CICERO Research Archive (CICERO Senter for klimaforskning)
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Smoothing a reference pathway based on discrete exogenous projections
Get PDFIn integrated assessment studies and scenario analysis, typically we need to calibrate a model to follow an exogenous pathway, e.g., the shared socioeconomic pathways. In these exogenous pathways, the data of key variables such as GDP and energy consumption are typically provided every five or ten years. In some cases, we need a yearly smooth pathway that is consistent with such an exogenous pathway with data of only every five years. Hence, this piece of study provides a method to obtain a smooth yearly pathway based on exogenous data of limited years.publishedVersio
Carbon dioxide removal policy in the making: Assessing developments in 9 OECD cases
No full textSince the adoption of the Paris Agreement in 2015, spurred by the 2018 IPCC Special Report on Global Warming of 1.5°C, net zero emission targets have emerged as a new organizing principle of climate policy. In this context, climate policymakers and stakeholders have been shifting their attention to carbon dioxide removal (CDR) as an inevitable component of net zero targets. The importance of CDR would increase further if countries and other entities set net-negative emissions targets. The scientific literature on CDR governance and policy is still rather scarce, with empirical case studies and comparisons largely missing. Based on an analytical framework that draws on the multi-level perspective of sociotechnical transitions as well as existing work on CDR governance, we gathered and assessed empirical material until early 2021 from 9 Organization for Economic Co-operation and Development (OECD) cases: the European Union and three of its Member States (Ireland, Germany, and Sweden), Norway, the United Kingdom, Australia, New Zealand, and the United States. Based on a synthesis of differences and commonalities, we propose a tripartite conceptual typology of the varieties of CDR policymaking: (1) incremental modification of existing national policy mixes, (2) early integration of CDR policy that treats emission reductions and removals as fungible, and (3) proactive CDR policy entrepreneurship with support for niche development. Although these types do not necessarily cover all dimensions relevant for CDR policy and are based on a limited set of cases, the conceptual typology might spur future comparative work as well as more fine-grained case-studies on established and emerging CDR policies.publishedVersio
Smart hedging against carbon leakage
Get PDFPolicy makers in the EU and elsewhere are concerned that unilateral pricing of the carbon externality induces carbon leakage through relocation of emission-intensive and trade-exposed production to other regions. A common measure to mitigate such leakage is to combine an emission trading system with output-based allocation (OBA) of allowances where the latter works as an implicit production subsidy to regulated industries. We show analytically that it is optimal to impose in addition a consumption tax on the OBA goods (i.e., goods that are entitled to OBA) at a rate which is equivalent in value to the OBA subsidy rate. The explanation is that the consumption tax alleviates excessive consumption of the OBA goods, which is a distortionary effect of introducing OBA. Using a multi-region multi-sector computable general equilibrium model calibrated to empirical data, we quantify the welfare gains for the EU of imposing such a consumption tax on top of its existing emission trading system with OBA. We run Monte Carlo simulations to account for uncertain leakage exposure of goods entitled to OBA. The consumption tax increases welfare whether the goods are highly exposed to leakage or not, and hence can be regarded as smart hedging against carbon leakage.acceptedVersio
MSc: Changes in radiative forcing due to clear-cutting in Sweden; PhD: The role of land-atmosphere interactions on temperature variability and extremes in Fennoscandia
No full textpublishedVersio
The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, part I: evaluation of precipitation
Get PDFHere we present the first multi-model ensemble of regional climate simulations at kilometer-scale horizontal grid spacing over a decade long period. A total of 23 simulations run with a horizontal grid spacing of ∼3 km, driven by ERA-Interim reanalysis, and performed by 22 European research groups are analysed. Six different regional climate models (RCMs) are represented in the ensemble. The simulations are compared against available high-resolution precipitation observations and coarse resolution (∼ 12 km) RCMs with parameterized convection. The model simulations and observations are compared with respect to mean precipitation, precipitation intensity and frequency, and heavy precipitation on daily and hourly timescales in different seasons. The results show that kilometer-scale models produce a more realistic representation of precipitation than the coarse resolution RCMs. The most significant improvements are found for heavy precipitation and precipitation frequency on both daily and hourly time scales in the summer season. In general, kilometer-scale models tend to produce more intense precipitation and reduced wet-hour frequency compared to coarse resolution models. On average, the multi-model mean shows a reduction of bias from ∼ −40% at 12 km to ∼ −3% at 3 km for heavy hourly precipitation in summer. Furthermore, the uncertainty ranges i.e. the variability between the models for wet hour frequency is reduced by half with the use of kilometer-scale models. Although differences between the model simulations at the kilometer-scale and observations still exist, it is evident that these simulations are superior to the coarse-resolution RCM simulations in the representing precipitation in the present-day climate, and thus offer a promising way forward for investigations of climate and climate change at local to regional scales.publishedVersio
A multi-model analysis of long-term emissions and warming implications of current mitigation efforts
Get PDFMost of the integrated assessment modelling literature focuses on cost-effective pathways towards given temperature goals. Conversely, using seven diverse integrated assessment models, we project global energy CO2 emissions trajectories on the basis of near-term mitigation efforts and two assumptions on how these efforts continue post-2030. Despite finding a wide range of emissions by 2050, nearly all the scenarios have median warming of less than 3 °C in 2100. However, the most optimistic scenario is still insufficient to limit global warming to 2 °C. We furthermore highlight key modelling choices inherent to projecting where emissions are headed. First, emissions are more sensitive to the choice of integrated assessment model than to the assumed mitigation effort, highlighting the importance of heterogeneous model intercomparisons. Differences across models reflect diversity in baseline assumptions and impacts of near-term mitigation efforts. Second, the common practice of using economy-wide carbon prices to represent policy exaggerates carbon capture and storage use compared with explicitly modelling policies.submittedVersio
