scholarly journals Variability, timescales, and non-linearity in climate responses to black carbon emissions

2018 ◽  
Author(s):  
Yang Yang ◽  
Steven J. Smith ◽  
Hailong Wang ◽  
Catrin M. Mills ◽  
Philip J. Rasch
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
Climate Models ◽  
The Arctic ◽  
Transient Temperature ◽  
Quasi Equilibrium ◽  
Earth System ◽  
Large Variability ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Black carbon (BC) particles exert a potentially large warming influence on the Earth system. Reductions in BC emissions have attracted attention as a possible means to moderate near-term temperature changes. For the first time, we evaluate regional climate responses, non-linearity, and short-term transient responses to BC emission perturbations in the Arctic, mid-latitudes, and globally based on a comprehensive set of emission-driven experiments using the Community Earth System Model (CESM). Surface temperature responses to BC emissions are complex, with surface warming over land from mid-latitude BC perturbations partially offset by ocean cooling. Climate responses do not scale linearity with emissions. While stronger BC emission perturbations have a higher burden efficiency, their temperature sensitivity is lower. BC impacts temperature much faster than greenhouse gas forcing, with transient temperature responses in the Arctic and mid-latitudes approaching a quasi-equilibrium state with a timescale of 2–3 years. We find large variability in BC-induced climate changes due to background model noise. As a result, perturbing present-day BC emission levels results in no discernible net global-average surface temperature signal. In order to better understand the climatic impacts of BC emissions, both the drivers of non-linear responses and response variability need to be assessed across climate models.

scholarly journals Variability, timescales, and nonlinearity in climate responses to black carbon emissions

2019 ◽  
Vol 19 (4) ◽  
pp. 2405-2420 ◽  
Author(s):  
Yang Yang ◽  
Steven J. Smith ◽  
Hailong Wang ◽  
Catrin M. Mills ◽  
Philip J. Rasch
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
The Arctic ◽  
Transient Temperature ◽  
Quasi Equilibrium ◽  
Earth System ◽  
Large Variability ◽  
Temperature Changes ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Black carbon (BC) particles exert a potentially large warming influence on the Earth system. Reductions in BC emissions have attracted attention as a possible means to moderate near-term temperature changes. For the first time, we evaluate regional climate responses, nonlinearity, and short-term transient responses to BC emission perturbations in the Arctic, midlatitudes, and globally based on a comprehensive set of emission-driven experiments using the Community Earth System Model (CESM). Surface temperature responses to BC emissions are complex, with surface warming over land from midlatitude BC perturbations partially offset by ocean cooling. Climate responses do not scale linearly with emissions. While stronger BC emission perturbations have a higher burden efficiency, their temperature sensitivity is lower. BC impacts temperature much faster than greenhouse gas forcing, with transient temperature responses in the Arctic and midlatitudes approaching a quasi-equilibrium state with a timescale of 2–3 years. We find large variability in BC-induced climate changes due to background model noise. As a result, removing present-day BC emissions results in discernible surface temperature changes for only limited regions of the globe. In order to better understand the climatic impacts of BC emissions, both the drivers of nonlinear responses and response variability need to be assessed across climate models.

scholarly journals Role of climate model dynamics in estimated climate responses to anthropogenic aerosols

