Regulatory control of vehicle and power plant emissions: how effective and at what cost?

Passenger vehicles and power plants are major sources of GHG emissions. While economic analyses generally indicate that a broader market-based approach to GHG reduction would be less costly and more effective, regulatory approaches have found greater political success. We evaluate a global regulatory regime that replaces coal with natural gas in the electricity sector and imposes technically achievable improvements in the efficiency of personal transport vehicles. Its performance and cost are compared with other scenarios of future policy development including a no-policy world, achievements under the Copenhagen Accord, and a price-based policy to reduce global emissions by 50% by 2050. The assumed regulations applied globally achieve a global emissions reduction larger than projected for the Copenhagen agreements, but they do not prevent global GHG emissions from continuing to grow. The reduction in emissions is achieved at a high cost compared to a price-based policy. Diagnosis of the reasons for the limited yet high-cost performance reveals influences including the partial coverage of emitting sectors, small or no influence on the demand for emissions-intensive products, leakage when a reduction in fossil use in the covered sectors lowers the price to others, and the partial coverage of GHGs. If these regulatory measures are in part correcting other barriers or behavioural limitations consumers face, the benefits of overcoming these could offset at least some of the costs we estimate. The extent of any efficiency gap – the difference between engineering estimates of best practice and what actually happens – is highly contested, and offers an important avenue for future research.

Policy relevance

While analysts concerned with national cost of GHG control have long advocated a GHG pricing policy, by a cap-and-trade system or a tax, covering all emissions sources and gases, governments more often pursue sectoral policies and technology standards. Given these political realities, the regulations represent a more politically practical approach to GHG reductions, focusing on solutions that are within reach and that do not depend on technological breakthroughs. If regulations are imposed as a way to get started on larger emissions reductions, and then combined with a broader GHG pricing policy pursuing a deep global cut in emissions, its requirements will eventually be overtaken by the pricing policy. The remaining higher costs of the regulatory targets become diluted so that in later years the difference in average cost per ton between a least-cost approach and one preceded by a period of regulatory action becomes very small.     

Russia's 2020 GHG emissions target: Emission trends and implementation

This article provides an overview of the recent modelling results on Russia's GHG emission trends, and reviews the success of mitigation policies in order to establish whether Russia's domestic target seems feasible. Various Russian GHG emission scenarios indicate that Russia's domestic target – emissions 25% below the 1990 level by 2020 – is not far from the business-as-usual emissions trajectory. In particular, two factors could deliver the required emissions reductions: the currently declining gross domestic product (GDP) growth and ongoing domestic mitigation policies. The former is more likely to secure the target level of emissions, because GDP growth has been contracting significantly in comparison to earlier forecasts of 3–5% annual growth, and this trend is expected to continue. The latter option – success with domestic mitigation measures – seems less likely, given the various meta-barriers to policy implementation, and the marginality of mitigation policies, problems with law-making processes, bureaucratic tradition, and informality of legislative and implementation systems.

Policy relevance

This article provides an assessment of the stringency of Russia's domestically set emissions limitation target by 2020 and the chances of Russia, the fourth largest GHG emitter in the world, achieving it. We base our assessment on a number of recent key sources that analyse Russia's GHG emission paths by applying socio-economic models, which have only been available in the Russian language prior to this publication. This knowledge is applicable for use by other negotiation parties to compare Russia's efforts to mitigate climate change to their own, and thus makes a contribution to facilitating a more equal burden-sharing of climate commitments under the future climate change agreement.     

Implications of different climate protection regimes for the EU-27 and its member states through 2050

It is a broadly accepted fact that a clear reduction of global GHG emissions is required to limit the increase of global warming to a tolerable level. A key issue in this context is the optimal breakdown of reduction targets among different world regions or even countries. Using the European Commission-funded PLANETS project, cost-optimal global burden sharing to reach global GHG reduction targets was analysed, and an optimal allocation of GHG reductions was identified, relative to the global target, to the commitments of different world regions and the trade possibilities for emission certificates. Specifically, it is evaluated how Europe can contribute in a cost-optimal way to keeping the global concentration of GHGs in the atmosphere below 530 parts per million equivalent (ppme) or below a stricter global reduction target of 500 ppme. Based on the energy system model TIMES PanEU, the potentials for emissions reduction in the different energy sectors and EU Member States and the role of key technologies are analysed. The most cost-effective potentials for GHG reductions in Europe are in the conversion/production, residential and industrial sectors. Substantial reductions in the transport sector occur only under very stringent reduction targets. Achieving ambitious reduction targets requires considerable contributions from all EU Member States until 2050.     

