Assessment of Climate Change Mitigation Pathways and Evaluation of the Robustness of Mitigation Cost Estimates
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Frauke Haneberg (Ms.)
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Grant agreement ID: 265139
1 February 2011
31 January 2014
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POTSDAM INSTITUT FUER KLIMAFOLGENFORSCHUNG
Enhancing predictive climate models
CLIMATE CHANGE AND ENVIRONMENT
Mathematical models of any process whose long-term behaviour is of interest must rely on careful formulation of relevant parameters and their inter-relationships while incorporating a statistical basis for extrapolations to the future. In the case of global climate change, the highly dynamic nature of the parameters of interest combined with their relatively recent documentation saddles predictions with unacceptable uncertainty. Scientists initiated the EU-funded project Ampere to compare 19 internationally recognised energy economy and integrated assessment models. Including the latest climate system information and scenarios will enable evaluation of underlying causes of model differences. The intercomparison of models will increase robustness of interpretations and thus effectiveness of associated policies. Such a comparison is quite complex, incorporating not only many models but many different parameters in each model and many outputs of interest. Obtaining interpretable results requires careful definition of a model intercomparison framework. This was established during the first project period and encompassed scenario specifications, harmonised baselines, reporting formats and documentation templates. Given that cost and policy are key components of the analysis, investigators harmonised population and gross domestic product (GDP) trajectories and established a policy benchmark capturing current and planned climate policies. The accompanying model validation framework has received considerable interest within the research community as there are currently no standards for evaluating an integrated assessment model. Ampere has completed two series of model comparisons. In addition, Ampere scientists developed a first-of-its-kind model diagnostics analysis for assessing differences among models in responses to carbon price signals. Scientists also assessed differences in emissions response of climate modules. Results should have important impact on integrated assessment modelling, diagnostics and intercomparison far beyond the scope of Ampere. Ampere results are expected to provide foundations for the preparation of long-term climate policy roadmaps focused on climate stabilisation. The range of models included in the analysis should ensure robust findings, reducing uncertainty and leading to more effective policies appropriately targeted at real-world scenarios.
Grant agreement ID: 265139
1 February 2011
31 January 2014
€ 4 259 720,35
€ 3 149 489,55
POTSDAM INSTITUT FUER KLIMAFOLGENFORSCHUNG
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Final Report Summary - AMPERE (Assessment of Climate Change Mitigation Pathways and Evaluation of the Robustness of Mitigation Cost Estimates)
Assessing the costs associated with ambitious climate stabilisation targets is a challenging task given the various factors that could impact such costs. And yet, cost assessments of climate change mitigation are more relevant than ever. Policy makers in the European Union and other major economies are debating the economic feasibility of more ambitious mitigation action – even while comprehensive global action remains elusive – and whether this could keep the prospect of climate stabilisation alive for the long run. These questions can be assessed with models that integrate the energy-economy and the climate system, but the answers are highly sensitive to a variety of factors, such as expected global policy developments and technology availability as well as the way in which models are structured and represent the economy and the climate system. The AMPERE project took on this issue and analysed a wide range of scenarios and models, thereby distinguishing findings that are highly sensitive to scenario assumptions and model types from those where robust conclusions can be drawn about the costs of near- and long-term progress on climate change stabilisation.
The AMPERE project was a collaborative effort among 22 institutions in Europe, Asia and North America that started in February 2011 and concluded in January 2014. The AMPERE results have improved our understanding of possible pathways toward medium- and long-term climate targets at the global and European levels and provided insights into the cost implications of policy delay, technology availability and unilateral action in a fragmented international policy landscape. Key research questions included the emissions budgets that specific climate targets allow; the impact of short-term climate policies on the achievability of such targets; the economic implications of unilateral regional mitigation, with a focus on Europe; and the roles of different technologies. The AMPERE teams used 17 energy economy and integrated assessment models with diverse strengths and structures to elucidate different aspects of these questions and to identify areas of uncertainty where models differ as well as areas where models concur. Overarching conclusions based on the most robust findings from the AMPERE model comparisons include:
• Global progress to reduce greenhouse gas emissions over the next two decades is crucial for achieving ambitious climate targets at low costs
• Europe can signal the will for strong emission reductions – with large climate benefits if others follow
• European decarbonisation requires strong 2030 targets and holds challenges as well as opportunities for Europe
Beneath these overarching conclusions, the AMPERE findings cover a wide variety of questions, on some of which the model results differed greatly. AMPERE performed diagnostic exercises that identified distinct classes of models that differ in their responses to climate policy scenarios. This underlines the importance of basing assessments on a variety of models and the value of a common modelling platform like AMPERE.
The AMPERE scenarios and findings have been published in 21 articles in scientific journals and provided a major contribution to the assessment of mitigation pathways in the IPCC 5th Assessment Report. AMPERE achieved innovations in integrated assessment model diagnostics and validation that offer tools for further refinement by the scientific community. The policy-relevant conclusions were discussed with a wider audience during two stakeholder workshops and at a final conference in Brussels.
Project Context and Objectives:
The project AMPERE was an EU-funded international research effort with the objective of providing an improved understanding of possible global and European climate change mitigation scenarios and of the underlying modelling. AMPERE stands for Assessment of Climate Change Mitigation Pathways and Evaluation of the Robustness of Mitigation Cost Estimates.
Climate stabilisation requires ambitious policies to transition economies to a low-carbon-emission trajectory within this century. Large uncertainty remains about the way forward, with a stark contrast between emissions abatement commitments made for 2020 at the conferences of parties in Copenhagen and Cancun on the one hand, and the ambitious long term target of limiting global warming to 2oC on the other. International climate policy to date has been fragmented and focused on the short term. The European Union has begun to discuss climate policy targets for 2030 and roadmaps for emissions reduction until 2050. However, these discussions are complicated by uncertainties about future scenarios of international climate policy and about the projected mitigation costs under any given scenario.
More robust insights into the costs of mitigation scenarios can be gleaned from comparing the results of multiple energy-economy and integrated assessment models – all with their own unique strengths and limitations. While model results may diverge due to different representations of economic and technological dynamics, model intercomparisons can help explain the underlying causes of model differences and their implications for policy assessments. The AMPERE project, a collaborative effort among 22 institutions in Europe, Asia and North America that started in February 2011 and concluded in January 2014, aimed to increase the consistency of cost-related policy information by systematically comparing the energy-economy components of models while taking account of the fragmented policy landscape and the latest climate system information.
To ensure robust results, AMPERE compared and combined the capabilities of 17 internationally recognised energy-economy and integrated assessment models with different structures and functions. The diversity of these models can offer particularly robust insights because it allows us to identify areas of uncertainty where model results differ widely as well as areas where models from across the spectrum concur. The objective of including a wide range of participating models and of examining a wide variety of questions was to significantly improve our understanding of possible pathways toward climate stabilisation, the impact of policy obstacles on mitigation costs, and the role of assumptions and uncertainties. In addition, AMPERE put an emphasis on diagnosing model behaviour and assessing model validity to improve our understanding of the differences between models and of how model-based analysis can best be used to inform policy makers.
By examining a broad range of mitigation scenarios including diagnostic scenarios of the model response to carbon price signals and different combinations of policy delay, technology availability, and international policy coverage, AMPERE addressed the following overarching questions:
• Climate system representation: What amounts of future emissions are consistent with specific long-term climate targets, taking into account the latest findings on climate feedbacks, the carbon cycle, and energy-land transformation dynamics?
• Path dependency: How do short-term climate policies impact the achievability of long-term climate targets?
• Internationally fragmented climate policy: What are the economic implications and climate benefits of unilateral mitigation by a first mover followed by delayed global action?
• European decarbonisation: What are the costs and benefits of potential European Union climate targets for 2030 and 2050, and what are the roles of different technologies?
• Model diagnostics and validation: Why do model responses to carbon pricing differ, and what can be learned for the differences in mitigation cost estimates between models? What model validation approaches are appropriate for energy-economy and integrated assessment models of climate change?
To ensure that the analyses of these questions provide solid and policy-relevant insights, AMPERE established a scenario and model evaluation framework that was designed for greater realism and to take account of how model behaviour impacts mitigation cost projections and how these relate to historical trends. The results of the AMPERE project are intended to benefit both the further advancement of integrated assessment modelling studies within the scientific community as well as the assessment of different possible climate change mitigation pathways by the policy community.
The AMPERE teams made sure to coordinate with other relevant projects by sharing experiences and findings so as to most efficiently advance concepts and methods. These relevant projects included the US-DOE-funded Program on Integrated Assessment Model Development, Diagnostics and Inter-Model Comparisons (PIAMDDI) regarding model diagnostics and validation; the Energy Modeling Forum’s EMF27 studies regarding technology variation scenarios; the EU-funded ADVANCE project, which took up lessons learned on diagnostics and technology learning from AMPERE. Furthermore, AMPERE contributed research on model evaluation methods to the work on evaluation and diagnostics by the Integrated Assessment Modeling Consortium (IAMC). This coordination between AMPERE and related efforts helped to create synergies between parallel research endeavours that were ongoing over the duration of the AMPERE project.