2019 ◽  
Vol 19 (15) ◽  
pp. 9969-9987 ◽  
Author(s):  
Kalle Nordling ◽  
Hannele Korhonen ◽  
Petri Räisänen ◽  
Muzaffer Ege Alper ◽  
Petteri Uotila ◽  
...  
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Climate Impacts ◽  
The Arctic ◽  
Anthropogenic Aerosols ◽  
Temperature And Precipitation ◽  
Model Aerosol ◽  
Regional Temperature ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Significant discrepancies remain in estimates of climate impacts of anthropogenic aerosols between different general circulation models (GCMs). Here, we demonstrate that eliminating differences in model aerosol or radiative forcing fields results in close agreement in simulated globally averaged temperature and precipitation responses in the studied GCMs. However, it does not erase the differences in regional responses. We carry out experiments of equilibrium climate response to modern-day anthropogenic aerosols using an identical representation of anthropogenic aerosol optical properties and the first indirect effect of aerosols, MACv2-SP (a simple plume implementation of the second version of the Max Planck Institute Aerosol CLimatology), in two independent climate models (NorESM, Norwegian Earth System Model, and ECHAM6). We find consistent global average temperature responses of −0.48 (±0.02) and −0.50 (±0.03) K and precipitation responses of −1.69 (±0.04) % and −1.79 (±0.05) % in NorESM1 and ECHAM6, respectively, compared to modern-day equilibrium climate without anthropogenic aerosols. However, significant differences remain between the two GCMs' regional temperature responses around the Arctic circle and the Equator and precipitation responses in the tropics. The scatter in the simulated globally averaged responses is small in magnitude when compared against literature data from modern GCMs using model intrinsic aerosols but same aerosol emissions −(0.5–1.1) K and −(1.5–3.1) % for temperature and precipitation, respectively). The Pearson correlation of regional temperature (precipitation) response in these literature model experiments with intrinsic aerosols is 0.79 (0.34). The corresponding correlation coefficient for NorESM1 and ECHAM6 runs with identical aerosols is 0.78 (0.41). The lack of improvement in correlation coefficients between models with identical aerosols and models with intrinsic aerosols implies that the spatial distribution of regional climate responses is not improved via homogenizing the aerosol descriptions in the models. Rather, differences in the atmospheric dynamic and snow/sea ice cover responses dominate the differences in regional climate responses. Hence, even if we would have perfect aerosol descriptions inside the global climate models, uncertainty arising from the differences in circulation responses between the models would likely still result in a significant uncertainty in regional climate responses.

scholarly journals Understanding the surface temperature response and its uncertainty to CO<sub>2</sub>, CH<sub>4</sub>, black carbon, and sulfate

2021 ◽  
Vol 21 (19) ◽  
pp. 14941-14958
Author(s):  
Kalle Nordling ◽  
Hannele Korhonen ◽  
Jouni Räisänen ◽  
Antti-Ilari Partanen ◽  
Bjørn H. Samset ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
Surface Albedo ◽  
Climate Models ◽  
Temperature Response ◽  
Regional Model ◽  
Climate Forcing ◽  
Clear Sky ◽  
Temperature Responses ◽  
Global Surface

Abstract. Understanding the regional surface temperature responses to different anthropogenic climate forcing agents, such as greenhouse gases and aerosols, is crucial for understanding past and future regional climate changes. In modern climate models, the regional temperature responses vary greatly for all major forcing agents, but the causes of this variability are poorly understood. Here, we analyze how changes in atmospheric and oceanic energy fluxes due to perturbations in different anthropogenic climate forcing agents lead to changes in global and regional surface temperatures. We use climate model data on idealized perturbations in four major anthropogenic climate forcing agents (CO2, CH4, sulfate, and black carbon aerosols) from Precipitation Driver Response Model Intercomparison Project (PDRMIP) climate experiments for six climate models (CanESM2, HadGEM2-ES, NCAR-CESM1-CAM4, NorESM1, MIROC-SPRINTARS, GISS-E2). Particularly, we decompose the regional energy budget contributions to the surface temperature responses due to changes in longwave and shortwave fluxes under clear-sky and cloudy conditions, surface albedo changes, and oceanic and atmospheric energy transport. We also analyze the regional model-to-model temperature response spread due to each of these components. The global surface temperature response stems from changes in longwave emissivity for greenhouse gases (CO2 and CH4) and mainly from changes in shortwave clear-sky fluxes for aerosols (sulfate and black carbon). The global surface temperature response normalized by effective radiative forcing is nearly the same for all forcing agents (0.63, 0.54, 0.57, 0.61 K W−1 m2). While the main physical processes driving global temperature responses vary between forcing agents, for all forcing agents the model-to-model spread in temperature responses is dominated by differences in modeled changes in longwave clear-sky emissivity. Furthermore, in polar regions for all forcing agents the differences in surface albedo change is a key contributor to temperature responses and its spread. For black carbon, the modeled differences in temperature response due to shortwave clear-sky radiation are also important in the Arctic. Regional model-to-model differences due to changes in shortwave and longwave cloud radiative effect strongly modulate each other. For aerosols, clouds play a major role in the model spread of regional surface temperature responses. In regions with strong aerosol forcing, the model-to-model differences arise from shortwave clear-sky responses and are strongly modulated by combined temperature responses to oceanic and atmospheric heat transport in the models.

