Stronger Arctic amplification from ozone-depleting substances than from carbon dioxide

Abstract Arctic amplification (AA) - the greater warming of the Arctic near-surface temperature relative to its global mean value - is a prominent feature of the climate response to increasing greenhouse gases. Recent work has revealed the importance of ozone-depleting substances (ODS) in contributing to Arctic warming and sea-ice loss. Here, using ensembles of climate model integrations, we expand on that work and directly contrast Arctic warming from ODS to that from carbon dioxide (CO$_2$), over the 1955-2005 period when ODS loading peaked. We find that the Arctic warming and sea-ice loss from ODS are slightly more than half (52-59\%) those from CO$_2$. We further show that the strength of AA for ODS is 1.44 times larger than that for CO$_2$, and that this mainly stems from more positive Planck, albedo, lapse-rate, and cloud feedbacks. Our results suggest that AA would be considerably stronger than presently observed had the Montreal Protocol not been signed.

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Substantial twentieth-century Arctic warming caused by ozone-depleting substances

10.5194/egusphere-egu2020-3961 ◽

2020 ◽

Author(s):

Lorenzo Polvani ◽

Michael Previdi ◽

Mark England ◽

Gabriel Chiodo ◽

Karen Smith

Keyword(s):

Climate Change ◽

Twentieth Century ◽

Greenhouse Gases ◽

Climate Model ◽

Dominant Role ◽

Montreal Protocol ◽

The Arctic ◽

Atmospheric Concentration ◽

Arctic Warming ◽

Ozone Depleting Substances

The rapid warming of the Arctic, perhaps the most striking evidence of climate change, is believed to arise from increases in atmospheric concentration of greenhouse gases since the industrial revolution. &#160;While the dominant role of carbon dioxide is undisputed, another important set of anthropogenic greenhouse gases was also being emitted over the second half of the twentieth century: ozone-depleting substances (ODS). &#160;These compounds, in addition to causing the ozone hole over Antarctica, have long been recognized as powerful greenhouse gases. &#160;However, their contribution to Arctic warming has not been quantified to date. &#160;We do so here by analyzing ensembles of climate model integrations specifically designed for this purpose, spanning the period 1955-2005 when atmospheric concentrations of ODS increased rapidly. &#160;We show that when ODS are kept fixed the forced Arctic surface warming, and the forced sea ice loss, are only half as large as when ODS are allowed to increase. &#160;We also demonstrate that the large Arctic impact of ODS occurs primarily via direct radiative warming, not via ozone depletion. &#160;Our findings reveal a substantial, and hitherto unrecognized, contribution of ODS to recent Arctic warming and highlight the importance of the Montreal Protocol as a major climate change mitigation treaty.

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Mid-Holocene Northern Hemisphere warming driven by Arctic amplification

Science Advances ◽

10.1126/sciadv.aax8203 ◽

2019 ◽

Vol 5 (12) ◽

pp. eaax8203 ◽

Cited By ~ 3

Author(s):

Hyo-Seok Park ◽

Seong-Joong Kim ◽

Andrew L. Stewart ◽

Seok-Woo Son ◽

Kyong-Hwan Seo

Keyword(s):

Sea Ice ◽

Northern Hemisphere ◽

High Latitude ◽

Climate Model ◽

Arctic Sea Ice ◽

The Arctic ◽

Arctic Amplification ◽

The Holocene ◽

Holocene Thermal Maximum ◽

Thermal Maximum

The Holocene thermal maximum was characterized by strong summer solar heating that substantially increased the summertime temperature relative to preindustrial climate. However, the summer warming was compensated by weaker winter insolation, and the annual mean temperature of the Holocene thermal maximum remains ambiguous. Using multimodel mid-Holocene simulations, we show that the annual mean Northern Hemisphere temperature is strongly correlated with the degree of Arctic amplification and sea ice loss. Additional model experiments show that the summer Arctic sea ice loss persists into winter and increases the mid- and high-latitude temperatures. These results are evaluated against four proxy datasets to verify that the annual mean northern high-latitude temperature during the mid-Holocene was warmer than the preindustrial climate, because of the seasonally rectified temperature increase driven by the Arctic amplification. This study offers a resolution to the “Holocene temperature conundrum”, a well-known discrepancy between paleo-proxies and climate model simulations of Holocene thermal maximum.

