Pub Date : 2023-10-04DOI: 10.5194/esd-14-1015-2023
Corinne Hartin, Erin E McDuffie, Karen Noiva, Marcus Sarofim, Bryan Parthum, Jeremy Martinich, Sarah Barr, Jim Neumann, Jacqueline Willwerth, Allen Fawcett
Evidence of the physical and economic impacts of climate change is a critical input to policy development and decision-making. In addition to the magnitude of potential impacts, detailed estimates of where, when, and to whom those damages may occur; the types of impacts that will be most damaging; uncertainties in these damages; and the ability of adaptation to reduce potential risks are all interconnected and important considerations. This study utilizes the reduced-complexity model, the Framework for Evaluating Damages and Impacts (FrEDI), to rapidly project economic and physical impacts of climate change across 10 000 future scenarios for multiple impact sectors, regions, and populations within the contiguous United States (US). Results from FrEDI show that net national damages increase overtime, with mean climate-driven damages estimated to reach USD 2.9 trillion (95 % confidence interval (CI): USD 510 billion to USD 12 trillion) annually by 2090. Detailed FrEDI results show that for the analyzed sectors the majority of annual long-term (e.g., 2090) damages are associated with climate change impacts to human health, including mortality attributable to climate-driven changes in temperature and air pollution (O3 and PM2.5) exposure. Regional results also show that annual long-term climate-driven damages vary geographically. The Southeast (all regions are as defined in Fig. 5) is projected to experience the largest annual damages per capita (mean: USD 9300 per person annually; 95 % CI: USD 1800-USD 37 000 per person annually), whereas the smallest damages per capita are expected in the Southwest (mean: USD 6300 per person annually; 95 % CI: USD 840-USD 27 000 per person annually). Climate change impacts may also broaden existing societal inequalities, with, for example, Black or African Americans being disproportionately affected by additional premature mortality from changes in air quality. Lastly, FrEDI projections are extended through 2300 to estimate the net present climate-driven damages within US borders from marginal changes in greenhouse gas emissions. Combined, this analysis provides the most detailed illustration to date of the distribution of climate change impacts within US borders.
{"title":"Advancing the estimation of future climate impacts within the United States.","authors":"Corinne Hartin, Erin E McDuffie, Karen Noiva, Marcus Sarofim, Bryan Parthum, Jeremy Martinich, Sarah Barr, Jim Neumann, Jacqueline Willwerth, Allen Fawcett","doi":"10.5194/esd-14-1015-2023","DOIUrl":"10.5194/esd-14-1015-2023","url":null,"abstract":"<p><p>Evidence of the physical and economic impacts of climate change is a critical input to policy development and decision-making. In addition to the magnitude of potential impacts, detailed estimates of where, when, and to whom those damages may occur; the types of impacts that will be most damaging; uncertainties in these damages; and the ability of adaptation to reduce potential risks are all interconnected and important considerations. This study utilizes the reduced-complexity model, the Framework for Evaluating Damages and Impacts (FrEDI), to rapidly project economic and physical impacts of climate change across 10 000 future scenarios for multiple impact sectors, regions, and populations within the contiguous United States (US). Results from FrEDI show that net national damages increase overtime, with mean climate-driven damages estimated to reach USD 2.9 trillion (95 % confidence interval (CI): USD 510 billion to USD 12 trillion) annually by 2090. Detailed FrEDI results show that for the analyzed sectors the majority of annual long-term (e.g., 2090) damages are associated with climate change impacts to human health, including mortality attributable to climate-driven changes in temperature and air pollution (O<sub>3</sub> and PM<sub>2.5</sub>) exposure. Regional results also show that annual long-term climate-driven damages vary geographically. The Southeast (all regions are as defined in Fig. 5) is projected to experience the largest annual damages per capita (mean: USD 9300 per person annually; 95 % CI: USD 1800-USD 37 000 per person annually), whereas the smallest damages per capita are expected in the Southwest (mean: USD 6300 per person annually; 95 % CI: USD 840-USD 27 000 per person annually). Climate change impacts may also broaden existing societal inequalities, with, for example, Black or African Americans being disproportionately affected by additional premature mortality from changes in air quality. Lastly, FrEDI projections are extended through 2300 to estimate the net present climate-driven damages within US borders from marginal changes in greenhouse gas emissions. Combined, this analysis provides the most detailed illustration to date of the distribution of climate change impacts within US borders.</p>","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":"14 5","pages":"1015-1037"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10631227/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71523800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. N. Reddy, Shilpa Gahlot, Somnath Baidya Roy, Gudimetla Venkateswara Varma, V. Sehgal, Gayatri Vangala
Abstract. Carbon fluxes from agroecosystems contribute to the variability of the carbon cycle and atmospheric [CO2]. This study is a follow-up to Gahlot et al. (2020), which used the Integrated Science Assessment Model (ISAM) to examine spring wheat production and its drivers. In this study, we look at the carbon fluxes and their drivers. ISAM was calibrated and validated against the crop phenology at the IARI wheat experimental site in Gahlot et al. (2020). We extended the validation of the model on a regional scale by comparing modeled leaf area index (LAI) and yield against site-scale observations and regional datasets. Later, ISAM-simulated carbon fluxes were validated against an experimental spring wheat site at IARI for the growing season of 2013–2014. Additionally, we compared with the published carbon flux data and found that ISAM captures the seasonality well. Following that, regional-scale runs were performed. The results revealed that fluxes vary significantly across regions, primarily owing to differences in planting dates. During the study period, all fluxes showed statistically significant increasing trends (p<0.1). Gross primary production (GPP), net primary production (NPP), autotrophic respiration (Ra), and heterotrophic respiration (Rh) increased at 1.272, 0.945, 0.579, 0.328, and 0.366 TgC yr−2, respectively. Numerical experiments were conducted to investigate how natural forcings such as changing temperature and [CO2] levels as well as agricultural management practices such as nitrogen fertilization and water availability could contribute to the rising trends. The experiments revealed that increasing [CO2], nitrogen fertilization, and irrigation water contributed to increased carbon fluxes, with nitrogen fertilization having the most significant effect.