When the AMPERE project began and the scenarios were designed, it had become apparent that international climate policy would remain largely fragmented for the foreseeable future and that the standard set of idealised climate change mitigation pathways that have been investigated by a suite of modelling studies in the past did not sufficiently capture this reality. In addition, the uncertainties of technological developments suggested the need for studies examining the impact of possible technology failures. Policy and technology uncertainties remained of high relevance throughout the duration of the project, and the AMPERE teams thus sought to account for these issues through scenarios that capture policy and technology imperfections such as carbon leakage and technology lock-ins. Several of the AMPERE multi-model comparisons were dedicated to analysing highly policy-relevant questions for EU stakeholders, including policy impacts on sectoral output and employment, mitigation cost impacts of technology availability, opportunities for technology advancement, and other issues. Some of the global AMPERE scenarios included delayed action situations, where moderate levels of mitigation stringency are aimed for in the short term (2030) and the long term target is only adopted thereafter. Another set of scenarios covered staged accession to a global climate regime, where some regions act as early movers and other join the global climate mitigation effort at later times (after 2030). Both scenario sets included the 2030 time frame as a turning point and allowed for analyses of the importance of medium-term targets and actions for the feasibility of long-term climate stabilisation. This time frame until 2030 is of high policy relevance, as it can be expected that the required stringency of post-2020 targets is a topic on which negotiations will need to increasingly focus over the coming years. As European leaders discuss the EU’s 2030 climate policy framework and prepare for the crucial Paris COP 21 in 2015, the results of AMPERE are expected to provide timely insights.
The timing of the AMPERE project was such that it offered the opportunity for contributions to the range of scenarios assessed by the IPCC Working Group III as it prepared the IPCC Fifth Assessment Report (AR5). Upon request by the European Commission, the AMPERE teams published their findings in time for them to be considered for the AR5. In this way, AMPERE made a major contribution to the 5th Assessment Report of Working Group 3 of the IPCC. It provided relevant insights on the consequences of delayed mitigation and a large number of scenarios on delay, technology limitations and international fragmentation that were assessed in the report. This amounted to 32% of baseline and mitigation scenarios in the AR5 database. Furthermore, AMPERE contributed a methodology to connect emissions scenarios with climate outcomes consistent with the findings of Working Group I of the IPCC.
The ultimate objective of the AMPERE project was to enable both the policy and scientific communities to use the insights gained throughout the project and to build upon the project outcome. To this end, the project plan included continuous interaction with stakeholders and the broader scientific community to share findings and concepts. Moreover, the AMPERE project offered the participating modelling teams a unique opportunity to strengthen their mutual cooperation and to lay the groundwork for future advanced model assessment collaborations at the European or international scale.
The AMPERE consortium partners included:
1. Potsdam-Institut für Klimafolgenforschung (PIK), Germany
2. International Institute for Applied Systems Analysis (IIASA), Austria
3. Universiteit Utrecht, Netherlands
4. Fondazione Eni Enrico Mattei (FEEM), Italy
5. Institute of Communication and Computer Systems (ICCS), Greece
6. Centre for European Policy Studies (CEPS), Belgium
7. Societé de Mathématiques Appliqués et de Sciences Humaines (SMASH-CIRED), France
8. Paul-Scherrer-Institut (PSI), Switzerland
9. Centre National de la Recherche Scientifique - LEPII, France
10. Enerdata, France
11. EU Joint Research Centre IPTS, Belgium
12. Universität Stuttgart IER, Germany
13. TU Wien EEG, Austria
14. Centraal Planbureau (CPB), Netherlands
15. ERASME Université Paris I, France
16. Met Office Hadley Centre, UK
17. ClimateAnalytics GmbH, Germany
18. National Institute for Environmental Studies (NIES), Japan
19. Research Institute of Innovative Technology for the Earth (RITE), Japan
20. NDRC Energy Research Institute (ERI), China
21. Indian Institute of Management Ahmedabad, India
22. External partner: Pacific Northwest National Laboratory?s Joint Global Change Research Institute (JGCRI), USA
The AMPERE project consisted of five scientific work packages, each of which contributed peer-reviewed papers to scientific publications and reports and presentations to stakeholders and the scientific community. These five work packages were:
- WP1: The role of climate system representation for mitigation pathways
- WP2: The role of path dependency in energy systems for mitigation pathways
- WP3: The role of inflexible carbon markets for mitigation pathways
- WP4: Mitigation pathways under climate, technology and policy constraints in context
- WP5: Decarbonisation scenarios for Europe
Work packages 1, 2 and 3 performed global scale analyses, whereas WP5 performed several analyses of the implications of mitigation policies and decarbonisation strategies in the European Union. WP4 fulfilled a bracketing function by establishing baseline and reference policy harmonisations for the model studies, by establishing concepts for model evaluation, and by synthesising the results of the other work packages. Additional work packages (WP6 and WP7) provided for the dissemination of results and project management.
The summary of scientific results is structured as follows:
1. Harmonisation of baseline and reference policy assumptions (WP4)
2. The role of climate system representation for mitigation pathways (WP1)
3. The role of path dependency in energy systems for mitigation pathways (WP2)
4. The role of internationally fragmented climate policy for mitigation pathways (WP3)
5. Decarbonisation scenarios for Europe (WP5)
6. Model diagnostics and validation (WP4+WP3)
7. Scientific publications and reports
1. HARMONISATION OF BASELINE AND REFERENCE POLICY ASSUMPTIONS
The AMPERE model studies conducted by work packages 2, 3 and 5 benefited from the participation of a wide range of models with different structures and characteristics. To allow for an intercomparison of the results from these models, it was important to harmonise the assumptions about population and economic growth in the baseline and the scenario specifications regarding the reference policies against which to compare the modelled mitigation pathways. Without such harmonisation, differing population, GDP and policy assumptions would have made it impossible to focus on the differences among the model results that are due to model structure and characteristics. The harmonisation of baseline assumption in AMPERE went beyond the usual approach to model inter-comparisons, which often are restricted to the harmonisation of policy assumptions. This greater degree of harmonization was needed to allow an in-depth analysis of the underlying reasons for differences in model results, which is a major objective of the AMPERE project. AMPERE work package 4 (WP4) performed the task of establishing the specifications for harmonisation.
A set of common base year and baseline population and GDP assumptions was specified for use by all global models participating in AMPERE. To harmonise population levels over time among the models, we used the medium-fertility variant of the UN World Population Prospects in its 2010 revision. The country-level data from this source was aggregated for the model regions. In their medium–fertility variant, the UN projections for the EU27 population match the European Commission population scenario well, so that the EU models and the global models used comparable population numbers. The harmonisation of gross domestic product among models received special attention, as GDP is one of the main factors driving emissions. AMPERE produced a GDP scenario for 26 world regions following a growth accounting methodology establishing GDP – both in market exchange rates (MER) and in purchasing power parity (PPP) – using total factor productivity, labour productivity, physical capital stock and labour force as inputs. For the participating European models, GDP scenarios were already available through the European Commission (published under the auspices of DG-Energy). The assumptions of the growth accounting method were chosen so as to ensure that the global models used scenarios that are comparable with those used by the European models. Modelling teams were given the option of expressing GDP in MER, PPP or both.
An important aspect of assessing the economic and climate mitigation implications of strong climate policies by some or all world regions is the assumed baseline against which such action is compared. The AMPERE studies were intended to account for the most important aspects of current national and regional climate policy aspirations. To this end, AMPERE designed a reference policy baseline that takes into account the most important aspects of current national and regional climate policy aspirations and provides a plausible representation of a world that continues to follow the current path of regionally fragmented climate policies. This reference policy scenario was based on an interpretation of the national pledges made at the Copenhagen and Cancun climate summits for reducing emissions or the emissions intensity of the economy by 2020, whereas some countries only achieve smaller reductions if their current policies appear to not match their pledges.
The reference policy specifications also incorporate region-specific energy technology deployment goals that have been established by several regions (e.g. the EU goal of a 20% renewable energy share by 2020). Beyond 2020, the regional emissions intensity trajectories that emerged from the short-term goals were extended into the future so as to establish specifications for the entire 21st century that assumes a continuation of current levels of ambition. An assessment of the climate outcomes of this regionally fragmented reference policy scenario estimated that it would lead to warming of about 3.5°C above pre-industrial levels by 2100 and rising further. This served as a starting point for assessing the effects of more stringent climate policies, as analysed in the first mover action and staged accession scenarios.
