Hinckley and Bosworth
Newark and Sherwood
King's Lynn and West Norfolk
City of London
Hammersmith and Fulham
Kensington and Chelsea
Kingston upon Thames
Blackburn with Darwen
Cheshire West and Chester
Basingstoke and Deane
Brighton and Hove
Epsom and Ewell
Folkestone and Hythe
Isle of Wight
Reigate and Banstead
City of Bristol
Forest of Dean
County of Herefordshire
Nuneaton and Bedworth
Argyll and Bute
City of Edinburgh
Dumfries and Galloway
Na h-Eileanan Siar
Setting Climate Committments for City of Bristol
Quantifying the implications of the United Nations Paris Agreement for City of Bristol
|Prepared By:||Dr Jaise Kuriakose, Dr Chris Jones, Prof Kevin Anderson, Dr John Broderick & Prof Carly McLachlan|
This report presents climate change targets for City of BristolDefined in terms of the administrative boundary of the City of Bristol area. that are derived from the commitments enshrined in the Paris Agreement , informed by the latest science on climate change  and defined in terms of science based carbon setting . The report provides City of Bristol with budgets for carbon dioxide (CO2) emissions and from the energy system for 2020 to 2100.
The carbon budgets in this report are based on translating the “well below 2°C and pursuing 1.5°C” global temperature target and equity principles in the United Nations Paris Agreement to a national UK carbon budget We base our global carbon budget on the latest IPCC Special Report on 1.5ºC (IPCC SR1.5) findings on how carbon emissions relate to global temperatures. The budget value we have selected provides a ‘likely’ chance of staying below 2°C and offers an outside chance at holding temperatures to 1.5°C. As IPCC SR1.5, notes there are no emissions pathways for limiting warming to 1.5°C that do not rely upon significant carbon dioxide removal technology deployment . The UK budget is then split between sub-national areas using different allocation regimes . Aviation and shipping emissions remain within the national UK carbon budget and are not scaled down to sub-national budgets. Land Use, Land Use Change and Forestry (LULUCF) and non-CO2 emissions are considered separately to the energy CO2 budget in this report.
Based on our analysis, for City of Bristol to make its ‘fair’ contribution towards the Paris Climate Change Agreement, the following recommendations should be adopted:
- Stay within a maximum cumulative carbon dioxide emissions budget of 10.3 million tonnes (MtCO2) for the period of 2020 to 2100. At 2017 CO2 emission levelsBased on BEIS LA statistics 2017 CO2 emissions City of Bristol (excluding aviation, shipping, process CO2 emissions from cement production and those from LULUCF)., City of Bristol would use this entire budget within 7 years from 2020.
- Initiate an immediate programme of CO2 mitigation to deliver cuts in emissions averaging a minimum of -12.9% per year to deliver a Paris aligned carbon budget. These annual reductions in emissions require national and local action, and could be part of a wider collaboration with other local authorities.
- Reach zero or near zero carbon no later than 2042. This report provides an indicative CO2 reduction pathway that stays within the recommended maximum carbon budget of 10.3 MtCO2. At 2042 5% of the budget remains. This represents very low levels of residual CO2 emissions by this time, or the Authority may opt to forgo these residual emissions and cut emissions to zero at this point. Earlier years for reaching zero CO2 emissions are also within the recommended budget, provided that interim budgets with lower cumulative CO2 emissions are also adopted.
Sections 1, 2 and 5 of this report - Introduction, Methods and References - can be found in the full print report
3.1 Energy Only Budgets for City of Bristol
Following the Method the recommended energy only CO2 carbon budget for the City of Bristol area for the period of 2020 to 2100 is 10.3 MtCO2. To translate this into near to long term commitments a CO2 reduction pathway within the 10.3 MtCO2 is proposed here. A consistent emissions reduction rate of -12.9% out to the end of the century is applied. In 2042 95% of the recommended carbon budget is emitted and low level CO2 emissions continue at a diminishing level to 2100.
Figure 1: An interactive chart of Energy related CO2 only emissions pathways (2010-2100) for City of Bristol premised on the recommended carbon budget.
Tracking your mouse over this chart will display the actual figures for each of the pathways, as well as for the lead-in historical values.
