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Looking at policies instead of promises shows that global climate targets may be missed by a large margin.

More than 100 countries have communicated or adopted new Nationally Determined Contributions (NDCs) and net-zero target pledges. We investigate the impact on global, national, sectoral, and individual greenhouse gas emissions projections under different scenarios based on the announced NDCs and net-zero pledges using the IMAGE integrated assessment model. Our results show that while the net-zero pledges, if implemented, could be an important step forward, they are still not enough to achieve the Paris Agreement goals of well below 2°C and preferably 1.5°C by the end of the century. Still, our net-zero scenarios project significant all-sector decarbonization, in particular, electricity; however, certain sectors like industry and transport prove hard to completely abate., (© 2023 New York Academy of Sciences.)

The Paris climate agreement aims at holding global warming to well below 2 degrees Celsius and to "pursue efforts" to limit it to 1.5 degrees Celsius. To accomplish this, countries have submitted Intended Nationally Determined Contributions (INDCs) outlining their post-2020 climate action. Here we assess the effect of current INDCs on reducing aggregate greenhouse gas emissions, its implications for achieving the temperature objective of the Paris climate agreement, and potential options for overachievement. The INDCs collectively lower greenhouse gas emissions compared to where current policies stand, but still imply a median warming of 2.6-3.1 degrees Celsius by 2100. More can be achieved, because the agreement stipulates that targets for reducing greenhouse gas emissions are strengthened over time, both in ambition and scope. Substantial enhancement or over-delivery on current INDCs by additional national, sub-national and non-state actions is required to maintain a reasonable chance of meeting the target of keeping warming well below 2 degrees Celsius.

This article shows the potential impact on global GHG emissions in 2030, if all countries were to implement sectoral climate policies similar to successful examples already implemented elsewhere. This assessment was represented in the IMAGE and GLOBIOM/G4M models by replicating the impact of successful national policies at the sector level in all world regions. The first step was to select successful policies in nine policy areas. In the second step, the impact on the energy and land-use systems or GHG emissions was identified and translated into model parameters, assuming that it would be possible to translate the impacts of the policies to other countries. As a result, projected annual GHG emission levels would be about 50 GtCO2e by 2030 (2% above 2010 levels), compared to the 60 GtCO2e in the ‘current policies’ scenario. Most reductions are achieved in the electricity sector through expanding renewable energy, followed by the reduction of fluorinated gases, reducing venting and flaring in oil and gas production, and improving industry efficiency. Materializing the calculated mitigation potential might not be as straightforward given different country priorities, policy preferences and circumstances. Key policy insights Considerable emissions reductions globally would be possible, if a selection of successful policies were replicated and implemented in all countries worldwide. This would significantly reduce, but not close, the emissions gap with a 2°C pathway. From the selection of successful policies evaluated in this study, those implemented in the sector ‘electricity supply’ have the highest impact on global emissions compared to the ‘current policies’ scenario. Replicating the impact of these policies worldwide could lead to emission and energy trends in the renewable electricity, passenger transport, industry (including fluorinated gases) and buildings sector, that are close to those in a 2°C scenario. Using successful policies and translating these to policy impact per sector is a more reality-based alternative to most mitigation pathways, which need to make theoretical assumptions on policy cost-effectiveness. [ABSTRACT FROM AUTHOR]

Over 40 studies that analyse future GHG emissions allowances or reduction targets for different regions based on a wide range of effort-sharing approaches and long-term concentration stabilization levels are compared. This updates previous work undertaken for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Regional reduction targets differ significantly for each effort-sharing approach. For example, in the Organisation for Economic Co-operation and Development (OECD) 1990 region, new proposals that emphasize the equity principles of responsibility, capability, and need, and those based on equal cumulative per capita emissions (carbon budgets), lead to relatively stringent emissions reduction targets. In order to reach a low concentration stabilization level of 450 ppm CO2e, the allowances under all effort sharing approaches in OECD1990 for 2030 would be approximately half of the emissions of 2010 with a large range, roughly two-thirds in the Economies in Transition (EIT), roughly at the 2010 emissions level or slightly below in Asia, slightly above the 2010 level in the Middle East and Africa and well below the 2010 level in Latin America. For 2050, allowances in OECD1990 and EIT would be a fraction of today's emissions, approximately half of 2010 emission levels in Asia, and possibly less than half of the 2010 level in Latin America. Policy relevance The concept of equity and the stringency of future national GHG reduction targets are at the heart of the current debate on the new international climate change agreement to be adopted in 2015. Policy insights gained from an analysis of over 40 studies, which have quantitatively analysed the proposed GHG reduction targets, are presented. It is found that the outcome of effort-sharing approaches is often largely determined by the way the equity principle is implemented and that the distributional impacts of such approaches can be significantly different depending on the criteria used, the stabilization level and shape of the global emissions pathway. However, the current literature only covers a small proportion of the possible allocation approaches. There should thus be an in-depth modelling comparison to ensure consistency and comparability of results and inform decision making regarding the reduction of GHG emissions. [ABSTRACT FROM PUBLISHER]

