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[en] This paper analyses the effect of different emission metrics and metric values on timing and costs of greenhouse gas mitigation in least-cost emission pathways aimed at a forcing level of 3.5 W m"−"2 in 2100. Such an assessment is currently relevant in view of UNFCCC’s decision to replace the values currently used. An emission metric determines the relative weights of non-CO_2 greenhouse gases in obtaining CO_2-equivalent emissions. For the first commitment period of the Kyoto Protocol, the UNFCCC has used 100 year global warming potential (GWP) values as reported in IPCC’s Second Assessment Report. For the second commitment period, the UNFCCC has decided to use 100 year GWP values from IPCC’s Fourth Assessment Report. We find that such a change has only a minor impact on (the optimal timing of) global emission reductions and costs. However, using 20 year or 500 year GWPs to value non-CO_2 greenhouse gases does result in a significant change in both costs and emission reductions in our model. CO_2 reductions are favored over non-CO_2 gases when the time horizon of the GWPs is increased. Application of GWPs with time horizons longer than 100 year can increase abatement costs substantially, by about 20% for 500 year GWPs. Surprisingly, we find that implementation of a metric based on a time-dependent global temperature potential does not necessary lead to lower abatement costs. The crucial factor here is how fast non-CO_2 emissions can be reduced; if this is limited, the delay in reducing methane emissions cannot be (fully) compensated for later in the century, which increases total abatement costs. (letter)
[en] A high probability of limiting temperature increase to 2 deg. C requires a radiative forcing below 3 W/m2, around the end of this century, according to current knowledge. This paper identifies conditions under which achieving such low radiative forcing levels is feasible. Calculations here show that such targets could be achieved, based on technical and physical considerations, provided some key conditions are met. These key conditions include early participation by major sectors and regions in sufficiently stringent policy regimes, and a wide portfolio of mitigation options. Bio-energy and carbon capture and storage (CCS) play an important role in achieving low stabilisation targets. This would require optimistic assumptions with respect to the expansion of the area needed for food production, to allow space for bio-energy crops, and a significant increase in the efficiency of second-generation biofuels. The sensitivity analysis shows that if certain technologies are removed from the available portfolio, low targets - especially the 2.6 W/m2 target - are no longer within reach.
[en] EU Heads of State and Government agreed in March 2007 that the EU will reduce its greenhouse gas emissions to 30% below 1990 levels by 2020 within an international post-2012 climate agreement, provided that other developed (Annex I) countries commit to comparable reductions. Within this context, this paper first explores the pros and cons of many possible conceptual approaches to assess the comparability of the mitigation efforts by Annex I countries. We selected six approaches for further analysis, which represent efforts well and are technically feasible. The implications of each of these six approaches were analysed in terms of the reductions and abatement costs that must be made by different Annex I countries to meet an aggregate reduction of 20% and 30%, respectively, below 1990 levels by 2020. The analysis indicates that significant reductions are necessary for all developed countries. This study shows that reductions by the EU of at least 30%, combined with comparable reduction efforts by other developed countries to meet the aggregate Annex I reduction target of 30% by 2020 and support of developed countries for developing countries to keep their emissions 15-30% below the baseline, are sufficient to achieve the EU climate goal of 2 deg. C.
[en] In this article we explore several scenarios that aim at meeting radiative forcing targets at 4.5, 3.7, 2.9 and 2.6 W/m2 by 2100. These scenarios are run under the assumption of participation of all countries by 2012 in climate policy and under the assumption of a significant delay in the participation of Russia and non-Annex I countries (up to 2030 and 2050). The study finds the lowest radiative forcing categories to be feasible under full participation, certainly if overshoot of targets is allowed and when bio-energy and carbon-capture-and-storage is added to the mitigation portfolio. In cases with severe delay in participation, the lowest targets become infeasible. For less strict targets (e.g. 3.7 W/m2), delayed participation leads to considerable costs increases (up to 90% for the stabilisation case). As a next step, scenarios with less delay in participation need to be explored.
[en] Potentials for bio-energy have been estimated earlier on the basis of estimates of potentially available land, excluding certain types of land use or land cover (land required for food production and forests). In this paper, we explore how such estimates may be influenced by other factors such as land degradation, water scarcity and biodiversity concerns. Our analysis indicates that of the original bio-energy potential estimate of 150, 80 EJ occurs in areas classified as from mild to severe land degradation, water stress, or with high biodiversity value. Yield estimates were also found to have a significant impact on potential estimates. A further 12.5% increase in global yields would lead to an increase in bio-energy potential of about 50%. Changes in bio-energy potential are shown to have a direct impact on bio-energy use in the energy model TIMER, although the relevant factor is the bio-energy potential at different cost levels and not the overall potential.