{"title":"Carbon fluxes in spring wheat agroecosystem in India","authors":"K. N. Reddy, Shilpa Gahlot, Somnath Baidya Roy, Gudimetla Venkateswara Varma, V. Sehgal, Gayatri Vangala","doi":"10.5194/esd-14-915-2023","DOIUrl":"https://doi.org/10.5194/esd-14-915-2023","url":null,"abstract":"Abstract. Carbon fluxes from agroecosystems contribute to the\u0000variability of the carbon cycle and atmospheric [CO2]. This study is a\u0000follow-up to Gahlot et al. (2020), which used the Integrated Science\u0000Assessment Model (ISAM) to examine spring wheat production and its drivers.\u0000In this study, we look at the carbon fluxes and their drivers. ISAM\u0000was calibrated and validated against the crop phenology at the IARI wheat\u0000experimental site in Gahlot et al. (2020). We extended the validation of\u0000the\u0000model on a regional scale by comparing modeled leaf area index (LAI) and yield against site-scale observations and regional datasets. Later, ISAM-simulated carbon\u0000fluxes were validated against an experimental spring wheat site at IARI for\u0000the growing season of 2013–2014. Additionally, we compared with the published\u0000carbon flux data and found that ISAM captures the seasonality well.\u0000Following that, regional-scale runs were performed. The results revealed\u0000that fluxes vary significantly across regions, primarily owing to\u0000differences in planting dates. During the study period, all fluxes showed\u0000statistically significant increasing trends (p<0.1). Gross primary production (GPP), net primary production (NPP), autotrophic\u0000respiration (Ra), and heterotrophic respiration\u0000(Rh) increased at 1.272,\u00000.945, 0.579, 0.328, and 0.366 TgC yr−2, respectively. Numerical experiments\u0000were conducted to investigate how natural forcings such as changing\u0000temperature and [CO2] levels as well as agricultural management practices such\u0000as\u0000nitrogen fertilization and water availability could contribute to the\u0000rising\u0000trends. The experiments revealed that increasing [CO2], nitrogen\u0000fertilization, and irrigation water contributed to increased carbon fluxes,\u0000with nitrogen fertilization having the most significant effect.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48437418","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. Soltani, Bert Hamelers, Abbas Mofidi, Christopher G. Fletcher, Arie Staal, Stefan C. Dekker, P. Laux, J. Arnault, H. Kunstmann, Ties van der Hoeven, Maarten Lanters
Abstract. Extreme precipitation events and associated flash floods caused by synoptic cyclonic systems profoundly impact society and the environment, particularly in arid regions. This study brings forward a satellite-reanalysis-based approach to quantify extreme precipitation characteristics over the Sinai Peninsula (SiP) in Egypt from a statistical–synoptic perspective for the period of 2001–2020. With a multi-statistical approach developed in this research, SiP's wet and dry periods are determined. Using satellite observations of precipitation and a set of derived precipitation indices, we characterize the spatiotemporal variations of extreme rainfall climatologies across the SiP. Then, using the reanalysis datasets, synoptic systems responsible for the occurrence of extreme precipitation events along with the major tracks of cyclones during the wet and dry periods are described. Our results indicate that trends and spatial patterns of the rainfall events across the region are inconsistent in time and space. The highest precipitation percentiles (∼20 mm per month), frequencies (∼15 d per month with rainfall ≥10 mm d−1), standard deviations (∼9 mm month per month), and monthly ratios (∼18 %) are estimated in the northern and northeastern parts of the region during the wet period, especially in early winter; also, a substantial below-average precipitation condition (drier trend) is clearly observed in most parts except for the south. Mediterranean cyclones accompanied by the Red Sea and Persian troughs are responsible for the majority of extreme rainfall events year-round. A remarkable spatial relationship is found between SiP's rainfall and the atmospheric variables of sea level pressure, wind direction, and vertical velocity. A cyclone-tracking analysis indicates that 125 cyclones (with rainfall ≥10 mm d−1) formed within, or transferred to, the Mediterranean basin and precipitated over the SiP during wet periods compared to 31 such cyclones during dry periods. It is estimated around 15 % of cyclones with sufficient rainfall >40 mm d−1 would be capable of leading to flash floods during the wet period. This study, therefore, sheds new light on the extreme precipitation characteristics over the SiP and its association with dominant synoptic-scale mechanisms over the eastern Mediterranean region.
