CICERO Research Archive (CICERO Senter for klimaforskning)
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Consumption-based emission inventories in Nordic municipalities—a quest to develop support for local climate action
Get PDFMunicipalities can play a large role in achieving global climate targets. Integrating a consumption-based perspective is key to being able to mitigate global emissions. We conducted a survey among municipality officials in four Nordic countries (Denmark, Finland, Norway, and Sweden) and held several workshops to deepen our understanding of municipalities' work to address consumption-based emissions. Findings show that less than half of the municipalities in the studied countries worked actively on measuring consumption-based emissions but that there is a broad interest in further developing GHG inventories that incorporate emissions from municipalities' own consumption as well as from citizens' consumption. Both expectations and challenges related to consumption-based inventories are remarkably similar across the four countries. A majority of the survey respondents perceived that the municipality could influence consumption-based emission from the municipality as a society by cooperating with residents and businesses. Similarly, information on consumption-based emissions was broadly identified as a key need to identify just and sustainable measures toward climate neutrality. The information generated was recognized by municipal employees to be useful for making better climate plans, optimizing their own operations' emission reductions, and helping residents and companies to reduce their emissions. We argue that it is essential that municipalities can base their actions on coherent and reliable information on consumption-based emissions that is comparable across municipalities and that can be connected to national tracking of emissions. This requires standardized methods and base-line data as not all municipalities can mobilize the needed human and financial resources to make their own inventories.publishedVersio
Representing storylines with causal networks to support decision making: Framework and example
Get PDFPhysical climate storylines, which are physically self-consistent unfoldings of events or pathways, have been powerful tools in understanding regional climate impacts. We show how embedding physical climate storylines into a causal network framework allows user value judgments to be incorporated into the storyline in the form of probabilistic Bayesian priors, and can support decision making through inspection of the causal network outputs. We exemplify this through a specific storyline, namely a storyline on the impacts of tropical cyclones on the European Union Solidarity Fund. We outline how the constructed causal network can incorporate value judgments, particularly the prospects on climate change and its impact on cyclone intensity increase, and on economic growth. We also explore how the causal network responds to policy options chosen by the user. The resulting output from the network leads to individualized policy recommendations, allowing the causal network to be used as a possible interface for policy exploration in stakeholder engagements.publishedVersio
A multi-model assessment of the Global Warming Potential of hydrogen
Get PDFWith increasing global interest in molecular hydrogen to replace fossil fuels, more attention is being paid to potential leakages of hydrogen into the atmosphere and its environmental consequences. Hydrogen is not directly a greenhouse gas, but its chemical reactions change the abundances of the greenhouse gases methane, ozone, and stratospheric water vapor, as well as aerosols. Here, we use a model ensemble of five global atmospheric chemistry models to estimate the 100-year time-horizon Global Warming Potential (GWP100) of hydrogen. We estimate a hydrogen GWP100 of 11.6 ± 2.8 (one standard deviation). The uncertainty range covers soil uptake, photochemical production of hydrogen, the lifetimes of hydrogen and methane, and the hydroxyl radical feedback on methane and hydrogen. The hydrogen-induced changes are robust across the different models. It will be important to keep hydrogen leakages at a minimum to accomplish the benefits of switching to a hydrogen economy.publishedVersio
Virkemidler for klimatiltak i jordbruket i andre land
Get PDFPå oppdrag fra Miljødirektoratet analyseres nasjonale virkemidler som støtter klimatiltak i jordbruket og matsystemet i seks land som er sammenlignbare med Norge: Danmark; Sverige; Finland; Nederland; Østerrike; Sveits. Seks ulike tiltak med tilhørende nasjonale virkemidler blir vurdert: Redusert forbruk av rødt kjøtt, Redusert matsvinn, Gjødseltiltak, Stans i nydyrking av myr og restaurering av dyrket organisk jord, Biokull og karbonlagring i jord. Virkemidlene inkluderer økonomiske, skattemessige, juridiske og regulatoriske, og informative, samt frivillige avtaler, forskning og private initiativer i ulik grad for de ulike tiltak. Virkemiddelbruk er kontekstavhengig, som bør inkluderes i vurderinger av overførbarhet.publishedVersio
Trends in atmospheric methane concentrations since 1990 were driven and modified by anthropogenic emissions
Get PDFThe atmospheric methane trend is not fully understood. Here we investigate the role of the main sink, the main natural source, and anthropogenic emissions on the methane growth rate over the last three decades using numerical models and emission inventories. We find that the long-term trend is driven by increased anthropogenic methane emissions, while wetland emissions show large variability and can modify the trend. The anthropogenic influence on hydroxyl radical, through nitrogen oxides and carbon monoxide emissions, has modified the trend over the last decades and contributed to the atmospheric methane stabilization from 2000 to 2007. The hydroxyl radical increase prior to this stabilization period might have contributed to the decline in the isotopic ratio after 2007 due to the time dependent isotopic response of hydroxyl radical. Emission reductions due to COVID-19 restrictions via the influence on hydroxyl radical, possibly contributed to approximately two thirds of the increase in methane growth from 2019 to 2020.publishedVersio
Climate effects of Black Carbon emissions: Updated GWP and GTP values after the IPCC AR6
Get PDFBlack Carbon (BC) is a type of atmospheric aerosol, emitted by many anthropogenic activities through incomplete combustion of, primarily, fossil fuels. Unlike other aerosols, BC absorbs sunlight, and can therefore heat the climate similarly to a greenhouse gas. However, the strength of BC as a driver of global warming, or other aspects of climate change, is still hotly debated.
