Suchergebnisse

100-year Global Warming Potentials (GWPs) are used almost universally to compare emissions of greenhouse gases in national inventories and reduction targets. GWPs have been criticised on several grounds, but little work has been done to determine global mitigation costs under alternative physics-based metrics . We used the integrated assessment model MESSAGE to compare emission pathways and abatement costs for fixed and time-dependent variants of the Global Temperature Change Potential (GTP) with those based on GWPs, for a policy goal of limiting the radiative forcing to a specified level in the year 2100. We find that fixed 100-year GTPs would increase global abatement costs (discounted and aggregated over the 21st century) under this policy goal by 5 20 % relative to 100-year GWPs, whereas time-varying GTPs would reduce costs by about 5 %. These cost differences are smaller than differences arising from alternative assumptions regarding agricultural mitigation potential and much smaller than those arising from alternative radiative forcing targets. Using the land-use model GLOBIOM, we show that alternative metrics affect food production differently in different world regions depending on regional characteristics of future land-use change to meet growing food demand. We conclude that under scenarios of complete participation, the choice of metric has a limited impact on global abatement costs but could be important for the political economy of regional and sectoral participation in collective mitigation efforts, in particular changing costs and gains over time for agriculture and energy-intensive sectors.

As climate change progresses, the risk of adverse impacts on vulnerable populations is growing. As governments seek increased and drastic action, policymakers are likely to seek quantification of climate-change impacts and the consequences of mitigation policies on these populations. Current models used in climate research have a limited ability to represent the poor and vulnerable, or the different dimensions along which they face these risks. Best practices need to be adopted more widely, and new model features that incorporate social heterogeneity and different policy mechanisms need to be developed. Increased collaboration between modellers, economists, and other social scientists could aid these developments. We review the history and state of the art of models used in climate research, including integrated assessment models (IAMs) and national studies, and those that model mitigation and climate-change impacts. We assess how and to what extent they represent distributional impacts within countries. We argue that there is much scope to improve the representation of income distribution and poverty. Given the diversity of models, this endeavour presents fundamental challenges for some models, but possibly requires only incremental changes in others.

As climate change progresses, the risk of adverse impacts on vulnerable populations is growing. As governments seek increased and drastic action, policymakers are likely to seek quantification of climate-change impacts and the consequences of mitigation policies on these populations. Current models used in climate research have a limited ability to represent the poor and vulnerable, or the different dimensions along which they face these risks. Best practices need to be adopted more widely, and new model features that incorporate social heterogeneity and different policy mechanisms need to be developed. Increased collaboration between modellers, economists, and other social scientists could aid these developments. We review the history and state of the art of models used in climate research, including integrated assessment models (IAMs) and national studies, and those that model mitigation and climate-change impacts. We assess how and to what extent they represent distributional impacts within countries. We argue that there is much scope to improve the representation of income distribution and poverty. Given the diversity of models, this endeavour presents fundamental challenges for some models, but possibly requires only incremental changes in others.

In implementing the European Green Deal to align with the Paris Agreement, the EU has raised its climate ambition and in 2022 is negotiating the distribution of increased mitigation effort among Member States. Such partitioning of targets among subsidiary entities is becoming a major challenge for implementation of climate policies around the globe. We contrast the 2021 European Commission proposal - an allocation based on a singular country attribute - with transparent and reproducible methods based on three ethical principles. We go beyond traditional effort-sharing literature and explore allocations representing an aggregated least regret compromise between different EU country perspectives on a fair allocation. While the 2021 proposal represents a nuanced compromise for many countries, for others a further redistribution could be considered equitable. Whereas we apply our approach within the setting of the EU negotiations, the framework can easily be adapted to inform debates worldwide on sharing mitigation effort among subsidiary entities.

In implementing the European Green Deal to align with the Paris Agreement, the EU has raised its climate ambition and in 2022 is negotiating the distribution of increased mitigation effort among Member States. Such partitioning of targets among subsidiary entities is becoming a major challenge for implementation of climate policies around the globe. We contrast the 2021 European Commission proposal - an allocation based on a singular country attribute - with transparent and reproducible methods based on three ethical principles. We go beyond traditional effort-sharing literature and explore allocations representing an aggregated least regret compromise between different EU country perspectives on a fair allocation. While the 2021 proposal represents a nuanced compromise for many countries, for others a further redistribution could be considered equitable. Whereas we apply our approach within the setting of the EU negotiations, the framework can easily be adapted to inform debates worldwide on sharing mitigation effort among subsidiary entities.