{"title":"A 20-year satellite-reanalysis-based climatology of extreme precipitation characteristics over the Sinai Peninsula","authors":"M. Soltani, Bert Hamelers, Abbas Mofidi, Christopher G. Fletcher, Arie Staal, Stefan C. Dekker, P. Laux, J. Arnault, H. Kunstmann, Ties van der Hoeven, Maarten Lanters","doi":"10.5194/esd-14-931-2023","DOIUrl":"https://doi.org/10.5194/esd-14-931-2023","url":null,"abstract":"Abstract. Extreme precipitation events and associated flash floods caused by\u0000synoptic cyclonic systems profoundly impact society and the environment,\u0000particularly in arid regions. This study brings forward a\u0000satellite-reanalysis-based approach to quantify extreme precipitation\u0000characteristics over the Sinai Peninsula (SiP) in Egypt from a\u0000statistical–synoptic perspective for the period of 2001–2020. With a\u0000multi-statistical approach developed in this research, SiP's wet and dry\u0000periods are determined. Using satellite observations of precipitation and a\u0000set of derived precipitation indices, we characterize the spatiotemporal\u0000variations of extreme rainfall climatologies across the SiP. Then, using the\u0000reanalysis datasets, synoptic systems responsible for the occurrence of\u0000extreme precipitation events along with the major tracks of cyclones during\u0000the wet and dry periods are described. Our results indicate that trends and\u0000spatial patterns of the rainfall events across the region are inconsistent\u0000in time and space. The highest precipitation percentiles (∼20 mm per month), frequencies (∼15 d per month with rainfall ≥10 mm d−1), standard deviations (∼9 mm month per month), and monthly\u0000ratios (∼18 %) are estimated in the northern and northeastern parts of\u0000the region during the wet period, especially in early winter; also, a\u0000substantial below-average precipitation condition (drier trend) is clearly\u0000observed in most parts except for the south. Mediterranean cyclones\u0000accompanied by the Red Sea and Persian troughs are responsible for the\u0000majority of extreme rainfall events year-round. A remarkable spatial\u0000relationship is found between SiP's rainfall and the atmospheric variables\u0000of sea level pressure, wind direction, and vertical velocity. A\u0000cyclone-tracking analysis indicates that 125 cyclones (with rainfall ≥10 mm d−1) formed within, or transferred to, the Mediterranean basin and\u0000precipitated over the SiP during wet periods compared to 31 such cyclones\u0000during dry periods. It is estimated around 15 % of cyclones with\u0000sufficient rainfall >40 mm d−1 would be capable of leading to\u0000flash floods during the wet period. This study, therefore, sheds new light\u0000on the extreme precipitation characteristics over the SiP and its association\u0000with dominant synoptic-scale mechanisms over the eastern Mediterranean\u0000region.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49028195","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}
Yanbin You, Zhenghui Xie, Binghao Jia, Yan Wang, Longhuan Wang, Ruichao Li, Heng Yan, Yuhang Tian, Si Chen
Abstract. Anthropogenic water regulation activities, including reservoir interception, surface water withdrawal, and groundwater extraction, alter riverine hydrologic processes and affect dissolved organic carbon (DOC) export from land to rivers and oceans. In this study, schemes describing soil DOC leaching, riverine DOC transport, and anthropogenic water regulation were developed and incorporated into the Community Land Model 5.0 (CLM5.0) and the River Transport Model (RTM). Three simulations by the developed model were conducted on a global scale from 1981–2013 to investigate the impacts of anthropogenic water regulation on riverine DOC transport. The validation results showed that DOC exports simulated by the developed model were in good agreement with global river observations. The simulations showed that DOC transport in most rivers was mainly influenced by reservoir interception and surface water withdrawal, especially in central North America and eastern China. Four major rivers, including the Danube, Yangtze, Mississippi, and Ganges rivers, have experienced reduced riverine DOC flows due to intense water management, with the largest effect occurring in winter and early spring. In the Danube and Yangtze river basins, the impact in 2013 was 4 to 5 times greater than in 1981, with a retention efficiency of over 50 %. The Ob river basin was almost unaffected. The total impact of anthropogenic water regulation reduced global annual riverine DOC exports to the ocean by approximately 13.36 ± 2.45 Tg C yr−1, and this effect increased from 4.83 % to 6.20 % during 1981–2013, particularly in the Pacific and Atlantic oceans.
