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End date: 2024 × DDC: 590 × Subject: climate change mitigation ×

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Now showing 1 - 4 of 4
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    Road to glory or highway to hell? Global road access and climate change mitigation
    (Bristol : IOP Publ., 2020) Wenz, Leonie; Weddige, Ulf; Jakob, Michael; Steckel, Jan Christoph
    Transportation infrastructure is considered a key factor for economic development and poverty alleviation. The United Nations have explicitly included the provision of transport infrastructure access, e.g. through all-season road access, in their Sustainable Development Goal agenda (SDGs, target 9.1). Yet, little is known about the number of people lacking access to roads worldwide, the costs of closing existing access gaps and the implications of additional roads for other sustainability concerns such as climate change mitigation (SDG-13). Here we quantify, for 250 countries and territories, the percentage of population without road access in 2 km. We find that infrastructure investments required to provide quasi-universal road access are about USD 3 trillion. We estimate that the associated cumulative CO2 emissions from construction work and additional traffic until the end of the century amount to roughly 16 Gt. Our geographically explicit global analysis provides a starting point for refined regional studies and for the quantification of further environmental and social implications of SDG-9.1.
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    What is important for achieving 2 °C? UNFCCC and IPCC expert perceptions on obstacles and response options for climate change mitigation
    (Bristol : IOP Publ., 2020) Kornek, Ulrike; Flachsland, Christian; Kardish, Chris; Levi, Sebastian; Edenhofer, Ottmar
    Global mitigation efforts remain insufficient to limit the global temperature increase to well below 2 °C. While a growing academic literature analyzes this problem, perceptions of which obstacles inhibit goal attainment and which responses might be most effective seem to differ widely. This makes prioritization and agreement on the way forward difficult. To inform prioritization in global climate policy and research agendas, we present quantitative data on how 917 experts from the IPCC and the UNFCCC perceive the importance of different obstacles and response options for achieving 2 °C. On average, respondents consider opposition from special interest groups the most important obstacle and technological R&D the most important response. Our survey also finds that the majority of experts perceives a wide range of issues as important, supporting an agenda that is inclusive in terms of coverage. Average importance ratings differ between experts from the Global North and South, suggesting that balanced representation in global fora and regionally differentiated agendas are important. In particular, opposition from special interest groups is a top priority among experts from North America, Europe and Oceania. Investigating the drivers of individual importance ratings, we find little difference between experts from the IPCC and the UNFCCC, while expert's perceptions correlate with their academic training and their national scientific, regulatory, and financial contexts.
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    Peatland protection and restoration are key for climate change mitigation
    (Bristol : IOP Publ., 2020) Humpenöder, Florian; Karstens, Kristine; Lotze-Campen, Hermann; Leifeld, Jens; Menichetti, Lorenzo; Barthelmes, Alexandra; Popp, Alexander
    Peatlands cover only about 3% the global land area, but store about twice as much carbon as global forest biomass. If intact peatlands are drained for agriculture or other human uses, peat oxidation can result in considerable CO2 emissions and other greenhouse gases (GHG) for decades or even centuries. Despite their importance, emissions from degraded peatlands have so far not been included explicitly in mitigation pathways compatible with the Paris Agreement. Such pathways include land-demanding mitigation options like bioenergy or afforestation with substantial consequences for the land system. Therefore, besides GHG emissions owing to the historic conversion of intact peatlands, the increased demand for land in current mitigation pathways could result in drainage of presently intact peatlands, e.g. for bioenergy production. Here, we present the first quantitative model-based projections of future peatland dynamics and associated GHG emissions in the context of a 2 °C mitigation pathway. Our spatially explicit land-use modelling approach with global coverage simultaneously accounts for future food demand, based on population and income projections, and land-based mitigation measures. Without dedicated peatland policy and even in the case of peatland protection, our results indicate that the land system would remain a net source of CO2 throughout the 21st century. This result is in contrast to the outcome of current mitigation pathways, in which the land system turns into a net carbon sink by 2100. However, our results indicate that it is possible to reconcile land use and GHG emissions in mitigation pathways through a peatland protection and restoration policy. According to our results, the land system would turn into a global net carbon sink by 2100, as projected by current mitigation pathways, if about 60% of present-day degraded peatlands would be rewetted in the coming decades, next to the protection of intact peatlands.
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    The role of capital costs in decarbonizing the electricity sector
    (Bristol : IOP Publ., 2016) Hirth, Lion; Steckel, Jan Christoph
    Low-carbon electricity generation, i.e. renewable energy, nuclear power and carbon capture and storage, is more capital intensive than electricity generation through carbon emitting fossil fuel power stations. High capital costs, expressed as high weighted average cost of capital (WACC), thus tend to encourage the use of fossil fuels. To achieve the same degree of decarbonization, countries with high capital costs therefore need to impose a higher price on carbon emissions than countries with low capital costs. This is particularly relevant for developing and emerging economies, where capital costs tend to be higher than in rich countries. In this paper we quantitatively evaluate how high capital costs impact the transformation of the energy system under climate policy, applying a numerical techno-economic model of the power system. We find that high capital costs can significantly reduce the effectiveness of carbon prices: if carbon emissions are priced at USD 50 per ton and the WACC is 3%, the cost-optimal electricity mix comprises 40% renewable energy. At the same carbon price and a WACC of 15%, the cost-optimal mix comprises almost no renewable energy. At 15% WACC, there is no significant emission mitigation with carbon pricing up to USD 50 per ton, but at 3% WACC and the same carbon price, emissions are reduced by almost half. These results have implications for climate policy; carbon pricing might need to be combined with policies to reduce capital costs of low-carbon options in order to decarbonize power systems.