M. Hofmann, Claudia D. Volosciuk, M. Dubrovský, D. Maraun, H. Schultz
Abstract. Extended periods without precipitation, observed for example in central Europe including Germany during the seasons from 2018 to 2020, can lead to water deficit and yield and quality losses for grape and wine production. Irrigation infrastructure in these regions to possibly overcome negative effects is largely non-existent. Regional climate models project changes in precipitation amounts and patterns, indicating an increase in frequency of the occurrence of comparable situations in the future. In order to assess possible impacts of climate change on the water budget of grapevines, a water balance model was developed, which accounts for the large heterogeneity of vineyards with respect to their soil water storage capacity, evapotranspiration as a function of slope and aspect, and viticultural management practices. The model was fed with data from soil maps (soil type and plant-available water capacity), a digital elevation model, the European Union (EU) vineyard-register, observed weather data, and future weather data simulated by regional climate models and downscaled by a stochastic weather generator. This allowed conducting a risk assessment of the drought stress occurrence for the wine-producing regions Rheingau and Hessische Bergstraße in Germany on the scale of individual vineyard plots. The simulations showed that the risk for drought stress varies substantially between vineyard sites but might increase for steep-slope regions in the future. Possible adaptation measures depend highly on local conditions and are needed to make targeted use of water resources, while an intense interplay of different wine-industry stakeholders, research, knowledge transfer, and local authorities will be required.
{"title":"Downscaling of climate change scenarios for a high-resolution, site-specific assessment of drought stress risk for two viticultural regions with heterogeneous landscapes","authors":"M. Hofmann, Claudia D. Volosciuk, M. Dubrovský, D. Maraun, H. Schultz","doi":"10.5194/esd-13-911-2022","DOIUrl":"https://doi.org/10.5194/esd-13-911-2022","url":null,"abstract":"Abstract. Extended periods without precipitation, observed for example in central Europe including Germany during the seasons from 2018 to 2020, can lead to water deficit and yield and quality losses for grape and wine production. Irrigation infrastructure in these regions to possibly overcome negative effects is largely non-existent. Regional climate models project changes in precipitation amounts and patterns, indicating an increase in frequency of the occurrence of comparable situations in the future. In order to assess possible impacts of climate change on the water budget of grapevines, a water balance model was developed, which accounts for the large heterogeneity of vineyards with respect to their soil water storage capacity, evapotranspiration as a function of slope and aspect, and\u0000viticultural management practices. The model was fed with data from soil\u0000maps (soil type and plant-available water capacity), a digital elevation\u0000model, the European Union (EU) vineyard-register, observed weather data, and\u0000future weather data simulated by regional climate models and downscaled by a\u0000stochastic weather generator. This allowed conducting a risk assessment of\u0000the drought stress occurrence for the wine-producing regions Rheingau and\u0000Hessische Bergstraße in Germany on the scale of individual vineyard\u0000plots. The simulations showed that the risk for drought stress varies\u0000substantially between vineyard sites but might increase for steep-slope\u0000regions in the future. Possible adaptation measures depend highly on local\u0000conditions and are needed to make targeted use of water resources, while\u0000an intense interplay of different wine-industry stakeholders, research,\u0000knowledge transfer, and local authorities will be required.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41722394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Koven, V. Arora, P. Cadule, R. Fisher, C. Jones, D. Lawrence, J. Lewis, K. Lindsay, S. Mathesius, M. Meinshausen, M. Mills, Zebedee R. J. Nicholls, B. Sanderson, R. Séférian, N. Swart, W. Wieder, K. Zickfeld
Abstract. Future 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.