{"title":"Impacts of anthropogenic water regulation on global riverine dissolved organic carbon transport","authors":"Yanbin You, Zhenghui Xie, Binghao Jia, Yan Wang, Longhuan Wang, Ruichao Li, Heng Yan, Yuhang Tian, Si Chen","doi":"10.5194/esd-14-897-2023","DOIUrl":"https://doi.org/10.5194/esd-14-897-2023","url":null,"abstract":"Abstract. Anthropogenic water regulation activities, including\u0000reservoir interception, surface water withdrawal, and groundwater\u0000extraction, alter riverine hydrologic processes and affect dissolved organic\u0000carbon (DOC) export from land to rivers and oceans. In this study, schemes\u0000describing soil DOC leaching, riverine DOC transport, and anthropogenic\u0000water regulation were developed and incorporated into the Community Land\u0000Model 5.0 (CLM5.0) and the River Transport Model (RTM). Three simulations\u0000by the developed model were conducted on a global scale from 1981–2013 to\u0000investigate the impacts of anthropogenic water regulation on riverine DOC\u0000transport. The validation results showed that DOC exports simulated by the\u0000developed model were in good agreement with global river observations. The\u0000simulations showed that DOC transport in most rivers was mainly influenced\u0000by reservoir interception and surface water withdrawal, especially in\u0000central North America and eastern China. Four major rivers, including the\u0000Danube, Yangtze, Mississippi, and Ganges rivers, have experienced reduced\u0000riverine DOC flows due to intense water management, with the largest effect\u0000occurring in winter and early spring. In the Danube and Yangtze river\u0000basins, the impact in 2013 was 4 to 5 times greater than in 1981, with\u0000a retention efficiency of over 50 %. The Ob river basin was almost\u0000unaffected. The total impact of anthropogenic water regulation reduced\u0000global annual riverine DOC exports to the ocean by approximately\u000013.36 ± 2.45 Tg C yr−1, and this effect increased from 4.83 %\u0000to 6.20 % during 1981–2013, particularly in the Pacific and Atlantic\u0000oceans.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41887747","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. Optimality concepts related to energy and entropy have long been proposed to govern Earth system processes, for instance in the form of propositions that certain processes maximize or minimize entropy production. These concepts, however, remain quite obscure, seem contradictory to each other, and have so far been mostly disregarded. This review aims to clarify the role of thermodynamics and optimality in Earth system science by showing that they play a central role in how, and how much, work can be derived from solar forcing and that this imposes a major constraint on the dynamics of dissipative structures of the Earth system. This is, however, not as simple as it may sound. It requires a consistent formulation of Earth system processes in thermodynamic terms, including their linkages and interactions. Thermodynamics then constrains the ability of the Earth system to derive work and generate free energy from solar radiative forcing, which limits the ability to maintain motion, mass transport, geochemical cycling, and biotic activity. It thus limits directly the generation of atmospheric motion and other processes indirectly through their need for transport. I demonstrate the application of this thermodynamic Earth system view by deriving first-order estimates associated with atmospheric motion, hydrologic cycling, and terrestrial productivity that agree very well with observations. This supports the notion that the emergent simplicity and predictability inherent in observed climatological variations can be attributed to these processes working as hard as they can, reflecting thermodynamic limits directly or indirectly. I discuss how this thermodynamic interpretation is consistent with established theoretical concepts in the respective disciplines, interpret other optimality concepts in light of this thermodynamic Earth system view, and describe its utility for Earth system science.