A low-carbon society: global visions,pathways, and challenges

The feasibility of two low-carbon society (LCS) scenarios, one with and one without nuclear power and carbon capture and storage (CCS), is evaluated using the AIM/Enduse[Global] model. Both scenarios suggest that achieving a 50% emissions reduction target (relative to 1990 levels) by 2050 is technically feasible if locally suited technologies are introduced and the relevant policies, including necessary financial transfers, are appropriately implemented. In the scenario that includes nuclear and CCS options, it will be vital to consider the risks and acceptance of these technologies. In the scenario without these technologies, the challenge will be how to reduce energy service demand. In both scenarios, the estimated investment costs will be higher in non-Annex I countries than in Annex I countries. Finally, the enhancement of capacity building to support the deployment of locally suited technologies will be central to achieving an LCS.

Policy relevance

Policies to reduce GHG emissions up to 2050 are critical if the long-term target of stabilizing the climate is to be achieved. From a policy perspective, the cost and social acceptability of the policy used to reduce emissions are two of the key factors in determining the optimal pathways to achieve this. However, the nuclear accident at Fukushima highlighted the risk of depending on large-scale technologies for the provision of energy and has led to a backlash against the use of nuclear technology. It is found that if nuclear and CCS are used it will be technically feasible to halve GHG emissions by 2050, although very costly. However, although the cost of halving emissions will be about the same if neither nuclear nor CCS is used, a 50% reduction in emissions reduction will not be achievable unless the demand for energy service is substantially reduced.     

National climate change mitigation legislation,strategy and targets: a global update

Global climate change governance has changed substantially in the last decade, with a shift in focus from negotiating globally agreed greenhouse gas (GHG) reduction targets to nationally determined contributions, as enshrined in the 2015 Paris Agreement. This paper analyses trends in adoption of national climate legislation and strategies, GHG targets, and renewable and energy efficiency targets in almost all UNFCCC Parties, focusing on the period from 2007 to 2017. The uniqueness and added value of this paper reside in its broad sweep of countries, the more than decade-long coverage and the use of objective metrics rather than normative judgements. Key results show that national climate legislation and strategies witnessed a strong increase in the first half of the assessed decade, likely due to the political lead up to the Copenhagen Climate Conference in 2009, but have somewhat stagnated in recent years, currently covering 70% of global GHG emissions (almost 50% of countries). In comparison, the coverage of GHG targets increased considerably in the run up to adoption of the Paris Agreement and 89% of global GHG emissions are currently covered by such targets. Renewable energy targets saw a steady spread, with 79% of the global GHG emissions covered in 2017 compared to 45% in 2007, with a steep increase in developing countries.

Key policy insights

• The number of countries that have national legislation and strategies in place increased strongly up to 2012, but the increase has levelled off in recent years, now covering 70% of global emissions by 2017 (48% of countries and 76% of global population).

• Economy-wide GHG reduction targets witnessed a strong increase in the build up to 2015 and are adopted by countries covering 89% of global GHG emissions (76% not counting USA) and 90% of global population (86% not counting USA) in 2017.

• Renewable energy targets saw a steady increase throughout the last decade with coverage of countries in 2017 comparable to that of GHG targets.

• Key shifts in national measures coincide with landmark international events – an increase in legislation and strategy in the build-up to the Copenhagen Climate Conference and an increase in targets around the Paris Agreement – emphasizing the importance of the international process to maintaining national momentum.

     

Brazil beyond 2020: from deforestation to the energy challenge

The main assumptions and findings are presented on a comparative analysis of three GHG long-term emissions scenarios for Brazil. Since 1990, land-use change has been the most important source of GHG emissions in the country. The voluntary goals to limit Brazilian GHG emissions pledged a reduction in between 36.1% and 38.9% of GHG emissions projected to 2020, to be 6–10% lower than in 2005. Brazil is in a good position to meet the voluntary mitigation goals pledged to the United Nations Framework Convention on Climate Change (UNFCCC) up to 2020: recent efforts to reduce deforestation have been successful and avoided deforestation will form the bulk of the emissions reduction commitment. In 2020, if governmental mitigation goals are met, then GHG emissions from the energy system would become the largest in the country. After 2020, if no additional mitigation actions are implemented, GHG emissions will increase again in the period 2020–2030, due to population and economic growth driving energy demand, supply and GHG emissions. However, Brazil is in a strong position to take a lead in low-carbon economic and social development due to its huge endowment of renewable energy resources allowing for additional mitigation actions to be adopted after 2020.

