• Barnes, E. A., and L. M. Polvani, 2015: CMIP5 projections of Arctic amplification, of the North American/North Atlantic circulation, and of their relationship. J. Climate, 28, 52545271, https://doi.org/10.1175/JCLI-D-14-00589.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barnes, E. A., and J. A. Screen, 2015: The impact of Arctic warming on the midlatitude jet-stream: Can it? Has it? Will it? Wiley Interdiscip. Rev.: Climate Change, 6, 277286, https://doi.org/10.1002/wcc.337.

    • Search Google Scholar
    • Export Citation
  • Blackport, R., and P. J. Kushner, 2017: Isolating the atmospheric circulation response to Arctic sea ice loss in the coupled climate system. J. Climate, 30, 21632185, https://doi.org/10.1175/JCLI-D-16-0257.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Blackport, R., and J. A. Screen, 2019: Influence of Arctic sea ice loss in autumn compared to that in winter on the atmospheric circulation. Geophys. Res. Lett., 46, 22132221, https://doi.org/10.1029/2018GL081469.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Blackport, R., and J. A. Screen, 2020: Insignificant effect of Arctic amplification on the amplitude of midlatitude atmospheric waves. Sci. Adv., 6, eaay2880, https://doi.org/10.1126/sciadv.aay2880.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Blackport, R., J. A. Screen, K. van der Wiel, and R. Bintanja, 2019: Minimal influence of reduced Arctic sea ice on coincident cold winters in mid-latitudes. Nat. Climate Change, 9, 697704, https://doi.org/10.1038/s41558-019-0551-4.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cohen, J., and et al. , 2014: Recent Arctic amplification and extreme mid-latitude weather. Nat. Geosci., 7, 627637, https://doi.org/10.1038/ngeo2234.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cohen, J., K. Pfeiffer, and J. A. Francis, 2018: Warm Arctic episodes linked with increased frequency of extreme winter weather in the United States. Nat. Commun., 9, 869, https://doi.org/10.1038/s41467-018-02992-9.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cohen, J., and et al. , 2020: Divergent consensuses on Arctic amplification influence on midlatitude severe winter weather. Nat. Climate Change, 10, 2029, https://doi.org/10.1038/s41558-019-0662-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Collow, T. W., W. Wang, and A. Kumar, 2018: Simulations of Eurasian winter temperature trends in coupled and uncoupled CFSv2. Adv. Atmos. Sci., 35, 1426, https://doi.org/10.1007/s00376-017-6294-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dai, A., and M. Song, 2020: Little influence of Arctic amplification on mid-latitude climate. Nat. Climate Change, 10, 231237, https://doi.org/10.1038/s41558-020-0694-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • De, B., and Y. Wu, 2019: Robustness of the stratospheric pathway in linking the Barents–Kara Sea sea ice variability to the mid-latitude circulation in CMIP5 models. Climate Dyn., 53, 193207, https://doi.org/10.1007/s00382-018-4576-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dee, D. P., and et al. , 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553597, https://doi.org/10.1002/qj.828.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deser, C., R. Tomas, M. Alexander, and D. Lawrence, 2010: The seasonal atmospheric response to projected Arctic sea ice loss in the late twenty-first century. J. Climate, 23, 333351, https://doi.org/10.1175/2009JCLI3053.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deser, C., R. Tomas, and L. Sun, 2015: The role of ocean–atmosphere coupling in the zonal-mean atmospheric response to Arctic sea ice loss. J. Climate, 28, 21682186, https://doi.org/10.1175/JCLI-D-14-00325.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deser, C., L. Sun, R. A. Tomas, and J. Screen, 2016: Does ocean coupling matter for the northern extratropical response to projected Arctic sea ice loss? Geophys. Res. Lett., 43, 21492157, https://doi.org/10.1002/2016GL067792.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deser, C., and et al. , 2020: Insights from Earth system model initial-condition large ensembles and future prospects. Nat. Climate Change, 10, 277286, https://doi.org/10.1038/s41558-020-0731-2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Francis, J. A., 2017: Why are Arctic linkages to extreme weather still up in the air? Bull. Amer. Meteor. Soc., 98, 25512557, https://doi.org/10.1175/BAMS-D-17-0006.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • García-Serrano, J., C. Frankignoul, G. Gastineau, and A. de la Cámara, 2015: On the predictability of the winter Euro-Atlantic climate: Lagged influence of autumn Arctic sea ice. J. Climate, 28, 51955216, https://doi.org/10.1175/JCLI-D-14-00472.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Garfinkel, C. I., D. L. Hartmann, and F. Sassi, 2010: Tropospheric precursors of anomalous Northern Hemisphere stratospheric polar vortices. J. Climate, 23, 32823299, https://doi.org/10.1175/2010JCLI3010.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gong, T., and D. Luo, 2017: Ural blocking as an amplifier of the Arctic sea ice decline in winter. J. Climate, 30, 26392654, https://doi.org/10.1175/JCLI-D-16-0548.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hay, S., P. J. Kushner, R. Blackport, and K. E. McCusker, 2018: On the relative robustness of the climate response to high-latitude and low-latitude warming. Geophys. Res. Lett., 45, 62326241, https://doi.org/10.1029/2018GL077294.