{"title":"Working at the limit: a review of thermodynamics and optimality of the Earth system","authors":"A. Kleidon","doi":"10.5194/esd-14-861-2023","DOIUrl":"https://doi.org/10.5194/esd-14-861-2023","url":null,"abstract":"Abstract. Optimality concepts related to energy and entropy have long been proposed to govern Earth system processes, for instance in the form of propositions that certain processes maximize or minimize entropy production. These concepts, however, remain quite obscure, seem contradictory to each other, and have so far been mostly disregarded. This review aims to clarify the role of thermodynamics and optimality in Earth system science by showing that they play a central role in how, and how much, work can be derived from solar forcing and that this imposes a major constraint on the dynamics of dissipative structures of the Earth system. This is, however, not as simple as it may sound. It requires a consistent formulation of Earth system processes in thermodynamic terms, including their linkages and interactions. Thermodynamics then constrains the ability of the Earth system to derive work and generate free energy from solar radiative forcing, which limits the ability to maintain motion, mass transport, geochemical cycling, and biotic activity. It thus limits directly the generation of atmospheric motion and other processes indirectly through their need for transport. I demonstrate the application of this thermodynamic Earth system view by deriving first-order estimates associated with atmospheric motion, hydrologic cycling, and terrestrial productivity that agree very well with observations. This supports the notion that the emergent simplicity and predictability inherent in observed climatological variations can be attributed to these processes working as hard as they can, reflecting thermodynamic limits directly or indirectly. I discuss how this thermodynamic interpretation is consistent with established theoretical concepts in the respective disciplines, interpret other optimality concepts in light of this thermodynamic Earth system view, and describe its utility for Earth system science.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48978021","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. A global aerosol–climate model is applied to quantify the impact of the transport sectors (land transport, shipping, and aviation) on aerosol and climate. Global simulations are performed for the present day (2015), based on the emission inventory of the Climate Model Intercomparison Project Phase 6 (CMIP6), and for near-term (2030) and mid-term (2050) future projections, under the Shared Socioeconomic Pathways (SSPs). The results for the present day show that land transport emissions have a large impact on near-surface concentrations of black carbon and aerosol nitrate over the most populated areas of the globe, but with contrasting patterns in terms of relative contributions between developed and developing countries. In spite of the recently introduced regulations to limit the fuel sulfur content in the shipping sector, shipping emissions are still responsible for a considerable impact on aerosol sulfate near-surface concentrations, about 0.5 to 1 µg m−3 in the most travelled regions, with significant effects on continental air pollution and in the northern polar regions as well. Aviation impacts on aerosol mass are found to be quite small, of the order of a few nanograms per cubic metre, while this sector considerably affects particle number concentrations, contributing up to 20 %–30 % of the upper-tropospheric particle number concentration at the northern mid-latitudes. The transport-induced impacts on aerosol mass and number concentrations result in a present-day radiative forcing of −164, −145, and −64 mW m−2 for land transport, shipping, and aviation, respectively, with a dominating contribution by aerosol–cloud interactions. These forcings represent a marked offset to the CO2 warming from the transport sectors and are therefore very relevant for climate policy. The projections under the SSPs show that the impact of the transport sectors on aerosol and climate are generally consistent with the narratives underlying these scenarios: the lowest impacts of transport on both aerosol and climate are simulated under SSP1, especially for the land transport sector, while SSP3 is generally characterized by the largest effects. Notable exceptions to this picture, however, exist, as the emissions of other anthropogenic sectors also contribute to the overall aerosol concentrations and thus modulate the relevance of the transport sectors in the different scenarios, not always consistently with their underlying storyline. On a qualitative level, the results for the present day mostly confirm the findings of our previous assessment for the year 2000, which used a predecessor version of the same model and the CMIP5 emission data. Some important quantitative differences are found, which can mostly be ascribed to the improved representation of aerosol background concentrations in the present study.
{"title":"The global impact of the transport sectors on the atmospheric aerosol and the resulting climate effects under the Shared Socioeconomic Pathways (SSPs)","authors":"M. Righi, J. Hendricks, S. Brinkop","doi":"10.5194/esd-14-835-2023","DOIUrl":"https://doi.org/10.5194/esd-14-835-2023","url":null,"abstract":"Abstract. A global aerosol–climate model is applied to quantify the impact of the transport sectors (land transport, shipping, and aviation) on aerosol and climate. Global simulations are performed for the present day (2015), based on the emission inventory of the Climate Model Intercomparison Project Phase 6 (CMIP6), and for near-term (2030) and mid-term (2050) future projections, under the Shared Socioeconomic Pathways (SSPs). The results for the present day show that land transport emissions have a large impact on near-surface concentrations of black carbon and aerosol nitrate over the most populated areas of the globe, but with contrasting patterns in terms of relative contributions between developed and developing countries. In spite of the recently introduced regulations to limit the fuel sulfur content in the shipping sector, shipping emissions are still responsible for a considerable impact on aerosol sulfate near-surface concentrations, about 0.5 to 1 µg m−3 in the most travelled regions, with significant effects on continental air pollution and in the northern polar regions as well. Aviation impacts on aerosol mass are found to be quite small, of the order of a few nanograms per cubic metre, while this sector considerably affects particle number concentrations, contributing up to 20 %–30 % of the upper-tropospheric particle number concentration at the northern mid-latitudes. The transport-induced impacts on aerosol mass and number concentrations result in a present-day radiative forcing of −164, −145, and −64 mW m−2 for land transport, shipping, and aviation, respectively, with a dominating contribution by aerosol–cloud interactions. These