The RCP2.6 emission and concentration pathway is representative of the literature on mitigation scenarios aiming to limit the increase of global mean temperature to 2°C. These scenarios form the low ...end of the scenario literature in terms of emissions and radiative forcing. They often show negative emissions from energy use in the second half of the 21st century. The RCP2.6 scenario is shown to be technically feasible in the IMAGE integrated assessment modeling framework from a medium emission baseline scenario, assuming full participation of all countries. Cumulative emissions of greenhouse gases from 2010 to 2100 need to be reduced by 70% compared to a baseline scenario, requiring substantial changes in energy use and emissions of non-CO
2
gases. These measures (specifically the use of bio-energy and reforestation measures) also have clear consequences for global land use. Based on the RCP2.6 scenario, recommendations for further research on low emission scenarios have been formulated. These include the response of the climate system to a radiative forcing peak, the ability of society to achieve the required emission reduction rates given political and social inertia and the possibilities to further reduce emissions of non-CO
2
gases.
Most global energy models are developed by institutes from developed countries, focusing primarily on issues that are important in industrialized countries. Evaluation of the results for Asia of the ...IPCC/SRES models shows that broad concepts of energy and development, the energy ladder and the environmental Kuznets curve, can be observed in the results of the models. However, improvements can be made in modeling the issues that underlie these concepts, like
traditional fuels,
electrification,
economic structural change,
income distribution, and
informal economies. Given the rapidly growing importance of energy trajectories of developing countries for global sustainability, the challenge for the future is to develop energy models that include all these aspects of energy and development.
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%.
The European Union (EU) has advocated an emission reduction target for developed countries of 80% to 95% below the 1990 level by 2050, and a global reduction target of 50%. Developing countries have ...resisted the inclusion of these targets in both the UN Framework Convention on Climate Change Copenhagen Accord and Cancún Agreements. This paper analyses what these targets would imply for emission targets, abatement costs and energy consumption of developing countries, taking into account the conditional emission reduction pledges for 2020. An 80% reduction target for developed countries would imply more stringent per capita emission targets for developing countries than developed countries by 2050. Moreover, abatement costs of developing countries would be higher than those of developed countries. An 85% to 90% reduction target for developed countries would result in similar per capita emission targets and abatement costs for developed and developing countries by 2050. Total reduction targets for developing countries would range from 30% to 40% below 2005 levels by 2050 and from 30% to 35% above 2005 levels by 2030. The 2030 target for China would be 40% to 45% above 2005 levels, compared to a target for the EU of 45% to 50% below 1990 and for the United States of America (USA) 30% to 35% below 1990. Emission target trajectories for Brazil, South Africa and China would peak before 2025 and for India by around 2025. From the analysis, we may conclude that from the viewpoint of developing countries either developed countries increase their target above 85%, and/or make substantial side-payments.
Hydrogen is named as possible energy carrier for future energy systems. However, the impact of large-scale hydrogen use on the atmosphere is uncertain. Application of hydrogen in clean fuel cells ...reduces emissions of air pollutants, but emissions from hydrogen production and leakages of molecular hydrogen could influence atmospheric chemistry. This paper combines a global energy system model and a global atmospheric model to explore the range of impacts of hydrogen on atmospheric chemistry. We found that emissions of molecular hydrogen may range from 0.2 up to 10% (or 25-167Tg hydrogen/yr) for a global hydrogen energy system. The lower end of this range would in fact be equal to current emissions from fossil fuel combustion. Hydrogen energy use leads to a clear decrease in emissions of carbon monoxide, nitrogen oxides and sulphur dioxide, but large-scale hydrogen production from coal may lead to net increase in emissions of nitrous oxide and volatile organic compound. Compared to a reference scenario, this would lead to positive impacts on surface concentrations of carbon monoxide, nitrogen oxides and ozone. However, if hydrogen leakage would not be minimised it leads to an increase in methane lifetimes and a decrease in stratospheric ozone concentrations.
This paper presents a modeling comparison project on how the 2°C climate target could affect economic and energy systems development in China and India. The analysis uses a framework that harmonizes ...baseline developments and soft-links seven national and global models being either economy wide (CGE models) or energy system models. The analysis is based on a global greenhouse gas emission pathway that aims at a radiative forcing of 2.9 W/m2 in 2100 and with a policy regime based on convergence of per capita CO2 emissions with emissions trading. Economic and energy implications for China and India vary across models. Decreased energy intensity is the most important abatement approach in the CGE models, while decreased carbon intensity is most important in the energy system models. Reliance on Coal without Carbon Capture and Storage (CCS) is significantly reduced in most models, while CCS is a central abatement technology in energy system models, as is renewable and nuclear energy. Concerning economic impacts China bears in general a higher cost than India, as China benefits less from emissions trading. Costs are also affected by changes in fossil fuel prices, currency depreciation from capital inflow from carbon trading and timing of emission reductions
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