2. THE ROLE OF CLIMATE SYSTEM REPRESENTATION FOR MITIGATION PATHWAYS
Assessing the economic challenges of climate change mitigation greatly depends on understanding the emission reductions that are needed to achieve specific climate targets. To this end, work package 1 (WP1) of AMPERE examined (a) the link between climate outcomes and cumulative emissions as determined by reduced-form climate models of the type used in integrated assessment models (IAMs), (b) methods to consistently link emissions scenarios to climate outcomes in a multi-model setting, including a comparison with the latest climate model intercomparison (CMIP5) results and approaches to adopt common targets for all models, (c) a diagnostic analysis of the treatment of non-CO2 gases in the atmospheric chemistry components of integrated assessment models, (d) the effect of the use of substitution metrics on climate policy costs, and (e) uncertainties in climate sensitivity, such as the effect of climate feedbacks on the carbon cycle and on overall emissions budgets compatible with long term climate targets.
(2a) Long-term temperature targets and cumulative carbon budgets:
A crucial question for climate policy making is the relationship between long-term temperature targets (such as the 2°C target) and cumulative carbon budgets. Recently, WG1 of the IPCC has emphasized the direct link between the two. However, the relationship is influenced by other factors such as the timing of emission reduction (certainly for overshoot scenarios), and the influence of non-CO2 gases. This relationship was analysed by running emissions scenarios from existing literature through the reduced-form climate model MAGICC, and identifying the link between carbon budgets and temperature outcomes via regression analysis. This analysis was also used to translate climate targets into carbon budgets to be used as long-term goals for the model comparison exercises on climate policy questions in other work packages. The latter was needed because energy-economy models and IAMs differ in their degree of representation of the climate system and forcing components. Some models look explicitly into a large range of different forcing agents (carbon, non-CO2 greenhouse gases, aerosols) while other models only cover a more limited range (e.g. only CO2 emissions from energy). In order to allow for a more systematic comparison, AMPERE focused on cumulative carbon emission budgets, as these can be represented in all models.
(2b) Methods to consistently link emissions scenarios to climate outcomes:
Given the differences in endogenous climate modules in IAMs, their climate outcomes are not directly comparable. This was remedied by applying the reduced-form climate model MAGICC6 to the emissions scenarios from global models produced in the various model comparison exercises in AMPERE to generate probabilistic information about the climate response. This analysis found that mitigation scenarios with equivalent 21st century CO2 emission budgets can have significantly different mid-term climate outcomes depending on the timing of mitigation, but also the differences in the models with respect to reduction potential of non-CO2 greenhouse gas emissions. . The analysis also determined the marginal increases in mid-term and long-term warming in scenarios in which emission budgets are exceeded due to delayed accession of world regions to global climate policy regime. The results were published in a paper in the journal Technological Forecasting and Social Change and provided an important contribution to the IPCC work by enabling a better assessment of the link between mitigation scenarios assessed in Working Group III and temperature outcomes assessed in Working Group I (documented in Schaeffer et al., 2014, and applied in Table SPM.1 of the Working Group III report).
(2c) The treatment of non-CO2 gases:
AMPERE analysed how integrated assessment models treat non-CO2 gases in their atmospheric chemistry components via a diagnostic model comparison of IAMs and expert climate models. Variations in non-CO2 climate representations play a potentially large role in the choice of an optimal mitigation strategy, given that roughly 40% of global warming can be attributed to non-CO2 gasses. It has been shown in various studies that increased non-CO2 emissions lead to considerably higher mitigation policy costs, since it requires more, costly CO2 abatement in order to achieve a set radiative forcing target. Differences between models in non-CO2 climate representations therefore also lead to large variation in projected mitigation costs. In order to assess the climate models used in the AMPERE project, WP1 examined the two latest versions of MAGICC (a climate model of intermediate complexity, used by most IAMs in AMPERE) and simple climate models used by different IAMs.
From this analysis of non-CO2 climate representation, it can be concluded that the overall behaviour of non-CO2 gasses captured by most models is within the range of expert models. Yet, there is a considerable spread across models, especially in mitigation scenarios. This implies that the choice of a climate model has large implications for determining the mitigation strategies in terms of CO2 reduction and associated policy costs. Differences in aerosol assumptions (notably indirect, cloud forming effects) account for the largest spread in forcing projections. Compared to expert models, all IAMs seem to show a less rapid decline of the negative aerosol forcing. Variations in N2O assumptions also play a large role in the spread in forcing outcomes. For N2O as well as for CH4, model differences mainly occur in calculation of concentrations while models show consistency in deriving forcing levels from concentrations. Because simple climate models generally do not include important forcers such as O3 and aerosols other than SOx, they run the risk of underestimating forcing differences between baseline and mitigation scenarios.
(2d) Substitution metrics
In climate research, so-called substitution metrics are used to determine the contribution of various greenhouse gases to emissions in a common unit (CO2¬equivalent emissions). Various values of these metrics are used in the literature. For global warming potentials (GWPs), the values vary between different integration periods and different assessment reports, and alternative metrics, such as global temperature potential (GTP), have been proposed. Several studies on the influence of metrics have been published by different IAMs leading to somewhat different conclusions. In order to look at the impact of metrics on costs, therefore, AMPERE performed an IAM model comparison study, running scenarios with the same radiative forcing targets while only varying the substitution metrics. This study found that in all the models the choice of commonly used GWPs (from different IPCC reports, with different integration periods: 20 or 100 years) has a relatively small influence on global climate policy costs. However, the choice of metrics was found to have a large impact on the timing of methane abatement versus CO2 abatement for meeting given climate policy targets. Some metrics that have low substitution values for methane and thus (partly) exclude that gas were found to clearly lead to higher-cost mitigation pathways. This confirms the earlier shown advantage of a multi-gas strategy in climate policy. The time-varying global temperature potential (GTP (t)) metric was also analysed. This metric is suggested to be more cost-efficient than GWP because it ensures a more optimal timing of (particularly methane) mitigation, to reach a temperature change in a specific target year. Interestingly, GTP (t) was found to lead to higher costs in some models and lower costs in other models than the default GWP100. These differences could be traced back to socio-technological model assumptions.
(2e) Uncertainties in climate sensitivity:
Uncertainties in climate sensitivity and other parameters of the physical system have a considerable impact on the cumulative greenhouse gas emissions that correspond to a long-term climate target and thus on the associated mitigation costs. AMPERE studied these relationships by considering how new information from the IPCC fifth assessment report (AR5) may impact the size of a carbon budget compatible with a particular warming level. In particular, AMPERE studied:
• the impact of using alternative equilibrium climate sensitivity distributions on the allowable carbon budget,
• the effect of using transient climate response in preference to equilibrium climate sensitivity as a constraint on future projections, and
• the possible impact of combined additional earth system feedbacks, such as emissions associated with permafrost thawing, methane release from wetlands, and interaction of the nitrogen cycle with the carbon cycle.
The methodological approach to this study was to use a simple climate model replicating key features of more complex general circulation models and earth system models that allows the simulation of a great range of emission scenarios and consideration of uncertainty. The study found that considerable uncertainty remains with regards to equilibrium sensitivity distribution (ECS) and the inclusion of additional earth system feedbacks, such as the thawing of permafrost and consequent release of additional carbon into the atmosphere. The effect of these physical uncertainties is to broaden the range of allowable carbon budgets compatible with a given level of warming. The difference of using transient climate response (TCR) as a constraint compared to using ECS as a constraint was found to be quite small, although the uncertainty tends to be higher with the latter approach because estimates of ocean heat uptake typically add some uncertainty to the ECS constraint.
The findings of the studies regarding the treatment of non-CO2 gases and climate system uncertainties are intended for publication within the months following the end of the AMPERE project.
3. THE ROLE OF PATH DEPENDENCY IN ENERGY SYSTEMS FOR MITIGATION PATHWAYS
The costs associated with climate change mitigation greatly depend on assumptions regarding the availability of mitigation options and when these options are implemented. Main clusters of mitigation options are energy efficiency, renewable energy, nuclear power, carbon capture and storage, and emissions reduction in land use, agriculture and forestry. The future cost of emissions mitigation will critically depend on the pace at which these options will diffuse into the market over the short term, and whether the up-scaling of those options to the global level will be successful in the long run. A major challenge in this respect is the path-dependency and inertia of the energy system, which is characterized by long-lived capital stock with technology lifetimes between 20 to 60 years. AMPERE work package 2 (WP2) conducted modelling comparisons to explore (a) implications of short-term emission targets for the cost and feasibility of long-term climate goals; (b) the role of technology for the attainability of climate targets; and (c) technology diffusion in integrated assessment models compared with successful examples of technology diffusion in the past.
