Section B. Results - Estimated Sources of Scottish Greenhouse Gas Emissions
Chart B1 presents the sources and sinks of Scottish Greenhouse Gas Emissions in 2012, grouped by Scottish Government sector.
- In 2012, Energy supply was the largest source of net emissions (17.1 Mt CO2e), followed by Agriculture and Related Land Use (11.2 Mt CO2e), and Transport (excluding International Aviation and Shipping), (10.5 Mt CO2e).
- Emissions from the energy supply sector were greater than emissions from public sector, development, international aviation and shipping, waste management and residential emissions combined.
- Forestry was the only aggregate sector in which there has been a net emissions sink (-9.9 Mt CO2e).
|TOTAL||Carbon dioxide||Methane||Nitrous oxide||Fluorinated gases|
|Agriculture and related land use||11.2||3.0||3.6||4.6||0.0|
|Transport (excluding international aviation and shipping)||10.5||10.4||0.0||0.1||0.0|
|Business and Industrial process||8.5||7.4||0.0||0.1||1.1|
|International Aviation and Shipping||2.4||2.3||0.0||0.0||0.0|
Carbon dioxide was the main greenhouse gas emitter or sink in most sectors, with the exceptions of Agriculture and related land use and Waste Management.
- Nitrous oxide was the main emitter in Agriculture and Related Land Use (4.6 Mt CO2e), followed by methane (3.6 Mt CO2e) and carbon dioxide (3.0 Mt CO2e).
- Almost all emissions in the Waste Management sector were emitted in the form of methane (2.7 Mt CO2e)
F gases were not the key emitters in any sector. Where these are emitted, it is in relatively small amounts via the Business and Industrial Process source sector, as well as the Residential sector.
Key Trends By Scottish Government Sector
Chart B2 presents the main sources of Scottish Greenhouse Gas Emissions in Scotland from 1990 to 2012, broken down by Scottish Government sector. Note that for the purposes of presentation, some sectors have been grouped together on the chart. Chart B6 contains information on the absolute and percentage reductions in greenhouse gas emissions in every Scottish sector over the entire time period, with Chart B7 containing the same information for the latest year.
Most sectors exhibit a general downward trend between 1990 and 2012, most clearly evident since 1998.
- In all years, energy supply is the main source of greenhouse gas emissions. The chart shows that energy supply is a very volatile sector, which is linked to the ambient temperature, particularly during the winter months; and fuel used for electricity production, which in turn is largely driven by the price coal relative to "cleaner" fuels. Charts B3 and B4 demonstrate these effects in more detail.
- Most of the fall in emissions from the Business and Industrial Processes has occurred between 1990 and 1995. This has been driven by a decline in emissions from manufacturing and the iron and steel industry over this time period.
- Agriculture and related land use has seen a gradual decline between 1998 and 2012, which can be linked to a decline in cattle and sheep numbers and in fertiliser use.
- Emissions from transport (including international aviation and shipping) have seen little overall change between 1990 and 2012, emissions rose to a peak in 2007, before falling slightly. This peak was caused by changes in road transport emissions which in turn has been driven by a drop in new car registrations between 2007 and 2008.
- Waste management emissions have fallen between 1998 and 2012. This has been driven by the progressive introduction of methane capture within landfill management.
Chart B3 shows that the generation of Scotland's electricity changes over time. Emissions from the electricity supply sector (such as power stations) are associated with these changes.
Data obtained from DECC Energy Trends, published December 2013
- There was a sharp decrease between 2011 and 2012 in the percentage of gas being used for Scotland's electricity mix (from 16.1 per cent to 8.0 per cent). This follows a decline in the relative share of gas from 2006 onwards.
- There was an increase in the percentage of coal being used for the generation of electricity between 2011 and 2012 (from 21.0 per cent to 24.9 per cent). Overall, there has been an relative increase in the relative share of coal since 2005, although this series is volatile, with 29.5 per cent of Scottish electricity supply being fuelled by coal in 2010.
- The renewables sector (including hydro natural flow) has seen an overall increase from 11.7% in 2004 to 29.9% in 2012, and this increase has been greatest between 2010 and 2012.