Abstract: This study assesses four proposals to generate funds for international climate financing in developing countries according to three criteria: adequacy, predictability and equitability. The focus year is 2020, in which USD 100 billion should be available for climate financing according to the Copenhagen Accord. The four financing proposals assessed include auctioning emission allowances (Norwegian Proposal), a global carbon tax (Swiss Proposal), an emissions trading (IET) levy, and a tax on international aviation and shipping emissions (bunker fuel emissions tax). Adequacy and predictability are assessed by calculating the revenue of the financing proposals for three mitigation scenarios. Equitability is assessed by comparing the regional distribution of costs of the financing proposals to that of a common but differentiated responsibilities and respective capabilities approach, which can be regarded as an equitable approach. For the calculations, the integrated FAIR model is used. Based on the three criteria above, we conclude that the Swiss Proposal and the bunker fuel emissions tax are the most promising financing proposals of the four. An IET levy receives a low score for all three criteria. Importantly, a low price on the carbon market, resulting from a low mitigation ambition level (as under the current unconditional Copenhagen Accord pledges), would undermine generating funding for all financing proposals analysed here except for the Swiss Proposal. Combining such proposals would therefore not increase the predictability of funding. [Copyright &y& Elsevier]

Abstract: As part of the Copenhagen Accord, individual countries have submitted greenhouse gas reduction proposals for the year 2020. This paper analyses the implications for emission reductions, the carbon price, and abatement costs of these submissions. The submissions of the Annex I (industrialised) countries are estimated to lead to a total reduction target of 12–18% below 1990 levels. The submissions of the seven major emerging economies are estimated to lead to an 11–14% reduction below baseline emissions, depending on international (financial) support. Global abatement costs in 2020 are estimated at about USD 60–100 billion, assuming that at least two-thirds of Annex I emission reduction targets need to be achieved domestically. The largest share of these costs are incurred by Annex I countries, although the costs as share of GDP are similar for Annex I as a group and the seven emerging economies as a group, even when assuming substantial international transfers from Annex I countries to the emerging economies to finance their abatement costs. If the restriction of achieving two-thirds of the emission reduction target domestically is abandoned, it would more than double the international carbon price and at the same time reduce global abatement costs by almost 25%. [Copyright &y& Elsevier]

Abstract: The Stern Review on the Economics of Climate Change compares costs and benefits of stringent climate policy and concludes that the benefits of stringent policy considerably outweigh the costs. Many other cost–benefit analyses have come up with less ambitious optimal emission reductions. In this study, we systematically explore the impacts of scientific uncertainties and value judgements on the suggested “optimal target” for international climate policy. In this context, we have varied the most important parameters using a range of values from several widely used Integrated Assessment Modes in one consistent framework. Our analysis shows that uncertainties about abatement and damage costs play an almost equally important role as the discount rate. Both stringent and moderate climate policy can be justified by using other parameter settings. Furthermore, for most parameter settings there is a wide range of concentration levels close to the optimal target, providing a much wider range for political choices than often suggested. [Copyright &y& Elsevier]

The “South–North Dialogue” Proposal, developed by researchers from developing and industrialised countries, outlined equitable approaches to mitigation. These approaches were based on the criteria of responsibility, capability and potential to mitigate, and include deep cuts in industrialised (Annex I) countries and differentiated mitigation commitments for developing countries. This paper quantitatively analyses the implications of the proposal for countries’ emissions and costs. The analysis focuses on a “political willingness” scenario and four stabilisation scenarios. The analysis shows that stringent stabilisation targets imply that many developing countries would have to take on quantitative mitigation obligations by 2030, even when the Annex I countries take on ambitious mitigation commitments far beyond the Kyoto obligations. The “political willingness scenario” will probably not suffice to limit a warming of the Earth''s atmosphere to below 2°C. [Copyright &y& Elsevier]

On the basis of the IPCC B2, A1b and B1 baseline scenarios, mitigation scenarios were developed that stabilize greenhouse gas concentrations at 650, 550 and 450 and--subject to specific assumptions--400 ppm CO2-eq. The analysis takes into account a large number of reduction options, such as reductions of non-CO2 gases, carbon plantations and measures in the energy system. The study shows stabilization as low as 450 ppm CO2-eq. to be technically feasible, even given relatively high baseline scenarios. To achieve these lower concentration levels, global emissions need to peak within the first two decades. The net present value of abatement costs for the B2 baseline scenario (a medium scenario) increases from 0.2% of cumulative GDP to 1.1% as the shift is made from 650 to 450 ppm. On the other hand, the probability of meeting a two-degree target increases from 0%--10% to 20%--70%. The mitigation scenarios lead to lower emissions of regional air pollutants but also to increased land use. The uncertainty in the cost estimates is at least in the order of 50%, with the most important uncertainties including land-use emissions, the potential for bio-energy and the contribution of energy efficiency. Furthermore, creating the right socio-economic and political conditions for mitigation is more important than any of the technical constraints. [ABSTRACT FROM AUTHOR]

This article summarises the results of an evaluation of the Climate Change Initiative launched by President Bush in February 2002. The policy target to reduce the greenhouse gas intensity of the US economy by 18% between 2002 and 2012 can be considered modest at best. The Initiative is likely to result in a 32% increase in US greenhouse gas emissions in 2012 compared to the 1990 levels. The effort also falls considerably short of efforts of the EU, Japan and Canada under the Kyoto Protocol. The Bush Initiative advocates using intensity targets in the international climate change regime, but overlooks fundamental problems associated with this approach. All the same, the Bush Initiative is of political significance as it recognises the importance of the climate change problem and may improve the longer-term prospects for US participation in a global climate regime. [ABSTRACT FROM AUTHOR]