[en] So-far, most climate mitigation studies look at climate policy strategies in a so-called first-best world, i.e. using the least expensive emission reduction options in all world regions and sectors. To explore the impact of limited participation of countries, we have run a set of scenarios that explore the impact of introducing a carbon tax in OECD, the BRIC countries (Brazil Russia, India and China) and the rest of the world. The results show that carbon taxes can effectively reduce greenhouse gas emissions. However, if low greenhouse gas concentration levels are to be achieved, early participation (in some form) of large developing countries is important to increase reduction potential. It should be noted that global carbon taxes (without additional assumptions) lead to relatively high costs in low-income regions. Cap-and-trade regimes have more flexibility to create a comparable distribution of costs amongst countries.
[en] Highlights: • Environmental NGOs have good contribution in natural resource management. • NGOs role in the land policy cycle is limited by legal and administrative barriers. • There is poor cooperation and networking among NGOs and between NGOs and the state. • NGOs with multiple donors and unrestricted type of fund rely on their own objective. • Most NGOs avoid involvement in policy advocacy in fear of collusions with the state. - Abstract: By law, non-governmental organizations (NGOs) in Ethiopia are severely restricted in their activities towards policy development. In this study we explore to what extent these restrictions have affected NGOs in Natural Resource Management in the Oromia regional state of Ethiopia. We quantitatively analyzed 106 semi-structured questionnaires, in order to assess 1) the general characteristics of these NGO, 2) the role of NGOs in natural resource management, 3) the factors that constrain their activities, especially in relation to the proclamation, and 4) the cooperation between NGOs as well as other stakeholders. Results indicate that NGOs are mainly involved in policy implementation, including afforestation, forest management, and soil and water conservation. We find that a more active role in agenda setting and policy formulation is hampered by the 2009 proclamation, which explicitly restricts the role of Ethiopian Residence Charities/Societies (ERCS) and Foreign Charities (FC). Consistently, NGOs, as well as their donors, often avoid involvement in policy development, in fear of potential collusion with the government. In addition, NGOs listed legal and administrative barriers, poor networking and cooperation among NGOs, lack of capacity, lack of information, and a lack of clear role on policy issues as constraints for influencing policies for natural resource management. The extent to which these factors affect NGOs is dependent on their type and the source of their funding.
[en] The Fourth Assessment Report of IPCC reports that greenhouse gas emissions can be reduced by about 30-50% in 2030 at costs below 100 US$/tCO2 based on an assessment of both bottom-up and top-down studies. Here, we have looked in more detail into the outcomes of specific models and also analyzed the economic potentials at the sectoral and regional level. At the aggregated level, the findings of the IPCC report are confirmed. However, substantial differences are found at the sectoral level. At the same time, there seems to be no systematic difference in the reduction potential reported by top-down and bottom-up approaches. The largest reduction potential as a response to carbon prices exists in the energy supply sector. Reduction potential in the building sector may carry relatively low costs. Although uncertainties are considerable, the modeling results and the bottom-up analyses all suggest that at the global level around 50% of greenhouse gas emissions may be reduced at carbon price (costs) below 100$/tCO2-eq-but with a wide range of 30-60%. At a carbon price (costs) less than 20$/tCO2-eq, still 10-35% of emissions may be abated. The variation of results is higher at low carbon-price levels than at high levels.
[en] 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%.
[en] This study provides a conceptual framework for exploring the bargaining space within international climate negotiations based on important economic, political and environmental considerations. Based on it, we analyse combinations of the proposed emission reduction ranges for Annex I countries as a group (25-40% below 1990 levels) and non-Annex I as a group (15-30% below baseline) by 2020 to limit global warming to 2 deg. C. We use results of the FAIR model with costs estimates based on two energy system models. We conclude that the range of targets that comply with a set of criteria for economic, political and environmental considerations is smaller than that by environmental considerations alone. More specifically, we find that according to our criteria, a 30% Annex I reduction target below 1990 levels, combined with a 20% non-Annex I reduction target below baseline emission levels (i.e. 20 to 30% above 2005 levels), is the only combination of targets fulfilling all our criteria for both energy system models. Otherwise, reaching the 2 deg. C target becomes less likely, technically infeasible, or non-Annex I abatement costs are likely to exceed those of Annex I, a result, which we consider less plausible from a political viewpoint in our conceptual framework. - Highlights: → We study ranges of reduction targets for Annex I and non-Annex I regions by 2020 currently discussed in international negotiations (25-40%; 15-30%). → Trade-offs between the targets occur in terms of environmental, economic and political criteria. → A set of simple criteria results in reductions around 30% and 20% for Annex I and non-Annex I, respectively. → The global abatement costs for such targets are around 0.45-0.65 %-GDP in 2020. → Several factors such as trading, abatement cost estimates, regional allocation and international financing influence the outcomes.