Chart B4 shows the gas and coal prices for large users in the UK. The use of coal rather than gas in electricity generation can be sourced to these price effects in many cases.
Data obtained from DECC: Digest of UK Energy Statistics
Long term (1990 to 2012) and short term (2011 to 2012) trends by sector
Overall, there has been a 22.6 Mt CO2e (29.9 per cent) decrease in net emissions between 1990 and 2012 and there has been a 0.4 Mt CO2e (0.8 per cent) increase in net emissions between 2011 and 2012.
This sector has seen a 5.3 Mt CO2e (23.5 per cent) fall in emissions between 1990 and 2012 - the biggest absolute fall of any sector. Between 2011 and 2012, there was a 0.2 Mt CO2e (1.4 per cent) increase in energy supply emissions. Charts B2 to B4 shows that this series is very volatile and this is largely driven by changes in the fuel mix for electricity production.
Business and Industrial Process
This sector has seen a 5.0 Mt CO2e (37.0 per cent) fall in emissions between 1990 and 2012. As shown in Chart B2, much of this decrease occurred between 1990 and 1995. There has been a decline in emissions from manufacturing and the iron and steel industry over this time period. Between 2011 and 2012, there was very little change in emissions in this sector (0.6 per cent increase)
This sector has seen a 3.9 Mt CO2e (58.6 per cent) fall in emissions between 1990 and 2012 - the biggest percentage fall of any sector. There has been a reduction in landfill emissions and this has been achieved by the progressive introduction of methane capture within landfill management. Between 2011 and 2012, there was a fall of 0.2 Mt CO2e (5.3 per cent), in line with the long-term decline.
This sector has seen a 2.9 Mt CO2e (41.9 per cent) increase in the carbon sink between 1990 and 2012. The majority of the sink arises from the large area of conifer plantations, which is subject to forest management such as thinning and varying harvesting rotations. There is an increasing trend in removals between 1990 and 2005, during which time there was harvesting of mature conifers planted in the 1920 to 1940s and a reduced rate of forest planting. Over the last 40 years the rate of afforestation has decreased. Combined with conifer plantations established in the mid-20th century reaching their planned rotation age now being felled and replanted, this has resulted in the size of this annual sink remaining relatively constant. Between 2011 and 2012, there was very little change in the size of the carbon sink from forestry.
Transport (Including International Aviation and Shipping)
Between 1990 and 2012, emissions from transport (including international aviation and shipping) have been fairly stable, although Chart B2 shows that emissions rose to a peak in 2007, before falling slightly. This has been caused by changes in road transport emissions which in turn has been driven by a drop in new car registrations between 2007 and 2008.
Breaking this category down further, between 1990 and 2012, there was no real change in transport emissions (excluding international aviation and shipping) and a 0.2 Mt CO2e decrease in emissions from international aviation and shipping. International aviation emissions have more than doubled between 1990 and 2012 (from 0.5 Mt CO2e to 1.1 Mt CO2e). This reflects the growth in aviation and the increase in international routes at airports. Emissions from international shipping have fallen by 35.1 per cent between 1990 and 2012 (from 2.0 Mt CO2e to 1.3 Mt CO2e). This is primarily due to a decrease in Scotland's port freight movements.
In the latest year, there was a 0.1 Mt CO2e increase in emissions from transport (excluding international aviation and shipping). This may be due to strong growth in transport demand but mitigated by improvements in efficiency of transport vehicles. There was a 0.2 Mt CO2e (8.7 per cent) decrease in emissions from international aviation and shipping. It should be noted that the data series for international shipping is particularly volatile.
Agriculture and Related Land Use
This sector has seen a 4.1 Mt CO2e (26.7 per cent) fall in net emissions between 1990 and 2012. This has been driven by a fall in emissions of methane (Chart B9) and nitrous oxide (Chart B10). Methane emissions from agriculture have fallen due to a decline in cattle and sheep numbers. Nitrous oxide emissions have fallen due to a decline in livestock numbers and nitrogen fertiliser use. Between 2011 and 2012, there was a 0.3 Mt CO2e (2.8 per cent) decrease in net emissions in this sector. This has been mainly driven by a reduction in wheat production and the resulting reduction in emissions from crop residues and fertilisers.