scholarly journals Sensitivity of black carbon concentrations and climate impact to aging and scavenging in OsloCTM2–M7

2017 ◽  
Vol 17 (9) ◽  
pp. 6003-6022 ◽  
Author(s):  
Marianne T. Lund ◽  
Terje K. Berntsen ◽  
Bjørn H. Samset
Keyword(s):  
Nitric Acid ◽  
Surface Temperature ◽  
Black Carbon ◽  
Radiative Forcing ◽  
Climate Models ◽  
Transport Model ◽  
Climate Impact ◽  
Climate Impacts ◽  
The Arctic ◽  
Effective Parameters

Abstract. Accurate representation of black carbon (BC) concentrations in climate models is a key prerequisite for understanding its net climate impact. BC aging and scavenging are treated very differently in current models. Here, we examine the sensitivity of three-dimensional (3-D), temporally resolved BC concentrations to perturbations to individual model processes in the chemistry transport model OsloCTM2–M7. The main goals are to identify processes related to aerosol aging and scavenging where additional observational constraints may most effectively improve model performance, in particular for BC vertical profiles, and to give an indication of how model uncertainties in the BC life cycle propagate into uncertainties in climate impacts. Coupling OsloCTM2 with the microphysical aerosol module M7 allows us to investigate aging processes in more detail than possible with a simpler bulk parameterization. Here we include, for the first time in this model, a treatment of condensation of nitric acid on BC. Using kernels, we also estimate the range of radiative forcing and global surface temperature responses that may result from perturbations to key tunable parameters in the model. We find that BC concentrations in OsloCTM2–M7 are particularly sensitive to convective scavenging and the inclusion of condensation by nitric acid. The largest changes are found at higher altitudes around the Equator and at low altitudes over the Arctic. Convective scavenging of hydrophobic BC, and the amount of sulfate required for BC aging, are found to be key parameters, potentially reducing bias against HIAPER Pole-to-Pole Observations (HIPPO) flight-based measurements by 60 to 90  %. Even for extensive tuning, however, the total impact on global-mean surface temperature is estimated to less than 0.04 K. Similar results are found when nitric acid is allowed to condense on the BC aerosols. We conclude, in line with previous studies, that a shorter atmospheric BC lifetime broadly improves the comparison with measurements over the Pacific. However, we also find that the model–measurement discrepancies can not be uniquely attributed to uncertainties in a single process or parameter. Model development therefore needs to be focused on improvements to individual processes, supported by a broad range of observational and experimental data, rather than tuning of individual, effective parameters such as the global BC lifetime.

scholarly journals Understanding the surface temperature response and its uncertainty to CO<sub>2</sub>, CH<sub>4</sub>, black carbon and sulfate

2021 ◽  
Author(s):  
Kalle Nordling ◽  
Hannele Korhonen ◽  
Jouni Räisänen ◽  
Antti-Ilari Partanen ◽  
Bjørn Samset ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
Surface Albedo ◽  
Climate Models ◽  
Temperature Response ◽  
Regional Model ◽  
Climate Forcing ◽  
Clear Sky ◽  
Temperature Responses ◽  
Global Surface