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The Emergence and Transient Nature of Arctic Amplification in Coupled Climate Models

Frontiers in Earth Science ◽

10.3389/feart.2021.719024 ◽

2021 ◽

Vol 9 ◽

Author(s):

Marika M. Holland ◽

Laura Landrum

Keyword(s):

Sea Ice ◽

21St Century ◽

Climate Models ◽

Internal Variability ◽

The Arctic ◽

Arctic Amplification ◽

Arctic Warming ◽

Transient Nature ◽

Coupled Climate Models ◽

Large Ensembles

Under rising atmospheric greenhouse gas concentrations, the Arctic exhibits amplified warming relative to the globe. This Arctic amplification is a defining feature of global warming. However, the Arctic is also home to large internal variability, which can make the detection of a forced climate response difficult. Here we use results from seven model large ensembles, which have different rates of Arctic warming and sea ice loss, to assess the time of emergence of anthropogenically-forced Arctic amplification. We find that this time of emergence occurs at the turn of the century in all models, ranging across the models by a decade from 1994–2005. We also assess transient changes in this amplified signal across the 21st century and beyond. Over the 21st century, the projections indicate that the maximum Arctic warming will transition from fall to winter due to sea ice reductions that extend further into the fall. Additionally, the magnitude of the annual amplification signal declines over the 21st century associated in part with a weakening albedo feedback strength. In a simulation that extends to the 23rd century, we find that as sea ice cover is completely lost, there is little further reduction in the surface albedo and Arctic amplification saturates at a level that is reduced from its 21st century value.

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Variations in Atmospheric Energy Transport across the Arctic Circle

10.5194/dach2022-124 ◽

2021 ◽

Author(s):

Ines Höschel ◽

Dörthe Handorf ◽

Annette Rinke ◽

Hélène Bresson

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Energy Transport ◽

Lapse Rate ◽

The Arctic ◽

Arctic Amplification ◽

Annual Average ◽

Arctic Circle ◽

Ice Melt ◽

Static Energy

Understanding the variability of energy transport and its components, and the mechanisms involved, is critical to improve our understanding of the Arctic amplification. Large amounts of energy are transported from the equator to the poles by the large-scale atmospheric circulation. At the Arctic Circle, this represents an annual average net transport of about two PW. The energy transport can be divided into latent and dry static components which, when increasing, indirectly contribute to the Arctic amplification. While the enhanced dry static energy transport favors sea ice melt and changes the lapse rate, the enhanced influx of latent energy affects the water vapor content and cloud formation, and thus also the lapse rate and sea ice melt via radiative effects. In this study, 40 years (1979-2018) of 6-hourly ERA-Interim reanalysis data are used to calculate the energy transport and its components. Inconsistencies due to spurious mass-flux are accounted for by barotropic wind field correction before the calculation. The first and last decade of the ERA-Interim period differ in terms of sea ice cover, sea surface temperature, and greenhouse gas concentrations, all of which affect the atmospheric circulation. The comparison between these periods shows significant changes in monthly and annual vertically integrated energy transport across the Arctic Circle. On an annual average, energy transport significantly increases in the late period for both total energy and its components, whereas the transport of dry static energy decreases in the winter season. The analysis of the atmospheric circulation reveals variations in the frequency of occurrence of preferred circulation regimes and the associated anomalies in energy transport as a potential cause for the observed changes. The hemispheric-scale and climatological view provides an expanded overall picture in terms of poleward energy transport to atmospheric events as cold air outbreaks and atmospheric rivers. This is demonstrated using the example of the atmospheric river which occurred over Svalbard on 6th & 7th June 2017.

