• Large future changes in climate variabil

    From ScienceDaily@1:317/3 to All on Thu Dec 9 21:30:46 2021
    Large future changes in climate variability
    New computer model simulations identify widespread changes in climate variability under sustained anthropogenic forcing

    Date:
    December 9, 2021
    Source:
    Institute for Basic Science
    Summary:
    Large future changes in climate variability. New computer model
    simulations identify widespread changes in climate variability
    under sustained anthropogenic forcing.



    FULL STORY ========================================================================== There is growing public awareness that climate change will impact
    society not only through changes in mean temperatures and precipitation
    over the 21st century, but also in the occurrence of more pronounced
    extreme events, and more generally in natural variability in the Earth
    system. Such changes could also have large impacts on vulnerable
    ecosystems in both terrestrial and marine habitats. A scientific
    exploration of projected future changes in climate and ecosystem
    variability is described in a new study published in the journal Earth
    System Dynamics, representing the result of a broad collaborative
    partnership between the IBS Center for Climate Physics (ICCP) at Pusan
    National University in South Korea and the Community Earth System Model
    (CESM) project at the National Center for Atmospheric Research (NCAR)
    in the US.


    ==========================================================================
    The team conducted a set of 100 global Earth system model simulations over 1850-2100, working with a "business-as-usual" scenario for relatively
    strong emissions of greenhouse gases over the 21st century. The runs
    were given different initial conditions, and by virtue of the butterfly
    effect they were able to represent a broad envelope of possible climate
    states over 1850-2100, enabling sophisticated analyses of changes in
    the variability of the Earth system over time. The nominally one-degree (~100km) resolution of the model, in conjunction with the 100-member set
    of runs, represented an unprecedented set of technical challenges that
    needed to be met before advancing to the goal of assessing how climate variability is impacted by sustained anthropogenic changes to the climate system. "We met these challenges by using the IBS/ICCP supercomputer
    Aleph, one of Korea's fastest supercomputers" says Dr. Sun-Seon Lee from
    the ICCP, a co-author of the study who ran the simulations together with
    her NCAR colleague Dr. Nan Rosenbloom. For the project, approximately
    80 million hours of supercomputer time were used, and approximately
    5 Petabytes of disc space (approximately 5000 normal hard discs) were
    required for storage of the model output.

    The main finding of the study is that the impact of climate change is
    apparent in nearly all aspects of climate variability, ranging from
    temperature and precipitation extremes over land to increased number of
    fires in California, to changes in bloom amplitude for phytoplankton in
    the North Atlantic Ocean. Each of these changes has important impacts
    for sustainable resource management. As an example, occurrences of
    extreme precipitation events over the 21st century (between 2000-2009 and 2090-2099) indicate that extremes are expected to become more commonplace
    over many regions. These projected changes in precipitation extremes
    are in fact representative of the omnipresence of changes in extremes
    in the future across a broad range of climate and ecosystem variables,
    which has important implications for future adaptation strategies.

    "In addition to large-scale changes in extreme events, our study also identified large-scale changes in the structure of the seasonal cycle
    over the 21st century, showing an enhanced growing season length over
    the continental regions north of 50DEGN," says Dr. Keith Rodgers from
    the ICCP, first author of the study and a co-lead of the CESM2 Large
    Ensemble Project. Largely due to mean state warming and ensuing changes
    in the timing of the retreat and advance of winter snow cover, by the
    end of the 21st century growing season length is projected to increase
    by three weeks.

    Taken together, the computer simulations reveal that across our
    planet we can expect widespread changes in climate variability,
    ranging in timescales from synoptic storms to seasons to that of El
    Nin~o to decades. Dr. Gokhan Danabasoglu, a co-author of the study and a co-lead of the project, says "an important step moving forward will be to identify more fully the potential societal impacts and to communicate the implications for adaptation strategies." This broader study has already motivated a number of more specialized scientific investigations using
    the tremendous volume of output from the simulations, spanning topics from marine ecosystem impacts to hydrological changes that affect water supply.

    The National Center for Atmospheric Research is sponsored by the US
    National Science Foundation and managed by the University Corporation
    for Atmospheric Research.

    ========================================================================== Story Source: Materials provided by Institute_for_Basic_Science. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Keith B. Rodgers, Sun-Seon Lee, Nan Rosenbloom, Axel Timmermann,
    Gokhan
    Danabasoglu, Clara Deser, Jim Edwards, Ji-Eun Kim, Isla R. Simpson,
    Karl Stein, Malte F. Stuecker, Ryohei Yamaguchi, Tama's Bo'dai,
    Eui-Seok Chung, Lei Huang, Who M. Kim, Jean-Franc,ois Lamarque,
    Danica L.

    Lombardozzi, William R. Wieder, Stephen G. Yeager. Ubiquity
    of human- induced changes in climate variability. Earth System
    Dynamics, 2021; 12 (4): 1393 DOI: 10.5194/esd-12-1393-2021 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2021/12/211209082609.htm

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