    • Search Google Scholar
    • Export Citation
  • Honda, M., J. Inoue, and S. Yamane, 2009: Influence of low Arctic sea-ice minima on anomalously cold Eurasian winters. J. Climate, 36, L08707, https://doi.org/10.1029/2008GL037079.

    • Search Google Scholar
    • Export Citation
  • Hurrell, J. W., J. J. Hack, D. Shea, J. M. Caron, and J. Rosinski, 2008: A new sea surface temperature and sea ice boundary dataset for the Community Atmosphere Model. J. Climate, 21, 51455153, https://doi.org/10.1175/2008JCLI2292.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Inoue, J., M. E. Hori, and K. Takaya, 2012: The role of Barents Sea ice in the wintertime cyclone track and emergence of a warm-Arctic cold-Siberian anomaly. J. Climate, 25, 25612568, https://doi.org/10.1175/JCLI-D-11-00449.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jaiser, R., K. Dethloff, D. Handorf, A. Rinke, and J. Cohen, 2012: Impact of sea ice cover changes on the Northern Hemisphere atmospheric winter circulation. Tellus, 64A, 11595, https://doi.org/10.3402/tellusa.v64i0.11595.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jang, Y.-S., J.-S. Kug, and B.-M. Kim, 2019: How well do current climate models simulate the linkage between Arctic warming and extratropical cold winters? Climate Dyn., 53, 40054018, https://doi.org/10.1007/s00382-019-04765-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kim, B.-M., S.-W. Son, S.-K. Min, J.-H. Jeong, S.-J. Kim, X. Zhang, T. Shim, and J.-H. Yoon, 2014: Weakening of the stratospheric polar vortex by Arctic sea-ice loss. Nat. Commun., 5, 4646, https://doi.org/10.1038/ncomms5646.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Koenigk, T., and et al. , 2019: Impact of Arctic sea ice variations on winter temperature anomalies in northern hemispheric land areas. Climate Dyn., 52, 31113137, https://doi.org/10.1007/s00382-018-4305-1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kolstad, E. W., and J. A. Screen, 2019: Nonstationary relationship between autumn Arctic sea ice and the winter North Atlantic oscillation. Geophys. Res. Lett., 46, 75837591, https://doi.org/10.1029/2019GL083059.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kretschmer, M., D. Coumou, J. F. Donges, and J. Runge, 2016: Using causal effect networks to analyze different Arctic drivers of midlatitude winter circulation. J. Climate, 29, 40694081, https://doi.org/10.1175/JCLI-D-15-0654.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kug, J.-S., J.-H. Jeong, Y.-S. Jang, B.-M. Kim, C. K. Folland, S.-K. Min, and S.-W. Son, 2015: Two distinct influences of Arctic warming on cold winters over North America and East Asia. Nat. Geosci., 8, 759762, https://doi.org/10.1038/ngeo2517.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Labe, Z., Y. Peings, and G. Magnusdottir, 2018: Contributions of ice thickness to the atmospheric response from projected Arctic sea ice loss. Geophys. Res. Lett., 45, 56355642, https://doi.org/10.1029/2018GL078158.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Labe, Z., Y. Peings, and G. Magnusdottir, 2019: The effect of QBO phase on the atmospheric response to projected Arctic sea ice loss in early winter. Geophys. Res. Lett., 46, 76637671, https://doi.org/10.1029/2019GL083095.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liang, Y.-C., and et al. , 2020: Quantification of the Arctic sea ice-driven atmospheric circulation variability in coordinated large ensemble simulations. Geophys. Res. Lett., 47, e2019GL085397, https://doi.org/10.1029/2019GL085397.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, J., J. A. Curry, H. Wang, M. Song, and R. M. Horton, 2012: Impact of declining Arctic sea ice on winter snowfall. Proc. Natl. Acad. Sci. USA, 109, 40744079, https://doi.org/10.1073/pnas.1114910109.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Luo, B., D. Luo, L. Wu, L. Zhong, and I. Simmonds, 2017: Atmospheric circulation patterns which promote winter Arctic sea ice decline. Environ. Res. Lett., 12, 054017, https://doi.org/10.1088/1748-9326/aa69d0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McCusker, K. E., J. C. Fyfe, and M. Sigmond, 2016: Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss. Nat. Geosci., 9, 838842, https://doi.org/10.1038/ngeo2820.