CICERO Research Archive (CICERO Senter for klimaforskning)
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1083 research outputs found
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African heritage sites threatened as sea-level rise accelerates
Get PDFThe African coast contains heritage sites of ‘Outstanding Universal Value’ that face increasing risk from anthropogenic climate change. Here, we generated a database of 213 natural and 71 cultural African heritage sites to assess exposure to coastal flooding and erosion under moderate (RCP 4.5) and high (RCP 8.5) greenhouse gas emission scenarios. Currently, 56 sites (20%) are at risk from a 1-in-100-year coastal extreme event, including the iconic ruins of Tipasa (Algeria) and the North Sinai Archaeological Sites Zone (Egypt). By 2050, the number of exposed sites is projected to more than triple, reaching almost 200 sites under high emissions. Emissions mitigation from RCP 8.5 to RCP 4.5 reduces the number of very highly exposed sites by 25%. These findings highlight the urgent need for increased climate change adaptation for heritage sites in Africa, including governance and management approaches, site-specific vulnerability assessments, exposure monitoring, and protection strategies.publishedVersio
Multi-century dynamics of the climate and carbon cycle under both high and net negative emissions scenarios
Get PDFFuture climate projections from Earth system models (ESMs) typically focus on the timescale of this century. We use a set of five ESMs and one Earth system model of intermediate complexity (EMIC) to explore the dynamics of the Earth's climate and carbon cycles under contrasting emissions trajectories beyond this century to the year 2300. The trajectories include a very-high-emissions, unmitigated fossil-fuel-driven scenario, as well as a mitigation scenario that diverges from the first scenario after 2040 and features an “overshoot”, followed by a decrease in atmospheric CO2 concentrations by means of large net negative CO2 emissions. In both scenarios and for all models considered here, the terrestrial system switches from being a net sink to either a neutral state or a net source of carbon, though for different reasons and centered in different geographic regions, depending on both the model and the scenario. The ocean carbon system remains a sink, albeit weakened by carbon cycle feedbacks, in all models under the high-emissions scenario and switches from sink to source in the overshoot scenario. The global mean temperature anomaly is generally proportional to cumulative carbon emissions, with a deviation from proportionality in the overshoot scenario that is governed by the zero emissions commitment. Additionally, 23rd century warming continues after the cessation of carbon emissions in several models in the high-emissions scenario and in one model in the overshoot scenario. While ocean carbon cycle responses qualitatively agree in both globally integrated and zonal mean dynamics in both scenarios, the land models qualitatively disagree in zonal mean dynamics, in the relative roles of vegetation and soil in driving C fluxes, in the response of the sink to CO2, and in the timing of the sink–source transition, particularly in the high-emissions scenario. The lack of agreement among land models on the mechanisms and geographic patterns of carbon cycle feedbacks, alongside the potential for lagged physical climate dynamics to cause warming long after CO2 concentrations have stabilized, points to the possibility of surprises in the climate system beyond the 21st century time horizon, even under relatively mitigated global warming scenarios, which should be taken into consideration when setting global climate policy.publishedVersio
Net Zero: Science, Origins, and Implications
Get PDFThis review explains the science behind the drive for global net zero emissions and why this is needed to halt the ongoing rise in global temperatures. We document how the concept of net zero carbon dioxide (CO2) emissions emerged from an earlier focus on stabilization of atmospheric greenhouse gas concentrations. Using simple conceptual models of the coupled climate–carbon cycle system, we explain why approximately net zero CO2 emissions and declining net energy imbalance due to other climate drivers are required to halt global warming on multidecadal timescales, introducing important concepts, including the rate of adjustment to constant forcing and the rate of adjustment to zero emissions. The concept of net zero was taken up through the 5th Assessment Report of the Intergovernmental Panel on Climate Change and the United Nations Framework Convention on Climate Change (UNFCCC) Structured Expert Dialogue, culminating in Article 4of the 2015 Paris Agreement. Increasing numbers of net zero targets have since been adopted by countries, cities, corporations, and investors. The degree to which any entity can claim to have achieved net zero while continuing to rely on distinct removals to compensate for ongoing emissions is at the heart of current debates over carbon markets and offsetting both inside and outside the UNFCCC. We argue that what matters here is not the precise makeup of a basket of emissions and removals at any given point in time, but the sustainability of a net zero strategy as a whole and its implications for global temperature over multidecadal timescales. Durable, climate-neutral net zero strategies require like-for-like balancing of anthropogenic greenhouse gas sources and sinks in terms of both origin (biogenic versus geological) and gas lifetime.publishedVersio
Land-atmosphere interactions in sub-polar and alpine climates in the CORDEX flagship pilot study Land Use and Climate Across Scales (LUCAS) models-Part 1: Evaluation of the snow-albedo effect
Get PDFSeasonal snow cover plays a major role in the climate system of the Northern Hemisphere via its effect on land surface albedo and fluxes. In climate models the parameterization of interactions between snow and atmosphere remains a source of uncertainty and biases in the representation of local and global climate. Here, we evaluate the ability of an ensemble of regional climate models (RCMs) coupled with different land surface models to simulate snow–atmosphere interactions over Europe in winter and spring. We use a previously defined index, the snow-albedo sensitivity index (SASI), to quantify the radiative forcing associated with snow cover anomalies. By comparing RCM-derived SASI values with SASI calculated from reanalyses and satellite retrievals, we show that an accurate simulation of snow cover is essential for correctly reproducing the observed forcing over middle and high latitudes in Europe. The choice of parameterizations, and primarily the choice of the land surface model, strongly influences the representation of SASI as it affects the ability of climate models to simulate snow cover accurately. The degree of agreement between the datasets differs between the accumulation and ablation periods, with the latter one presenting the greatest challenge for the RCMs. Given the dominant role of land surface processes in the simulation of snow cover during the ablation period, the results suggest that, during this time period, the choice of the land surface model is more critical for the representation of SASI than the atmospheric model.publishedVersio
