Metrics for Aviation non-CO2 emissions and Policy Levers (MAPLE)
Lead Research Organisation:
Manchester Metropolitan University
Department Name: School of Science and the Environment
Abstract
The context of the work is Theme 2, "Mitigating aviation's non-CO2 impacts", and in particular, Theme 2.3 - "Other approaches to mitigating aviation's non-CO2 impacts, including but not limited to, contrail prediction and avoidance technology" and also addresses Theme 1 "Improving our understanding of aviation's non-CO2 impacts", quantifying present and future impacts of mitigation approaches.
The challenge that the project addresses is to link uncertain science on aviation non-CO2 effects with proposed interventions to inform climate policies, consistent with various climate targets. In order to do this, we will apply aviation non-CO2 emission equivalent (CO2e) metrics to a range of policy-driven mitigation approaches. Aviation CO2e metrics have thus far had only limited success in providing useful, policy-applicable results because either the metric values are too uncertain, or policy goals can be unclear, and a large inherent dependence on the metrics' 'time-horizon' (the time over which the calculation of the effects is made). For aviation, there are risks that both technological and operational mitigation approaches may result in an increase in CO2 emissions, which need to be 'traded' against reductions in non-CO2 effects.
We will develop a framework that informs aviation climate policy design, reflecting evolving uncertainties in non-CO2 climate science and emerging technologies with practical actions to limit CO2 and non-CO2 impacts, such as proposed technological/operational advances from decreased NOx emissions, or avoidance of contrails, thereby providing a robust science base on which to quantify the net CO2e contribution. Possible goals could consider aviation's contribution to Article 2 of the Paris Agreement ('well below 2° C, aiming for 1.5° C') and Article 4 ('greenhouse gas balance') in terms of CO2 and non-CO2 contributions. Other policy examples include the International Civil Aviation Organization's commitment to net-zero carbon emissions by 2050, in terms of the implied non-CO2 contribution, and the UK's Climate Change Committee's goal of no further warming after 2050 from non-CO2 emissions.
Aims:
The overall aim of the project is to formulate a credible and robust framework to account for non-CO2 factors applicable to a range of aviation climate policies.
Objectives:
To calculate the uncertainties inherent in a range of CO2e metrics, according to best updated knowledge.
To benchmark a range of climate emulators such as MAGICC, FaIR, LinClim, CICERO-SCM to characterize the range of responses in the aviation CO2e metrics to an identical scenario.
To calculate the range of 'CO2 tradeoffs' implied by technological and operational responses and what the temperature responses are for a range of CO2e metrics/time horizons and determine the limitations of such approaches.
To determine the best form of CO2e metrics (e.g. Global Warming Potential, Global Temperature change Potential etc.) to account for appropriate temperature reductions.
To calculate the additional CO2 greenhouse gas removal required for a given temperature response requirement to account for aviation non-CO2 forcings for net zero by 2050 according to a range of scenarios and CO2e metrics and time horizons.
To study the outcomes and implications of using different CO2e metrics under a range of emissions scenarios and make policy-relevant recommendations for their usage.
Potential applications and benefits:
The project will benefit policy makers and stakeholders in providing them with a framework by which aviation non-CO2 emissions might be abated while minimizing the risks of perverse outcomes.
The challenge that the project addresses is to link uncertain science on aviation non-CO2 effects with proposed interventions to inform climate policies, consistent with various climate targets. In order to do this, we will apply aviation non-CO2 emission equivalent (CO2e) metrics to a range of policy-driven mitigation approaches. Aviation CO2e metrics have thus far had only limited success in providing useful, policy-applicable results because either the metric values are too uncertain, or policy goals can be unclear, and a large inherent dependence on the metrics' 'time-horizon' (the time over which the calculation of the effects is made). For aviation, there are risks that both technological and operational mitigation approaches may result in an increase in CO2 emissions, which need to be 'traded' against reductions in non-CO2 effects.
We will develop a framework that informs aviation climate policy design, reflecting evolving uncertainties in non-CO2 climate science and emerging technologies with practical actions to limit CO2 and non-CO2 impacts, such as proposed technological/operational advances from decreased NOx emissions, or avoidance of contrails, thereby providing a robust science base on which to quantify the net CO2e contribution. Possible goals could consider aviation's contribution to Article 2 of the Paris Agreement ('well below 2° C, aiming for 1.5° C') and Article 4 ('greenhouse gas balance') in terms of CO2 and non-CO2 contributions. Other policy examples include the International Civil Aviation Organization's commitment to net-zero carbon emissions by 2050, in terms of the implied non-CO2 contribution, and the UK's Climate Change Committee's goal of no further warming after 2050 from non-CO2 emissions.
Aims:
The overall aim of the project is to formulate a credible and robust framework to account for non-CO2 factors applicable to a range of aviation climate policies.
Objectives:
To calculate the uncertainties inherent in a range of CO2e metrics, according to best updated knowledge.
To benchmark a range of climate emulators such as MAGICC, FaIR, LinClim, CICERO-SCM to characterize the range of responses in the aviation CO2e metrics to an identical scenario.
To calculate the range of 'CO2 tradeoffs' implied by technological and operational responses and what the temperature responses are for a range of CO2e metrics/time horizons and determine the limitations of such approaches.
To determine the best form of CO2e metrics (e.g. Global Warming Potential, Global Temperature change Potential etc.) to account for appropriate temperature reductions.
To calculate the additional CO2 greenhouse gas removal required for a given temperature response requirement to account for aviation non-CO2 forcings for net zero by 2050 according to a range of scenarios and CO2e metrics and time horizons.
To study the outcomes and implications of using different CO2e metrics under a range of emissions scenarios and make policy-relevant recommendations for their usage.
Potential applications and benefits:
The project will benefit policy makers and stakeholders in providing them with a framework by which aviation non-CO2 emissions might be abated while minimizing the risks of perverse outcomes.