Policy relevance

The period beyond 2020 is now relevant in climate policy due to the Durban Platform agreeing a ‘protocol, legal instrument or agreed outcome with legal force’ that will have effect from 2020. After 2020, Brazil will be in a situation more similar to other industrialized countries, faced with a new challenge of economic development with low GHG energy-related emissions, requiring the adoption of mitigation policies and measures targeted at the energy system. Unlike the mitigation actions in the land-use change sector, where most of the funding will come from the national budgets due to sovereignty concerns, the huge financial resources needed to develop low-carbon transport and energy infrastructure could benefit from soft loans channelled to the country through nationally appropriate mitigation actions (NAMAs).     

Carbon reduction in the real world: how the UK will surpass its Kyoto obligations

Abstract

Carbon dioxide emissions from UK energy use have fallen by more than 20% over the last 30 years, and carbon intensity—carbon emissions per unit of GDP—has halved. These reductions have been achieved by a combination of decarbonisation of the energy system and substantial improvements in energy efficiency. Use of natural gas in power generation has been a big factor in recent years, but energy efficiency improvements in households and particularly industry have been more important over a longer period. Government policies designed primarily to address climate change have not been important contributors, until recently.

Future reductions in emissions will require more proactive policies. However, they are possible without any economic difficulties, notably by adopting cost-effective energy efficiency measures, using new renewable energy sources and reducing dependence on private cars. These policies will improve economic efficiency. The new UK Climate Change Programme includes policies that combine regulation, investment, fiscal measures and other economic instruments. By working with the grain of other social, environmental and economic policies, they can achieve far more than a carbon tax alone, set at any politically acceptable level. Modelling the costs of emission reductions using a carbon tax as the only instrument would not only massively over-estimate costs, it would bear little resemblance to real world politics.

The paper demonstrates that a more diverse set of policy instruments is likely to be an effective and politically acceptable approach in a mature industrial economy. It is concluded that the UK's Kyoto target of a 12.5% reduction in greenhouse gas emissions is not challenging. The UK Government's target of reducing carbon dioxide emissions by 20% between 1990 and 2010 is also achievable. By 2010 per capita emissions from the UK will be well below 2.5 tC per year. Claims that some countries, notably the USA, could not reduce per capita emissions below 6 tC per year seem inconsistent with this experience.     

The global carbon market-mechanism landscape: pre and post 2020 perspectives

With market-mechanisms likely to achieve emission reductions at lower cost than alternative approaches, there is a presumption that they will be embraced by those who are serious about achieving ambitious reductions. Two broad messages exist; there is already considerable activity and some ambition in many parts of the world – a fragmented but embryonic ‘global’ trading landscape is emerging – and there are efforts at UN level to provide a unifying framework for these bottom-up developments. The topography of interest and response varies considerably across groups of countries, and there have been delays in making progress on a unifying framework. This article analyses the current carbon market landscape in terms of market dynamics and market-mechanism developments whilst undertaking an examination of how climate change negotiations under the United Nations Framework Convention on Climate Change (UNFCCC) is shaping the future carbon market landscape. This work shows that the combination of existing, emerging, and potential carbon market-mechanisms can be regarded as an emerging pre-2020 fragmented ‘global’ carbon market landscape based on differing bottom-up market based approaches. One outcome of a 2015 Climate Agreement could be a post-2020 global carbon market which would include new domestic and international market initiatives such as the Framework for Various Approaches and New Market Mechanism, together with reformed Kyoto mechanisms.

Policy relevance

With the 2015 Agreement under the United Nations Framework Convention on Climate Change (UNFCCC) expected to see Parties commit to ambitious mitigation commitments, post-2020 could see significant Party (& industry) investment in market-mechanisms and associated emissions units in an effort to achieve some of the abatement cost minimization offered by market approaches. This article is written for those who have an interest in understanding what is happening – and what is not happening – as regards the emergence of market-related approaches to GHG mitigation globally in the run up to the 21st Conference of the Parties (COP) of the UNFCCC which meets in Paris in December 2015, and what could be the shape of things to come post-2020.     

