scholarly journals Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies

2007 ◽  
Vol 7 (6) ◽  
pp. 15669-15692 ◽  
Author(s):  
P. K. Quinn ◽  
T. S. Bates ◽  
E. Baum ◽  
N. Doubleday ◽  
A. M. Fiore ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Tropospheric Ozone ◽  
Temperature Increase ◽  
Current Knowledge ◽  
Temperature Response ◽  
Climate Impact ◽  
Mitigation Strategies ◽  
Arctic Climate ◽  
The Arctic ◽  
Future Research

Abstract. Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources, the mechanism of forcing, seasonally averaged forcing values for the Arctic, and the corresponding surface temperature response. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address remaining uncertainties.

scholarly journals Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies

2008 ◽  
Vol 8 (6) ◽  
pp. 1723-1735 ◽  
Author(s):  
P. K. Quinn ◽  
T. S. Bates ◽  
E. Baum ◽  
N. Doubleday ◽  
A. M. Fiore ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Current Knowledge ◽  
Temperature Response ◽  
Climate Impact ◽  
Mitigation Strategies ◽  
Arctic Climate ◽  
The Arctic ◽  
Future Research ◽  
Surface Warming ◽  
Reduce Emissions

Abstract. Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources and the mechanism of forcing. We also provide the first seasonally averaged forcing and corresponding temperature response estimates focused specifically on the Arctic. The calculations indicate that the forcings due to black carbon, methane, and tropospheric ozone lead to a positive surface temperature response indicating the need to reduce emissions of these species within and outside the Arctic. Additional aerosol species may also lead to surface warming if the aerosol is coincident with thin, low lying clouds. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address the large remaining uncertainties.

scholarly journals The Arctic response to remote and local forcing of black carbon

2012 ◽  
Vol 12 (7) ◽  
pp. 18379-18418 ◽  
Author(s):  
M. Sand ◽  
T. K. Berntsen ◽  
J. E. Kay ◽  
J. F. Lamarque ◽  
Ø. Seland ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Temperature Response ◽  
Mitigation Strategies ◽  
Arctic Climate ◽  
The Arctic ◽  
Comprehensive Treatment ◽  
Model Calculations ◽  
The Impact ◽  
Ice Fraction

Abstract. Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend on the location of the forcing. We investigate how BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to BC located in the Arctic it self. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to determine how BC transported to the Arctic and BC sources not reaching the Arctic impact the Arctic climate, forcing from BC aerosols is artificially increased by a factor of 10 in different latitude bands in the mid-latitudes (28° N–60° N) and in the Arctic (60° N–90° N), respectively. Estimates of the impact on the Arctic energy budget are represented by analyzing radiation fluxes at the top of the atmosphere, at the surface and at the lateral boundaries. Our calculations show that increased BC forcing in the Arctic atmosphere reduces the surface air temperature in the Arctic with a corresponding increase in the sea-ice fraction, despite the increased planetary absorption of sunlight. The analysis indicates that this effect may be due to a combination of a weakening of the northward heat transport caused by a reduction in the meridional temperature gradient and a reduction in the turbulent mixing of heat downward to the surface. The latter factor is explained by the fact that most of the BC is located in the free troposphere and causes a warming at higher altitudes which increases the static stability in the Arctic. On the other hand we find that BC forcing at the mid-latitudes warms the Arctic surface significantly and decreases the sea-ice fraction. Our model calculations indicate that atmospheric BC forcing outside the Arctic is more important for the Arctic climate change than the forcing in the Arctic itself. Although the albedo effect of BC on snow does show a more regional response to an Arctic forcing, these results suggest that mitigation strategies for the Arctic climate should also address BC sources in locations outside the Arctic even if they do not contribute much to BC in the Arctic.

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 Nitrogen Fixation in a Changing Arctic Ocean: An Overlooked Source of Nitrogen?

2020 ◽  
Vol 11 ◽  
Author(s):  
Lisa W. von Friesen ◽  
Lasse Riemann
Keyword(s):  
Climate Change ◽  
Nitrogen Fixation ◽  
Primary Production ◽  
Arctic Ocean ◽  
Current Knowledge ◽  
Carbon Sink ◽  
Spatial Scales ◽  
The Arctic ◽  
Future Research ◽  
The Arctic Ocean

