The Contribution of Non-CO2 Greenhouse Gas Mitigation to Achieving Long-Term Temperature Goals

Ajay Gambhir,Fabian Wagner,Pallav Purohit,Adam Hawkes,Wilfried Winiwarter,Tamaryn Napp,Lena Höglund-Isaksson,Jason Lowe,Dan Bernie

doi:10.3390/en10050602

Abstract

This paper analyses the emissions and cost impacts of mitigation of non-CO2 greenhouse gases (GHGs) at a global level, in scenarios aimed at meeting a range of long-term temperature goals (LTTGs). The study combines an integrated assessment model (TIAM-Grantham) representing CO2 emissions (and their mitigation) from the fossil fuel combustion and industrial sectors, coupled with a model covering non-CO2 emissions (GAINS), using the latest global warming potentials from the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. We illustrate that in general non-CO2 mitigation measures are less costly than CO2 mitigation measures, with the majority of their abatement potential achievable at US2005$100/tCO2e or less throughout the 21st century (compared to a marginal CO2 mitigation cost which is already greater than this by 2030 in the most stringent mitigation scenario). As a result, the total cumulative discounted cost over the period 2010–2100 (at a 5% discount rate) of limiting global average temperature change to 2.5 °C by 2100 is $48 trillion (about 1.6% of cumulative discounted GDP over the period 2010–2100) if only CO2 from the fossil fuel and industrial sectors is targeted, whereas the cost falls to $17 trillion (0.6% of GDP) by including non-CO2 GHG mitigation in the portfolio of options—a cost reduction of about 65%. The criticality of non-CO2 mitigation recommends further research, given its relatively less well-explored nature when compared to CO2 mitigation.

Highlights

Achieving stringent mitigation of greenhouse gases (GHGs) is likely to require a multi-gas approach
To demonstrate how an integrated assessment model (TIAM-Grantham) representing CO2 emissions from the energy and industrial sectors is coupled with a model covering non-CO2 emissions (GAINS) in order to provide a complete picture of GHG emissions in a reference scenario in which there is no mitigation of either CO2 or non-CO2 gases, as well as in scenarios in which both CO2 and non-CO2 gases are mitigated in order to achieve different long-term temperature goals (LTTGs)
This unmitigated scenario follows from running the TIAM-Grantham model to produce a scenario for a least-cost energy system that meets future energy needs under the Shared Socio-Economic Pathways 2 (SSP2) shared socio-economic pathways assumptions [33], but with no climate constraints

Summary

Introduction

Achieving stringent mitigation of greenhouse gases (GHGs) is likely to require a multi-gas approach. It is important to understand the contribution of non-CO2 mitigation to achieving different long-term temperature goals. This requires simulations of future energy, industrial and agricultural systems to account for all GHGs together, in as consistent a manner as possible. Energies 2017, 10, 602 mitigation of both CO2 and non-CO2 GHGs at a global level, in scenarios which are focused on meeting a range of long-term temperature goals (LTTGs). To demonstrate the degree of indirect mitigation of non-CO2 gases that results from mitigation of CO2 sources This principally applies to methane (CH4 ) emission reductions which result from reduced extraction and distribution of fossil fuels in CO2 mitigation scenarios which see a shift from fossil fuel energy sources to renewables and nuclear

Methods

Results

Conclusion