CICERO Research Archive (CICERO Senter for klimaforskning)
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Estimating carbon leakage from aviation by combining sectoral and general equilibrium models
Get PDFThis article describes a procedure for estimating carbon leakage from policies targeting aviation based on alternative scenarios. The key innovation to ensure greater robustness is that all scenarios are simulated by two different types of models: a sectoral model for aviation and a computable general equilibrium model. • The implementation of scenario simulation in both models is explained • The calculation of carbon leakage is explained step by stepEstimating carbon leakage from aviation by combining sectoral and general equilibrium modelspublishedVersio
Climate policy integration as a process: from shallow to embedded integration
Get PDFAcross many policy areas, policymakers try to integrate new policy issues into old policy processes. This is challenging. Getting to net-zero greenhouse gas emissions requires radical change across a broad range of societal sectors; thus, climate policy integration is essential. This article develops a new processual perspective on climate policy integration, allowing assessment, classification, and comparison of various stages of integration across policy processes, and over time. The integration process can be shaped by differing institutional logics. In a study of Norwegian agricultural policy, we identify three logics: multifunctional, market failure, and socio-technological transition. These portray differing frames, objectives, instruments, and sector involvement as appropriate ways of linking climate concerns to agricultural policy. We suggest that a shallow integration process is characterized by a sector-specific logic that facilitates discussions of policy frames and goals. In an embedded integration process, multiple logics are mobilized, and a broader range of policy elements are discussed: frames, goals, instruments, and sector involvement in the process. Consistent and contested integration processes are intermediate categories. Climate integration in Norwegian agricultural policy had the hallmarks of a shallow process in 2006–2009 but changed to a contested process in 2016–2021.publishedVersio
Emission location affects impacts on atmosphere and climate from alternative fuels for Norwegian domestic aviation
Get PDFAviation emissions contribute to climate change and local air pollution, with important contributions from non-CO2 emissions. These exhibit diverse impacts on atmospheric chemistry and radiative forcing (RF), varying with location, altitude, and time. Assessments of local mitigation strategies with global emission metrics may overlook this variability, but detailed studies of aviation emissions in areas smaller than continents are scarce. Integrating the AviTeam emission model and OsloCTM3, we quantify CO2, NOx, BC, OC, and SOx emissions, tropospheric concentration changes, RF, region-specific metrics, and assess alternative fuels for Norwegian domestic aviation. Mitigation potentials for a fuel switch to LH2 differ by up to 3,1X10kgCO2-equivalents (GWP20) when using region-specific compared to global metrics. These differences result from a lower, region-specific contribution of non-CO2 emissions, particularly related to NOx.This study underscores the importance of accounting for non-CO2 variability in regional assessments, whether through region-specific metrics or advanced atmospheric modelling techniques.Emission location affects impacts on atmosphere and climate from alternative fuels for Norwegian domestic aviationpublishedVersio
Increased Asian Sulfate Aerosol Emissions Remarkably Enhance Sahel Summer Precipitation
Get PDFObservational evidence shows that Sahel summer precipitation has experienced a considerable increase since the 1980s, coinciding with significant diverging trends of increased sulfate emissions in Asia and decreased emissions in Europe (dipole pattern of aerosols between Asia and Europe). The decrease in European sulfate aerosols has substantial effects on the Sahel summer precipitation increase, but the corresponding effect of increased Asian sulfate is unknown. Multi-model simulations in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP) show, compared to decreased European aerosols, that increased Asian aerosols similarly enhance the Sahel summer precipitation but with different large-scale atmospheric circulation changes. Further analysis of the Sixth Coupled Model Intercomparison Project (CMIP6) simulations under historical attribution and various emission scenarios reinforces the results about the climate impacts of anthropogenic aerosols and suggests that in future scenarios with strong international cooperation and rapid climate mitigations (SSP2-45), the Sahel drought will be intensified likely due to the decline in Asian aerosol emissions. Our results suggest that Asian anthropogenic aerosols are likely a non-negligible driver of the recent recovery in Sahel precipitation amounts.publishedVersio
Strong contribution from sensible heat to global precipitation increase in climate models is not supported by observational based data
Get PDFIt has previously been shown that trends in sensible heat from climate models have had a substantial contribution to global precipitation changes. We illustrate that this is the case also in the most recent Coupled Model Intercomparison Project Phase 6 (CMIP6). However, we find that over the period since 1980 reanalyses do not support the reduction in sensible heat from the CMIP6 models and rather estimate a global increase in sensible heat which would contribute to a precipitation reduction. Satellite data over a period of two decades over global ocean generally show an opposite sign of the sensible heat trend to the CMIP6 models, similarly to the reanalyses.publishedVersio