The Arctic Ocean is the smallest ocean on Earth, yet estimated to play a substantial role as a global carbon sink. As climate change is rapidly changing fundamental components of the Arctic, it is of local and global importance to understand and predict consequences for its carbon dynamics. Primary production in the Arctic Ocean is often nitrogen-limited, and this is predicted to increase in some regions. It is therefore of critical interest that biological nitrogen fixation, a process where some bacteria and archaea termed diazotrophs convert nitrogen gas to bioavailable ammonia, has now been detected in the Arctic Ocean. Several studies report diverse and active diazotrophs on various temporal and spatial scales across the Arctic Ocean. Their ecology and biogeochemical impact remain poorly known, and nitrogen fixation is so far absent from models of primary production in the Arctic Ocean. The composition of the diazotroph community appears distinct from other oceans – challenging paradigms of function and regulation of nitrogen fixation. There is evidence of both symbiotic cyanobacterial nitrogen fixation and heterotrophic diazotrophy, but large regions are not yet sampled, and the sparse quantitative data hamper conclusive insights. Hence, it remains to be determined to what extent nitrogen fixation represents a hitherto overlooked source of new nitrogen to consider when predicting future productivity of the Arctic Ocean. Here, we discuss current knowledge on diazotroph distribution, composition, and activity in pelagic and sea ice-associated environments of the Arctic Ocean. Based on this, we identify gaps and outline pertinent research questions in the context of a climate change-influenced Arctic Ocean – with the aim of guiding and encouraging future research on nitrogen fixation in this region.

scholarly journals Global and Arctic climate engineering: numerical model studies

2008 ◽  
Vol 366 (1882) ◽  
pp. 4039-4056 ◽  
Author(s):  
Ken Caldeira ◽  
Lowell Wood
Keyword(s):  
Temperature Response ◽  
Climate System ◽  
Arctic Climate ◽  
The Arctic ◽  
High Latitudes ◽  
Climate Engineering ◽  
Model Studies ◽  
Global Mean Temperature ◽  
Albedo Change ◽  
Global Mean

We perform numerical simulations of the atmosphere, sea ice and upper ocean to examine possible effects of diminishing incoming solar radiation, insolation, on the climate system. We simulate both global and Arctic climate engineering in idealized scenarios in which insolation is diminished above the top of the atmosphere. We consider the Arctic scenarios because climate change is manifesting most strongly there. Our results indicate that, while such simple insolation modulation is unlikely to perfectly reverse the effects of greenhouse gas warming, over a broad range of measures considering both temperature and water, an engineered high CO 2 climate can be made much more similar to the low CO 2 climate than would be a high CO 2 climate in the absence of such engineering. At high latitudes, there is less sunlight deflected per unit albedo change but climate system feedbacks operate more powerfully there. These two effects largely cancel each other, making the global mean temperature response per unit top-of-atmosphere albedo change relatively insensitive to latitude. Implementing insolation modulation appears to be feasible.

scholarly journals Antarctic climate change and the environment

2009 ◽  
Vol 21 (6) ◽  
pp. 541-563 ◽  
Author(s):  
P. Convey ◽  
R. Bindschadler ◽  
G. di Prisco ◽  
E. Fahrbach ◽  
J. Gutt ◽  
...  
Keyword(s):  
Numerical Models ◽  
Global Climate ◽  
Climate Impact ◽  
Climate System ◽  
Arctic Climate ◽  
The Arctic ◽  
Historical Period ◽  
Climate Impact Assessment ◽  
Arctic Climate Impact Assessment ◽  
The Antarctic

AbstractThe Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (∼the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.

scholarly journals Arctic Climate Variability and Trends from Satellite Observations

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Xuanji Wang ◽  
Jeffrey Key ◽  
Yinghui Liu ◽  
Charles Fowler ◽  
James Maslanik ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Surface Temperature ◽  
Cloud Fraction ◽  
Arctic Sea Ice ◽  
Satellite Observations ◽  
Arctic Climate ◽  
The Arctic ◽  
Climate Indices ◽  
Surface Warming

Arctic climate has been changing rapidly since the 1980s. This work shows distinctly different patterns of change in winter, spring, and summer for cloud fraction and surface temperature. Satellite observations over 1982–2004 have shown that the Arctic has warmed up and become cloudier in spring and summer, but cooled down and become less cloudy in winter. The annual mean surface temperature has increased at a rate of 0.34°C per decade. The decadal rates of cloud fraction trends are −3.4%, 2.3%, and 0.5% in winter, spring, and summer, respectively. Correspondingly, annually averaged surface albedo has decreased at a decadal rate of −3.2%. On the annual average, the trend of cloud forcing at the surface is −2.11 W/m2per decade, indicating a damping effect on the surface warming by clouds. The decreasing sea ice albedo and surface warming tend to modulate cloud radiative cooling effect in spring and summer. Arctic sea ice has also declined substantially with decadal rates of −8%, −5%, and −15% in sea ice extent, thickness, and volume, respectively. Significant correlations between surface temperature anomalies and climate indices, especially the Arctic Oscillation (AO) index, exist over some areas, implying linkages between global climate change and Arctic climate change.