This sector has seen a 0.9 Mt CO2e (10.8 per cent) fall in emissions between 1990 and 2012. Between 2011 and 2012, there was 0.7 Mt CO2e (11.1 per cent) increase in emissions from this sector. Residential emissions are partly generated by space-heating homes and thus are related to external temperatures. Mean annual temperatures in 2012 were 0.7°C lower than in 2011. This is due to relatively colder weather in late autumn and early winter 2012 and a cold snap in April. As a result of this relationship to external temperatures, residential emissions can exhibit some large annual fluctuations.
This sector contributes a small proportion of Scotland's net greenhouse gas emissions. The was a 0.3 Mt CO2e (17.8 per cent) fall in public sector emissions between 1990 and 2012. Between 2011 and 2012, there was an increase of 0.1 Mt CO2e (4.3 per cent) in emissions from this sector. This is due to an increase in natural gas consumption in 2012 which is associated with colder winter temperatures in that year.
This sector contributes to a small proportion of Scotland's net greenhouse gas emissions. There was a 0.1 Mt CO2e decrease in development emissions between 1990 and 2012. Between 2011 and 2012, there was very little change in emissions from this sector.
Emissions by type of gas
Chart B7 shows the trends in emissions, broken down by gas from 1990 to 2012.
- Carbon dioxide is by far the largest contributor of Scottish greenhouse gas emissions in all years (75.2 per cent of all emissions in 2012) and is the most volatile series of all gases - largely driven by changes in energy supply emissions and to a lesser extent, residential emissions.
- Methane in the second most common greenhouse gas in 2012 (12.9 per cent of all net emissions) followed by nitrous oxide (9.6 per cent) and F-gases making up the remainder (2.3 per cent).
- Methane has seen the largest percentage reduction from 1990 to 2012 (46.9 per cent), driven by a reduction in waste management emissions. There have been similar percentage reductions for both carbon dioxide (28.4 per cent) and nitrous oxide (27.4 per cent). Fluorinated gases have shown an 8-fold increase from 1990 to 2012 and this increase is driven by the introduction of hydrofluourocarbons (HFCs) from 1995 onwards. These HFCs replace chlorofluorocarbons (CFCs) which were banned by the Montreal Protocol due to their impact on the ozone layer.
Charts B8 to B11 present results on individual gases broken down by main Scottish government sector over time. Table B3 contains figures on all greenhouse gas emissions across the time series. Chart B8 shows how carbon dioxide emissions have changed from 1990 to 2012.
Carbon Dioxide (CO2)
- Chart B8 shows that energy supply is the key source of carbon dioxide emissions in all years between 1990 and 2012, followed by transport (including international aviation and shipping).
- Much of the decrease in carbon dioxide emissions between 1990 and 2012 has been driven by overall falls in the energy supply sector across the time period and in business and industrial processes between 1990 and 1995. Carbon dioxide emissions from the energy supply sector have been quite volatile over the time period, with the highest emissions occurring between 1995 and 2003, and a spike in 2006, related to a greater use of coal in that year.
- Forestry has been a net sink of carbon dioxide consistently between 1990 and 2012.
- Methane emissions from waste management have fallen from 6.5 Mt CO2e in 1990 to 2.7 Mt CO2e in 2012 (a 59.4 per cent reduction) due to capture of methane from landfill.
- Methane emissions in the agriculture and related land use sector have fallen from 4.3 Mt CO2e in 1990 to 3.6 Mt CO2e in 2012.
- In the Energy Supply sector, methane emissions have fallen from 1.7 Mt CO2e in 1990 to 0.4 Mt CO2e in 2012.
Nitrous Oxide (N2O)
- Agriculture and related land use is by far the main contributor to emissions of nitrous oxide.
- Emissions of nitrous oxide in this sector have fallen from 6.0 Mt CO2e in 1990 to 4.6 Mt CO2e in 2012 and has been driven by a decline in livestock numbers and in nitrogen fertiliser use.