Including animal to plant protein shifts in climate change mitigation policy: a proposed three-step strategy

Strong and rapid greenhouse gas (GHG) emission reductions, far beyond those currently committed to, are required to meet the goals of the Paris Agreement. This allows no sector to maintain business as usual practices, while application of the precautionary principle requires avoiding a reliance on negative emission technologies. Animal to plant-sourced protein shifts offer substantial potential for GHG emission reductions. Unabated, the livestock sector could take between 37% and 49% of the GHG budget allowable under the 2°C and 1.5°C targets, respectively, by 2030. Inaction in the livestock sector would require substantial GHG reductions, far beyond what are planned or realistic, from other sectors. This outlook article outlines why animal to plant-sourced protein shifts should be taken up by the Conference of the Parties (COP), and how they could feature as part of countries’ mitigation commitments under their updated Nationally Determined Contributions (NDCs) to be adopted from 2020 onwards. The proposed framework includes an acknowledgment of ‘peak livestock’, followed by targets for large and rapid reductions in livestock numbers based on a combined ‘worst first’ and ‘best available food’ approach. Adequate support, including climate finance, is needed to facilitate countries in implementing animal to plant-sourced protein shifts.

Key policy insights

• Given the livestock sector’s significant contribution to global GHG emissions and methane dominance, animal to plant protein shifts make a necessary contribution to meeting the Paris temperature goals and reducing warming in the short term, while providing a suite of co-benefits.

• Without action, the livestock sector could take between 37% and 49% of the GHG budget allowable under the 2°C and 1.5°C targets, respectively, by 2030.

• Failure to implement animal to plant protein shifts increases the risk of exceeding temperate goals; requires additional GHG reductions from other sectors; and increases reliance on negative emissions technologies.

• COP 24 is an opportunity to bring animal to plant protein shifts to the climate mitigation table.

• Revised NDCs from 2020 should include animal to plant protein shifts, starting with a declaration of ‘peak livestock’, followed by a ‘worst first’ replacement approach, guided by ‘best available food’.

     

Effects of economic recession and local weather on climate change attitudes

How are large companies responding to the challenges of reducing their greenhouse gas (GHG) emissions? An analysis of the published climate change policies and performance of 125 large European companies is presented. The results suggest that most large European companies have now developed the management systems and processes necessary for them to effectively manage their GHG emissions and related business risks. However, there is a significant disconnect between the targets that companies set for themselves and the more ambitious targets being set by the European Union (which has committed to a 20% reduction in its emissions by 2020 against a 1990 baseline). Of the companies surveyed, just over one-third had stabilized or reduced their total GHG emissions over the period 2002–2007, and fewer than one-third expected their emissions to stabilize or reduce in the coming years. The relationship between the quality of corporate policies and performance outcomes (in terms of GHG emissions) suggests that while companies with stronger policies are likely to have relatively better performance, only a minority of those companies with the highest-quality policies are committing to absolute reductions in their GHG emissions.     

Dynamics of energy sector and GHG emissions in Saudi Arabia

The energy sector is the main contributor to GHG emissions in Saudi Arabia. The tremendous growth of GHG emissions poses serious challenges for the Kingdom in terms of their reduction targets, and also the mitigation of the associated climate changes. The rising trend of population and urbanization affects the energy demand, which results in a faster rate of increase in GHG emissions. The major energy sector sources that contribute to GHG emissions include the electricity generation, road transport, desalination plants, petroleum refining, petrochemical, cement, iron and steel, and fertilizer industries. In recent years, the energy sector has become the major source, accounting for more than 90% of national CO₂ emissions. Although a substantial amount of research has been conducted on renewable energy resources, a sustainable shift from petroleum resources is yet to be achieved. Public awareness, access to energy-efficient technology, and the development and implementation of a legislative framework, energy pricing policies, and renewable and alternative energy policies are not mature enough to ensure a significant reduction in GHG emissions from the energy sector. An innovative and integrated solution that best serves the Kingdom's long-term needs and exploits potential indigenous, renewable, and alternative energy resources while maintaining its sustainable development stride is essential.

Policy relevance

The main contributor to GHG emissions in Saudi Arabia is the energy sector that accounts for more than 90% of the national CO₂ emissions. Tremendous growth of GHG emissions poses serious challenges for the Kingdom in their reduction and mitigating the associated climate changes. This study examines the changing patterns of different activities associated with energy sector, the pertinent challenges, and the opportunities that promise reduction of GHG emissions while providing national energy and economic security. The importance of achieving timely, sustained, and increasing reductions in GHG emissions means that a combination of policies may be needed. This study points to the long-term importance of making near- and medium-term policy choices on a well-informed, strategic basis. This analytical paper is expected to provide useful information to the national policy makers and other decision makers. It may also contribute to the GHG emission inventories and the climate change negotiations.     