{"title":"Multi-century dynamics of the climate and carbon cycle under both high and net negative emissions scenarios","authors":"C. Koven, V. Arora, P. Cadule, R. Fisher, C. Jones, D. Lawrence, J. Lewis, K. Lindsay, S. Mathesius, M. Meinshausen, M. Mills, Zebedee R. J. Nicholls, B. Sanderson, R. Séférian, N. Swart, W. Wieder, K. Zickfeld","doi":"10.5194/esd-13-885-2022","DOIUrl":"https://doi.org/10.5194/esd-13-885-2022","url":null,"abstract":"Abstract. Future climate projections from Earth system models\u0000(ESMs) typically focus on the timescale of this century. We use a set of\u0000five ESMs and one Earth system model of intermediate complexity (EMIC) to\u0000explore the dynamics of the Earth's climate and carbon cycles under\u0000contrasting emissions trajectories beyond this century to the year 2300.\u0000The trajectories include a very-high-emissions, unmitigated fossil-fuel-driven scenario, as well as a mitigation scenario that diverges from the\u0000first scenario after 2040 and features an “overshoot”, followed by a\u0000decrease in atmospheric CO2 concentrations by means of large\u0000net negative CO2 emissions. In both scenarios and for all models\u0000considered here, the terrestrial system switches from being a net sink to\u0000either a neutral state or a net source of carbon, though for different\u0000reasons and centered in different geographic regions, depending on both the\u0000model and the scenario. The ocean carbon system remains a sink, albeit\u0000weakened by carbon cycle feedbacks, in all models under the high-emissions\u0000scenario and switches from sink to source in the overshoot scenario. The\u0000global mean temperature anomaly is generally proportional to cumulative\u0000carbon emissions, with a deviation from proportionality in the overshoot\u0000scenario that is governed by the zero emissions commitment. Additionally,\u000023rd century warming continues after the cessation of carbon emissions in\u0000several models in the high-emissions scenario and in one model in the\u0000overshoot scenario. While ocean carbon cycle responses qualitatively agree\u0000in both globally integrated and zonal mean dynamics in both scenarios, the\u0000land models qualitatively disagree in zonal mean dynamics, in the relative\u0000roles of vegetation and soil in driving C fluxes, in the response of the\u0000sink to CO2, and in the timing of the sink–source transition,\u0000particularly in the high-emissions scenario. The lack of agreement among\u0000land models on the mechanisms and geographic patterns of carbon cycle\u0000feedbacks, alongside the potential for lagged physical climate dynamics to\u0000cause warming long after CO2 concentrations have stabilized, points to\u0000the possibility of surprises in the climate system beyond the 21st century\u0000time horizon, even under relatively mitigated global warming scenarios,\u0000which should be taken into consideration when setting global climate policy.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46101989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Reconstruction and explanation of past climate evolution using proxy records is the essence of paleoclimatology. In this study, we use dimensional analysis of a dynamical model on orbital timescales to recognize theoretical limits of such forensic inquiries. Specifically, we demonstrate that major past events could have been produced by physically unsimilar processes making the task of paleo-record attribution to a particular phenomenon fundamentally difficult if not impossible. It also means that any future scenario may not have a unique cause and, in this sense, the orbital timescale future may be to some extent less sensitive to specific terrestrial circumstances.
{"title":"Inarticulate past: similarity properties of the ice–climate system and their implications for paleo-record attribution","authors":"M. Verbitsky","doi":"10.5194/esd-13-879-2022","DOIUrl":"https://doi.org/10.5194/esd-13-879-2022","url":null,"abstract":"Abstract. Reconstruction and explanation of past climate evolution using\u0000proxy records is the essence of paleoclimatology. In this study, we use\u0000dimensional analysis of a dynamical model on orbital timescales to\u0000recognize theoretical limits of such forensic inquiries. Specifically, we\u0000demonstrate that major past events could have been produced by physically\u0000unsimilar processes making the task of paleo-record attribution to a\u0000particular phenomenon fundamentally difficult if not impossible. It\u0000also means that any future scenario may not have a unique cause and, in this\u0000sense, the orbital timescale future may be to some extent less sensitive to\u0000specific terrestrial circumstances.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42253358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Melnikova, O. Boucher, P. Cadule, Katsumasa Tanaka, T. Gasser, T. Hajima, Y. Quilcaille, H. Shiogama, R. Séférian, K. Tachiiri, N. Vuichard, T. Yokohata, P. Ciais
Abstract. Stringent mitigation pathways frame the deployment of second-generation bioenergy crops combined with carbon capture and storage (CCS) to generate negative CO2 emissions. This bioenergy with CCS (BECCS) technology facilitates the achievement of the long-term temperature goal of the Paris Agreement. Here, we use five state-of-the-art Earth system models (ESMs) to explore the consequences of large-scale BECCS deployment on the climate–carbon cycle feedbacks under the CMIP6 SSP5-3.4-OS overshoot scenario keeping in mind that all these models use generic crop vegetation to simulate BECCS. First, we evaluate the land cover representation by ESMs and highlight the inconsistencies that emerge during translation of the data from integrated assessment models (IAMs) that are used to develop the scenario. Second, we evaluate the land-use change (LUC) emissions of ESMs against bookkeeping models. Finally, we show that an extensive cropland expansion for BECCS causes ecosystem carbon loss that drives the acceleration of carbon turnover and affects the CO2 fertilization effect- and climate-change-driven land carbon uptake. Over the 2000–2100 period, the LUC for BECCS leads to an offset of the CO2 fertilization effect-driven carbon uptake by 12.2 % and amplifies the climate-change-driven carbon loss by 14.6 %. A human choice on land area allocation for energy crops should take into account not only the potential amount of the bioenergy yield but also the LUC emissions, and the associated loss of future potential change in the carbon uptake. The dependency of the land carbon uptake on LUC is strong in the SSP5-3.4-OS scenario, but it also affects other Shared Socioeconomic Pathway (SSP) scenarios and should be taken into account by the IAM teams. Future studies should further investigate the trade-offs between the carbon gains from the bioenergy yield and losses from the reduced CO2 fertilization effect-driven carbon uptake where BECCS is applied.