AERA-MIP: emission pathways, remaining budgets, and carbon cycle dynamics compatible with 1.5 and 2 °C global warming stabilization
Get PDFWhile international climate policies now focus on limiting global warming to well below 2 °C or pursuing a 1.5 °C level of global warming, the climate modelling community has not provided an experimental design in which all Earth system models (ESMs) converge and stabilize at the same prescribed global warming levels. This gap hampers accurate estimations based on comprehensive ESMs of the carbon emission pathways and budgets needed to meet such agreed warming levels and of the associated climate impacts under temperature stabilization. Here, we apply the Adaptive Emission Reduction Approach (AERA) with ESMs to provide such simulations in which all models converge at 1.5 and 2.0 °C warming levels by adjusting their emissions over time. These emission-driven simulations provide a wide range of emission pathways and resulting atmospheric CO2 projections for a given warming level, uncovering uncertainty ranges that were previously missing in the traditional Coupled Model Intercomparison Project (CMIP) scenarios with prescribed greenhouse gas concentration pathways. Meeting the 1.5 °C warming level requires a 40 % (full model range: 7 % to 76 %) reduction in multi-model mean CO2-forcing-equivalent (CO2-fe) emissions from 2025 to 2030, a 98 % (57 % to 127 %) reduction from 2025 to 2050, and a stabilization at 1.0 (−1.7 to 2.9) PgC yr−1 from 2100 onward after the 1.5 °C global warming level is reached. Meeting the 2.0 °C warming level requires a 47 % (8 % to 92 %) reduction in multi-model mean CO2-fe emissions until 2050 and a stabilization at 1.7 (−1.5 to 2.7) PgC yr−1 from 2100 onward. The on-average positive emissions under stabilized global temperatures are the result of a decreasing transient climate response to cumulative CO2-fe emissions over time under stabilized global warming. This evolution is consistent with a slightly negative zero emissions commitment – initially assumed to be zero – and leads to an increase in the post-2025 CO2-fe emission budget by a factor of 2.2 (−0.8 to 6.9) by 2150 for the 1.5 °C warming level and a factor of 1.4 (0.9 to 2.4) for the 2.0 °C warming level compared to its first estimate in 2025. The median CO2-only carbon budget by 2150, relative to 2020, is 800 GtCO2 for the 1.5 °C warming level and 2250 GtCO2 for the 2.0 °C warming level. These median values exceed the median IPCC AR6 estimates by 60 % for the 1.5 °C warming level and 67 % for 2.0 °C. Some of the differences may be explained by the choice of the mitigation scenario for non-CO2 radiative agents. Our simulations highlight shifts in carbon uptake dynamics under stabilized temperature, such as a cessation of the carbon sinks in the North Atlantic and in tropical forests. On the other hand, the Southern Ocean remains a carbon sink centuries after temperatures stabilize. Overall, this new type of warming-level-based emission-driven simulation offers a more coherent assessment across climate models and opens up a wide range of possibilities for studying both the carbon cycle and climate impacts, such as extreme events, under climate stabilization.publishedVersio
Heat and cause-specific cardiopulmonary mortality in Germany: a case-crossover study using small-area assessment
Get PDFBackground High temperatures have been associated with increased mortality, with evidence reported predominately in large cities and for total cardiovascular or respiratory deaths. This case-crossover study examined heat-related cause-specific cardiopulmonary mortality and vulnerability factors using small-area data from Germany. Methods We analyzed daily counts of cause-specific cardiopulmonary deaths from 380 German districts (2000–2016) and daily mean temperatures estimated by spatial–temporal models. We applied conditional quasi-Poisson regression using distributed lag nonlinear models to examine heat effects during May–September in each district and randomeffects meta-analysis to pool the district-specific estimates. Potential individual- and district-level vulnerability factors were examined by subgroup analyses and meta-regressions, respectively. Findings Heat was associated with increased mortality risks for all cardiopulmonary sub-causes. The relative risk (RR) of total cardiovascular and respiratory mortality for a temperature increment from the 75th to the 99th percentile was 1.24 (95% confidence interval: 1.23, 1.26) and 1.34 (1.30, 1.38), respectively. The RRs of cardiovascular sub-causes ranged from 1.16 (1.13, 1.19) for myocardial infarction to 1.32 (1.29, 1.36) for heart failure. For respiratory subcauses, the RR was 1.27 (1.22, 1.31) for COPD and 1.49 (1.42, 1.57) for pneumonia. We observed greater susceptibility related to several individual- and district-level characteristics, e.g., among females or in highly urbanized districts. Heat vulnerability factors remained consistent between urban and rural areas. Interpretation Our study highlights heat-related increases in cause-specific cardiopulmonary mortality across Germany and identifies key vulnerability factors, offering insights for improving public health practices to mitigate heat-related health impactspublishedVersio
Choice of metrics matters—Future scenarios on milk and beef production in Norway using an LCA approach