Growing stocks of buildings,infrastructures and machinery as key challenge for compliance with climate targets

Drastic reductions of greenhouse-gas (GHG) emissions are required to meet the goal of the 2015 Paris climate accord to limit global warming to 1.5–2.0 °C over pre-industrial levels. We introduce the material stock-flow framework as a novel way to develop scenarios for future GHG emissions using methods from social metabolism research. The basic assumption behind our exploratory scenario approach is that nearly all final energy is required to either expand and maintain stocks of buildings, infrastructures and machinery or to provide services by using them. Distinguishing three country groups, we develop GDP- and population-driven scenarios for the development of these material stocks and the corresponding energy requirements based on historically calibrated model parameters. We analyze the results assuming different future pathways of CO₂ emissions per unit of primary energy. The resulting cumulative carbon emissions from 2018 to 2050 range from 361 Gt C in the lower GDP-driven to 568 GtC in the higher population-driven scenario. The findings from the population-driven scenarios point towards the huge implications of a hypothetical convergence of per-capita levels of material stocks assuming current trajectories of technological improvements. Results indicate that providing essential services with a considerably lower level of material stocks could contribute to large reductions in global resource demand and GHG emissions. A comparison of different stock levels in 2050 demonstrates that complying with ambitious climate targets requires much faster declines of CO₂ emissions per unit of primary energy if growth of material stocks is not limited.     

Funding low carbon cities: local perspectives on opportunities and risks

There are compelling reasons for policy makers to be interested in the low-carbon agenda. More than half of the world's population lives in, and more than half of the world's economic output comes from, cities. Up to 70% of global carbon emissions can also be attributed to consumption that takes place in cities. Recent research has shown that cost-effective investments in low-carbon options could deliver a 40% reduction in GHG emissions from cities by 2020, while also providing wider economic benefits such as enhanced competitiveness and increased employment. As yet, however, investments in low-carbon cities have not been made at scale due mainly to the scale of the finance required, local government budgetary constraints, and perceptions about their costs and benefits. With a focus on the UK, a contemporary account is provided of what local authorities see as the major financial risks associated with funding low-carbon cities. Practical proposals – which also have more general relevance to the future financing of low-carbon cities around the world – are offered on how local authorities, in conjunction with central government, the private sector, and institutional investors, can effectively manage these risks.

Policy relevance

Cities house more than half of the world's population, generate more than half of the world's economic output, and produce between 40% and 70% of all anthropogenic GHG emissions. In the UK, 70% of such emissions are under the influence of its local authorities. Thus, one of the key public policy challenges for the low-carbon transition is how it should be financed. There are several obstacles and related risks to this transition, including financial and legal obstacles and the differing views and perceptions of stakeholders. These can be attenuated, somewhat, by national government support at scale, local authority leadership, and cooperation between other authorities and the private sector, and the development of tools and guidance to reduce transaction costs.     

欧盟《气候与能源2030政策框架》要点分析与启示

通过分析《气候与能源2030政策框架》（以下简称《框架》）方案要点,认为欧盟2030年的减排目标相对2020年承诺目标更为积极,可再生能源目标略高于之前官方预期。由于东欧国家的参与,欧盟一方面获得了这些国家盈余的排放配额,帮助欧盟作为一个整体实现减排目标;另一方面,成员国经济发展水平差异增大,导致欧盟施行相对积极的环境政策阻力加大,未来大幅调整减排目标的可能性不大。《框架》目标将可能对2020年后国际碳市场需求预估产生影响,未来国际碳市场的健康运行,将不仅需要欧盟外的发达国家提出具有雄心的减排目标,也需要欧盟提高减排目标,增加其对于国际减排配额的需求;此外,欧盟辅助实现40%减排目标的相关生产标准和措施,可能对未来全球自由贸易产生影响,其他国家尤其是对外贸易依存度较高的发展中国家需要密切关注相关动向。《框架》方案所提出的以应对气候变化引领和促进经济发展、采用组合目标且针对不同目标采取不同实现形式、展现制定目标的透明度、充分考虑成员国差异等提法和操作方式值得中国借鉴。     