forcings represent a marked offset to the CO2 warming from the transport sectors and are therefore very relevant for climate policy. The projections under the SSPs show that the impact of the transport sectors on aerosol and climate are generally consistent with the narratives underlying these scenarios: the lowest impacts of transport on both aerosol and climate are simulated under SSP1, especially for the land transport sector, while SSP3 is generally characterized by the largest effects. Notable exceptions to this picture, however, exist, as the emissions of other anthropogenic sectors also contribute to the overall aerosol concentrations and thus modulate the relevance of the transport sectors in the different scenarios, not always consistently with their underlying storyline. On a qualitative level, the results for the present day mostly confirm the findings of our previous assessment for the year 2000, which used a predecessor version of the same model and the CMIP5 emission data. Some important quantitative differences are found, which can mostly be ascribed to the improved representation of aerosol background concentrations in the present study.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43518959","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}
Christopher D. Wells, L. Jackson, A. Maycock, P. Forster
Abstract. The regional climate impacts of hypothetical future emissions scenarios can be estimated by combining Earth system model simulations with a linear pattern scaling model such as MESMER (Modular Earth System Model Emulator with spatially Resolved output), which uses estimated patterns of the local response per degree of global temperature change. Here we use the mean trend component of MESMER to emulate the regional pattern of the surface temperature response based on historical single-forcer and future Shared Socioeconomic Pathway (SSP) CMIP6 (Coupled Model Intercomparison Project Phase 6) simulations. Errors in the emulations for selected target scenarios (SSP1–1.9, SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5) are decomposed into two components, namely (1) the differences in scaling patterns between scenarios as a consequence of varying combinations of external forcings and (2) the intrinsic time series differences between the local and global responses in the target scenario. The time series error is relatively small for high-emissions scenarios, contributing around 20 % of the total error, but is similar in magnitude to the pattern error for lower-emissions scenarios. This irreducible time series error limits the efficacy of linear pattern scaling for emulating strong mitigation pathways and reduces the dependence on the predictor pattern used. The results help guide the choice of predictor scenarios for simple climate models and where to target for the introduction of other dependent variables beyond global surface temperature into pattern scaling models.
{"title":"Understanding pattern scaling errors across a range of emissions pathways","authors":"Christopher D. Wells, L. Jackson, A. Maycock, P. Forster","doi":"10.5194/esd-14-817-2023","DOIUrl":"https://doi.org/10.5194/esd-14-817-2023","url":null,"abstract":"Abstract. The regional climate impacts of hypothetical future emissions scenarios can be estimated by combining Earth system model simulations with a linear pattern scaling model such as MESMER (Modular Earth System Model Emulator with spatially Resolved output), which uses estimated patterns of the local response per degree of global temperature change. Here we use the mean trend component of MESMER to emulate the regional pattern of the surface temperature response based on historical single-forcer and future Shared Socioeconomic Pathway (SSP) CMIP6 (Coupled Model Intercomparison Project Phase 6) simulations. Errors in the emulations for selected target scenarios (SSP1–1.9, SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5) are decomposed into two components, namely (1) the differences in scaling patterns between scenarios as a consequence of varying combinations of external forcings and (2) the intrinsic time series differences between the local and global responses in the target scenario. The time series error is relatively small for high-emissions scenarios, contributing around 20 % of the total error, but is similar in magnitude to the pattern error for lower-emissions scenarios. This irreducible time series error limits the efficacy of linear pattern scaling for emulating strong mitigation pathways and reduces the dependence on the predictor pattern used. The results help guide the choice of predictor scenarios for simple climate models and where to target for the introduction of other dependent variables beyond global surface temperature into pattern scaling models.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45241521","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. The frequency of precipitation extremes is set to change in response to a warming climate. Thereby, the change in extreme precipitation event occurrence is influenced by both a shift in the mean and a change in variability. How large the individual contributions are from either of them (mean or variability) to the change in precipitation extremes is largely unknown. This is, however, relevant for a better understanding of how and why climate extremes change. For this study, two sets of forcing experiments from the regional CRCM5 initial-condition large ensemble are used: a set of 50 members with historical and RCP8.5 forcing and a 35-member (700-year) ensemble of pre-industrial natural forcing. The concept of the probability risk ratio is used to partition the change in extreme-event occurrence into contributions from a change in mean climate or a change in variability. The results show that the contributions from a change in variability are in parts equally important to changes in the mean and can even exceed them. The level of contributions shows high spatial variation, which underlines the importance of regional processes for changes in extremes. While over Scandinavia or central Europe the mean influences the increase in extremes more, the increase is driven by changes in variability over France, the Iberian Peninsula, and the Mediterranean. For annual extremes, the differences between the ratios of contribution of mean and variability are smaller, while on seasonal scales the difference in contributions becomes larger. In winter (DJF) the mean contributes more to an increase in extreme events, while in summer (JJA) the change in variability drives the change in extremes. The level of temporal aggregation (3, 24, 72 h) has only a small influence on annual and winterly extremes, while in summer the contribution from variability can increase with longer durations. The level of extremeness for the event definition generally increases the role of variability. These results highlight the need for a better understanding of changes in climate variability to better understand the mechanisms behind changes in climate extremes.