Nine modelling teams participated in WP2 to explore these subjects as part of a model inter-comparison study and the findings have been published in an AMPERE special issue in the international journal Technological Forecasting and Social Change. Moreover, the data from these scenarios was transferred to the database of the IPCC 5th Assessment Report (AR5) and assessed by Working Group III of the IPCC.
(3a) From short-term policies to long-term climate targets:
AMPERE studied the implications of near-term policies for the costs and attainability of long-term climate objectives. The allowable budgets of cumulative greenhouse gas emissions under stringent climate change stabilisation objectives were adopted from the studies performed by WP1. In particular, the analyses focused on a budget that is broadly consistent with keeping long-term temperature change below 2°C compared to pre-industrial levels.
The emissions budget approach implied that any lack of emission mitigation over the near term would have to be compensated by more stringent and more rapid emission reductions later in the century. The participating models explored what consequences different emission targets for the year 2030 would have on the post-2030 mitigation efforts needed to keep cumulative emissions within a budget. In particular, this permitted an analysis of the consequences of global near-term emissions that would result from extending to 2030 the proposed policy stringency of the national pledges made in the Copenhagen Accord and Cancún Agreements. The results from the model intercomparison suggest that a 2030 mitigation effort comparable to the pledges would result in a further lock-in of the energy system into fossil fuels and thus impede the required energy transformation to reach ambitious climate stabilisation levels. Major implications include faster rates of required emission cuts after 2030, significant increases in mitigation costs, and increased risk that low stabilization targets become unattainable.
A particular focus of this analysis was to assess how emission reductions required between 2030 and 2050 depend on the mitigation effort up to 2030. The study found that a mitigation effort until 2030 that is comparable to the proposed national pledges would require a rapid transformation of the energy system in the two decades between 2030 and 2050. The transformation needed to meet a 2° C target would require rates of decarbonisation of 6-8% per year and unprecedented deployment of low-carbon technologies, which according to the model median would have to nearly quadruple in their share of global primary energy between 2030 and 2050. This challenge could be reduced by more stringent short-term mitigation efforts that prevent the early exhaustion of the carbon budget and that avoid costly lock-ins while stimulating the progress of mitigation technologies. The insights regarding the impact of delayed policy action on the deployment of low-carbon technologies and rates of decarbonisation were prominently featured in both chapters 6 and 7 of the IPCC Working Group III report and provided relevant insights on the consequences of delayed mitigation for the Summary for Policy Makers and the Technical Summary of the report.
(3b) The role of technology for the attainability of climate targets:
The availability of mitigation technologies as well as society's ability to limit energy demand play a critical role for the feasibility and pace of the energy transformation required to reach long-term climate targets. In the context of its multi-model study of the implications of short-term policies for long-term targets, AMPERE WP2 also explored the role of technology in meeting stringent long-term climate targets. This included the assessment of so-called “second-best” scenarios in which the potential of some technology clusters are limited. These scenarios were intended to provide insight into the relative importance of different technologies for the cost and attainability of long-term climate targets.
AMPERE conducted a systematic technology sensitivity analysis and explored the implications of restrictions for the deployment of certain mitigation technologies. These restrictions reflect possible political choices with respect to more controversial options, such as nuclear or carbon capture and storage (CCS), but can also be the result of technical or other implementation barriers, such as variable renewable energy that may face challenges with respect to systems integration or biomass that may face restrictions due to competition over land. The analysis of supply-side technologies was complemented by a sensitivity analysis on the demand-side to better understand the potential contribution of efficiency and energy intensity improvements. The technology sensitivity cases were closely coordinated with the parallel ongoing modeling comparison of the Energy Modeling Forum (EMF27).
The analysis found that unless the stringency of mitigation policies is substantially increased beyond the national pledges from the Copenhagen Accord and Cancún Agreements, significant further investments into carbon-intensive energy supply infrastructure, such as coal-fired power plants, would occur. This would be inconsistent with ambitious climate targets and would thus turn such infrastructure into stranded investments under a delayed strengthening of climate policy. Furthermore, the lack of near-term emission reductions would narrow the range of future policy choices and increase the risk that some currently optional technologies, such as carbon capture and storage (CCS) or the large-scale deployment of bioenergy, would become “a must” by 2030. On the other hand, the AMPERE analysis clearly found that energy efficiency improvements can reduce the cost of mitigation significantly.
(3c) Technology diffusion rates:
The attainable pace of technology diffusion is of central importance for rapid transformations of energy systems and thus determines to a large extent whether stringent climate targets can be achieved or not. The pace of technology diffusion is especially important if stringent mitigation is implemented only after substantial delays that deplete much of the available emissions budget. AMPERE thus compared the technology dynamics in the participating integrated assessment models vis-à-vis historical observations. For this purpose, the technology diffusion dynamics found among the model results were compared to diffusion dynamics of successful technologies in the past.
The analysis found that the technology diffusion dynamics in the WP2 scenarios are substantially more drawn out in time than those observed historically, but with broadly consistent extents for a given duration. These longer diffusion durations are attributable to the more pervasive diffusion of technologies over centennial time-frames compared to the relatively shorter diffusion periods observed historically. In addition, model preferences for continuous, steady growth over multi-decadal timeframes, smooth technological transitions, and balanced, concurrent growth among technologies within a portfolio explain the results. Some key features of model design and function that drive the results include perfect foresight, growth or market heterogeneity constraints, capital stock turnover with limited potential for premature retirement, and additional parametric constraints.
To support its research on technology diffusion, AMPERE collaborated with the EU-funded ADVANCE project and the PIAMDDI project, funded by the U.S. Department of Energy, and hosted a workshop on the modelling of technological progress in May 2013. This workshop helped to strengthen the analyses of technological change and of the relationship between historical observations and endogenous technology dynamics in large-scale energy or integrated assessment models. The workshop combined the perspectives of researchers involved in climate policy modelling with those of researchers more specialized in the economics of technological change.
4. THE ROLE OF INTERNATIONALLY FRAGMENTED CLIMATE POLICY FOR MITIGATION PATHWAYS
Considering that for at least the next one to two decades, real-world climate change mitigation policies will likely fall short of comprehensive global cooperation, AMPERE work package 3 (WP3) assessed the economic implications and the impact on greenhouse gas emissions of internationally fragmented climate policy. To this end, AMPERE (a) conducted modelling comparisons to assess unilateral action by a first mover pursuing strong climate policy despite lack of global participation before 2030, as well as staged accession by the rest of the world to a global climate regime after 2030. In addition, WP3 performed (b) a comparison of 21st century emission drivers in the model study scenarios with historical trends.
Eleven modelling teams participated in WP3 to explore these subjects via model intercomparison studies, the findings from which have been published as part of an AMPERE special issue of the international journal Technological Forecasting and Social Change. Moreover, the data from these scenarios was transferred to the database of the IPCC 5th Assessment Report (AR5) and assessed by Working Group III of the IPCC.
(4a) First mover action and staged accession to a global climate regime
To explore possible dynamics of more ambitious climate policy emerging from the current situation of regionally fragmented and moderate climate action, WP3 analysed scenarios in which a front runner coalition – the EU or the EU and China – embarks on immediate ambitious climate action while the rest of the world makes a transition to a global climate regime between 2030 and 2050. The impacts of such dynamics on regional mitigation costs, fossil fuel markets and carbon leakage, as well as technology diffusion were studied, and the trade-offs between early action and later accession to a global regime were examined. The European Union received particular attention as a plausible front runner on ambitious climate mitigation.
The analysis found that Europe can pursue unilateral ambitious climate action at manageable economic cost. The specifications for ambitious European climate action used in the analysis were based on the EU’s 2050 Low Carbon Economy Roadmap, issued in 2011, which envisions greenhouse gas emission reductions compared to 1990 of at least 40% by 2030 and 80% by 2050. Compared to the reference policy case, which would achieve about 30% emission reductions by 2030, the AMPERE modelling suggested that the mitigation costs of following the more ambitious Roadmap would reduce cumulative EU consumption by 2030 by between 0% and 0.8%. This assessment was based on the assumption of the availability of a full portfolio of mitigation technologies. The impact of possible technology limitations was studied by work package 5, which found a limited impact of technology limitations until 2030 but significant impacts of technology availability as the stringency of decarbonisation targets further increases after 2030.
All but one model suggested that overall carbon leakage from unilateral European climate action would be below 20% of the emissions reduced by the EU. Conversely, the diffusion effect of advanced low carbon technology from the EU to other world regions is small according the models. This suggests that the economic impacts of EU early mover action depend largely on the domestic potential of low-cost mitigation and its impact on global climate outcomes depends mainly on whether such action influences the dynamics of international climate action.