{"title":"Impact of bioenergy crop expansion on climate–carbon cycle feedbacks in overshoot scenarios","authors":"I. Melnikova, O. Boucher, P. Cadule, Katsumasa Tanaka, T. Gasser, T. Hajima, Y. Quilcaille, H. Shiogama, R. Séférian, K. Tachiiri, N. Vuichard, T. Yokohata, P. Ciais","doi":"10.5194/esd-13-779-2022","DOIUrl":"https://doi.org/10.5194/esd-13-779-2022","url":null,"abstract":"Abstract. Stringent mitigation pathways frame the deployment of second-generation bioenergy crops combined with carbon capture and storage (CCS) to generate negative CO2 emissions. This bioenergy with CCS (BECCS) technology facilitates the achievement of the long-term temperature goal of the Paris Agreement. Here, we use five state-of-the-art Earth system models (ESMs) to explore the consequences of large-scale BECCS deployment on the climate–carbon cycle feedbacks under the CMIP6 SSP5-3.4-OS overshoot scenario keeping in mind that all these models use generic crop vegetation\u0000to simulate BECCS. First, we evaluate the land cover representation by ESMs\u0000and highlight the inconsistencies that emerge during translation of the data from integrated assessment models (IAMs) that are used to develop the\u0000scenario. Second, we evaluate the land-use change (LUC) emissions of ESMs\u0000against bookkeeping models. Finally, we show that an extensive cropland\u0000expansion for BECCS causes ecosystem carbon loss that drives the acceleration of carbon turnover and affects the CO2 fertilization\u0000effect- and climate-change-driven land carbon uptake. Over the 2000–2100\u0000period, the LUC for BECCS leads to an offset of the CO2 fertilization effect-driven carbon uptake by 12.2 % and amplifies the climate-change-driven carbon loss by 14.6 %. A human choice on land area\u0000allocation for energy crops should take into account not only the potential\u0000amount of the bioenergy yield but also the LUC emissions, and the associated loss of future potential change in the carbon uptake. The dependency of the land carbon uptake on LUC is strong in the SSP5-3.4-OS scenario, but it also affects other Shared Socioeconomic Pathway (SSP) scenarios and should be taken into account by the IAM teams. Future studies should further investigate the trade-offs between the carbon gains from the bioenergy yield and losses from the reduced CO2 fertilization effect-driven carbon uptake where BECCS is applied.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41375756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Fluctuations in atmospheric CO2 can be measured with great precision and are used to identify human-driven sources as well as natural cycles of ocean and land carbon. One source of variability is the stratosphere, where the influx of aged CO2-depleted air can produce fluctuations at the surface. This process has been speculated to be a potential source of interannual variability (IAV) in CO2 that might obscure the quantification of other sources of IAV. Given the recent success in demonstrating that the stratospheric influx of N2O- and chlorofluorocarbon-depleted air is a dominant source of their surface IAV in the Southern Hemisphere, I apply the same model and measurement analysis here to CO2. Using chemistry-transport modeling or scaling of the observed N2O variability, I find that the stratosphere-driven surface variability in CO2 is at most 10 % of the observed IAV and is not an important source. Diagnosing the amplitude of the CO2 annual cycle and its increase from 1985 to 2021 through the annual variance gives rates similar to traditional methods in the Northern Hemisphere (BRW, MLO) but can identify the emergence of small trends (0.08 ppm per decade) in the Southern Hemisphere (SMO, CGO).
