Paris After Dark
It has been almost five years since those iconic images of global political leaders’ hand in hand beamed around the world in the early hours of the morning. The Paris Climate Concordat was widely heralded as a landmark agreement; global average temperature rises would be kept well below 2°C compared to pre-industrial levels, with a stretch target of limiting it to 1.5°C to avoid the most dangerous impacts of climate change. It was agreed that this would be delivered by achieving a carbon neutral equilibrium by the second half of the 21st century; in effect, balancing carbon emissions with carbon removal.
Source: Wikimedia Commons (2020) [1]
A lot has changed since that Parisian night. The 2008 Climate Change Act now enshrines the legal requirement to meet net zero in the UK by 2050, however, the climate emergency strikes led by Greta Thunberg in 2019 laid bare the political stagnation on agreeing what decisive action is needed when to achieve this. Amidst this stagnation, key national infrastructure policies like the Airport National Policy Statement and the Road Investment Strategy 2, have been the subject of legal challenges as they continue to pedal the ‘business as usual’ approach.
How Do You Solve A Problem Like Carbon?
In 2018 the UK emitted a net total of 451 million tonnes of CO2 equivalent (MtCO2e). Businesses were the third largest carbon emitter in the UK with around 95MtCO2e, followed closely by energy with approximately 110 MtCO2e. In pole position were emissions from transport which were responsible for around 127 MtCO2e domestically and an additional 45 MtCO2e when international aviation and shipping are also considered . More worryingly, emissions from transport have generally plateaued since 1990 against a backdrop of significant reductions in other sectors.
The scale of the decarbonisation challenge we face dictates that carbon offsetting (also known as sequestration) is not the answer; the planting of trees does not guarantee a permanent solution given the potential for future deforestation both human-caused and from wildfires, planting would have a significant land take opportunity cost and there is a lengthy time lag between planting trees and the absorption of carbon emissions. The only realistic solution is therefore to take decisive action to facilitate concerted reductions in emissions.
Tree seedling planting has become a popular way to ‘offset’ carbon emissions
Choosing The Right Zero Carbon Path
The dilemma decision makers are grappling with to achieve such fundamental carbon reductions is where do you start? If you were to stop and ask a person in the street what the most effective decarbonisation measure would be, you would likely get a wide range of answers; investing in active travel to catalyse a modal shift from private vehicles as a means to recover from coronavirus; incentivising electric vehicles, investing in large scale offshore renewable energy schemes; enhancing the energy efficiency of homes and businesses or taking less frequent flights.
The reality is that whilst there is not one silver bullet, at City Science, our recommended approach is that embedding an evidence-led carbon accounting process will provide critical information to decision makers allowing transparent prioritisation of activities and monitoring of progress.
Through acquiring DfT transport-technology research (T-TRIG) funding, City Science have recently developed an online user-friendly Decarbonisation Tool. Initially adapted for Somerset County Council and three other counties in England’s Economic Heartland, this carbon accounting tool provides a useful mechanism for local authorities to plot their ability to meet their own respective transport decarbonisation targets within a customised timeline up to 2050.
The Decarbonisation Tool works using open transport datasets from the National Travel Survey (NTS), ONS, the Department for Business, Energy and Industrial Strategy (BEIS) and the DfT to establish baseline carbon emissions and plot an idealised pathway from its current rate to a specified carbon goal. A secondary policy intervention pathway is then plotted to review the relative ability of the local authority to meet this goal and ascertain the magnitude of carbon emission reductions that are still required. This intervention pathway is iteratively customised through the addition of specific policies alongside forecast travel demand impacts to assess their relative success and understand priorities in meeting the goal.
Local authorities can create their own interventions based on key drivers such as trip rates, modal share and fuel type across both short and long-distance journeys. The tool then aggregates the effect of all interventions to show the residual carbon target still required to meet.
As well as being able to prioritise policy measures at the outset and enhance public engagement in the decision-making process, another key benefit of the Decarbonisation Tool is its ability to monitor progress. With its use of open-source data, there is an ability to update the interventions pathway on an annual basis to ascertain whether further adjustments to existing policies are necessary.
Somerset County Council Worked Example
To inform their investment priorities for reducing carbon emissions, Somerset County Council may wish to understand the relative carbon impact of two transport intervention measures: investment in active travel infrastructure (Measure 1) or investment in bus priority schemes (Measure 2).
Through applying outcome assumptions[2] to these two measures, the Decarbonisation Tool outputs, shown below, identifies that the latter intervention would be more succesful in reducing carbon emissions within Somerset. The aggregate output of the measures also indicates that more significant transport related carbon reduction measures, such as reducing trip rates through the planning process or investing in electric vehicle infrastructure, would be required to achieve net zero by 2050.
Carbon impact of intervention measure 1 to invest in active travel infrastructure
Carbon impact of intervention measure 2 to invest in bus priority schemes
Aggregate carbon impact of both measures
The Spirit of Paris – A Coordinated Approach
The consideration of transport initially within the Decarbonisation Tool has been driven by emissions data; it is the largest contributor and has made the slowest progress. As the tool is developed further there will be a need to incorporate a more coordinated approach which considers the carbon impact of transport alongside other high emitting sectors like energy to ensure decision makers have a holistic understanding of policy interventions.
Enhancing the accountability of carbon at all levels of the decision-making process will be fundamental to unlocking the current decarbonisation inertia and choosing the right path. As the clock ticks, the time is upon us all to take decisive evidence-based action to ensure that the Paris Concordat was not in vain.
By Elliot Reid, Principal Transport Planner at City Science
A preliminary version of City Science’s interactive Decarbonisation Tool can be accessed here.
Footnotes
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[2] The following outcome assumptions were applied:
- Measure 1 would result in a modal shift from cars to active travel equating to 50% for all short journeys and 5% for longer distance journeys.
- Measure 2 would result in a modal shift from cars to public transport equating to 35% for all short journeys and 45% for longer distance journeys alongside a 10% reduction in public transport emissions.