WP3 analysed possible dynamics that early EU action could bring about by assessing staged accession scenarios in which the rest of the world to transition to a global climate regime between 2030 and 2050. This assumed that the ensuing regime involves strong global mitigation efforts but does not require late joiners adhere to strict emission budgets by compensating for their initially higher emissions. From the emission outcomes of these staged accession scenarios, as modelled by the participating integrated assessment models, the medium-complexity climate model MAGICC derived climate outcomes indicating that staged accession can reductions global warming during the 21st century by more than 1°C compared to the reference case of moderate fragmented climate policies. However, the resulting climate outcome is unlikely to be consistent with the goal of limiting global warming to 2°C above preindustrial levels.
In addition to unilateral EU early mover action, WP3 also assessed the impacts of a larger early mover coalition of the EU and China. The inclusion of China in the front runner coalition can reduce pre-2050 excess emissions by 20–30%, increasing the likelihood of staying below 2°C. Most models also found that compared to unilateral EU early mover action, an EU-China coalition reduces carbon leakage to below 10% of the emissions reduced by the coalition partners. Not accounting for potential co-benefits, the cost of front runner action was found to be higher for China than for the EU, due to the greater carbon intensity of the Chinese economy and due to China’s less stringent reference policy against which early mover action was compared. However, it was found that generally, for China and for other regions, there is a trade-off between early costs and later transitional challenges. Regions that delay their accession to the climate regime reduce their short term costs but face higher transitional requirements once they accede to a climate regime due to larger carbon lock-ins and more rapidly increasing carbon prices.
The AMPERE teams published their findings on staged accession in time for them to be considered for the IPCC Fifth Assessment Report (AR5). This way, AMPERE provided relevant insights to Working Group III of the IPCC on the consequences of international fragmentation that were assessed in the report
(4b) Comparison of 21st century emission drivers with historical trends
To compare the drivers behind the emission trajectories in the modelled 21st century scenarios of WP3 with historical trends, the data was decomposed into alternative factors, such as GDP changes, energy intensity changes, and carbon intensity changes. The results were compared with historical trends from the period 1990 to 2010. This analysis was done at the regional level for the major emitters USA, EU-27, Japan, China, India, Brazil, and Russia.
Decomposing the emission drivers in the baseline scenario without any climate policy and the reference policy scenario with moderate regional policies showed that model projections of the no-policy baseline scenario come close to a continuation of historical energy and carbon intensity trends for most regions. For the EU, however, the reference policy scenario more closely represents a continuation of historical trends, which include recent improvements in energy and carbon intensity. For all regions, the decomposition analysis found that the reduction in the energy intensity of GDP is a key factor to offset part or all of the upward pressure on emissions from economic growth and thus help achieve climate change mitigation objectives. However, with more stringent mitigation targets, the reduction in energy intensity of GDP is not enough to achieve ambitious decarbonization. The role of the carbon intensity of energy thus increases with the level of stringency of climate policies and is higher in the long term. In the case of the EU, the reduction in carbon intensity becomes the leading long-term driver of decarbonisation even in the reference scenario. In the ambitious global climate policy scenario, the reduction of carbon intensity clearly dominates as a driver of decarbonisation in the long run (after 2050) in most models and regions. Only one model shows a strong role of GDP reduction as a driver of decarbonisation.
The analysis also focused on the sectoral and technological drivers of decarbonisation in the EU based on the staged accession scenario with unilateral EU leadership. The different models showed a variety of combinations of decarbonisation options but concurred in that decarbonisation of the power sector is a dominant driver and that the transportation sector is hardest to decarbonise.
The findings from the decomposition analysis suggest that both the baseline and the reference policy scenarios run by the models are close to historical trends, although with regional differences. Ambitious climate policy scenarios, on the other hand, lead to a course that significantly differs from historical trends. The decomposition of the drivers of decarbonisation in the climate policy scenarios showed that carbon intensity reduction becomes relatively more relevant than energy intensity reduction as stringency increases and over time. However, there were differences between models regarding the relative role of carbon intensity versus energy intensity. These differences mainly corresponded to the differences in model behaviour identified by the model diagnostics performed by AMPERE.
5. DECARBONISATION SCENARIOS FOR EUROPE
Given the possibility of strong leadership by the European Union on near-term climate policies, AMPERE supplemented its global modelling studies of WP2 and WP3 with additional model inter-comparison studies in WP5 with a scope that focused specifically on the European Union. These were designed in analogy to the global scenarios but were performed by models with greater sectoral and energy systems resolution at the European level. Seven well established energy-economy models (GAINS, GEM-E3, Green-X, NEMESIS, PRIMES, TIMES-PanEU and WorldScan) provided the energy and climate policy analysis for the EU. This allowed for an extensive model inter-comparison, for the first time at such an extent, with regard to emissions abatement policies, energy system transformations, decarbonisation costs and macro-economic implications. The use of regional European models for the EU-specific studies provided insights that would not have been available by using only global models. At the same time, the global model results provided the international context that reflected the impact of European policies on global energy markets and trade flows.
The analysis of EU decarbonisation scenarios allowed AMPERE to address specific questions regarding (a) the role of interim emissions targets, limitations in technological options, and path dependency for the achievement of the European decarbonisation target for 2050; (b) the impact of unilateral European climate policy on different economic sectors; and (c) the possibility of economic advantages arising from technological advances in clean energy producing sectors due to European climate policy.
The global boundary conditions that were applied to these analyses were in line with the global mitigation studies conducted by AMPERE WP3. The carbon budget used for the EU decarbonisation scenarios was consistent with the specifications of the “Energy Roadmap 2050” and the “Roadmap for moving to a low carbon economy in 2050” of the European Commission, published in 2011.
(5a) The role of path dependency:
The choice of medium-term (2020-2030) emission targets and the choice and availability of emissions reduction technologies can steer the European Union onto quite different paths for long-term decarbonization. AMPERE compared different scenarios based on the same EU-wide emissions budget through 2050 but with different available technology portfolios and interim emission targets to answer the following questions:
a) What are the energy system costs and further macro-economic implications for the EU in case of pursuing strong decarbonisation targets?
b) How does limited availability of technology options affect the feasibility of the long-term decarbonisation target and the associated mitigation costs?
c) Does myopia about EU emissions reductions targets lead to specific lock-ins in the energy sector? What are the additional decarbonisation costs for the EU in case of weaker emission reduction actions in the period until 2030?
All models showed that a stringent EU emissions budget in line with the EU climate and energy roadmap is feasible with currently known technological options at relatively low costs (lower than 1% of GDP cumulatively in the period of 2010-2050). As a cost-effective milestone for the achievement of the long-term decarbonisation objective, the analysis suggested a reduction in EU emissions by 2030 relative to 1990 levels of 37% to 47%, depending on the model (median of the models: 41%). The combined results of the energy-economy models suggested that the key mitigation priorities for the restructuring of the EU energy system are:
• Decarbonisation of power generation (high deployment of renewable energy and CCS options)
• Acceleration of energy efficiency improvements in all energy demand sectors
• Substitution of fossil fuels with electricity in stationary final energy demand
• Transport electrification with increased penetration of plug-in hybrids and electric vehicles
Non-availability of some decarbonisation options implies an increase in marginal abatement costs, as the remaining options have to be used at levels characterised by higher marginal costs and closer to their maximum potential. The models converged to the assessment that technological limitations – such as a nuclear phase-out, limited availability of CCS, and delays in transport electrification – lead to higher costs compared to the optimal decarbonisation scenario.
The models found that delaying strong climate action until 2030 implies a very steep emissions reduction pathway for the EU in the period 2030-2050 if the same carbon budget is applied. The energy system models showed that climate policy delays stress the system capabilities for decarbonisation after 2030 and require massive deployment of renewable energy technologies and increased renovation rates for buildings. The higher abatement efforts after 2030, the lock-ins in the energy sector, the lack of timely development of infrastructure and the delays in learning progress for important mitigation technologies would lead to higher cumulative mitigation costs for the EU compared to scenarios with strong early climate action.
The results of this analysis have been published in the articles “European decarbonisation pathways under alternative technological and policy choices: A multi-model analysis” and “Description of models and scenarios used to assess European decarbonisation pathways”, both by Capros et al. (2014), in Energy Strategy Reviews.
(5b) Impacts of unilateral European mitigation action:
The impact on Europe of limited global coverage of climate policies was analysed with global as well as European models in order to capture both the global dynamics of incomplete/fragmented policy coverage as well as the effects on the European economy in particular. This addressed the following questions:
a) What are the economic costs and benefits for the EU in case that it unilaterally adopts a decarbonisation policy earlier than other regions?
b) How are the costs for the EU affected by coalitions with other early movers (e.g. China) on climate policy?
c) What role will carbon leakage play in a fragmented climate policy world with the EU (or a larger coalition) as a first mover?