Macroeconomic analysis of the employment impacts of future EU climate policies

This article gives a detailed account of part of the modelling that was carried out for the assessment of the EU's proposed energy and climate targets for 2030. Using the macro-econometric simulation model, E3ME, and drawing on results from the PRIMES energy systems model, it shows that a 40% reduction in GHG emissions (compared to 1990 levels) could lead to an increase in employment of up to 0.7 million jobs in Europe. Furthermore, if the same GHG reduction target was combined with targets for renewables and energy efficiency, the net increase in jobs could be as high as 1.2 million. Both results are in contrast to the standard findings from computable general equilibrium (CGE) models, reflecting the different underlying assumptions (e.g. labour supply) to the modelling approach. Additional sensitivity testing shows that the ways in which the energy efficiency and renewable measures are funded are important factors in determining overall economic impact.

Policy relevance

In recent years there has been much debate as to whether the European Union should have a single GHG reduction target or a set of targets that also cover renewables and energy efficiency. This paper elaborates on part of the modelling that was carried out for the official assessment of the European Union's proposed energy and climate targets for 2030. Using an empirical, model-based approach, it compares a scenario where there is a single 40% GHG reduction target to a scenario that also includes a 30% renewables target and stricter energy efficiency standards. The model results show that the large investment stimulus needed to meet the combined targets leads to higher levels of GDP and employment. This suggests that there could be medium-term economic and social benefits to including all three targets in the future energy and climate package.     

Corrigendum to: Incremental CH4 and N2O mitigation benefits consistent with the U.S. Government's SC-CO2 estimates

The light bulb ban introduced by the EU is used as an example to illustrate how to assess the climate impact of a policy that overlaps with a cap-and-trade scheme. The European Commission estimates that by 2020 the reduction in GHG emissions induced by banning incandescent light bulbs will reach 15 million tons annually. The number is a conservative estimate for the reduction in emissions from lighting if the total residential stock of incandescent light bulbs in 2008 is replaced by more efficient lighting sources. However, it ignores that use-phase and some non-use-phase emissions are covered by the EU Emission Trading Scheme (EU ETS). This drastically reduces the amount of GHG emissions saved.

Policy relevance

Several policies such as the EU-wide ban on incandescent light bulbs, energy efficiency mandates and support mechanisms for renewable energy overlap with the EU ETS. While there are typically several justifications for these policies, a chief reason is the reduction of GHG emissions. However, given that the aggregate emissions of the industries covered are fixed by the EU ETS, the climate change mitigation aspect of these policies is not obvious. Using the light bulb ban as an example, this article illustrates how a focus on non-EU ETS emissions changes the assessment of an intervention in terms of GHG reductions.     

Comparative assessment of Japan's long-term carbon budget under different effort-sharing principles

This article assesses Japan's carbon budgets up to 2100 in the global efforts to achieve the 2?°C target under different effort-sharing approaches based on long-term GHG mitigation scenarios published in 13 studies. The article also presents exemplary emission trajectories for Japan to stay within the calculated budget.

The literature data allow for an in-depth analysis of four effort-sharing categories. For a 450?ppm CO₂e stabilization level, the remaining carbon budgets for 2014–2100 were negative for the effort-sharing category that emphasizes historical responsibility and capability. For the other three, including the reference ‘Cost-effectiveness’ category, which showed the highest budget range among all categories, the calculated remaining budgets (20th and 80th percentile ranges) would run out in 21–29 years if the current emission levels were to continue. A 550?ppm CO₂e stabilization level increases the budgets by 6–17 years-equivalent of the current emissions, depending on the effort-sharing category. Exemplary emissions trajectories staying within the calculated budgets were also analysed for ‘Equality’, ‘Staged’ and ‘Cost-effectiveness’ categories. For a 450?ppm CO₂e stabilization level, Japan's GHG emissions would need to phase out sometime between 2045 and 2080, and the emission reductions in 2030 would be at least 16–29% below 1990 levels even for the most lenient ‘Cost-effectiveness’ category, and 29–36% for the ‘Equality’ category. The start year for accelerated emissions reductions and the emissions convergence level in the long term have major impact on the emissions reduction rates that need to be achieved, particularly in the case of smaller budgets.

