the UK responding?

Fossil fuel energy use for the four highest sectors in the UK, 1990 to 2019 million tonnes of oil equivalent (Mtoe)

Source: Office for National Statistics

  1. Industry aggregations are based on the UK Standard Industrial Classification (SIC) 2007. Households include “consumer expenditure” and “activities of households as employers; undifferentiated goods and services — producing activities of households for own use” (for example, employing a cleaner and growing vegetables for your own consumption). The electricity, gas, steam and air conditioning supply sector is referred to as the energy supply sector. The transport and storage sector is referred to as the transport sector.

  2. Energy use is considered in this chart on a residence basis not a territorial basis (BEIS: Digest of UK Energy Statistics). For more information see bridging tables which explain the differences between such estimates.

  3. Fossil fuels here refers to: coal, natural gas, petrol, DERV, Fuel oil, Gas oil, Aviation turbine fuel, Aviation spirit, Anthracite, Blast furnace gas, Burning oil, Coke, Coke oven gas, Colliery methane, LPG, Lubricants, Naphtha, OPG, Orimulsion, Peat, Petroleum coke, Refinery miscellaneous, Sour gas, SSF, Waste oils and Waste solvent.

The provisional 2020 figures enable us to look at the emissions impacts of the early part of the coronavirus pandemic. The transport industry recorded the biggest proportional fall in emissions across industries, down 40% from 2019 to 2020, compared with a 9% fall in the previous year.

Emissions from households fell 10% between 2019 to 2020. With many people working remotely, being on furlough, or losing their job in 2020 during the COVID-19 pandemic, more people were staying at home and therefore generating more emissions through energy for heating but less emissions from commuting for work. The reduction in emissions from personal travel including commuting in 2020 outweighed the additional emissions from heating. For more information see here.

The UK’s carbon footprint

A further measure of UK emissions looks at consumption and is known as the ‘carbon footprint’.

These account for emissions through the supply chain of goods and services consumed in the UK wherever they are produced in the world, so allow for emissions from UK imports but exclude emissions arising from UK produced goods that are exported.

This measure, published by the Department for Environment, Food and Rural Affairs (Defra), helps to understand the UK’s global contribution to climate change. For more information on the UK’s carbon footprint see article Emissions embedded in trade and impacts on climate change.

UK footprint emissions in 2018, the latest available year, were 703Mt CO2e4.

Comparing the three emissions measures

In 2018, the latest year that all three measures are available, territorial emissions were 468 Mt CO2e, residence emissions 569 Mt CO2e and footprint emissions 703 Mt CO2e.

Figure 5 below shows how these three UK emissions measures compare over time. The territorial and residence measures have broadly moved downwards together, while footprint emissions have fallen since the mid-2000s.

Estimates of UK greenhouse gas emissions on a footprint (consumption) basis have fallen more slowly than estimates on other bases

Source: Office for National StatisticsDepartment for Business, Energy & Industrial StrategyDepartment for Environment, Food & Rural Affairs

  1. Footprint estimates are classified as Experimental Statistics and are subject to uncertainty. The methodology used to produce them is subject to ongoing review and refinement.

  2. ONS Environmental Accounts air emissions bridging tables provide further detail of the relationship between the different estimates of emissions provided in this figure.

The UK works continually to improve its emission statistics which will be regularly updated.

  1. Emissions from International aviation and shipping will be included within the UK-wide net zero target and carbon budgets from 2033.

  2. The net zero target under the Climate Change Act follows international guidelines such that carbon dioxide emissions from biomass combustion are reported as changes in carbon stocks in the Land-Use, Land-Use Change and Forestry (LULUCF) sector of the country where biomass is harvested. So while UK emissions are reported as a memorandum item by the sector where the biomass fuel is used, they are not included in UK emissions to avoid double-counting. Emissions of GHGs other than carbon dioxide are included.

  3. The seven main GHGs covered are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3).

  4. Unlike the other two emissions measures, the carbon footprint estimates are an Experimental Statistic due to inherent uncertainties. The methodology used to produce them is subject to ongoing review and refinement.

Contact details for this article: climate.change@ons.gov.uk