One hundred and ninety-three governments adopted the Paris Agreement on Climate Change in 2015. The agreement foresees, for the near term, a new bottom-up process where countries pledge so-called nationally determined contributions (NDCs) for reducing their greenhouse gas (GHG) emissions by 2025–2030. At the same time, the Paris Agreement defines the longterm objective to hold temperature change to well below 2 °C and to pursue efforts to limit it further to 1.5 °C. The consistency between the NDCs and the long-term temperature goals is planned to be regularly assessed in global stocktaking exercises as part of the international negotiations. At the same time, countries have also committed themselves to implement a set of Sustainable Development Goals (SDGs) in order to eradicate poverty, protect the global environment and spur inclusive economic development. Within this context, the CD-LINKS project (www.cd-links.org) brought together an international team of researchers with global, national and sectoral expertise to explore possible linkages between national and global pathways consistent with the overall objective of the Paris Agreement and sustainable development. Part of this work is summarised in this special issue in Climatic Change, which contains eleven papers, including this introductory one, presenting the insights from the collaboration between national and global modelling teams and yielding a more coherent and detailed picture of the future than is typical of climate change mitigation pathways studies focusing on the global level only.

One hundred and ninety-three governments adopted the Paris Agreement on Climate Change in 2015. The agreement foresees, for the near term, a new bottom-up process where countries pledge so-called nationally determined contributions (NDCs) for reducing their greenhouse gas (GHG) emissions by 2025–2030. At the same time, the Paris Agreement defines the longterm objective to hold temperature change to well below 2 °C and to pursue efforts to limit it further to 1.5 °C. The consistency between the NDCs and the long-term temperature goals is planned to be regularly assessed in global stocktaking exercises as part of the international negotiations. At the same time, countries have also committed themselves to implement a set of Sustainable Development Goals (SDGs) in order to eradicate poverty, protect the global environment and spur inclusive economic development. Within this context, the CD-LINKS project (www.cd-links.org) brought together an international team of researchers with global, national and sectoral expertise to explore possible linkages between national and global pathways consistent with the overall objective of the Paris Agreement and sustainable development. Part of this work is summarised in this special issue in Climatic Change, which contains eleven papers, including this introductory one, presenting the insights from the collaboration between national and global modelling teams and yielding a more coherent and detailed picture of the future than is typical of climate change mitigation pathways studies focusing on the global level only.

After having agreed in the European Council of December 2019 on transforming the European Union to climate neutrality by 2050, the next step requires adjusting the 2030 targets on climate and energy accordingly. This Research Brief focuses on the effort sharing (ES) sector, which covers all greenhouse gas (GHG) emissions that are neither included in the EU Emissions Trading Scheme (EU ETS) nor covered under "land use and land use change"1. Starting from the Effort Sharing Decision of 2018, this Brief frames the issue in the broader context of global emission budgets that are compatible with the Paris Agreement climate targets and considers criteria for allocating the respective EU budget among the EU-27. The Research Brief (full version) is available upon request: wegcenter@uni-graz.at

After having agreed in the European Council of December 2019 on transforming the European Union to climate neutrality by 2050, the next step requires adjusting the 2030 targets on climate and energy accordingly. This Research Brief focuses on the effort sharing (ES) sector, which covers all greenhouse gas (GHG) emissions that are neither included in the EU Emissions Trading Scheme (EU ETS) nor covered under "land use and land use change"1. Starting from the Effort Sharing Decision of 2018, this Brief frames the issue in the broader context of global emission budgets that are compatible with the Paris Agreement climate targets and considers criteria for allocating the respective EU budget among the EU-27. The Research Brief (full version) is available upon request: wegcenter@uni-graz.at

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr−1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time.

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr−1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time.

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: Limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr-1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time.

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr−1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time.