- Business and industrial processes have seen a fall from 0.5 Mt CO2e in 1990 to 0.1 Mt CO2e in 2012.
Fluorinated gases (F-gases)
- F gas emissions in Scotland contribute less to global warming than other greenhouse gases. They are the most potent gases with high global warming potentials but they are emitted in very small quantities.
- There has been a sharp increase in F gas emissions from business and industrial processes from 1990 and 2012 (0.1 Mt CO2e in 1990 to 1.1 Mt CO2e in 2012), although the year-on-year rate of increase is slowing in recent years. This is because F gases were introduced to replace cholofluorocarbons (CFCs), which were used in, amongst others, industrial air conditioning units. CFCs were banned under the Montreal Protocol, as they were contributing to the depletion of the ozone layer.
- F gas emissions in the residential sector are caused by the use of aerosols and metered dose (usually asthma) inhalers.
|Source Sector||Baseline||1990||1995||1998||1999||2000||2001||2002||2003||2004||2005||2006||2007||2008||2009||2010||2011||2012||Change between 1990 and 2012||% change between 1990 and 2012|
|Total greenhouse gas emissions||75.6||75.5||75.4||74.2||70.3||72.0||71.3||67.0||66.7||64.4||63.1||66.8||62.2||60.2||56.3||58.3||52.5||52.9||-22.6||-29.9%|
|Agriculture and Related land Use||15.2||15.2||15.4||15.5||15.3||15.1||14.5||14.3||14.3||13.9||13.6||13.1||12.7||12.2||12.0||11.8||11.5||11.2||-4.1||-26.7%|
|Business and Industrial process||13.6||13.5||9.3||9.5||9.6||9.9||10.4||9.4||9.5||9.4||9.8||9.5||9.1||9.1||8.1||8.2||8.5||8.5||-5.0||-37.0%|
|Transport (excluding IA&S)||10.5||10.5||10.5||10.9||11.0||10.9||10.8||11.1||11.2||11.3||11.4||11.6||11.9||11.3||10.9||10.7||10.5||10.5||0.0||0.1%|
|International Aviation and Shipping (IA&S)||2.5||2.5||2.5||3.1||2.6||2.3||2.3||1.9||2.1||2.4||2.6||3.0||2.9||3.1||2.9||2.5||2.6||2.4||-0.2||-6.4%|
|Other sources *||3.4||3.4||3.5||3.4||3.4||3.3||3.4||3.1||3.1||3.2||3.2||3.0||2.9||3.0||2.9||3.0||3.0||3.0||-0.4||-10.4%|
|Baseline||1990||1995||1998||1999||2000||2001||2002||2003||2004||2005||2006||2007||2008||2009||2010||2011||2012||% Change from 1990 to 2012 (in Mt CO2e)||Share of Greenhouse Gases, 2012|
|Total Greenhouse Gases||75.6||75.5||75.4||74.2||70.3||72.0||71.3||67.0||66.7||64.4||63.1||66.8||62.2||60.2||56.3||58.3||52.5||52.9||-29.9%||100.0%|
|Carbon dioxide (CO2)||55.6||55.6||56.0||55.1||52.2||54.6||54.3||50.2||50.6||48.9||47.9||51.7||47.6||45.9||42.4||44.8||39.1||39.8||-28.4%||75.2%|
|Nitrous oxide (N2O)||7.0||7.0||6.5||6.8||6.6||6.4||6.3||6.3||6.1||6.0||5.8||5.7||5.5||5.3||5.3||5.2||5.2||5.1||-27.4%||9.6%|
|* F gases||0.2||0.1||0.2||0.5||0.6||0.7||0.7||0.8||0.9||1.0||1.0||1.1||1.1||1.1||1.2||1.2||1.2||1.2||812.6%||2.3%|
|of which HFCs||0.1||0.0||0.1||0.4||0.4||0.5||0.6||0.7||0.8||0.8||0.9||1.0||1.0||1.0||1.1||1.1||1.1||1.1||124357%||2.1%|
Note on F-gases:
HFCs are hydrofluorocarbons
PFCs are perfluorocarbons
SF6 is sulphur hexafluoride
Email: Martin Macfie
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