{"title":"Role of mean and variability change in changes in European annual and seasonal extreme precipitation events","authors":"R. R. Wood","doi":"10.5194/esd-14-797-2023","DOIUrl":"https://doi.org/10.5194/esd-14-797-2023","url":null,"abstract":"Abstract. The frequency of precipitation extremes is set to change\u0000in response to a warming climate. Thereby, the change in\u0000extreme precipitation event occurrence is influenced by both a shift in the mean and a\u0000change in variability. How large the individual contributions are from either of\u0000them (mean or variability) to the change in precipitation extremes is\u0000largely unknown. This is, however, relevant for a better understanding of how\u0000and why climate extremes change. For this study, two sets of forcing\u0000experiments from the regional CRCM5 initial-condition large ensemble are\u0000used: a set of 50 members with historical and RCP8.5 forcing and a\u000035-member (700-year) ensemble of pre-industrial natural forcing. The concept\u0000of the probability risk ratio is used to partition the change in extreme-event occurrence into contributions from a change in mean climate or a\u0000change in variability. The results show that the contributions from a change\u0000in variability are in parts equally important to changes in the mean and\u0000can even exceed them. The level of contributions shows high spatial\u0000variation, which underlines the importance of regional processes for changes\u0000in extremes. While over Scandinavia or central Europe the mean influences the\u0000increase in extremes more, the increase is driven by changes in\u0000variability over France, the Iberian Peninsula, and the Mediterranean. For\u0000annual extremes, the differences between the ratios of contribution of mean\u0000and variability are smaller, while on seasonal scales the difference in\u0000contributions becomes larger. In winter (DJF) the mean contributes more to\u0000an increase in extreme events, while in summer (JJA) the change in\u0000variability drives the change in extremes. The level of temporal aggregation\u0000(3, 24, 72 h) has only a small influence on annual and winterly extremes,\u0000while in summer the contribution from variability can increase with longer\u0000durations. The level of extremeness for the event definition generally\u0000increases the role of variability. These results highlight the need for a\u0000better understanding of changes in climate variability to better understand\u0000the mechanisms behind changes in climate extremes.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46050740","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}
S. Kou‐Giesbrecht, V. Arora, C. Seiler, A. Arneth, Stefanie Falk, Atul K. Jain, F. Joos, D. Kennedy, Jürgen Knauer, S. Sitch, M. O’Sullivan, Naiqing Pan, Qing Sun, H. Tian, N. Vuichard, S. Zaehle
Abstract. Terrestrial carbon (C) sequestration is limited by nitrogen (N), an empirically established constraint that could intensify under CO2 fertilization and future global change. The terrestrial C sink is estimated to currently sequester approximately a third of annual anthropogenic CO2 emissions based on an ensemble of terrestrial biosphere models, which have been evaluated in their ability to reproduce observations of the C, water, and energy cycles. However, their ability to reproduce observations of N cycling and thus the regulation of terrestrial C sequestration by N have been largely unexplored. Here, we evaluate an ensemble of terrestrial biosphere models with coupled C–N cycling and their performance at simulating N cycling, outlining a framework for evaluating N cycling that can be applied across terrestrial biosphere models. We find that models exhibit significant variability across N pools and fluxes, simulating different magnitudes and trends over the historical period, despite their ability to generally reproduce the historical terrestrial C sink. Furthermore, there are no significant correlations between model performance in simulating N cycling and model performance in simulating C cycling, nor are there significant differences in model performance between models with different representations of fundamental N cycling processes. This suggests that the underlying N processes that regulate terrestrial C sequestration operate differently across models and appear to be disconnected from C cycling. Models tend to overestimate tropical biological N fixation, vegetation C : N ratio, and soil C : N ratio but underestimate temperate biological N fixation relative to observations. However, there is significant uncertainty associated with measurements of N cycling processes given their scarcity (especially relative to those of C cycling processes) and their high spatiotemporal variability. Overall, our results suggest that terrestrial biosphere models that represent coupled C–N cycling could be overestimating C storage per unit N, which could lead to biases in projections of the future terrestrial C sink under CO2 fertilization and future global change (let alone those without a representation of N cycling). More extensive observations of N cycling processes and comparisons against experimental manipulations are crucial to evaluate N cycling and its impact on C cycling and guide its development in terrestrial biosphere models.