{"title":"CO<sub>2</sub> surface variability: from the stratosphere or not?","authors":"M. Prather","doi":"10.5194/esd-13-703-2022","DOIUrl":"https://doi.org/10.5194/esd-13-703-2022","url":null,"abstract":"Abstract. Fluctuations in atmospheric CO2 can be measured with\u0000great precision and are used to identify human-driven sources as well as\u0000natural cycles of ocean and land carbon. One source of variability is the\u0000stratosphere, where the influx of aged CO2-depleted air can produce fluctuations at the surface. This process has been speculated to be a potential source of interannual variability (IAV) in CO2 that might obscure the quantification of other sources of IAV. Given the recent success in demonstrating that the stratospheric influx of N2O- and chlorofluorocarbon-depleted air is a dominant source of their surface IAV in the Southern Hemisphere, I apply the same model and measurement analysis here to CO2. Using chemistry-transport modeling or scaling of the observed N2O variability, I find that the stratosphere-driven surface variability in CO2 is at most 10 % of the observed IAV and is not an important source. Diagnosing the amplitude of the CO2 annual cycle and its increase from 1985 to 2021 through the annual variance gives rates similar to traditional methods in the Northern Hemisphere (BRW, MLO) but can identify the emergence of small trends (0.08 ppm per decade) in the Southern Hemisphere (SMO, CGO).\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45257147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. In the autumn, the French Mediterranean area is frequently exposed to heavy precipitation events whose daily accumulation can exceed 300 mm. One of the key processes contributing to these precipitation amounts is deep convection, which can be explicitly resolved by state-of-the-art convection-permitting models to reproduce heavy rainfall events that are comparable to observations. This approach has been tested and performed at climate scale in several studies in recent decades for different areas. In this research, we investigate the added value of using an ensemble of three climate simulations at convection-permitting resolution (approx. 3 km) to replicate extreme precipitation events at both daily and shorter timescales over the south of France. These three convection-permitting simulations are performed with the Weather Research and Forecasting (WRF) Model. They are forced by three EURO-CORDEX simulations, which are also run with WRF at the resolution of 0.11∘ (approx. 12 km). We found that a convection-permitting approach provides a more realistic representation of extreme daily and 3-hourly rainfall in comparison with EURO-CORDEX simulations. Their similarity to observations allows use for climate change studies and its impacts.
{"title":"Evaluation of convection-permitting extreme precipitation simulations for the south of France","authors":"Linh N. Luu, R. Vautard, P. Yiou, J. Soubeyroux","doi":"10.5194/esd-13-687-2022","DOIUrl":"https://doi.org/10.5194/esd-13-687-2022","url":null,"abstract":"Abstract. In the autumn, the French Mediterranean area is\u0000frequently exposed to heavy precipitation events whose daily accumulation\u0000can exceed 300 mm. One of the key processes contributing to these\u0000precipitation amounts is deep convection, which can be explicitly resolved\u0000by state-of-the-art convection-permitting models to reproduce\u0000heavy rainfall events that are comparable to observations. This approach has\u0000been tested and performed at climate scale in several studies in recent\u0000decades for different areas. In this research, we investigate the added\u0000value of using an ensemble of three climate simulations at\u0000convection-permitting resolution (approx. 3 km) to replicate extreme\u0000precipitation events at both daily and shorter timescales over the south of\u0000France. These three convection-permitting simulations are performed with the\u0000Weather Research and Forecasting (WRF) Model. They are forced by three\u0000EURO-CORDEX simulations, which are also run with WRF at the resolution of\u00000.11∘ (approx. 12 km). We found that a convection-permitting approach\u0000provides a more realistic representation of extreme daily and 3-hourly\u0000rainfall in comparison with EURO-CORDEX simulations. Their similarity to\u0000observations allows use for climate change studies and its impacts.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41747624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Kuliński, G. Rehder, E. Asmala, A. Bartošová, J. Carstensen, B. Gustafsson, P. Hall, C. Humborg, T. Jilbert, K. Jürgens, H. Meier, Bärbel Müller-Karulis, M. Naumann, J. Olesen, O. Savchuk, A. Schramm, C. Slomp, M. Sofiev, A. Sobek, B. Szymczycha, Emma Undeman