To address these questions, AMPERE used global integrated assessment models as well as macro-economic European models. The use of regional European models for the EU-specific studies provided insights that would not have been available by using only global models. At the same time, the global model results provided the international context that reflected the impact of European policies on global energy and capital markets and trade flows. The comparison of the model results enhanced the robustness of the main findings of the analysis. The models suggest that Europe can afford to unilaterally commit to strong climate targets, as the additional costs incurred for the region are limited by 2050. However, the models show a broad range of carbon leakage in the case of unilateral EU action that can induce economic and environmental inefficiencies, e.g. relocation of industrial production of energy intensive sectors (metals, chemicals, cement) away from Europe. To examine the effect of a larger coalition, the case of China joining early mover action in tandem with the EU was studied. The models suggest that leakage is significantly reduced when China joins the early EU climate effort due to the large market size and the high energy and carbon intensity of the Chinese economy. The engagement of China in the first mover coalition has mixed impacts on mitigation costs incurred for the EU, as reduced carbon leakage benefits the EU economy but the economic costs of mitigation for China and the reduction of Chinese demand for EU products also impact the EU as a major trading partner. Whereas the costs of strong EU mitigation compared to current policies are limited, the cost mark-ups for China are much higher, largely due to the high energy and carbon intensity of the rapidly growing Chinese economy.
The participating European macro-economic models, namely GEM-E3 and NEMESIS, represent multiple economic sectors and can handle scenarios that assume incomplete carbon markets. Thus, these models have been used to analyse in detail the macro-economic implications of the EU’s first mover action, in terms of changes in investment patterns, balance of trade and sectoral production and employment. The EU decarbonisation scenarios generally involve substitution of imported fuels by domestically produced goods and services, which are used to improve energy efficiency and implement renewable energy and other emission reduction technologies. The models show that the higher energy costs arising from the imposition of strong climate policies tend to increase production costs and reduce the overall economic activity. The reduction is more pronounced in sectors that are directly affected by strong climate policy, mainly concerning fossil fuels and energy intensive industries. On the other hand, decarbonisation increases output and employment in energy efficiency services, equipment goods and in the agricultural sector due to higher demand for bioenergy. The overall employment impacts can be even positive if carbon revenues are redistributed to reduce labour costs. Overall, the AMPERE analysis shows a mixed impact of strong climate action on employment in the various economic sectors identified in the macro-economic models.
The findings on the macro-economic implications of unilateral EU climate actions are included in the “Report on impacts for Europe of incomplete carbon markets”, which is publicly available on the AMPERE website.
(5c) Potential co-benefits of mitigation for Europe
AMPERE conducted an in-depth comparative analysis of the European clean energy producing industrial sectors and the conditions that enable the European economy to get first mover advantages by pursuing ambitious climate targets earlier than other regions. Particular questions to be addressed were:
a) What would be the macroeconomic cost for the EU for acting unilaterally versus waiting to synchronize decarbonisation actions with the rest of the world until 2030?
b) In the case that non-EU regions decide to perform strong emission reductions after 2030, can first-mover action by the EU achieve a competitive advantage in global trade of clean energy technologies?
For this task, AMPERE used European macro-economic models that explicitly incorporate endogenous mechanisms for technical change (through both learning by doing and learning by research) as well as productivity improvements and R&D allocation to different sectors, activities and technologies. Two macro-economic models within AMPERE were equipped with such mechanisms: the GEM-E3-RD world Computable General Equilibrium model and the NEMESIS macro-econometric model for the EU.
The GEM-E3-RD results suggested that early EU climate action sets into motion R&D effort on clean energy technologies which combines with learning by doing obtained by drastically increased uptake within the EU and leads to cost reductions. Such reductions can be appropriated by EU industries leading to increased global market shares, which can be particularly important if world markets for these technologies increase rapidly after 2030 in the case of international adoption of strong climate policies in line with the 2oC climate stabilisation target. The increased European exports in clean energy producing sectors and the longer time frame for restructuring the EU energy system away from fossil fuels lead to lower GDP losses compared to delayed climate action. The NEMESIS model concurred with these findings and suggested that European first mover action created additional jobs in industrial sectors producing clean energy technologies.
The most important among the technological options stimulated by early EU action was found to be electric vehicles. According to GEM-E3-RD, their deployment is an essential part of decarbonisation as they offer a mitigation solution for the road transport sector and the EU already enjoys a comparative advantage in vehicle construction. Other decarbonisation options that can generate a large global market and increased possibilities for expansion of European exports under appropriate policy conditions are CCS technologies and photovoltaics. On the other hand, wind turbines are a relatively mature option with few possibilities for further improvement and therefore offer a less fertile ground for export expansion.
The findings on the macro-economic implications of unilateral EU climate actions are included in the “Report on potential co-benefits of mitigation for Europe”, which is publicly available on the AMPERE website.
6. MODEL DIAGNOSTICS AND VALIDATION
To fulfil the ultimate objective of the AMPERE project, it was crucial to systematically explore the different model behavior patterns and the robustness of the modelled mitigation pathways and costs. This required (a) diagnostic model analyses that went beyond producing policy-relevant findings and provided insights into differences in model characteristics, as well as (b) a framework for the validation of model results.
(6a) Model diagnostics
The diagnostic analysis focused on the AMPERE models with global coverage but also compared the global results with regional results, including those of the EU model PRIMES. The diagnostic work developed a rough model classification scheme. This was based on a diagnosis of the model-specific behaviour of the AMPERE models under harmonised scenarios as a common basis for comparison. These scenarios included a no-policy baseline run and four different diagnostic scenarios with different global carbon tax levels and harmonised GDP and population baselines.
The analysis provided insights about interrelated model characteristic that allow the distinction of different groups of models. These characteristics include
1) the relative abatement of emissions in response to carbon taxes;
2) the reduction of carbon intensity of energy production compared to the reduction of energy intensity of economic production;
3) the structural transformation of energy supply; and
4) the mitigation cost relative to the value of abatement.
These characteristics were captured in a set of diagnostic indicators. A key insight of the diagnostic analysis was that there is a correlation between the different diagnostic indicators. Models that show a strong emissions response to a carbon price also tend to exhibit a strong carbon intensity response and a significant transformation of the energy sector, and vice versa. Consequently, it was possible to establish a model classification scheme that distinguishes between low-response, medium-response and high-response models.
The diagnostic indicators and the model classification scheme established in this task provide an important basis for further diagnostic studies of integrated assessment models. The IAM community can build on the peer-reviewed paper “Diagnostic indicators of integrated assessment models of climate policy” that contributed to the AMPERE special issue in the journal Technological Forecasting and Social Change, which has been published with open access. To invite the IAM community to contribute to further diagnostic efforts, the AMPERE team presented the concept at several scientific conferences.
(6b) Model validation framework
The AMPERE project entered uncharted scientific territory with concepts for validating integrated assessment model results. Therefore, model validation was advanced with input from other scientific communities that had gained more experience with different validation methodologies. Since the integrated assessment modelling community lacked standardised approaches to systematic model validation, the scoping studies on this topic and initial evaluation of model intercomparison results performed by AMPERE explored new ground and will inform further efforts within the community.
Reflecting on experience from other modelling communities, AMPERE developed an evaluation framework for integrated assessment models (IAMs) of global climate change. It builds on a systematic step-by-step evaluation of a model’s behaviour. Steps in the evaluation hierarchy are: a) setting up an evaluation framework, b) evaluation of the conceptual model, c) code verification and documentation, d) model evaluation, e) uncertainty and sensitivity analysis, f) documentation of the evaluation process, and g) communication with stakeholders. An important element in evaluating IAMs of global climate change is the use of stylised behaviour patterns derived from historical observation. This concept, a discussion of two examples, and action items for establishing consistent evaluation processes were published in the peer-reviewed article “Evaluating integrated assessment models of global climate change” in the international journal Environmental Modelling and Software.
For further exploration of the topic of IAM evaluation, AMPERE conducted a one-and-a-half-day workshop in Seville in May 2013 in cooperation with the US-DOE-funded PIAMDDI project. This workshop brought together researchers from the integrated assessment modelling community with scholars who have worked on the evaluation of models in a variety of fields. Discussions ranged from philosophy of science perspectives to the application in energy, environmental, climate and economic modelling. The discussions of this workshop brought further clarity to the task of developing a community-wide understanding on the terms ‘evaluation’, ‘validation’, and ‘model confidence’ and how they relate to diagnostic experiments, possible future community tests, as well as to the way of communicating IAM results to other parties (e.g. policy-makers). A long-term goal is to develop community guidelines for IAM validation (sub-system, full system tests, performance standards and benchmark cases). The experience from the climate modelling community, however, suggests that this is a matter of years. For the immediate aftermath of the AMPERE project, several AMPERE partners decided to conduct a limited study of stylised facts with regards to AMPERE model results.