Pathway projections for City of Bristol
Table 1 presents the City of Bristol energy CO2 only budget in the format of the 5-year carbon budget periods in the UK Climate Change Act. To align the 2020 to 2100 carbon budget with the budget periods in the Climate Change Act we have included estimated CO2 emissions for City of Bristol for 2018 and 2019, based on BEIS provisional national emissions data for 2018  and assuming the same year on year reduction rate applied to 2019. The combined carbon budget for 2018 to 2100 is therefore 13.3 MtCO2.
Table 1: Periodic Carbon Budgets for 2018 for City of Bristol.
|Carbon Budget Period||Recommended Carbon Budget (Mt CO2)|
|2018 - 2022||6.5|
|2023 - 2027||3.4|
|2028 - 2032||1.7|
|2033 - 2037||0.9|
|2038 - 2042||0.4|
|2043 - 2047||0.2|
|2048 - 2100||0.2|
The recommended budget is the maximum cumulative CO2 amount we consider consistent with City of Bristol’s fair contribution to the Paris Agreement. A smaller carbon budget, with accelerated reduction rates and an earlier zero carbon year, is compatible with this approach. It is however important that for an alternative zero carbon year the proposed 5 year budget periods are the same or lower that those specified in Figure 2. Furthermore meeting the budget must not rely on carbon offsets.
Figure 2: Cumulative CO2 emissions for budget period (based on Table 1) from 2018 to 2100 for City of Bristol
3.2 Recommended Allocation Regime for Carbon Budget
The recommended carbon budget is based on a grandfathering allocation regime for sub-dividing the UK sub-national energy only carbon budget. There are three distinct allocation regimes that can be applied to determine sub-national budgets. We have opted to recommend one common approach for allocating carbon budgets that can be applied to all Local Authority areas. This enables straightforward compatibility between carbon budgets set at different administrative scales. For example this makes it easier for individual Local Authorities to calculate their own carbon budgets that are compatible with a budget set at Combined Authority scale. It also means that under the recommended carbon budgets, all Authorities are contributing to a common total UK carbon budget. If for example all Authorities selected the allocation regime that offered them largest carbon budget the combined UK budget would not comply with the objectives of the Paris Agreement. The common approach to allocation we recommend therefore further assures that the carbon budget adopted is Paris Agreement compatible.
We have chosen a grandfathering as our common allocation approach because, based on our analysis, it is the most appropriate and widely applicable regime within the UK.
Population and Gross Value AddedBalanced approach at current basic prices (GVA) are alternative allocation regimes. Population shares the carbon budget equally across the UK on a per capita basis. In this allocation regime the UK population  is compared to that of City of Bristol  from 2011 to 2016. The carbon budget (2020-2100) for City of Bristol is then apportioned based on its average proportion of the UK population for the period 2011-2016. For regions where per capita energy demand deviates significantly from the average (e.g. a large energy intensive industry is currently located there) the budget allocated may not be equitable for all regions, therefore it is not recommended as the preferred allocation. GVA is used as an economic metric to apportion carbon budgets. For example, the UK total GVA  is compared to that of City of Bristol  from 2011 to 2016. The carbon budget (2020-2100) for City of Bristol is then apportioned based on City of Bristol's average proportion of UK GVA for the period 2011-2016. GVA can be useful as a proxy for allocation on economic value, however without an adjustment for the type of economic activity undertaken, areas with high economic ‘value’ relative to energy use can get a relatively large budget, while the inverse is true for areas with energy intensive industries, and/or lower relative economic productivity. We would therefore not recommend GVA as an appropriate allocation regime for all regions.
Table 2 presents the result outcomes for alterative allocation regimes – population and gross value added (GVA).