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An energy budget approach to understand the Arctic warming during the Last Interglacial

10.5194/cp-2021-70 ◽

2021 ◽

Author(s):

Marie Sicard ◽

Masa Kageyama ◽

Sylvie Charbit ◽

Pascale Braconnot ◽

Jean-Baptiste Madeleine

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Air Temperature ◽

Energy Budget ◽

Surface Air Temperature ◽

The Arctic ◽

Last Interglacial ◽

Near Surface ◽

Arctic Warming ◽

The Arctic Ocean

Abstract. The Last Interglacial period (129–116 ka BP) is characterized by a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the pre-industrial period. In particular, these changes amplify the seasonality of the insolation in the high latitudes of the northern hemisphere. Here, we investigate the Arctic climate response to this forcing by comparing the CMIP6 lig127k and pi-Control simulations performed with the IPSL-CM6A-LR model. Using an energy budget framework, we analyse the interactions between the atmosphere, ocean, sea ice and continents. In summer, the insolation anomaly reaches its maximum and causes a near-surface air temperature rise of 3.2 °C over the Arctic region. This warming is primarily due to a strong positive surface downwelling shortwave radiation anomaly over continental surfaces, followed by large heat transfers from the continents back to the atmosphere. The surface layers of the Arctic Ocean also receives more energy, but in smaller quantity than the continents due to a cloud negative feedback. Furthermore, while heat exchanges from the continental surfaces towards the atmosphere are strengthened, the ocean absorbs and stores the heat excess due to a decline in sea ice cover. However, the maximum near-surface air temperature anomaly does not peak in summer like insolation, but occurs in autumn with a temperature increase of 4.0 °C relative to the pre-industrial period. This strong warming is driven by a positive anomaly of longwave radiations over the Arctic ocean enhanced by a positive cloud feedback. It is also favoured by the summer and autumn Arctic sea ice retreat (−1.9 × 106 and −3.4 × 106 km2 respectively), which exposes the warm oceanic surface and allows heat stored by the ocean in summer and water vapour to be released. This study highlights the crucial role of the sea ice cover variations, the Arctic ocean, as well as changes in polar clouds optical properties on the Last Interglacial Arctic warming.

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Arctic amplification as a rapid response to increased CO2

10.5194/egusphere-egu21-8500 ◽

2021 ◽

Author(s):

Tyler Janoski ◽

Michael Previdi ◽

Gabriel Chiodo ◽

Karen Smith ◽

Lorenzo Polvani

Keyword(s):

Sea Ice ◽

General Circulation ◽

Coupled Model ◽

General Circulation Models ◽

Forced Response ◽

Arctic Sea Ice ◽

Lapse Rate ◽

The Arctic ◽

Cmip5 Models ◽

Arctic Amplification

Arctic amplification (AA), or enhanced surface warming of the Arctic, is ubiquitous in observations, and in model simulations subjected to increased greenhouse gas (GHG) forcing. Despite its importance, the mechanisms driving AA are not entirely understood. Here, we show that in CMIP5 (Coupled Model Intercomparison Project 5) general circulation models (GCMs), AA develops within a few months following an instantaneous quadrupling of atmospheric CO2. We find that this rapid AA response can be attributed to the lapse rate feedback, which acts to disproportionately warm the Arctic, even before any significant changes in Arctic sea ice occur. Only on longer timescales (beyond the first few months) does the decrease in sea ice become an important contributor to AA via the albedo feedback and increased ocean-to-atmosphere heat flux. An important limitation of our CMIP5 analysis is that internal climate variability is large on the short time scales considered. To overcome this limitation &#8211; and thus better isolate the GHG-forced response &#8211; we produced a large ensemble (100 members) of instantaneous CO2-quadrupling simulations using a single GCM, the NCAR Community Earth System Model (CESM1). In our new CESM1 ensemble we find the same rapid AA response seen in the CMIP5 models, confirming that AA ultimately owes its existence to fast atmospheric processes.

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Stable climate and surface mass balance in Svalbard over 1979–2013 despite the Arctic warming

The Cryosphere ◽

10.5194/tc-9-83-2015 ◽

2015 ◽

Vol 9 (1) ◽

pp. 83-101 ◽

Cited By ~ 33

Author(s):

C. Lang ◽

X. Fettweis ◽

M. Erpicum

Keyword(s):