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McCusker, K. E., P. J. Kushner, J. C. Fyfe, M. Sigmond, V. V. Kharin, and C. M. Bitz, 2017: Remarkable separability of circulation response to Arctic sea ice loss and greenhouse gas forcing. Geophys. Res. Lett., 44, 79557964, https://doi.org/10.1002/2017GL074327.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGraw, M. C., and E. A. Barnes, 2018: Memory matters: A case for Granger causality in climate variability studies. J. Climate, 31, 32893300, https://doi.org/10.1175/JCLI-D-17-0334.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGraw, M. C., and E. A. Barnes, 2019: New insights on subseasonal Arctic–midlatitude causal connections from a regularized regression model. J. Climate, 33, 213228, https://doi.org/10.1175/JCLI-D-19-0142.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meier, W. N., and et al. , 2014: Arctic sea ice in transformation: A review of recent observed changes and impacts on biology and human activity. Rev. Geophys., 52, 185217, https://doi.org/10.1002/2013RG000431.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mori, M., M. Watanabe, H. Shiogama, J. Inoue, and M. Kimoto, 2014: Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades. Nat. Geosci., 7, 869873, https://doi.org/10.1038/ngeo2277.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mori, M., Y. Kosaka, M. Watanabe, H. Nakamura, and M. Kimoto, 2019: A reconciled estimate of the influence of Arctic sea-ice loss on recent Eurasian cooling. Nat. Climate Change, 9, 123129, https://doi.org/10.1038/s41558-018-0379-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nakamura, T., K. Yamazaki, K. Iwamoto, M. Honda, Y. Miyoshi, Y. Ogawa, and J. Ukita, 2015: A negative phase shift of the winter AO/NAO due to the recent Arctic sea-ice reduction in late autumn. J. Geophys. Res. Atmos., 120, 32093227, https://doi.org/10.1002/2014JD022848.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ogawa, F., and et al. , 2018: Evaluating impacts of recent Arctic sea ice loss on the Northern Hemisphere winter climate change. Geophys. Res. Lett., 45, 32553263, https://doi.org/10.1002/2017GL076502.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Oudar, T., E. Sanchez-Gomez, F. Chauvin, J. Cattiaux, L. Terray, and C. Cassou, 2017: Respective roles of direct GHG radiative forcing and induced Arctic sea ice loss on the Northern Hemisphere atmospheric circulation. Climate Dyn., 49, 36933713, https://doi.org/10.1007/s00382-017-3541-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Overland, J. E., and M. Wang, 2018: Resolving future Arctic/midlatitude weather connections. Earth’s Future, 6, 11461152, https://doi.org/10.1029/2018EF000901.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Peings, Y., 2019: Ural blocking as a driver of early-winter stratospheric warmings. Geophys. Res. Lett., 46, 54605468, https://doi.org/10.1029/2019GL082097.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ringgaard, I. M., S. Yang, E. Kaas, and J. H. Christensen, 2020: Barents-Kara sea ice and European winters in EC-Earth. Climate Dyn., 54, 33233338, https://doi.org/10.1007/s00382-020-05174-w.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., and J. A. Francis, 2016: Contribution of sea-ice loss to Arctic amplification is regulated by Pacific Ocean decadal variability. Nat. Climate Change, 6, 856860, https://doi.org/10.1038/nclimate3011.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., and R. Blackport, 2019a: How robust is the atmospheric response to projected Arctic sea ice loss across climate models? Geophys. Res. Lett., 46, 11 40611 415, https://doi.org/10.1029/2019GL084936.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., and R. Blackport, 2019b: Is sea-ice-driven Eurasian cooling too weak in models? Nat. Climate Change, 9, 934936, https://doi.org/10.1038/s41558-019-0635-1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., I. Simmonds, C. Deser, and R. Tomas, 2013: The atmospheric response to three decades of observed Arctic sea ice loss. J. Climate, 26, 12301248, https://doi.org/10.1175/JCLI-D-12-00063.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., C. Deser, I. Simmonds, and R. Tomas, 2014: Atmospheric impacts of Arctic sea-ice loss, 1979–2009: Separating forced change from atmospheric internal variability. Climate Dyn., 43, 333344, https://doi.org/10.1007/s00382-013-1830-9.