Get PDFThe consumption of dairy and beef products is expected to increase globally in the future, and at the same time, food must be produced in a more sustainable way, including reduced greenhouse gas (GHG) emissions, avoided feed-food competition, and reduced biodiversity loss. The purpose of the study was to a) provide an overall life cycle assessment (LCA) of these impacts for various future milk and beef production systems in Norway and b) determine how the choice of metrics for climate change affects the results. System boundaries were from cradle to farm gate and the temporal boundary was 2017 with future scenarios for 2040. The actual production and consumption in Norway in 2017 was used as a baseline (BL), and the sustainability of future Norwegian domestic production of milk and beef was assessed through three scenarios for 2040: 1) a trend yield scenario (TrendY) based on an expected increase in milk yield following the present trend, 2) a high yield scenario (HighY) with higher increase in the milk yield per cow per year than the trend, and 3) a low yield scenario (LowY) where the milk yield per cow per year was adjusted for covering the domestic demand for beef solely from dual-purpose production and no domestic specialized beef production. The beef production per dual-purpose cow was kept constant and the remaining domestic demand in scenario 1 and 2 were covered by specialized beef production. Climate change was assessed using both a GWP100 and a GWP* approach. The HighY scenario had the lowest impact on climate change using GWP100, but when taking the different behaviors of short- and long-term climate pollutants into account (GWP*), the ranking of the future scenarios changed and favored LowY. The potential biodiversity loss was lower for the LowY scenario because the proportion of concentrates in the dairy cow ration was decreased due to lower milk yield. Similarly, the feed-food competition was lower (land use ratio < 1) for the LowY. The results of our study suggest that the choice of metric for GWP and time frame highly affects the results and conclusions and strategies for climate smart and sustainable livestock production should therefore be made with caution.publishedVersio
Combining Fleetwide AviTeam Aviation Emission Modeling with LCA Perspectives for an Alternative Fuel Impact Assessment
Get PDFReducing aviation emissions is important as they contribute to air pollution and climate change. Several alternative aviation fuels that may reduce life cycle emissions have been proposed. Comparative life cycle assessments (LCAs) of fuels are useful for inspecting individual fuels, but systemwide analysis remains difficult. Thus, systematic properties like fleet composition, performance, or emissions and changes to them under alternative fuels can only be partially addressed in LCAs. By integrating the geospatial fuel and emission model, AviTeam, with LCA, we can assess the mitigation potential of a fleetwide use of alternative aviation fuels on 210 000 shorter haul flights. In an optimistic case, liquid hydrogen (LH2) and power-to-liquid fuels, when produced with renewable electricity, may reduce emissions by about 950 GgCO2eq when assessed with the GWP100 metric and including non-CO2 impacts for all flights considered. Mitigation potentials range from 44% on shorter flights to 56% on longer flights. Alternative aviation fuels’ mitigation potential is limited because of short-lived climate forcings and additional fuel demand to accommodate LH2 fuel. Our results highlight the importance of integrating system models into LCAs and are of value to researchers and decision-makers engaged in climate change mitigation in the aviation and transport sectors.publishedVersio
Challenges in assessing and managing multi-hazard risks: A European stakeholders perspective
Get PDFThe latest evidence suggests that multi-hazards and their interrelationships (e.g., triggering, compound, and consecutive hazards) are becoming more frequent across Europe, underlying a need for resilience building by moving from single-hazard-focused to multi-hazard risk assessment and management. Although significant advancements were made in our understanding of these events, mainstream practice is still focused on risks due to single hazards (e.g., flooding, earthquakes, droughts), with a limited understanding of the stakeholder needs on the ground. To overcome this limitation, this paper sets out to understand the challenges for moving towards multi-hazard risk management through the perspective of European stakeholders. Based on five workshops across different European pilots (Danube Region, Veneto Region, Scandinavia, North Sea, and Canary Islands) and an expert workshop, we identify five prime challenges: i) governance, ii) knowledge of multi-hazards and multi-risks, iii) existing approaches to disaster risk management, iv) translation of science to policy and practice, and v) lack of data. These challenges are inherently linked and cannot be tackled in isolation with path dependency posing a significant hurdle in transitioning from single- to multi-hazard risk management. Going forward, we identify promising approaches for overcoming some of the challenges, including emerging approaches for multi-hazard characterisation, a common understanding of terminology, and a comprehensive framework for guiding multi-hazard risk assessment and management. We argue for a need to think beyond natural hazards and include other threats in creating a comprehensive overview of multi-hazard risks, as well as promoting thinking of multi-hazard risk reduction in the context of larger development goals.publishedVersio