Household air pollution from traditional cook stoves presents a greater health hazard than any other environmental factor. Despite government efforts to support clean-burning cooking fuels, over 700 million people in South Asia could still rely on traditional stoves in 2030. This number could rise if climate change mitigation efforts increase energy costs. Here we quantify the costs of support policies to make clean cooking affordable to all South Asians under four increasingly stringent climate policy scenarios. Our most sringent mitigation scenario increases clean fuel costs 38% in 2030 relative to the baseline, keeping 21% more South Asians on traditional stoves or increasing the minimum support policy cost to achieve universal clean cooking by up to 44%. The extent of this increase depends on how poliymakers allocate subsidies between clean fuels and stoves. These additional costs are within the range of financial transfers to South Asia estimated in efforts-sharing scenarios of international climate agreements. Three billion people globally burn solid fuels such as firewood, charcoal, coal, dung, and crop resides in open fires and traditional stoves for cooking and heating. Household air pollution from the incomplete combustion of these fuels globally leads to 4.3 million premature deaths each year, with 1.7 million of those in South Asia. This exceeds the burden of disease from any other energy-related or environmental risk factor. Solid-fuel use also perpetuates income and gender inequality by forcing users, mostly poor women and children, to spend long hours collecting fuels and to suffer from its adverse health effects. To address this problem, the United Nations Secretary-General's Sustainable Energy for All (SE4All) initiative and the new Sustainable Development Goals aim to achieve universal access to modern energy services by 2030. Numerous intervention efforts have focused on distributing more efficient and cleaner burning biomass stoves, but several of these programmes have had little or no demonstrable impact on health outcomes. In India, the nation with the largest population of solid-fuel users globally, government interventions have sought to make petroleum-based fuels, such as kerosene and liquefied petroleum gas (LPG), more affordable through subsidy at an estimated cost of over US$6 billion per year. Although LPG use has grown rapidly, particularly in rural areas, over 72% of Indians continued to rely primarily on solid fuels in 2012. In the future, expanding clean cooking may become more challenging if climate policies increase the cost of fuels. Previous research has found that greenhouse gas (GHG) emissions reductions in Asia and Africa would increase the cost of kerosene and LPG. However, these studies do not explore compensatory policies that could counteract these effects, and assess only a limited set of climate mitigation scenarios. Only two studies explore normative scenarios that achieve access and climate goals simultanously, both of which do not explore the cost-effectiveness or distributional impacts on population subgroups of these policies. Meanwhile, studies that have evaluated the cost-effectiveness of energy access policies have not considered the impact of climate policy. Te latest assessment of the Intergovernmental Panel on Climate Change (IPCC) concludes that we have only low confidence in our understanding of the possible impacts of climate policy on access to modern energy services, and medium confidence in the policies needed to counteract them. In this study, we contribute new insights to the interaction of climate policy and clean cooking acces policies by quantifying the feasibility and costs of achieving universal access by 2030 for a range of climate policy stringencies, and under a wide range of fuel and stove price support policies. Our analysis suggests that the potential trade-offs between the two goals might be arger than suggested by previous studies. However, we find that efficient policy design could partially compensate for the additional access policy costs associated with climate mitigation. Furthermore, these costs fall below the level of potential financial transfers to South Asia that may result from international climate agreements.

Household air pollution from traditional cook stoves presents a greater health hazard than any other environmental factor. Despite government efforts to support clean-burning cooking fuels, over 700 million people in South Asia could still rely on traditional stoves in 2030. This number could rise if climate change mitigation efforts increase energy costs. Here we quantify the costs of support policies to make clean cooking affordable to all South Asians under four increasingly stringent climate policy scenarios. Our most sringent mitigation scenario increases clean fuel costs 38% in 2030 relative to the baseline, keeping 21% more South Asians on traditional stoves or increasing the minimum support policy cost to achieve universal clean cooking by up to 44%. The extent of this increase depends on how poliymakers allocate subsidies between clean fuels and stoves. These additional costs are within the range of financial transfers to South Asia estimated in efforts-sharing scenarios of international climate agreements. Three billion people globally burn solid fuels such as firewood, charcoal, coal, dung, and crop resides in open fires and traditional stoves for cooking and heating. Household air pollution from the incomplete combustion of these fuels globally leads to 4.3 million premature deaths each year, with 1.7 million of those in South Asia. This exceeds the burden of disease from any other energy-related or environmental risk factor. Solid-fuel use also perpetuates income and gender inequality by forcing users, mostly poor women and children, to spend long hours collecting fuels and to suffer from its adverse health effects. To address this problem, the United Nations Secretary-General's Sustainable Energy for All (SE4All) initiative and the new Sustainable Development Goals aim to achieve universal access to modern energy services by 2030. Numerous intervention efforts have focused on distributing more efficient and cleaner burning biomass stoves, but several of these programmes have had little or no demonstrable impact on health outcomes. In India, the nation with the largest population of solid-fuel users globally, government interventions have sought to make petroleum-based fuels, such as kerosene and liquefied petroleum gas (LPG), more affordable through subsidy at an estimated cost of over US$6 billion per year. Although LPG use has grown rapidly, particularly in rural areas, over 72% of Indians continued to rely primarily on solid fuels in 2012. In the future, expanding clean cooking may become more challenging if climate policies increase the cost of fuels. Previous research has found that greenhouse gas (GHG) emissions reductions in Asia and Africa would increase the cost of kerosene and LPG. However, these studies do not explore compensatory policies that could counteract these effects, and assess only a limited set of climate mitigation scenarios. Only two studies explore normative scenarios that achieve access and climate goals simultanously, both of which do not explore the cost-effectiveness or distributional impacts on population subgroups of these policies. Meanwhile, studies that have evaluated the cost-effectiveness of energy access policies have not considered the impact of climate policy. Te latest assessment of the Intergovernmental Panel on Climate Change (IPCC) concludes that we have only low confidence in our understanding of the possible impacts of climate policy on access to modern energy services, and medium confidence in the policies needed to counteract them. In this study, we contribute new insights to the interaction of climate policy and clean cooking acces policies by quantifying the feasibility and costs of achieving universal access by 2030 for a range of climate policy stringencies, and under a wide range of fuel and stove price support policies. Our analysis suggests that the potential trade-offs between the two goals might be arger than suggested by previous studies. However, we find that efficient policy design could partially compensate for the additional access policy costs associated with climate mitigation. Furthermore, these costs fall below the level of potential financial transfers to South Asia that may result from international climate agreements.