To further support model evaluation and comparisons, AMPERE documented important model parameters such as resource and technology limitations, cost metrics and other techno-economic and climate forcing parameters via a model questionnaire. The collected information was a prerequisite to identifying implications for appropriate benchmarks for the model intercomparisons. This AMPERE model documentation has been published as supplementary material to the AMPERE special issue in Technological Forecasting and Social Change.
7. SCIENTIFIC PUBLICATIONS AND REPORTS
Publications and reports that emanated from the AMPERE project are posted on the AMPERE website at http://ampere-project.eu.
AMPERE special issue on climate stabilisation in Technological Forecasting and Social Change (2014):
E. Kriegler, K. Riahi, N. Bauer, V.J. Schwanitz, N. Petermann, V. Bosetti, A. Marcucci, S. Otto, L. Paroussos, S. Rao, T. Arroyo Currás, S. Ashina, J. Bollen, J. Eom, M. Hamdi-Cherif, T. Longden, A. Kitous, A. Méjean, F. Sano, M. Schaeffer, K. Wada, P. Capros, D.P. van Vuuren, O. Edenhofer (2013): Making or breaking climate targets: The AMPERE study on staged accession scenarios for climate policy, DOI: 10.1016/j.techfore.2013.09.021.
K. Riahi, E. Kriegler, N. Johnson, C. Bertram, M. den Elzen, J. Eom, M. Schaeffer, J. Edmonds, M. Isaac, V. Krey, T. Longden, G. Luderer, A. Méjean, D.L. McCollum, S. Mima, H. Turton, D.P. van Vuuren, K. Wada, V. Bosetti, P. Capros, P. Criqui, M. Hamdi-Cherif, M. Kainuma, O. Edenhofer, Locked into Copenhagen Pledges - Implications of short-term emission targets for the cost and feasibility of long-term climate goals, DOI: 10.1016/j.techfore.2013.09.016.
E. Kriegler, N. Petermann, V. Krey, V.J. Schwanitz, G. Luderer, S. Ashina, V. Bosetti, J. Eom, A. Kitous, A. Méjean, L. Paroussos, F. Sano, H. Turton, C. Wilson, D.P. van Vuuren, Diagnostic indicators for integrated assessment models of climate policies, DOI: 10.1016/j.techfore.2013.09.020.
C. Bertram, N. Johnson, G. Luderer, K. Riahi, M. Isaac, J. Eom, Carbon lock-in through capital stock inertia associated with weak near-term climate policies, DOI: 10.1016/j.techfore.2013.10.001
J. Eom, J. Edmonds, V. Krey, N. Johnson, T. Longden, G. Luderer, K. Riahi, D.P. Van Vuuren, The Impact of Near-term Climate Policy Choices on Technology and Emission Transition Pathways, DOI: 10.1016/j.techfore.2013.09.017
V.J. Schwanitz, T. Longden, B. Knopf, P. Capros, The implications of initiating immediate climate change mitigation - A potential for co-benefits?, DOI: 10.1016/j.techfore.2014.01.003
N. Bauer, V. Bosetti, K. Calvin, M. Hamdi-Cherif, A. Kitous, D.L. McCollum, A. Méjean, S. Rao, H. Turton, L. Paroussos, S. Ashina, K. Wada, D.P. van Vuuren, CO2 emission mitigation and fossil fuel markets: Dynamic and international aspects of climate policies, DOI: 10.1016/j.techfore.2013.09.009
M. Schaeffer, L. Gohar, E. Kriegler, J. Lowe, K. Riahi, D.P. van Vuuren, Mid- and long-term climate projections for fragmented and delayed-action scenarios, DOI: 10.1016/j.techfore.2013.09.013
G. Iyer, N. Hultman, J. Eom, H. McJeon, P. Patel, L. Clarke, Diffusion of low-carbon technologies and the feasibility of long-term climate targets, DOI: 10.1016/j.techfore.2013.08.025
R. Bibas, A. Méjean, M. Hamdi-Cherif, Energy efficiency policies and the timing of action: An assessment of climate mitigation costs, not yet published as of 3/2014
P. Criqui, S. Mima, P. Menanteau, A. Kitous, Mitigation strategies and energy technology learning: an assessment with the POLES model, not yet published as of 3/2014
N.A.C. Johnson, V. Krey, D.L. McCollum; S. Rao, K. Riahi, J. Rogelj, Stranded on a Low-Carbon Planet: Implications of Climate Policy for the Phase-out of Coal-based Power Plants, 10.1016/j.techfore.2014.02.028
F. Sano, K. Wada, K. Akimoto, J. Oda, Assessments of GHG emission reduction scenarios of different levels and different short-term pledges through macro and sectoral decomposition analyses, DOI: 10.1016/j.techfore.2013.11.002
T. Arroyo Currás, N. Bauer, E. Kriegler, J.V. Schwanitz, G. Luderer, T. Aboumahboub, A. Giannousakis, J. Hilaire, Carbon leakage in a fragmented climate regime: the dynamic response of global energy markets, DOI: 10.1016/j.techfore.2013.10.002
J. Bollen, The Value of Air Pollution Co-benefits of Climate Policies: Analysis with a Global Sector-Trade CGE model called WorldScan, not yet published as of 3/2014
A. Marcucci, H. Turton, Induced technological change in moderate and fragmented climate change mitigation regimes, DOI: 10.1016/j.techfore.2013.10.027
L. Paroussos, P. Fragkos, P. Capros, K. Fragkiadakis, Assessment of carbon leakage through the industry channel: The EU perspective, 10.1016/j.techfore.2014.02.011
S.A. Otto, D.E. Gernaat, M. Isaac, P.L. Lucas, M.A. van Sluisveld, M. van den Berg, J. van Vliet, D.P. van Vuuren, Impact of fragmented emission reduction regimes on the energy market and on CO2 emissions related to land use: a case study with China and the European Union as first movers, 10.1016/j.techfore.2014.01.015
AMPERE papers on EU decarbonisation in Energy Strategy Reviews (2013):
P. Capros, L. Paroussos, P. Fragkos, S. Tsani, B. Boitier, F. Wagner, S. Busch, G. Resch, M. Blesl, J. Bollen, European decarbonisation pathways under alternative technological and policy choices: A multi-model analysis, DOI: 10.1016/j.esr.2013.12.007
P. Capros, L. Paroussos, P. Fragkos, S. Tsani, B. Boitier, F. Wagner, S. Busch, G. Resch, M. Blesl, J. Bollen, Description of models and scenarios used to assess European decarbonisation pathways, DOI: 10.1016/j.esr.2013.12.008
AMPERE paper on model evaluation in Environmental Modelling & Software (2013):
V.J. Schwanitz, Evaluating integrated assessment models of global climate change, DOI: 10.1016/j.envsoft.2013.09.005
AMPERE scientific reports:
V.J. Schwanitz (2012), Report on model benchmarking & validation
P. Fragkos, L. Paroussos, P. Capros, B. Boitier (2013), Report on impacts for Europe of incomplete carbon markets
P. Capros, P. Karkatsoulis, N. Kouvaritakis, P. Fragkos, L. Paroussos, B. Boitier (2013), Report on potential co-benefits of mitigation for Europe
P. Fragkos, A. Marcucci, N. Petermann, L. Paroussos (2013) The role of inflexible carbon markets for mitigation pathways
D.P. van Vuuren, A. Hof, M. Schaeffer, M. van den Bergh, M. Isaac, M. Harmsen (2014), Report on assessment of differences in current climate/forcing representations in IAMs
IIASA (2014), Report on model validation, comparing successful examples of technology diffusion in the past with technology diffusion in IAMs
J.A. Lowe, D. Bernie, L. Gohar (2014), Report on assessment of uncertainty in carbon budgets using new information from IPCC AR5
E. Kriegler, K. Riahi, N. Petermann, V. Bosetti, P. Capros, D.P. van Vuuren, P. Criqui, C. Egenhofer, P. Fragkos, N. Johnson, L. Paroussos, A. Behrens, O. Edenhofer, The AMPERE Consortium (2014), Assessing Pathways toward Ambitious Climate Targets at the Global and European Levels: A synthesis of results from the AMPERE project
The AMPERE project aimed to increase the consistency of cost-related policy information by systematically comparing the economic components of models while taking full account of fragmented policy outlooks and the latest climate system information. The objective of including a wide range of participating models and of examining a wide variety of questions was to significantly improve our understanding of possible pathways toward climate stabilisation, the impact of policy obstacles on mitigation costs, and the role of assumptions and uncertainties. The results of the AMPERE project are expected to benefit both the further advancement of integrated assessment modelling studies within the scientific community as well as the assessment of different possible climate change mitigation pathways by the policy community. To help ensure that AMPERE delivered positive results on both accounts, the project established scenario and model evaluation frameworks providing greater realism and robustness of the findings, and disseminated these findings through publications and workshops. The AMPERE findings offer timely input as European leaders discuss the EU’s 2030 climate policy framework and prepare for the crucial Paris COP 21 in 2015.