Abstract. Understanding the regional surface temperature responses to different anthropogenic climate forcing agents, such as greenhouse gases and aerosols, is crucial for understanding past and future regional climate changes. In modern climate models, the regional temperature responses vary greatly for all major forcing agents, but the causes of this variability are poorly understood. Here, we analyse how changes in atmospheric and oceanic energy fluxes due to perturbations in different anthropogenic climate forcing agents lead to changes in global and regional surface temperatures. We use climate model data on idealized perturbations in four major anthropogenic climate forcing agents (CO2, CH4, and sulfate and black carbon aerosols) from PDRMIP climate experiments for six climate models (CanESM2, HadGEM2-ES, NCAR-CESM1-CAM4, NorESM1, MIROC-SPRINTARS, GISS-E2). Particularly, we decompose the regional energy budget contributions to the surface temperature responses due to changes in longwave and shortwave fluxes under clear-sky and cloudy conditions, surface albedo changes, and oceanic and atmospheric energy transport. We also analyse the regional model-to-model temperature response spread due to each of these components. The global surface temperature response stems from changes in longwave emissivity for greenhouse gases (CO2 and CH4) and mainly from changes in shortwave clear-sky fluxes for aerosols (sulfate and black carbon). The global surface temperature response normalized by effective radiative forcing is nearly the same for all forcing agents (0.63, 0.54, 0.57, 0.61 KW−1 m2). While the main physical processes driving global temperature responses vary between forcing agents, for all forcing agents the model-to-model spread in temperature responses is dominated by differences in modelled changes in longwave clear-sky emissivity. Furthermore, in polar regions for all forcing agents the differences in surface albedo change is a key contributor to temperature responses and its spread. For black carbon the modelled differences in temperature response due to shortwave clear-sky radiation are also important in the Arctic. Regional model-to-model differences due to changes in shortwave and longwave cloud radiative effect strongly modulate each other. For aerosols clouds play a major role in the model spread of regional surface temperature responses. In regions with strong aerosol forcing the model-to-model differences arise from shortwave clear-sky responses and are strongly modulated by combined temperature responses to oceanic and atmospheric heat transport in the models.

scholarly journals How Asian aerosols impact regional surface temperatures across the globe

2020 ◽  
Author(s):  
Joonas Merikanto ◽  
Kalle Nordling ◽  
Petri Räisänen ◽  
Jouni Räisänen ◽  
Declan O'Donnell ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Temperature Effects ◽  
Energy Transport ◽  
Temperature Response ◽  
The Arctic ◽  
Anthropogenic Aerosols ◽  
Atmospheric Energy ◽  
Atmospheric Energy Transport ◽  
Temperature Responses ◽  
Global Surface

Abstract. South and East Asian anthropogenic aerosols mostly reside in an air mass extending from the Indian Ocean to the North Pacific. Yet the surface temperature effects of Asian aerosols spread across the whole globe. Here, we remove Asian anthropogenic aerosols from two independent climate models (ECHAM6.1 and NorESM1) using the same representation of aerosols via MACv2-SP (a simple plume implementation of the 2nd version of the Max Planck Institute Aerosol Climatology). We then robustly decompose the global distribution of surface temperature responses into contributions from atmospheric energy flux changes. We find that the horizontal atmospheric energy transport strongly moderates the surface temperature response over the regions where Asian aerosols reside. Atmospheric energy transport and changes in clear-sky longwave radiation redistribute the temperature effects efficiently across the Northern hemisphere, and to a lesser extent also over the Southern hemisphere. The model-mean global surface temperature response to Asian anthropogenic aerosol removal is 0.26 ± 0.04 °C (0.22 ± 0.03 for ECHAM6.1 and 0.30 ± 0.03 °C for NorESM1) of warming. Model-to-model differences in global surface temperature response mainly arise from differences in longwave cloud (0.01 ± 0.01 for ECHAM6.1 and 0.05 ± 0.01 °C for NorESM1) and shortwave cloud (0.03 ± 0.03 for ECHAM6.1 and 0.07 ± 0.02 °C for NorESM1) responses. The differences in cloud responses between the models also dominate the differences in regional temperature responses. In both models, the Northern hemispheric surface warming amplifies towards the Arctic, where the total temperature response is highly seasonal and weakest during the Arctic summer. We estimate that under a strong Asian aerosol mitigation policy tied with strong climate mitigation (Shared Socioeconomic Pathway 1-1.9) the Asian aerosol reductions can add around 8 years' worth of current day global warming during the next few decades.