Abstract. Location, specific topography, and hydrographic setting together with climate change and strong anthropogenic pressure are the main factors shaping the biogeochemical functioning and thus also the ecological status of the Baltic Sea. The recent decades have brought significant changes in the Baltic Sea. First, the rising nutrient loads from land in the second half of the 20th century led to eutrophication and spreading of hypoxic and anoxic areas, for which permanent stratification of the water column and limited ventilation of deep-water layers made favourable conditions. Since the 1980s the nutrient loads to the Baltic Sea have been continuously decreasing. This, however, has so far not resulted in significant improvements in oxygen availability in the deep regions, which has revealed a slow response time of the system to the reduction of the land-derived nutrient loads. Responsible for that is the low burial efficiency of phosphorus at anoxic conditions and its remobilization from sediments when conditions change from oxic to anoxic. This results in a stoichiometric excess of phosphorus available for organic-matter production, which promotes the growth of N2-fixing cyanobacteria and in turn supports eutrophication. This assessment reviews the available and published knowledge on the biogeochemical functioning of the Baltic Sea. In its content, the paper covers the aspects related to changes in carbon, nitrogen, and phosphorus (C, N, and P) external loads, their transformations in the coastal zone, changes in organic-matter production (eutrophication) and remineralization (oxygen availability), and the role of sediments in burial and turnover of C, N, and P. In addition to that, this paper focuses also on changes in the marine CO2 system, the structure and functioning of the microbial community, and the role of contaminants for biogeochemical processes. This comprehensive assessment allowed also for identifying knowledge gaps and future research needs in the field of marine biogeochemistry in the Baltic Sea.
{"title":"Biogeochemical functioning of the Baltic Sea","authors":"K. Kuliński, G. Rehder, E. Asmala, A. Bartošová, J. Carstensen, B. Gustafsson, P. Hall, C. Humborg, T. Jilbert, K. Jürgens, H. Meier, Bärbel Müller-Karulis, M. Naumann, J. Olesen, O. Savchuk, A. Schramm, C. Slomp, M. Sofiev, A. Sobek, B. Szymczycha, Emma Undeman","doi":"10.5194/esd-13-633-2022","DOIUrl":"https://doi.org/10.5194/esd-13-633-2022","url":null,"abstract":"Abstract. Location, specific topography, and hydrographic setting together with climate change and strong anthropogenic pressure are the main factors shaping the biogeochemical functioning and thus also the ecological status of the Baltic Sea. The recent decades have brought significant changes in the Baltic Sea. First, the rising nutrient loads from land in the second half of the 20th century led to eutrophication and spreading of hypoxic and anoxic areas, for which permanent stratification of the water column and limited ventilation of deep-water layers made favourable conditions. Since the 1980s the nutrient loads to the Baltic Sea have been continuously decreasing. This, however, has so far not resulted in significant improvements in oxygen availability in the deep regions, which has revealed a slow response time of the system to the reduction of the land-derived nutrient loads. Responsible for that is the low burial efficiency of phosphorus at anoxic conditions and its remobilization from sediments when conditions change from oxic to anoxic. This results in a stoichiometric excess of phosphorus available for organic-matter production, which promotes the growth of N2-fixing cyanobacteria and in turn supports eutrophication. This assessment reviews the available and published knowledge on the\u0000biogeochemical functioning of the Baltic Sea. In its content, the paper\u0000covers the aspects related to changes in carbon, nitrogen, and phosphorus (C, N, and P) external loads, their transformations in the coastal zone, changes in organic-matter production (eutrophication) and remineralization (oxygen availability), and the role of sediments in burial and turnover of C, N, and P. In addition to that, this paper focuses also on changes in the marine CO2 system, the structure and functioning of the microbial community, and the role of contaminants for biogeochemical processes. This comprehensive assessment allowed also for identifying knowledge gaps and future research needs in the field of marine biogeochemistry in the Baltic Sea.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49129432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Gröger, C. Dieterich, C. Dutheil, H. Meier, D. Sein