{"title":"Evaluating nitrogen cycling in terrestrial biosphere models: a disconnect between the carbon and nitrogen cycles","authors":"S. Kou‐Giesbrecht, V. Arora, C. Seiler, A. Arneth, Stefanie Falk, Atul K. Jain, F. Joos, D. Kennedy, Jürgen Knauer, S. Sitch, M. O’Sullivan, Naiqing Pan, Qing Sun, H. Tian, N. Vuichard, S. Zaehle","doi":"10.5194/esd-14-767-2023","DOIUrl":"https://doi.org/10.5194/esd-14-767-2023","url":null,"abstract":"Abstract. Terrestrial carbon (C) sequestration is limited by nitrogen (N), an\u0000empirically established constraint that could intensify under CO2\u0000fertilization and future global change. The terrestrial C sink is estimated\u0000to currently sequester approximately a third of annual anthropogenic\u0000CO2 emissions based on an ensemble of terrestrial biosphere models,\u0000which have been evaluated in their ability to reproduce observations of the\u0000C, water, and energy cycles. However, their ability to reproduce\u0000observations of N cycling and thus the regulation of terrestrial C\u0000sequestration by N have been largely unexplored. Here, we evaluate an\u0000ensemble of terrestrial biosphere models with coupled C–N cycling and their\u0000performance at simulating N cycling, outlining a framework for evaluating N\u0000cycling that can be applied across terrestrial biosphere models. We find\u0000that models exhibit significant variability across N pools and fluxes,\u0000simulating different magnitudes and trends over the historical period,\u0000despite their ability to generally reproduce the historical terrestrial C\u0000sink. Furthermore, there are no significant correlations between model\u0000performance in simulating N cycling and model performance in simulating C\u0000cycling, nor are there significant differences in model performance between\u0000models with different representations of fundamental N cycling processes.\u0000This suggests that the underlying N processes that regulate terrestrial C\u0000sequestration operate differently across models and appear to be\u0000disconnected from C cycling. Models tend to overestimate tropical biological\u0000N fixation, vegetation C : N ratio, and soil C : N ratio but underestimate\u0000temperate biological N fixation relative to observations. However, there is\u0000significant uncertainty associated with measurements of N cycling processes\u0000given their scarcity (especially relative to those of C cycling processes)\u0000and their high spatiotemporal variability. Overall, our results suggest that\u0000terrestrial biosphere models that represent coupled C–N cycling could be\u0000overestimating C storage per unit N, which could lead to biases in\u0000projections of the future terrestrial C sink under CO2 fertilization\u0000and future global change (let alone those without a representation of N\u0000cycling). More extensive observations of N cycling processes and comparisons\u0000against experimental manipulations are crucial to evaluate N cycling and its\u0000impact on C cycling and guide its development in terrestrial\u0000biosphere models.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42920604","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. An oscillation of about 6 years has been reported in Earth's fluid core motions, magnetic field, rotation, and crustal deformations. Recently, a 6-year cycle has also been detected in several climatic parameters (e.g., sea level, surface temperature, precipitation, land hydrology, land ice, and atmospheric angular momentum). Here, we suggest that the 6-year oscillations detected in the Earth's deep interior, rotation, and climate are linked together and that the core processes previously proposed as drivers of the 6-year cycle in the Earth's rotation additionally cause the atmosphere to oscillate together with the mantle, inducing fluctuations in the climate system with similar periodicities.
{"title":"ESD Ideas: A 6-year oscillation in the whole Earth system?","authors":"A. Cazenave, J. Pfeffer, M. Mandea, V. Dehant","doi":"10.5194/esd-14-733-2023","DOIUrl":"https://doi.org/10.5194/esd-14-733-2023","url":null,"abstract":"Abstract. An oscillation of about 6 years has been reported in Earth's fluid\u0000core motions, magnetic field, rotation, and crustal deformations.\u0000Recently, a 6-year cycle has also been detected in several climatic\u0000parameters (e.g., sea level, surface temperature, precipitation, land\u0000hydrology, land ice, and atmospheric angular momentum). Here, we suggest that\u0000the 6-year oscillations detected in the Earth's deep interior, rotation, and\u0000climate are linked together and that the core processes previously proposed\u0000as drivers of the 6-year cycle in the Earth's rotation additionally cause\u0000the atmosphere to oscillate together with the mantle, inducing fluctuations\u0000in the climate system with similar periodicities.\u0000","PeriodicalId":92775,"journal":{"name":"Earth system dynamics : ESD","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49061293","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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