Mass Balance ◽

Atmospheric Circulation ◽

Climate Model ◽

Coupled Model ◽

Recent Change ◽

The Arctic ◽

Surface Mass Balance ◽

Near Surface ◽

Arctic Warming ◽

Surface Mass

Abstract. With the help of the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-Interim reanalysis (MARERA) and the MIROC5 (Model for Interdisciplinary Research on Climate) global model (MARMIROC5) from the CMIP5 (Coupled Model Intercomparison Project) database, we have modelled the climate and surface mass balance of Svalbard at a 10 km resolution over 1979–2013. The integrated total surface mass balance (SMB) over Svalbard modelled by MARERA is negative (−1.6 Gt yr−1) with a large interannual variability (7.1 Gt) but, unlike over Greenland, there has been no acceleration of the surface melt over the past 35 years because of the recent change in atmospheric circulation bringing northwesterly flows in summer over Svalbard, contrasting the recent observed Arctic warming. However, in 2013, the atmospheric circulation changed to a south–southwesterly flow over Svalbard causing record melt, SMB (−20.4 Gt yr−1) and summer temperature. MIROC5 is significantly colder than ERA-Interim over 1980–2005 but MARMIROC5 is able to improve the near-surface MIROC5 results by simulating not significant SMB differences with MARERA over 1980–2005. On the other hand, MIROC5 does not represent the recent atmospheric circulation shift in summer and induces in MARMIROC5 a significant trend of decreasing SMB (−0.6 Gt yr−2) over 1980–2005.

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The NorESM1-Happi used for evaluating differences between a global warming of 1.5 °C and 2 °C, and the role of Arctic Amplification

10.5194/esd-2017-115 ◽

2017 ◽

Cited By ~ 4

Author(s):

Trond Iversen ◽

Ingo Bethke ◽

Jens B. Debernard ◽

Lise S. Graff ◽

Øyvind Seland ◽

...

Keyword(s):

Global Change ◽

Sea Ice ◽

Extratropical Cyclone ◽

The Arctic ◽

Cmip5 Models ◽

Arctic Amplification ◽

Near Surface ◽

Model Simulations ◽

Slab Ocean ◽

Fully Coupled

Abstract. Abstract. The global NorESM1-M model that produced results for CMIP5 (http://cmip-pcmdi.llnl.gov/cmip5/index.html) has been slightly upgraded to NorESM1-Happi, and has been run with double resolution (~ 1° in the atmosphere and the land surface) to provide model simulations to address the differences between a 1.5 °C and a 2.0 °C warmer climate than the 1850 pre-industrial. As a part of the validation of temperature-targeted model simulations, the atmosphere and land models have been run fully coupled with deep ocean and sea-ice as an extension of the NorESM1-M which produced CMIP5-results. Selected results from a standard set of validation experiments are discussed: a 500-year 1850 pre-industrial control run, three runs for the historical period 1850–2005, three detection and attribution runs, and three future projection runs based on RCPs. NorESM1-Happi has a better representation of sea-ice, improved Northern Hemisphere (NH) extratropical cyclone and blocking activity, and a fair representation of the Madden-Julian oscillation. The amplitude of ENSO signals is reduced and is too small, although the frequency is improved. The strength of the AMOC is larger and probably too large. Modern era global near-surface temperatures and the cloudiness are considerably under-estimated, while the precipitation and the intensity of the hydrological cycle are over-estimated, although the atmospheric residence time of water-vapour appears satisfactory. An ensemble of AMIP-type runs with prescribed SSTs and sea-ice from observations at present-day and a set of global CMIP5 models for a 1.5 °C and a 2.0 °C world (i.e. AMIP) has been provided by the model to a multi-model project (HAPPI, http://www.happimip.org/). This paper concentrates on the results from the NorESM1-Happi AMIP runs, which are compared to results from a slab-ocean version of the model (NorESM1-HappiSO) designed to emulate the AMIP simulation allowing SST and sea-ice to respond. The paper discusses the Arctic Amplification of the global change signal. The slab-ocean results generally show stronger response than the AMIP results to a global change, such as reduced NH extratropical cyclone activity, and different changes in the occurrence of blocking. A considerable difference in the reduction of sea-ice in the Arctic between a 1.5 °C and a 2.0 °C world is simulated. Ice-free summer conditions in the Arctic is estimated to be very rare for the 1.5 °C case, but to occur 40 % of the time for the 2.0 °C case. These results agree with some fully coupled models, but need to be further confirmed.