scholarly journals Historical black carbon deposition in the Canadian High Arctic: A 190-year long ice-core record from Devon Island

2017 ◽  
Author(s):  
Christian M. Zdanowicz ◽  
Bernadette C. Proemse ◽  
Ross Edwards ◽  
Wang Feiteng ◽  
Chad M. Hogan ◽  
...  
Keyword(s):  
Black Carbon ◽  
20Th Century ◽  
Ice Core ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Large Variability ◽  
Coal Burning ◽  
Ice Cap ◽  
Devon Ice Cap ◽  
Ice Core Record

Abstract. Black carbon aerosol (BC) emitted from natural and anthropogenic sources (e.g., wildfires, coal burning) can contribute to magnify climate warming at high latitudes by darkening snow- and ice-covered surfaces, thus lowering their albedo. Modeling the atmospheric transport and deposition of BC to the Arctic is therefore important, and historical archives of BC accumulation in polar ice can help to validate such modeling efforts. Here we present a 190-year ice-core record of refractory BC (rBC) deposition on Devon ice cap, Canada, spanning calendar years 1810–1990, the first such record ever developed from the Canadian Arctic. The estimated mean deposition flux of rBC on Devon ice cap for 1963–1990 is 0.2 mg m−2 a−1, which is low compared to most Greenland ice-core sites over the same period. The Devon ice cap rBC record also differs from existing Greenland records in that it shows no evidence of a substantial increase in rBC deposition during the early-mid 20th century, which, for Greenland, has been attributed to mid-latitude coal burning emissions. The deposition of other contaminants such as sulfate and Pb increased on Devon ice cap in the 20th century but without a concomitant rise in rBC. Part of the difference with Greenland may be due to local factors such as wind scouring of winter snow at the coring site on Devon ice cap. Air back-trajectory analyses also suggest that Devon ice cap receives BC from more distant North American and Eurasian sources than Greenland, and aerosol mixing and removal during long-range transport over the Arctic Ocean likely masks some of the specific BC source-receptor relationships. Findings from this study underscore the large variability in BC aerosol deposition across the Arctic region that may arise from different transport patterns. This variability needs to be accounted for when estimating the large-scale albedo lowering effect of BC deposition on Arctic snow/ice.

scholarly journals Rapid and reliable assessment of methane impacts on climate

2018 ◽  
Author(s):  
Ilissa B. Ocko ◽  
Vaishali Naik ◽  
David Paynter
Keyword(s):  
Carbon Dioxide ◽  
Climate Models ◽  
Climate Model ◽  
Temporal Dynamics ◽  
Methane Emissions ◽  
Basic Knowledge ◽  
Reliable Assessment ◽  
Reduced Complexity ◽  
Temperature Responses ◽  
Climate Responses

Abstract. It is clear that the most effective way to limit global temperature rise and associated impacts is to reduce human emissions of greenhouse gases, including methane. However, quantification of the climate benefits of mitigation options are complicated by the contrast in the timescales at which short-lived climate pollutants, such as methane, persist in the atmosphere as compared to carbon dioxide. Whereas simple metrics fail to capture the differential impacts across all timescales, sophisticated climate models that can address these temporal dynamics are often inaccessible, time-intensive, and require special infrastructure. Reduced-complexity models offer an ideal compromise in that they provide quick, reliable insights into the benefits across types of climate pollutants using basic knowledge and limited computational infrastructure. In this paper, we build on previous evaluations of the freely-available and easy-to-run reduced-complexity climate model MAGICC by confirming its ability to reproduce temperature responses to historical methane emissions. By comparing MAGICC model results to those from the reference GFDL CM3 coupled global chemistry-climate model, we build confidence in using MAGICC for purposes of understanding the climate implications of methane mitigation. MAGICC can easily and rapidly provide robust data on climate responses to changes in methane emissions.

scholarly journals Enhancement of snow albedo reduction and radiative forcing due to coated black carbon in snow