The Climatic Impact-Driver Framework for Assessment of Risk-Relevant Climate Information
Get PDFThe climate science and applications communities need a broad and demand-driven concept to assess physical climate conditions that are relevant for impacts on human and natural systems. Here, we augment the description of the “climatic impact-driver” (CID) approach adopted in the Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report. CIDs are broadly defined as “physical climate system conditions (e.g., means, events, and extremes) that affect an element of society or ecosystems. Depending on system tolerance, CIDs and their changes can be detrimental, beneficial, neutral, or a mixture of each across interacting system elements and regions.” We give background information on the IPCC Report process that led to the development of the 7 CID types (heat and cold, wet and dry, wind, snow and ice, coastal, open ocean, and other) and 33 distinct CID categories, each of which may be evaluated using a variety of CID indices. This inventory of CIDs was co-developed with WGII to provide a useful collaboration point between physical climate scientists and impacts/risk experts to assess the specific climatic phenomena driving sectoral responses and identify relevant CID indices within each sector. The CID Framework ensures that a comprehensive set of climatic conditions informs adaptation planning and risk management and may also help prioritize improvements in modeling sectoral dynamics that depend on climatic conditions. CIDs contribute to climate services by increasing coherence and neutrality when identifying and communicating relevant findings from physical climate research to risk assessment and planning activities.publishedVersio
Separating the shortwave and longwave components of greenhouse gas radiative forcing
Get PDFMany important greenhouse gases (including water vapour, carbon dioxide, methane and ozone) absorb solar radiation. When gas concentrations change, this absorption exerts a radiative forcing that modifies the thermal infrared (‘longwave’) radiative forcing which is predominant for most gases (ozone being a major exception). The nature of the solar forcing differs from the longwave forcing in several ways. For example, the sign of the instantaneous solar forcing can differ between the tropopause and top-of-atmosphere, and the sign can differ between gases. In addition, a significant part of the solar forcing can be manifested in the longwave, following stratospheric temperature adjustment, which can counteract or enhance the instantaneous solar forcing. Here the nature of solar forcing is examined via a mixture of idealised and more realistic calculations, which consider the effect of perturbations in carbon dioxide, methane and ozone. An apparent contradiction in the sign of the solar forcing of carbon dioxide is resolved; it is shown to be negative, reducing the net carbon dioxide forcing by about 2.3%. The relevance of this work to the effective radiative forcing concept is also discussed.publishedVersio
Balancing cost and justice concerns in the energy transition: comparing coal phase-out policies in Germany and the UK
Get PDFEurope’s two largest economies – Germany and the UK – are phasing out coal from electricity production as part of European efforts to fulfil increased climate policy ambitions that require comprehensive energy system transitions. German and UK governments varied in the ways they sought support from diverse societal interests to make the transition socially acceptable and politically feasible. Drawing on 22 expert interviews and process-tracing methods, this paper compares and explains how political and economic institutional differences influenced efforts to balance energy transition concerns, like speed and cost-effectiveness with justice for companies, workers and communities most adversely affected by the transition. We find that the increasing attention to just transition perspectives after the Paris Agreement affected the design of coal phase-out processes in different ways in the two countries. Just transition concerns were given priority by policymakers in Germany, but more so if they overlapped with the interests of incumbents. In the end, politically powerful stakeholders dominated the policy outcome. In the UK, policymakers and stakeholders gave only weak attention to just transition concerns, mainly because coal’s market position had collapsed. Coal interests did not have strong representation in the decision-making process. But we find that just transition concerns are likely to gain more attention in the UK because a more challenging transition away from gas will take place over the next two decades.Balancing cost and justice concerns in the energy transition: comparing coal phase-out policies in Germany and the UKpublishedVersio
Klimakur vs. klimaku: En retorisk dokumentanalyse av kostholdstiltaket i Klimakur 2030
Get PDFJanuar 2020 la Miljødirektoratet frem rapporten Klimakur 2030 med 60 tiltak som samlet skal kunne kutte Norges klimagassutslipp i tråd med forpliktelsene over Parisavtalen og EUs klimaregelverk. Det «billigste» og mest effektive tiltaket i rapporten går ut på at Norges befolkning skal redusere inntaket av rødt kjøtt til fordel for planter og fisk i tråd med anbefalingene fra Helsedirektoratet. Dette kostholdstiltaket møtte stor motstand i den offentlige debatten og i høringsprosessen som fulgte. Jordbruksorganisasjonene hevdet at tiltaket er i konflikt med de vedtatte målene for norsk landbrukspolitikk og at det vil ha fatale konsekvenser for jordbruket i Norge. Med kostholdstiltaket som utgangspunkt er problemstillingen for denne oppgaven: I hvilken grad mangler en felles, konstruktiv doxa i arbeidet med klima- og jordbrukspolitikken? For å nærme meg dette forsøker analysen å svare på to forskningsspørsmål: 1) På hvilke måter utøver dokumenter og høringsuttalelser makt, og hva har det å si for en felles, konstruktiv doxa? Og 2) I hvilken grad legger strukturen i nettverket av tekster til rette for etablering av doxa?
