• Ancient El Nin~os reveal limits to futur

    From ScienceDaily@1:317/3 to All on Tue Mar 15 22:30:44 2022
    Ancient El Nin~os reveal limits to future climate projections

    Date:
    March 15, 2022
    Source:
    University of Texas at Austin
    Summary:
    The climate pattern El Nin~o varies to such a degree that scientists
    will have a hard time detecting signs that it is getting stronger
    with global warming. That's the conclusion of a study that analyzed
    9,000 years of Earth's history. The scientists drew on climate
    data contained within ancient corals and used one of the world's
    most powerful supercomputers to conduct their research.



    FULL STORY ==========================================================================
    The climate pattern El Nin~o varies over time to such a degree that
    scientists will have difficulty detecting signs that it is getting
    stronger with global warming.


    ========================================================================== That's the conclusion of a study led by scientists at The University
    of Texas at Austin that analyzed 9,000 years of Earth's history. The
    scientists drew on climate data contained within ancient corals and used
    one of the world's most powerful supercomputers to conduct their research.

    The study of the past, which was recently published in Science Advances,
    was motivated by the need to get a clearer picture of how climate change
    may affect El Nin~o in the future.

    El Nin~o is the warm phase of the El Nin~o Southern Oscillation,
    a climate phenomenon that sets the stage every few years for weather
    patterns worldwide.

    Strong El Nin~o events, such as the ones in 1997 and 2015 that brought wildfires to the rainforests of Borneo in Asia and caused widespread
    bleaching to the world's coral reefs, happened about once a decade.

    Computer models, however, are unclear about whether El Nin~o events will
    become weaker or stronger as the world warms due to climate change.

    "Much of the world's temperature and rainfall are influenced by what
    happens in the tropical Pacific Ocean where El Nin~o starts," said
    the study's lead author, Allison Lawman, who began the research as
    a Ph.D. project at the UT Jackson School of Geosciences and is now
    a postdoctoral researcher at the University of Colorado Boulder. "The difference in rainfall between greater or fewer strong El Nin~o events is
    going to be a critical question for infrastructure and resource planners." Lawman and her collaborators used the Lonestar5 supercomputer at UT's
    Texas Advanced Computing Center to run a series of climate simulations
    of a period in Earth's history before human influences, when the main
    source of climate change came from a tilt in the planet's orbit. The simulations were verified using a coral emulator Lawman had previously developed to compare them with climate records from ancient corals.

    They found that although the occurrence of strong El Nin~o events
    intensified over time, the change was small compared with El Nin~o's
    highly variable nature.

    "It's like trying to listen to soft music next to a jackhammer," said
    study co- author Jud Partin, a research scientist at the University of
    Texas Institute for Geophysics.

    To achieve this, Partin, Lawman and the study's other authors call
    for further investigations into even earlier times in Earth's history,
    such as the last ice age, to see how El Nin~o responded to more intense
    changes in climate forces.

    "Scientists need to keep pushing the limits of models and look
    at geological intervals deeper in time that could offer clues on
    how sensitive El Nin~o is to changes in climate," said co-author
    Pedro DiNezio, an associate professor at University of Colorado
    Boulder. "Because if there's another big El Nin~o, it's going to be very
    hard to attribute it to a warming climate or to El Nin~o's own internal variations." The research, including much of Lawman's doctoral degree,
    was funded by the National Science Foundation. Project partners included
    Rice University and The University of Arizona.


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


    ========================================================================== Journal Reference:
    1. Allison E. Lawman, Pedro N. Di Nezio, Judson W. Partin, Sylvia
    G. Dee,
    Kaustubh Thirumalai, Terrence M. Quinn. Unraveling forced responses
    of extreme El Nin~o variability over the Holocene. Science Advances,
    2022; 8 (9) DOI: 10.1126/sciadv.abm4313 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220315141816.htm

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