2021 ◽  
Vol 15 (5) ◽  
pp. 2255-2272
Author(s):  
Wei Pu ◽  
Tenglong Shi ◽  
Jiecan Cui ◽  
Yang Chen ◽  
Yue Zhou ◽  
...  
Keyword(s):  
Black Carbon ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Climate Models ◽  
Northern China ◽  
Climate Impact ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Core Shell ◽  
Snow Albedo

Abstract. When black carbon (BC) is mixed internally with other atmospheric particles, the BC light absorption effect is enhanced. This study explicitly resolved the optical properties of coated BC in snow based on the core / shell Mie theory and the Snow, Ice, and Aerosol Radiative (SNICAR) model. Our results indicated that the BC coating effect enhances the reduction in snow albedo by a factor ranging from 1.1–1.8 for a nonabsorbing shell and 1.1–1.3 for an absorbing shell, depending on the BC concentration, snow grain radius, and core / shell ratio. We developed parameterizations of the BC coating effect for application to climate models, which provides a convenient way to accurately estimate the climate impact of BC in snow. Finally, based on a comprehensive set of in situ measurements across the Northern Hemisphere, we determined that the contribution of the BC coating effect to snow light absorption exceeds that of dust over northern China. Notably, high enhancements of snow albedo reduction due to the BC coating effect were found in the Arctic and Tibetan Plateau, suggesting a greater contribution of BC to the retreat of Arctic sea ice and Tibetan glaciers.

scholarly journals Siberian Arctic black carbon: gas flaring and wildfire impact

2021 ◽  
Author(s):  
Olga B. Popovicheva ◽  
Nikolaos Evangeliou ◽  
Vasilii O. Kobelev ◽  
Marina A. Chichaeva ◽  
Konstantinos Eleftheriadis ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Western Siberia ◽  
Oil And Gas ◽  
Cold Period ◽  
The Arctic ◽  
Transport Modelling ◽  
Large Variability ◽  
Gas Flaring ◽  
Siberian Arctic

Abstract. As explained in the latest Arctic Monitoring and Assessment Programme (AMAP) report released in early 2021, the Arctic has warmed three times more quickly than the planet as a whole, and faster than previously thought. The Siberian Arctic is of great interest largely because observations are sparse or largely lacking. A research aerosol station has been developed on the Bely Island, Kara Sea, in Western Siberia. Measurements of equivalent black carbon (EBC) concentrations were carried out at the “Island Bely” station continuously from August 2019 to November 2020. The source origin of the measured EBC, and the main contributing sources were assessed using atmospheric transport modelling coupled with the most updated emission inventories for anthropogenic and biomass burning sources of BC. The obtained BC climatology for BC during the period of measurements showed a seasonal variation comprising the highest concentrations between December and April (60 ± 92 ng/m3) and the lowest between June and September (18 ± 72 ng/m3), typical of the Arctic Haze seasonality reported elsewhere. When air masses arrived at the station through the biggest oil and gas extraction regions of Kazakhstan, Volga-Ural, Komi, Nenets and Western Siberia, BC contribution from gas flaring dominated over domestic, industrial, and traffic sectors, ranging from 47 to 68 %, with a maximum contribution in January. When air was transported from Europe during the cold season, emissions from transportation became important. Accordingly, shipping emissions increased due to the touristic cruise activities and the ice retreat in summertime. Biomass burning (BB) played the biggest role between April and October, contributing 81 % at maximum in June. Long-range transport of BB aerosols appear to induce large variability to the Absorption Ångström Exponent (AAE) with values ranging from 1.2 to 1.4. As regards to the continental contribution to surface BC at the “Island Bely” station, Russian emissions dominated during the whole year, while European and Asian emissions contributed up to 20 % in the cold period. Quantification of several pollution episodes showed an increasing trend in surface concentrations and frequency during the cold period as the station is directly in the Siberian gateway of the highest anthropogenic pollution to the Russian Arctic.

Sign in / Sign up

Export Citation Format

Share Document