Oppgaven er en retorisk dokumentanalyse i to deler. Del 1 tar for seg hvordan kostholdstiltaket endres og utvikles gjennom Intensjonsavtalen mellom jordbruket og regjeringen (2019), kunnskapsrapporten Klimakur 2030 (2020) og regjeringens klimamelding, Klimaplan 2021-2030 (2021). Del to undersøker høringsuttalelsene (2020) fra Norges Bondelag og Norsk Bonde- og Småbrukarlag til kostholdstiltaket i Klimakur 2030, samt Miljødirektoratets oppsummering av disse. Dokumentanalysen er en nærlesning av de seks tekstene i lys av den politiske konteksten, retorisk sjangeranalyse, modalitet, aktører, tekstmaktdimensjoner, deliberasjon, doxa og klarspråk.
Utviklingen av kostholdstiltaket viser hvordan staten og jordbruket inngår i en vedvarende forhandling om definisjonsmakt og posisjonering. Men den viser også hvordan ulike doxa manifesterer seg i tekstene fra klimabyråkratiet og jordbrukssektoren. I diskusjonen har jeg tre oppfordringer: embetsverket må legge til rette for bedre strukturell klarspåklighet, det bør være enkelt å forstå hva slags sosial handling et offentlig dokument er, og at vi trenger å forstå høringsprosessen som demokratisk verktøy bedre. Alt i alt viser analysen at klimaendringene først og fremst er vår tids største kommunikative utfordring og at det krever at vi har gode systemer for demokratisk deliberasjon.publishedVersio
Understanding low-carbon food consumption transformation through social practice theory: The case of community supported agriculture in Norway
Get PDFDrawing on a qualitative case study of consumers involved in community-supported agriculture farms in Norway, this article applies social practice theory to understand pro-environmental behaviour transformation in relation to community-supported agriculture. Situating social practice theory in the larger framework of the political economy of low-carbon transformation provides a holistic and grounded perspective on consumer behaviour change and potential for social transformation. In contrast to conventional individualistic and rationalist approaches, our study suggests that there is no linear path of transformation; rather, people join community-supported agriculture to use their consumer power to push for social transformation. Simultaneously, community-supported agriculture influences a reorientation of values and practices because it opens up opportunities and resources for sustainable lifestyles. We argue that the collaborative aspects of community-supported agriculture can challenge unsustainable consumption by emphasising sharing over private ownership and frugality over accumulation of growth. However, the consumer practices of the wider political economy produced by the ‘culture of capitalism’ continue to be ingrained in people’s social relations and contexts, and thus weaken new and more sustainable forms of food consumption.Understanding low-carbon food consumption transformation through social practice theory: The case of community supported agriculture in NorwaypublishedVersio
Predictive Skill of Teleconnection Patterns in Twentieth Century Seasonal Hindcasts and Their Relationship to Extreme Winter Temperatures in Europe
Get PDFEuropean winter weather is dominated by several low-frequency teleconnection patterns, the main ones being the North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian patterns. We analyze the century-long ERA-20C reanalysis and ASF-20C seasonal hindcast data sets and find that these patterns are subject to decadal variability and fluctuations in predictive skill. Using indices for determining periods of extreme cold or warm temperatures, we establish that the teleconnection patterns are, for some regions, significantly correlated or anti-correlated to cold or heat waves. The seasonal hindcasts are however only partly able to capture these relationships. There do not seem to be significant changes to the observed links between large-scale circulation patterns and extreme temperatures between periods of higher and lower predictive skill.publishedVersio