Abstract. Atmospheric rivers (ARs) are important drivers of hazardous precipitation levels and are often associated with intense floods. So far, the response of ARs to climate change in Europe has been investigated using global climate models within the CMIP5 framework. However, the spatial resolution of those models (1–3∘) is too coarse for an adequate assessment of local to regional precipitation patterns. Using a regional climate model with 0.22∘ resolution, we downscaled an ensemble consisting of 1 ERA-Interim (ERAI) reanalysis data hindcast simulation, 9 global historical, and 24 climate scenario simulations following greenhouse gas emission scenarios RCP2.6, RCP4.5, and RCP8.5. The performance of the climate model to simulate AR frequencies and AR-induced precipitation was tested against ERAI. Overall, we find a good agreement between the downscaled CMIP5 historical simulations and ERAI. However, the downscaled simulations better represented small-scale spatial characteristics. This was most evident over the terrain of the Iberian Peninsula, where the AR-induced precipitation pattern clearly reflected prominent east–west topographical elements, resulting in zonal bands of high and low AR impact. Over central Europe, the models simulated a smaller propagation distance of ARs toward eastern Europe than obtained using the ERAI data. Our models showed that ARs in a future warmer climate will be more frequent and more intense, especially in the higher-emission scenarios (RCP4.5, RCP8.5). However, assuming low emissions (RCP2.6), the related changes can be mostly mitigated. According to the high-emission scenario RCP8.5, AR-induced precipitation will increase by 20 %–40 % in western central Europe, whereas mean precipitation rates increase by a maximum of only 12 %. Over the Iberian Peninsula, AR-induced precipitation will slightly decrease (∼6 %) but the decrease in the mean rate will be larger (∼15 %). These changes will lead to an overall increased fractional contribution of ARs to heavy precipitation, with the greatest impact over the Iberian Peninsula (15 %–30 %) and western France (∼15 %). Likewise, the fractional share of yearly maximum precipitation attributable to ARs will increase over the Iberian Peninsula, the UK, and western France. Over Norway, average AR precipitation rates will decline by −5 % to −30 %, most likely due to dynamic changes, with ARs originating from latitudes > 60∘ N decreasing by up to 20 % and those originating south of 45∘ N increasing. This suggests that ARs over Norway will follow longer routes over the continent, such that additional moisture uptake will be impeded. By contrast, ARs from >60∘ N will take up moisture from the North Atlantic before making landfall over Norway. The found changes in the local AR pathway are probably driven by larger-scale circulation changes such as a change in dominating weather regimes and/or changes in the winter storm track over the North Atlantic.
{"title":"Atmospheric rivers in CMIP5 climate ensembles downscaled with a high-resolution regional climate model","authors":"M. Gröger, C. Dieterich, C. Dutheil, H. Meier, D. Sein","doi":"10.5194/esd-13-613-2022","DOIUrl":"https://doi.org/10.5194/esd-13-613-2022","url":null,"abstract":"Abstract. Atmospheric rivers (ARs) are important drivers of hazardous precipitation\u0000levels and are often associated with intense floods. So far, the response of ARs to climate change in Europe has been investigated using global climate models within the CMIP5 framework. However, the spatial resolution of those models (1–3∘) is too coarse for an adequate assessment of local to regional precipitation patterns. Using a regional climate model with 0.22∘ resolution, we downscaled an ensemble consisting of 1 ERA-Interim (ERAI) reanalysis data hindcast simulation, 9 global historical, and 24 climate scenario\u0000simulations following greenhouse gas emission scenarios RCP2.6, RCP4.5, and\u0000RCP8.5. The performance of the climate model to simulate AR frequencies and AR-induced precipitation was tested against ERAI. Overall, we find a good agreement between the downscaled CMIP5 historical simulations and ERAI. However, the downscaled simulations better represented small-scale spatial characteristics. This was most evident over the terrain of the Iberian Peninsula, where the AR-induced precipitation pattern clearly reflected prominent east–west topographical elements, resulting in zonal bands of high and low AR impact. Over central Europe, the models simulated a smaller propagation distance of ARs toward eastern Europe than obtained using the ERAI data. Our models showed that ARs in a future warmer climate will be more frequent\u0000and more intense, especially in the higher-emission scenarios (RCP4.5, RCP8.5). However, assuming low emissions (RCP2.6), the related changes can\u0000be mostly mitigated. According to the high-emission scenario RCP8.5,\u0000AR-induced precipitation will increase by 20 %–40 % in western central\u0000Europe, whereas mean precipitation rates increase by a maximum of only\u000012 %. Over the Iberian Peninsula, AR-induced precipitation will slightly\u0000decrease (∼6 %) but the decrease in the mean rate will be larger (∼15 %). These changes will lead to an overall increased fractional contribution of ARs to heavy precipitation, with the greatest impact over the Iberian Peninsula (15 %–30 %) and western France (∼15 %). Likewise, the fractional share of yearly maximum precipitation attributable to ARs will increase over the Iberian Peninsula, the UK, and western France. Over Norway, average AR precipitation rates will decline by −5 % to\u0000−30 %, most likely due to dynamic changes, with ARs originating from\u0000latitudes > 60∘ N decreasing by up to 20 % and those originating south of 45∘ N increasing. This suggests that ARs over\u0000Norway will follow longer routes over the continent, such that additional\u0000moisture uptake will be impeded. By contrast, ARs from >60∘ N will take up moisture from the North Atlantic before making landfall over Norway. The found changes in the local AR pathway are probably driven by larger-scale circulation changes such as a change in dominating weather regimes and/or changes in the winter storm track over the North Atlantic.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48800902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-22DOI: 10.5194/esd-13-1667-2022