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A Robust Arctic Amplification Factor Throughout the Last 21,000 Years

10.21203/rs.3.rs-1111875/v1 ◽

2022 ◽

Author(s):

Yuzhen Yan ◽

Xinyu Wen

Keyword(s):

Sea Ice ◽

Climate Model ◽

Arctic Sea Ice ◽

The Arctic ◽

Climate Projections ◽

Arctic Amplification ◽

The Past ◽

Wide Range ◽

Arctic Sea ◽

New Evidence

Abstract Arctic amplification (AA), a phenomenon that a larger change in temperature near the Arctic areas than the Northern Hemisphere average in the past 100+ years, has significant impacts on mid-latitude weather and climate, and therefore is of great concern in current climate projections. Previous studies suggest a wide range of AA factors from 1.0 to 12.5 using either the 20th century observations or climate model hindcasts. In the present paper, we explore the diversity of AA factor in a long-term transient simulation covering the past glacial-to-interglacial years. It is shown that the natural AA phenomenon is essentially linked with North Atlantic sea ice changes through ice-albedo feedback with a narrowed and robust AA factor of 2.5±0.8 throughout the last 21,000 years. Current observed AA phenomenon is a mixed result combining sea ice melting induced AA mode with GHGs induced global uniform warming, and thus has an AA factor slightly less than 2.5. In the future, as Arctic sea ice gradually melts off, we speculate that AA phenomenon might fade off accordingly and the AA factor will decline close to 1.0 in 1-2 centuries. Our findings provide new evidence for better understanding the range of AA factor and associated key physical processes, and provide new insights for AA’s projection in current anthropogenic warming climate.

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Montreal Protocol to delay ice-free Arctic by a decade

10.5194/egusphere-egu21-3555 ◽

2021 ◽

Author(s):

Mark England ◽

Lorenzo Polvani

Keyword(s):

Sea Ice ◽

Internal Variability ◽

Arctic Sea Ice ◽

Montreal Protocol ◽

The Arctic ◽

Climate Mitigation ◽

Sea Ice Extent ◽

Arctic Sea ◽

Ozone Depleting Substances ◽

The Impact

Recent work has shown that a rapid rise in the emission of ozone depleting substances resulted in substantial Arctic warming and accelerated Arctic sea ice loss over the second half of the twentieth century. However, ozone depleting substances have been heavily regulated since the Montreal Protocol entered into effect in 1989, and their atmospheric concentrations have been stabilized and are now decreasing. This raises the obvious and important questions of the impact of the Montreal Protocol on climate change in the Arctic.More specifically we are here interested in quantifying the impact of the Montreal Protocol on the date of the first ice-free Arctic summer (defined as the first occurrence of Arctic sea ice extent below 1 million km2). The timing of the ice-free Arctic is of great interest both to stakeholders in the Arctic and to the scientific community.To address this question, we have performed and analyzed ten-member &#8216;World Avoided&#8217; companion ensembles to the CESM Large Ensemble (using RCP8.5 forcings) and to the CESM Medium Ensemble (using RCP4.5 forcings). The companion ensembles are identical to their CESM-LE and CESM-ME counterparts, respectively, except for the levels of ozone depleting substances which do not decrease following the Montreal Protocol, but instead increase at a rate of 3.5% a year. This allows us to isolate the effect of the Montreal Protocol on Arctic sea ice trends by simulating what would have happened if it had never been enacted (hence the name, &#8216;World Avoided&#8217;). We examine both RCP8.5 and RCP4.5 forcings, to quantify the uncertainty related to emissions scenarios over the coming decades.We find that without the Montreal Protocol the mean date of the first ice-free Arctic advances from 2041 to 2033 for the RCP8.5 forcings, and from 2050 to 2035 for the RCP4.5 forcings. Thus, enacting the Montreal Protocol has delayed the onset of an ice-free Arctic by approximately one decade. This signal is robust when accounting for the high levels of internal variability in Arctic sea ice trends. Our results are also robust to different definitions of &#8216;ice-free Arctic&#8217;. Overall our results highlight the importance of the Montreal Protocol as a major climate mitigation treaty, even for the Arctic, where no ozone-hole has formed.

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