Policy relevance

In previous climate mitigation target formulation processes for 2020 and 2030 in Japan, neither equity principles nor long-term management of cumulative GHG emissions was at the centre of discussion. This article quantitatively assesses how much more GHGs Japan can emit by 2100 to achieve the 2?°C target in light of different effort-sharing approaches, and how Japan's GHG emissions can be managed up to 2100. The long-term implications of recent energy policy developments following the Fukushima nuclear disaster for the calculated carbon budgets are also discussed.     

Book review

In 2007 the US Congress began considering a set of bills to implement a cap-and-trade system to limit the nation's greenhouse gas (GHG) emissions. The MIT Integrated Global System Model (IGSM)—and its economic component, the Emissions Prediction and Policy Analysis (EPPA) model—were used to assess these proposals. In the absence of policy, the EPPA model projects a doubling of US greenhouse gas emissions by 2050. Global emissions, driven by growth in developing countries, are projected to increase even more. Unrestrained, these emissions would lead to an increase in global CO₂ concentration from a current level of 380 ppmv to about 550 ppmv by 2050 and to near 900 ppmv by 2100, resulting in a year 2100 global temperature 3.5–4.5°C above the current level. The more ambitious of the Congressional proposals could limit this increase to around 2°C, but only if other nations, including developing countries, also strongly controlled greenhouse gas emissions. With these more aggressive reductions, the economic cost measured in terms of changes in total welfare in the United States could range from 1.5% to almost 2% by the 2040–2050 period, with 2015 CO₂-equivalent prices between $30 and $55, rising to between $120 and $210 by 2050. This level of cost would not seriously affect US GDP growth but would imply large-scale changes in its energy system.     

Evaluating the US Mid-Century Strategy for Deep Decarbonization amidst early century uncertainty

The recent change in US presidential administrations has introduced significant uncertainty about both domestic and international policy support for continued reductions in GHG emissions. This brief analysis estimates the potential climate ramifications of changing US leadership, contrasting the Mid-Century Strategy for Deep Decarbonization (MCS) released under the Obama Administration, with campaign statements, early executive actions, and prevailing market conditions to estimate potential emission pathways under the Trump Administration. The analysis highlights areas where GHG reductions are less robust to changing policy conditions, and offers brief recommendations for addressing emissions in the interim. It specifically finds that continued reductions in the electricity sector are less vulnerable to changes in federal policy than those in the built environment and land use sectors. Given the long-lived nature of investments in these latter two sectors, however, opportunities for near-term climate action by willing cities, states, private landowners, and non-profit organizations warrant renewed attention in this time of climate uncertainty.

Key policy insights

• The recent US presidential election has already impacted mitigation goals and practices, injecting considerable uncertainty into domestic and international efforts to address climate change.

• A strategic assessment issued in the final days of the Obama Administration for how to reach long-term climate mitigation objectives provides a baseline from which to gauge potential changes under the Trump Administration.

• Though market trends may continue to foster emission declines in the energy sector, emission reductions in the land use sector and the built environment are subject to considerable uncertainty.

• Regardless of actions to scale back climate mitigation efforts, US emissions are likely to be flat in the coming years. Assuming that emissions remain constant under President Trump and that reductions resume afterwards to meet the Obama Administration mid-century targets in 2050, this near-term pause in reductions yields a difference in total emissions equivalent to 0.3–0.6 years of additional global greenhouse gas emissions, depending on the number of terms served by a Trump Administration.

     

Importance of programme design for potential US domestic GHG offset supply and quality

Greenhouse gas (GHG) offsets are a central feature of most regional and national cap-and-trade systems. A greenhouse offset credit represents a tonne of carbon dioxide equivalent (CO₂e) reduced, avoided or sequestered by a project implemented specifically to compensate for emissions occurring elsewhere. Several existing modelling studies estimate the technically and economically achievable supply of GHG offsets from uncapped sources in the US. This analysis is among the few that consider how the design of offset protocols – and the corresponding rules for eligibility, measuring, verifying and awarding offsets – might impact actual offset crediting and the realization of GHG mitigation potential. The presented analysis demonstrates how rules for each of these factors could impact the supply of offset credits, as well as the emissions-reduction benefits of an offset programme. Findings indicate that although lenient offset rules and protocols may bring several times more credits to market than a conservative approach, these gains in offset supply would come at a significant cost to the effectiveness of the cap-and-trade system in achieving its central purpose: reducing overall GHG emissions. In particular, lenient rules and protocols could conceivably lead US emissions to exceed legislative targets by as much as 500 million tonnes CO₂e in 2020.