Isobel Parry, P. Ritchie, P. Cox
Abstract. Amazon forest dieback is seen as a potential tipping point under climate change. These concerns are partly based on an early coupled climate–carbon cycle simulation that produced unusually strong drying and warming in Amazonia. In contrast, the fifth-generation Earth system models (Phase 5 of the Coupled Model Intercomparison Project, CMIP5) produced few examples of Amazon dieback under climate change. Here we examine results from seven sixth-generation models (Phase 6 of the Coupled Model Intercomparison Project, CMIP6), which include interactive vegetation carbon and in some cases interactive forest fires. Although these models typically project increases in area-mean forest carbon across Amazonia under CO2-induced climate change, five of the seven models also produce abrupt reductions in vegetation carbon, which indicate localised dieback events. The northern South America (NSA) region, which contains most of the rainforest, is especially vulnerable in the models. These dieback events, some of which are mediated by fire, are preceded by an increase in the amplitude of the seasonal cycle in near-surface temperature, which is consistent with more extreme dry seasons. Based on the ensemble mean of the detected dieback events we estimate that 7±5 % of the NSA region will experience abrupt downward shifts in vegetation carbon for every degree of global warming past 1.5 ∘C.
{"title":"Evidence of localised Amazon rainforest dieback in CMIP6 models","authors":"Isobel Parry, P. Ritchie, P. Cox","doi":"10.5194/esd-13-1667-2022","DOIUrl":"https://doi.org/10.5194/esd-13-1667-2022","url":null,"abstract":"Abstract. Amazon forest dieback is seen as a potential tipping point under climate change. These concerns are partly based on an early coupled climate–carbon cycle simulation that produced unusually strong drying and warming in Amazonia. In contrast, the fifth-generation Earth system models (Phase 5 of the Coupled Model Intercomparison Project, CMIP5) produced few examples of Amazon dieback under climate change. Here we examine results from seven sixth-generation models (Phase 6 of the Coupled Model Intercomparison Project, CMIP6), which include interactive vegetation carbon and in some cases interactive forest fires. Although these models typically project increases in area-mean forest carbon across Amazonia under CO2-induced climate change, five of the seven models also produce abrupt reductions in vegetation carbon, which indicate localised dieback events. The northern South America (NSA) region, which contains most of the rainforest, is especially vulnerable in the models. These dieback events, some of which are mediated by fire, are preceded by an increase in the amplitude of the seasonal cycle in near-surface temperature, which is consistent with more extreme dry seasons. Based on the ensemble mean of the detected dieback events we estimate that 7±5 % of the NSA region will experience abrupt downward shifts in vegetation carbon for every degree of global warming past 1.5 ∘C.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42720840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Here we intend to further the understanding of the planetary burden (and its dynamics) caused by the effect of the continued increase in carbon dioxide (CO2) emissions from fossil fuel burning and land use as well as by global warming from a new rheological (stress–strain) perspective. That is, we perceive the emission of anthropogenic CO2 into the atmosphere as a stressor and survey the condition of Earth in stress–strain units (stress in units of Pa, strain in units of 1) – allowing access to and insight into previously unknown characteristics reflecting Earth's rheological status. We use the idea of a Maxwell body consisting of elastic and damping (viscous) elements to reflect the overall behavior of the atmosphere–land and ocean system in response to the continued increase in CO2 emissions between 1850 and 2015. Thus, from the standpoint of a global observer, we see that the CO2 concentration in the atmosphere is increasing (rather quickly). Concomitantly, the atmosphere is warming and expanding, while some of the carbon is being locked away (rather slowly) in land and oceans, likewise under the influence of global warming. It is not known how reversible and how out of sync the latter process (uptake of carbon by sinks) is in relation to the former (expansion of the