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Screen, J. A., and et al. , 2018: Consistency and discrepancy in the atmospheric response to Arctic sea-ice loss across climate models. Nat. Geosci., 11, 155163, https://doi.org/10.1038/s41561-018-0059-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Siew, P. Y. F., C. Li, S. P. Sobolowski, and M. P. King, 2020: Intermittency of Arctic–mid-latitude teleconnections: Stratospheric pathway between autumn sea ice and the winter North Atlantic oscillation. Wea. Climate Dyn., 1, 261275, https://doi.org/10.5194/wcd-1-261-2020.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sigmond, M., and J. C. Fyfe, 2016: Tropical Pacific impacts on cooling North American winters. Nat. Climate Change, 6, 970974, https://doi.org/10.1038/nclimate3069.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smith, D. M., N. J. Dunstone, A. A. Scaife, E. K. Fiedler, D. Copsey, and S. C. Hardiman, 2017: Atmospheric response to Arctic and Antarctic sea ice: The importance of ocean–atmosphere coupling and the background state. J. Climate, 30, 45474565, https://doi.org/10.1175/JCLI-D-16-0564.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smith, K. L., C. G. Fletcher, and P. J. Kushner, 2010: The role of linear interference in the annular mode response to extratropical surface forcing. J. Climate, 23, 60366050, https://doi.org/10.1175/2010JCLI3606.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sorokina, S. A., C. Li, J. J. Wettstein, and N. G. Kvamstø, 2016: Observed atmospheric coupling between Barents Sea ice and the warm-Arctic cold-Siberian anomaly pattern. J. Climate, 29, 495511, https://doi.org/10.1175/JCLI-D-15-0046.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stroeve, J., and D. Notz, 2018: Changing state of Arctic sea ice across all seasons. Environ. Res. Lett., 13, 103001, https://doi.org/10.1088/1748-9326/aade56.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, L., C. Deser, and R. A. Tomas, 2015: Mechanisms of stratospheric and tropospheric circulation response to projected Arctic sea ice loss. J. Climate, 28, 78247845, https://doi.org/10.1175/JCLI-D-15-0169.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, L., J. Perlwitz, and M. Hoerling, 2016: What caused the recent “warm arctic, cold continents” trend pattern in winter temperatures? Geophys. Res. Lett., 43, 53455352, https://doi.org/10.1002/2016GL069024.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, L., M. Alexander, and C. Deser, 2018: Evolution of the global coupled climate response to Arctic sea ice loss during 1990–2090 and its contribution to climate change. J. Climate, 31, 78237843, https://doi.org/10.1175/JCLI-D-18-0134.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tachibana, Y., K. K. Komatsu, V. A. Alexeev, L. Cai, and Y. Ando, 2019: Warm hole in Pacific Arctic sea ice cover forced mid-latitude Northern Hemisphere cooling during winter 2017–18. Sci. Rep., 9, 5567, https://doi.org/10.1038/s41598-019-41682-4.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tang, Q., X. Zhang, X. Yang, and J. A. Francis, 2013: Cold winter extremes in northern continents linked to Arctic sea ice loss. Environ. Res. Lett., 8, 014036, https://doi.org/10.1088/1748-9326/8/1/014036.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vavrus, S. J., 2018: The influence of Arctic amplification on mid-latitude weather and climate. Curr. Climate Change Rep., 4, 238249, https://doi.org/10.1007/s40641-018-0105-2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Warner, J. L., J. A. Screen, and A. A. Scaife, 2020: Links between Barents–Kara Sea ice and the extratropical atmospheric circulation explained by internal variability and tropical forcing. Geophys. Res. Lett., 47, e2019GL085679, https://doi.org/10.1029/2019GL085679.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zappa, G., F. Pithan, and T. G. Shepherd, 2018: Multimodel evidence for an atmospheric circulation response to Arctic sea ice loss in the CMIP5 future projections. Geophys. Res. Lett., 45, 10111019, https://doi.org/10.1002/2017GL076096.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, P., Y. Wu, I. R. Simpson, K. L. Smith, X. Zhang, B. De, and P. Callaghan, 2018: A stratospheric pathway linking a colder Siberia to Barents-Kara Sea sea ice loss. Sci. Adv., 4, eaat6025, https://doi.org/10.1126/sciadv.aat6025.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 629 629 101
Full Text Views 188 188 33
PDF Downloads 259 259 40