Table 2: Energy only CO2 budgets and annual mitigation rates for City of Bristol (2020-2100) by allocation regime
|Allocation regime (% of UK Budget allocated to City of Bristol||UK BudgetAfter deducting an emissions budget for aviation, shipping and military transport of 1,518 MtCO2 (MtCO2)||City of Bristol Budget (MtCO2)||Average Annual Mitigation Rate (%)|
|Grandfathering to City of Bristol from UK (0.5%)||2,239||10.3||-12.9%|
|Population split to City of Bristol from UK (0.7%)||2,239||15.3||-9.0%|
|GVA split to City of Bristol from UK (0.8%)||2,239||18.3||-7.6%|
To view the pathways for the Population and GVA allocation regimes, select the checkbox under Fig. 1
3.3 Land Use, Land Use Change and Forestry emissions for City of Bristol
Land Use, Land Use Change and Forestry (LULUCF) consist of both emissions and removals of CO2 from land and forests. We recommend that CO2 emissions and sequestration from LULUCF are monitored separately from the energy-only carbon budgets provided in this report. City of Bristol should increase sequestration of CO2 through LULUCF in the future, aligned with Committee on Climate Change's high level ambition of tree planting, forestry yield improvements and forestry management . Where LULUCF is considered, we recommend it compensate for the effects of non-CO2 greenhouse gas emissions (within the geographical area) that cannot be reduced to zero, such as non-CO2 emissions from agriculture.
3.4 Non-CO2 Emissions
The IPCC SR1.5 report identifies the importance of non-CO2 climate forcers (for instance methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), sulphur dioxide (SO2) and black carbon) in influencing the rate of climate change. However, a cumulative emission budget approach is not appropriate for all non-CO2 greenhouse gases, as the physical and chemical properties of each leads to differing atmospheric lifetimes and warming effects . There are also substantial relative uncertainties in the scale, timing and location of their effects.
We do not provide further analysis or a non-CO2 emissions reduction pathway in this report. However the global carbon budget in the IPCC Special Report on 1.5ºC, that our analysis is based on, assumes a significant reduction in rate of methane and other non-CO2 emissions over time. Therefore to be consistent with carbon budgets City of Bristol should continue to take action to reduce these emissions.
The Department of Business Energy and Industrial Strategy’s Local Authority emissions statistics do not at this time provide non-CO2 emissions data at the regional level. Given the absence of robust non-CO2 emissions data, any non-CO2 emissions inventory by other organisations at scope 1 and 2 for City of Bristol may form the basis of monitoring and planning for these emissions. We recommend considering the adoption of a LULUCF pathway that includes CO2 sequestration sufficient to help compensate for non-CO2 emissions within City of Bristol's administrative area.
The results in this report show that for City of Bristol to make its fair contribution to delivering the Paris Agreement's commitment to staying “well below 2°C and pursuing 1.5°C” global temperature rise, then an immediate and rapid programme of decarbonisation is needed. At 2017 CO2 emission levelsBased on City of Bristol's 2016 CO2 emissions (excluding aviation, shipping, process CO2 emissions from cement production and those from LULUCF)., City of Bristol will exceed the recommended budget available within 7 years from 2020. To stay within the recommended carbon budget City of Bristol will, from 2020 onwards, need to achieve average mitigation rates of CO2 from energy of around -12.9% per year. This will require that City of Bristol rapidly transitions away from unabated fossil fuel use. For context the relative change in CO2 emissions from energy compared to a 2015 Paris Agreement reference year are shown in Table 3.
Table 3: Percentage reduction of annual emissions for the recommended CO2-only pathway out to 2050 in relation to 2015
|Year||Reduction in Annual Emissions (based on recommended pathway)|
The carbon budgets recommended should be reviewed on a five yearly basis to reflect the most up-to-date science, any changes in global agreements on climate mitigation and progress on the successful deployment at scale of negative emissions technologies.
These budgets do not downscale aviation and shipping emissions from the UK national level. However if these emissions continue to increase as currently envisaged by Government, aviation and shipping will take an increasing share of the UK carbon budget, reducing the available budgets for combined and local authorities. We recommend therefore that City of Bristol seriously consider strategies for significantly limiting emissions growth from aviation and shipping. This could include interactions with the UK Government or other local authority and local enterprise partnership discussions on aviation that reflect the need of the carbon budget to limit aviation and shipping emissions growth.
CO2 emissions in the carbon budget related to electricity use from the National Grid in City of Bristol are largely dependent upon national government policy and changes to power generation across the country. It is recommended however that City of Bristol promote the deployment of low carbon electricity generation within the region and where possible influence national policy on this issue.
We also recommend that the LULUCF sector should be managed to ensure CO2 sequestration where possible. The management of LULUCF could also include action to increase wider social and environmental benefits..