Here, we have calculated updated values for common metrics of the climate impact of BC emissions, relative to the values presented in the IPCC 5th Assessment Report (AR5). These values were not updated for the 6th Assessment Report (AR6). We give revised values for its Global Warming Potential (GWP) and Global Temperature Potential (GTP), at three different time horizons (20, 50 and 100 years).
Recent scientific advances somewhat reduce the values of common metrics of the climate impact of BC emissions, relative to the values presented in AR5. As an example, we find a GWP100 for BC of 342, compared to the AR5 value of 658. For GTP100, we find a value of 63, compared to the AR5 values of 91
While the values presented here are numerically lower than previous estimates, we emphasise that BC remains a potent climate warming agent, in particular when the emissions occur at high latitudes.publishedVersio
Intermediating climate change: conclusions and new research directions
Get PDFThe urgency and threats of climate change have elevated the issue to a prominent – albeit often contested – position within the policy process. Resultantly, climate politics and climate change governance have received enhanced attention in both the academic literature and in real-life discourse. Yet, except regarding certain empirical contexts, there has been a lack of conceptualization or analysis of intermediating actors in climate politics – what we term “climate intermediaries” – that bridge between different types of actors and different levels of governance. This Special Issue sought to reduce this research gap by analyzing the strategies, interactions, and impacts in the policy process of these “go-betweens”, across three continents. In this concluding article, we take stock of the insights provided by the individual contributions and offer answers to the three research questions that guided the Special Issue. In addition, we provide some suggestions for future research avenues and concluding reflections.publishedVersio
Environmental and nutritional assessment of young children’s diets in Norway: comparing the current diet with national dietary guidelines and the EAT-Lancet reference diet
Get PDFIntroducing healthy and sustainable diets early in life can promote lifelong healthy dietary patterns with a low environmental impact. Therefore, we aimed to estimate the environmental and nutritional consequences of a dietary change for 2-year-old children in Norway towards healthier dietary patterns.publishedVersionpublishedVersio
Observations suggest that North African dust absorbs less solar radiation than models estimate
Get PDFDesert dust accounts for a large fraction of shortwave radiation absorbed by aerosols, which adds to the climate warming produced by greenhouse gases. However, it remains uncertain exactly how much shortwave radiation dust absorbs. Here, we leverage in-situ measurements of dust single-scattering albedo to constrain absorption at mid-visible wavelength by North African dust, which accounts for approximately half of the global dust. We find that climate and chemical transport models overestimate North African dust absorption aerosol optical depth (AAOD) by up to a factor of two. This occurs primarily because models overestimate the dust imaginary refractive index, the effect of which is partially masked by an underestimation of large dust particles. Similar factors might contribute to an overestimation of AAOD retrieved by the Aerosol Robotic Network, which is commonly used to evaluate climate and chemical transport models. The overestimation of dust absorption by models could lead to substantial biases in simulated dust impacts on the Earth system, including warm biases in dust radiative effects.publishedVersio
Air pollution and child health impacts of decarbonization in 16 global cities: Modelling study
Get PDFMost research on the air pollution-related health effects of decarbonization has focused on adults. We assess the potential health benefits that could be achieved in children and young people in a global sample of 16 cities through global decarbonization actions. We modelled annual average concentrations of fine particulate matter (PM2.5) and nitrogen dioxide (NO2) at 1x1 km resolution in the cities using a general circulation/atmospheric chemistry model assuming removal of all global combustion-related emissions from land transport, industries, domestic energy use and power generation. We modelled the impact on childhood asthma incidence and adverse birth outcomes (low birthweight, pre-term births) using published exposure–response relationships. Removal of combustion emissions was estimated to decrease annual average PM2.5 by between 2.9 μg/m3 (8.4%) in Freetown and 45.4 μg/m3 (63.7%) in Dhaka. For NO2, the range was from 0.3 ppb (7.9%) in Freetown to 18.8 ppb (92.3%) in Mexico City. Estimated reductions in asthma incidence ranged from close to zero in Freetown, Tamale and Harare to 149 cases per 100,000 population in Los Angeles. For pre-term birth, modelled impacts ranged from a reduction of 135 per 100,000 births in Dar es Salaam to 2,818 per 100,000 births in Bhubaneswar and, for low birthweight, from 75 per 100,000 births in Dar es Salaam to 2,951 per 100,000 births in Dhaka. The large variations chiefly reflect differences in the magnitudes of air pollution reductions and estimated underlying disease rates. Across the 16 cities, the reduction in childhood asthma incidence represents more than one-fifth of the current burden, and an almost 10% reduction in pre-term and low birthweight births. Decarbonization actions that remove combustion-related emissions contributing to ambient PM2.5 and NO2 would likely lead to substantial but geographically-varied reductions in childhood asthma and adverse birth outcomes, though there are uncertainties in causality and the precision of estimates.publishedVersio