Observed Statistical Connections Overestimate the Causal Effects of Arctic Sea Ice Changes on Midlatitude Winter Climate

View More View Less
  • 1 College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, United Kingdom
© Get Permissions
Restricted access

Abstract

Disentangling the contribution of changing Arctic sea ice to midlatitude winter climate variability remains challenging because of the large internal climate variability in midlatitudes, difficulties separating cause from effect, methodological differences, and uncertainty around whether models adequately simulate connections between Arctic sea ice and midlatitude climate. We use regression analysis to quantify the links between Arctic sea ice and midlatitude winter climate in observations and large initial-condition ensembles of multiple climate models, in both coupled configurations and so-called Atmospheric Model Intercomparison Project (AMIP) configurations, where observed sea ice and/or sea surface temperatures are prescribed. The coupled models capture the observed links in interannual variability between winter Barents–Kara sea ice and Eurasian surface temperature, and between winter Chukchi–Bering sea ice and North American surface temperature. The coupled models also capture the delayed connection between reduced November–December Barents–Kara sea ice, a weakened winter stratospheric polar vortex, and a shift toward the negative phase of the North Atlantic Oscillation in late winter, although this downward impact is weaker than observed. The strength and sign of the connections both vary considerably between individual 35-yr-long ensemble members, highlighting the need for large ensembles to separate robust connections from internal variability. All the aforementioned links are either absent or are substantially weaker in the AMIP experiments prescribed with only observed sea ice variability. We conclude that the causal effects of sea ice variability on midlatitude winter climate are much weaker than suggested by statistical associations, evident in observations and coupled models, because the statistics are inflated by the effects of atmospheric circulation variability on sea ice.

Blackport’s current affiliation: Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, British Columbia, Canada.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Russell Blackport, russell.blackport@canada.ca

Abstract

Disentangling the contribution of changing Arctic sea ice to midlatitude winter climate variability remains challenging because of the large internal climate variability in midlatitudes, difficulties separating cause from effect, methodological differences, and uncertainty around whether models adequately simulate connections between Arctic sea ice and midlatitude climate. We use regression analysis to quantify the links between Arctic sea ice and midlatitude winter climate in observations and large initial-condition ensembles of multiple climate models, in both coupled configurations and so-called Atmospheric Model Intercomparison Project (AMIP) configurations, where observed sea ice and/or sea surface temperatures are prescribed. The coupled models capture the observed links in interannual variability between winter Barents–Kara sea ice and Eurasian surface temperature, and between winter Chukchi–Bering sea ice and North American surface temperature. The coupled models also capture the delayed connection between reduced November–December Barents–Kara sea ice, a weakened winter stratospheric polar vortex, and a shift toward the negative phase of the North Atlantic Oscillation in late winter, although this downward impact is weaker than observed. The strength and sign of the connections both vary considerably between individual 35-yr-long ensemble members, highlighting the need for large ensembles to separate robust connections from internal variability. All the aforementioned links are either absent or are substantially weaker in the AMIP experiments prescribed with only observed sea ice variability. We conclude that the causal effects of sea ice variability on midlatitude winter climate are much weaker than suggested by statistical associations, evident in observations and coupled models, because the statistics are inflated by the effects of atmospheric circulation variability on sea ice.

Blackport’s current affiliation: Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, British Columbia, Canada.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Russell Blackport, russell.blackport@canada.ca
Save