Competing effects of aerosol reductions and circulation changes for future improvements in Beijing haze
No full textDespite local emission reductions, severe haze events remain a serious issue in Beijing. Previous studies have suggested that both greenhouse gas increases and aerosol decreases are likely to increase the frequency of weather patterns conducive to haze events. However, the combined effect of atmospheric circulation changes and aerosol and precursor emission changes on Beijing haze remains unclear. We use the Shared Socioeconomic Pathways (SSPs) to explore the effects of aerosol and greenhouse gas emission changes on both haze weather and Beijing haze itself. We confirm that the occurrence of haze weather patterns is likely to increase in future under all SSPs and show that even though aerosol reductions play a small role, greenhouse gas increases are the main driver, especially during the second half of the 21st century. However, the severity of the haze events decreases on decadal timescales by as much as 70 % by 2100. The main influence on the haze itself is the reductions in local aerosol emissions, which outweigh the effects of changes in atmospheric circulation patterns. This demonstrates that aerosol reductions are beneficial, despite their influence on the circulation.publishedVersio
Threshold Effect of Economic Growth on Energy Intensity — Evidence from 21 Developed Countries
Get PDFBased on threshold regression models, this paper analyzes the effect of economic growth on energy intensity by using panel data from 21 developed countries from 1996 to 2015. Results show that a 1% increase in GDP per capita can lead to a 0.62–0.78% reduction in energy intensity, implying economic growth can significantly reduce energy intensity. The extent of the reduction in energy intensity varies depending on the economic development stages represented by key influencing factors including energy mix in consumption, urbanization, industrial structure, and technological progress. Specifically, the reduction in energy intensity due to economic growth can be enhanced with relatively more renewable energy consumption and more urban population until a threshold point, where the enhancement disappears. On the other hand, the extent of the energy intensity reduction due to economic growth can be weakened with relatively more tertiary industry activities and more research and development (R&D) investment in an economy until a threshold point, where the weakening cannot continue. However, compared to the early stages represented by the low ends of renewable energy consumption, urban population, tertiary industry activities, and R&D investment, the later stages represented by the high ends of these key factors after a threshold show the weakened effect of economic growth on the decline of energy intensity. Hence, when an economy is well-developed, policy makers are advised to put fewer expectations on the role of economic growth to reduce energy intensity, while pursuing relatively cleaner energy, greater urbanization, more tertiary industry activities, and advanced technologiespublishedVersio
Evaluation of the Large EURO-CORDEX Regional Climate Model Ensemble
Get PDFThe use of regional climate model (RCM)-based projections for providing regional climate information in a research and climate service contexts is currently expanding very fast. This has been possible thanks to a considerable effort in developing comprehensive ensembles of RCM projections, especially for Europe, in the EURO-CORDEX community (Jacob et al., 2014, 2020). As of end of 2019, EURO-CORDEX has developed a set of 55 historical and scenario projections (RCP8.5) using 8 driving global climate models (GCMs) and 11 RCMs. This article presents the ensemble including its design. We target the analysis to better characterize the quality of the RCMs by providing an evaluation of these RCM simulations over a number of classical climate variables and extreme and impact-oriented indices for the period 1981–2010. For the main variables, the model simulations generally agree with observations and reanalyses. However, several systematic biases are found as well, with shared responsibilities among RCMs and GCMs: Simulations are overall too cold, too wet, and too windy compared to available observations or reanalyses. Some simulations show strong systematic biases on temperature, others on precipitation or dynamical variables, but none of the models/simulations can be defined as the best or the worst on all criteria. The article aims at supporting a proper use of these simulations within a climate services context.publishedVersio
The United States: conditions for accelerating decarbonisation in a politically divided country
Get PDFPresident Biden faces tremendous challenges to overcome political polarisation as he re-commits the United States to the Paris Agreement on Climate Change and promises decarbonisation of the US economy over the next three decades. To achieve deep decarbonisation, recent scholarship identifies the crucial role of broad policy mixes that create reinforcing effects between climate and energy policies to trigger technological innovation, restrict polluting activities, promote green growth, and ensure just energy transitions. Drawing on this literature, the article explores the conditions for developing such policy mixes in the US context in three policy phases. How and why have key policy conditions developed differently in the climate- and energy policy fields, and to what effect for decarbonisation policies? The analysis shows that growing political polarisation blocked bipartisan agreement, produced negative policy feedback, and caused instability in the climate policy field, whereas these mechanisms did not dominate the energy policy field. A more bipartisan approach to renewable energy policy allowed long-term experience and positive feedback in energy-policy programmes that helped to trigger technology innovation and subsequent GHG emissions cuts. Different policy conditions within these policy fields discouraged a coupling between them that could have facilitated green-growth policies. The economic shock caused by the coronavirus pandemic may potentially change policy conditions and build a path to deep US decarbonisation in the future, but only if political polarisation on climate change can be overcome.publishedVersio