A major impact of the AMPERE project has been the contribution of findings on the implications of delayed policy action for meeting long-term climate targets and on the implications of staged accession to a global climate policy regime to IPCC Working Group III and the IPCC Fifth Assessment Report (AR5). Upon request by the European Commission, most of the AMPERE studies were submitted for publication in time to be considered for the IPCC AR5, in which the scenario results have been included and provided relevant insights on the consequences of delayed mitigation (as reflected in the Summary for Policy Makers, the Technical Summary, and Chapter 6 of the report). AMPERE contributed a large number of scenarios on delay, technology limitations and international fragmentation that were assessed in the report (amounting to 32% of baseline and mitigation scenarios in the AR5 database), and a methodology to connect emissions scenarios with climate outcomes consistent with the findings of Working Group I of the IPCC (documented in Schaeffer et al., 2014, and applied in Table SPM.1 of the Working Group III report).
The AMPERE scenarios have contributed new insights and data to the wider scientific and policy communities by going beyond past efforts, which have often focussed on idealised policy settings (e.g. complete coverage of emission caps). AMPERE combined the long-term perspective of climate protection targets with the short- to medium-term perspective of emissions reduction targets currently discussed in the policy arena. Taking into account the current fragmented state of international climate policies and the possibility of policy delays, technology failures, and unevenly emerging efforts by different world regions, AMPERE aimed to ensure that possible impacts of high policy relevance, such as carbon leakage and technology lock-ins, are adequately captured in its analyses. The findings are expected to be useful for the discussion of European climate policy goals for 2030 and for the preparation of international post-2015 climate policy roadmaps with a long-term path toward climate stabilisation. Since one of the AMPERE work packages focussed specifically on different aspects of EU decarbonisation, various multi-model comparisons were dedicated to analysing highly policy-relevant questions for EU stakeholders, including policy impacts on sectoral output and employment, mitigation cost impacts of technology availability, and opportunities for technology advancement. AMPERE provided insights from these studies to the European Commission's public consultation in mid-2013 for the development of a 2030 framework for climate and energy policies. This input emphasised the importance of strong climate mitigation action during the decade of 2020 to 2030 for a cost-effective path toward the EU’s climate mitigation objectives for 2050. At the global scale, AMPERE analysed delayed action situations as well as staged accession to a global climate regime. Both scenario sets included the 2030 time frame as a turning point and allowed for analyses of the importance of medium-term targets and actions for the feasibility of long-term climate stabilisation. This time frame until 2030 is of high policy relevance, as it can be expected that the required stringency of post-2020 targets is a topic on which negotiations will need to increasingly focus over the coming years. The relevance of the findings was further enhanced by the broad range of models that participated in order to produce robust results on these climate mitigation scenarios.
The AMPERE findings have been disseminated to the policy community and economic stakeholders, primarily from within the European Union, through a final conference in January 2014, a synthesis report of the most policy-relevant AMPERE results, and input to the public consultation for the European Commission's development of a 2030 framework for climate and energy policies. Additionally, international policy experts, external researchers and industry representatives were involved during the project with advice for identifying priorities among the range of research questions that the project teams considered when analysing the model data.
The close collaboration among European and international modelling teams in the AMPERE consortium – comprising 22 institutions from Europe, Asia and the United States and combined the capabilities of 17 energy-economy and integrated assessment models – laid the ground for a unique European modelling platform for coordinated future research efforts.
Despite the progress by AMPERE on improving the robustness of assessing the mitigation costs associated with a wide range of plausible mitigation pathways and on identifying the most relevant areas of model divergence, uncertainties and differences between model results will not disappear. Nor would this be desirable, as the range of model results provides valuable insights into the various ways in which technological and economic dynamics could play out. However, the insights generated by AMPERE are expected to provide a firm basis for further advancing the robustness and transparency of climate policy assessments so as to facilitate discussions of international long-term climate change mitigation strategies.
INTERACTION WITH RELEVANT STAKEHOLDERS AND THE POLICY COMMUNITY
The AMPERE project consortium exchanged ideas and insights with relevant stakeholders throughout the project. The first stakeholder workshop was held in Venice in May 2012. Participants joined from institutions such as the UN, the European Commission's DG Energy and DG Climate, IEA and EURELECTRIC, amongst others. The workshop discussions helped to clarify what policy analysts and stakeholders need to learn from model-based climate policy assessments and what type of assessments the AMPERE studies should aim for.
A second stakeholder workshop, focusing on what conclusions could be drawn from the various AMPERE studies, was held in June 2013 in Brussels. 25 participants from the European Commission, industry, and research institutions discussed stakeholder perspectives and AMPERE research results related to mitigation pathways and the role of European climate policy.
In July 2013, Prof. Pantelis Capros as coordinator of AMPERE Work Package 5 provided insights from the AMPERE project to a public consultation for the European Commission's development of a 2030 framework for climate and energy policies. Based on the WP 5 research, Prof. Capros emphasised the importance of strong climate mitigation action during the decade of 2020 to 2030 for a cost-effective path toward the EU’s climate mitigation objectives for 2050. This would include emission reduction targets for 2030 of at least 40% below 1990 levels as well as policies for overcoming non-market barriers to energy efficiency and encouraging the diffusion of advanced technologies.
On January 21, 2014, AMPERE researchers presented the findings from three years of model assessment studies to a stakeholder audience of almost 200 in Brussels. This final AMPERE conference was dedicated to discussing Europe’s role in future global climate policy and how the AMPERE findings can inform mitigation strategies within Europe and in the global context. Aside from AMPERE consortium members, the panellists and speakers included climate policy experts from the EU commission, business, and research institutions in Europe, China and the United States. The almost 200 participants included representatives of European institutions, international organisations, national governments, energy, technology, and financial business, research institutions, NGOs, and media. Taking place one day before the publication of the Commission’s 2030 energy and climate change policy framework, the conference was particularly timely. Experts also discussed the prospects for internationally coordinated action based on the Durban platform. The presentations and proceedings of the conference are posted at www.ampere-project.eu. At the conference, the AMPERE team disseminated the AMPERE synthesis report “Assessing Pathways toward Ambitious Climate Targets at the Global and European Levels” also available on the AMPERE website.
DISSEMINATION OF RESULTS TO THE GENERAL PUBLIC
The AMPERE findings on the implications of short-term climate action for the achievability of long-term targets, the implications of regional climate policies and staged accession to a global climate regime, the climate response to a large range of emissions scenarios, the costs and benefits of the climate policy options faced by the European Union, and model diagnostics have been published in a number of papers in academic journals. The majority of these papers are contained in a special issue of the international journal Technological Forecasting and Social Change. Eight of these papers, including the overview and cross cut papers, are freely available in their published format via the journal website through open access. The other papers are openly available in their final draft formats via open repositories maintained by the AMPERE partners that can be accessed via the AMPERE project website http://ampere-project.eu.
The project website has served to inform the interested public about the objectives, tasks and progress of the project since July 2011. The website was updated throughout the project period and AMPERE material was added once completed. The annual progress of the project was reported continuously. Newsletters were posted on the website in February 2012, February 2013 and January 2014. The outcomes of the AMPERE meetings and workshops were summarized on the website along with PDF copies of presentations that presenters had agreed to make publicly available. The website also links visitors to AMPERE publications and deliverables and includes presentations slides of key AMPERE findings for public use in not-for-profit educational presentations.
Throughout the project, results from all modelling teams have been housed in a database managed by IIASA. This database includes graphics capabilities that allow users to compare results between models, regions, and scenarios. This database will enable the public to review and analyse the data used in the AMPERE project. In addition, all data relevant to the IPCC 5th Assessment Report (AR5) has already been transferred to the IPCC database, which is also housed by IIASA. The transfer of data to a public database is currently in development and will be completed by mid-April 2014. It will be available at https://tntcat.iiasa.ac.at/AMPEREDB.
List of Websites:
Public website: http://ampere-project.eu
Potsdam Institute for Climate Impact Research (PIK)
Telegrafenberg A 31
Phone: +49 331 288 2500
Grant agreement ID: 265139
1 February 2011
31 January 2014
€ 4 259 720,35
€ 3 149 489,55
POTSDAM INSTITUT FUER KLIMAFOLGENFORSCHUNG
Deliverables not available
Grant agreement ID: 265139
1 February 2011
31 January 2014
€ 4 259 720,35
€ 3 149 489,55
POTSDAM INSTITUT FUER KLIMAFOLGENFORSCHUNG
Grant agreement ID: 265139
1 February 2011
31 January 2014
€ 4 259 720,35
€ 3 149 489,55
POTSDAM INSTITUT FUER KLIMAFOLGENFORSCHUNG