atmosphere). All we know is that the slower process remembers the influence of the faster one, which runs ahead. Important questions arise as to whether this global-scale memory – Earth's memory – can be identified and quantified, how it behaves dynamically, and, last but not least, how it interlinks with persistence by which we understand Earth's path dependency. We go beyond textbook knowledge by introducing three parameters that characterize the system: delay time, memory, and persistence. The three parameters depend, ceteris paribus, solely on the system's characteristic viscoelastic behavior and allow deeper and novel insights into that system. The parameters come with their own limits which govern the behavior of the atmosphere–land and ocean carbon system, independently from any external target values (such as temperature targets justified by means of global change research). We find that since 1850, the atmosphere–land and ocean system has been trapped progressively in terms of persistence (i.e., it will become progressively more difficult to relax the system), while its ability to build up memory has been reduced. The ability of a system to build up memory effectively can be understood as its ability to respond still within its natural regime or, if the build-up of memory is limited, as a measure for system failures globally in the future. Approximately 60 % of Earth's memory had already been exploited by humankind prior to 1959. Based on these stress–strain insights we expect that the atmosphere–land and ocean carbon system will be forced outside its natural regime well before 2050 if the current trend in emissions is not reversed immediately and sustainably.
{"title":"Quantifying memory and persistence in the atmosphere–land and ocean carbon system","authors":"M. Jonas, R. Bun, I. Ryzha, P. Żebrowski","doi":"10.5194/esd-13-439-2022","DOIUrl":"https://doi.org/10.5194/esd-13-439-2022","url":null,"abstract":"Abstract. Here we intend to further the understanding of the planetary burden (and its dynamics) caused by the effect of the continued increase in carbon dioxide (CO2) emissions from fossil fuel burning and land use as well as by global warming from a new rheological (stress–strain) perspective. That is, we perceive the emission of anthropogenic CO2 into the atmosphere as a stressor and survey the condition of Earth in stress–strain units (stress in units of Pa, strain in units of 1) – allowing access to and insight into previously unknown characteristics reflecting Earth's rheological status. We use the idea of a Maxwell body consisting of elastic and damping (viscous) elements to reflect the overall behavior of the atmosphere–land and ocean system in response to the continued increase in CO2 emissions between 1850 and 2015. Thus, from the standpoint of a global observer, we see that the CO2 concentration in the atmosphere is increasing (rather quickly). Concomitantly, the atmosphere is warming and expanding, while some of the carbon is being locked away (rather slowly) in land and oceans, likewise under the influence of global warming. It is not known how reversible and how out of sync the latter process (uptake of carbon by sinks) is in relation to the former (expansion of the atmosphere). All we know is that the slower process remembers the influence of the faster one, which runs ahead. Important questions arise as to whether this global-scale memory – Earth's memory – can be identified and quantified, how it behaves dynamically, and, last but not least, how it interlinks with persistence by which we understand Earth's path dependency. We go beyond textbook knowledge by introducing three parameters that characterize the system: delay time, memory, and persistence. The three parameters depend, ceteris paribus, solely on the system's characteristic viscoelastic behavior and allow deeper and novel insights into that system. The parameters come with their own limits which govern the behavior of the atmosphere–land and ocean carbon system, independently from any external target values (such as temperature targets justified by means of global change research). We find that since 1850, the atmosphere–land and ocean system has been trapped progressively in terms of persistence (i.e., it will become progressively more difficult to relax the system), while its ability to build up memory has been reduced. The ability of a system to build up memory effectively can be understood as its ability to respond still within its natural regime or, if the build-up of memory is limited, as a measure for system failures globally in the future. Approximately 60 % of Earth's memory had already been exploited by humankind prior to 1959. Based on these stress–strain insights we expect that the atmosphere–land and ocean carbon system will be forced outside its natural regime well before 2050 if the current trend in emissions is not reversed immediately and sustainably.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48117817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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