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

2021 ◽  
Vol 21 (8) ◽  
pp. 5865-5881
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 second 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 Isolating the Temperature Feedback Loop and Its Effects on Surface Temperature

2016 ◽  
Vol 73 (8) ◽  
pp. 3287-3303 ◽  
Author(s):  
Sergio A. Sejas ◽  
Ming Cai
Keyword(s):  
Surface Temperature ◽  
Feedback Loop ◽  
Temperature Response ◽  
Feedback Loops ◽  
The Arctic ◽  
Response Analysis ◽  
Surface Warming ◽  
Temperature Feedback ◽  
The Tropics ◽  
Temperature Responses

Abstract Climate feedback processes are known to substantially amplify the surface warming response to an increase of greenhouse gases. When the forcing and feedbacks modify the temperature response they trigger temperature feedback loops that amplify the direct temperature changes due to the forcing and nontemperature feedbacks through the thermal–radiative coupling between the atmosphere and surface. This study introduces a new feedback-response analysis method that can isolate and quantify the effects of the temperature feedback loops of individual processes on surface temperature from their corresponding direct surface temperature responses. The authors analyze a 1% yr−1 increase of CO2 simulation of the NCAR CCSM4 at the time of CO2 doubling to illustrate the new method. The Planck sensitivity parameter, which indicates colder regions experience stronger surface temperature responses given the same change in surface energy flux, is the inherent factor that leads to polar warming amplification (PWA). This effect explains the PWA in the Antarctic, while the direct temperature response to the albedo and cloud feedbacks further explains the greater PWA of the Arctic. Temperature feedback loops, particularly the one associated with the albedo feedback, further amplify the Arctic surface warming relative to the tropics. In the tropics, temperature feedback loops associated with the CO2 forcing and water vapor feedback cause most of the surface warming. Overall, the temperature feedback is responsible for most of the surface warming globally, accounting for nearly 76% of the global-mean surface warming. This is 3 times larger than the next largest warming contribution, indicating that the temperature feedback loop is the preeminent contributor to the surface warming.

scholarly journals Process drivers, inter-model spread, and the path forward: A review of amplified Arctic warming

2021 ◽  
Author(s):  
Patrick Taylor ◽  
Robyn Boeke ◽  
Linette Boisvert ◽  
Nicole Feldl ◽  
Matthew Henry ◽  
...  
Keyword(s):  
Conceptual Model ◽  
Current Knowledge ◽  
Stable Stratification ◽  
Surface Energy Budget ◽  
Arctic Climate ◽  
Climate Feedback ◽  
Future Research ◽  
Climate Projections ◽  
Driving Mechanisms ◽  
Near Term

Arctic amplification (AA) is a coupled atmosphere-sea ice-ocean process. This understanding has evolved from the early concept of AA, as a consequence of snow-ice line progressions, through more than a century of research that has clarified the relevant processes and driving mechanisms of AA. The predictions made by early modeling studies, namely the fall/winter maximum, bottom-heavy structure, the prominence of surface albedo feedback, and the importance of stable stratification have withstood the scrutiny of multi-decadal observations and more complex models. Yet, the uncertainty in Arctic climate projections is larger than in any other region of the planet, making assessment of high-impact, near-term regional changes difficult or impossible. Reducing this large spread in Arctic climate projections requires a quantitative process understanding. This manuscript aims to build such understanding by synthesizing current knowledge of AA and to produce a set of recommendations to guide future research. It briefly reviews the history of AA science, summarizes observed Arctic changes, discusses modeling approaches and feedback diagnostics, and assesses the current understanding of the most relevant feedbacks to AA. These sections culminate in a conceptual model of the fundamental physical mechanisms causing AA and a collection of recommendations to accelerate progress towards reduced uncertainty in Arctic climate projections. Our conceptual model highlights the need to account for local feedback and remote process interactions, specifically the water vapor triple effect, within the context of the annual cycle to constrain projected AA. We recommend raising the priority of Arctic climate sensitivity research, improving the accuracy of Arctic surface energy budget observations, rethinking climate feedback definitions, coordinating new model experiments and intercomparisons, and pursuing the role of episodic variability in AA as a research focus area.

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