• Disastrous duo: Heatwaves and droughts

    From ScienceDaily@1337:3/111 to All on Mon Sep 28 21:30:36 2020
    Disastrous duo: Heatwaves and droughts
    Climate change at the heart of more frequent and intense dry and hot
    extremes in recent decades

    Date:
    September 28, 2020
    Source:
    McGill University
    Summary:
    Simultaneous heatwaves and droughts are becoming increasingly
    common in western parts of the Unites States, according to a new
    study. Periods of dry and hot weather, which can make wildfires
    more likely, are becoming larger, more intense, and more frequent
    because of climate change.



    FULL STORY ========================================================================== Simultaneous heatwaves and droughts are becoming increasingly common
    in western parts of the Unites States, according to a new study led
    by researchers from McGill University. Periods of dry and hot weather,
    which can make wildfires more likely, are becoming larger, more intense,
    and more frequent because of climate change.


    ==========================================================================
    In a study published by Science Advances, the researchers analyzed heat
    and drought events across the contiguous United States over the past
    122 years.

    They found that combined dry and hot events have not only increased
    in frequency, but also in size geographically. Where such events were
    once confined to small parts of the United States, now they cover whole regions, such as the entire west coast and parts of the Northeast and Southeast.

    "Dry-hot events can cause large fires. Add wind and a source of ignition,
    and this results in 'megafires' like the 2020 fires across the west coast
    of the United States. Drought and record-breaking heatwaves, coupled with
    a storm that brought strong winds and 12,000 lightning events in a span of
    72 hours, caused more than 500 wildfires," says lead author Mohammad Reza Alizadeh, a PhD student under the supervision of Professor Jan Adamowski
    in the Department of Bioresource Engineering at McGill University.

    The researchers also found that dry and hot weather
    events are intensifying, with longer periods of drought and
    higher temperatures. These dual "dry-hot extremes" are not only self-intensifying -- more heat causes more drought and vice versa --
    but are also self-propagating, meaning they are able to move from region
    to region. "As increased temperatures are driving and expanding aridity, droughts and heatwaves move from one region to downwind regions," says Alizadeh. These extremes can be particularly damaging for agricultural production and ecosystems, they warn.

    According to the researchers, the trigger for these hot-dry events
    is shifting.

    Looking back at the catastrophic Dust Bowl of the 1930s, they explain
    that the dust storms were driven by a lack of rainfall coupled with poor
    land management practices. In recent decades, however, dry-hot disasters
    are driven more often by excess heat than a lack of rainfall.

    The future will bring us more of these disasters, if the current warming
    trends continue, the researchers caution. They suggest their findings
    could be used to inform climate mitigation and adaptation efforts. "We
    need to understand how things are changing in order to adapt," says
    Professor Jan Adamowski.


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


    ========================================================================== Journal Reference:
    1. Mohammad Reza Alizadeh, Jan Adamowski, Mohammad Reza Nikoo, Amir
    AghaKouchak, Philip Dennison, Mojtaba Sadegh. A century of
    observations reveals increasing likelihood of continental-scale
    compound dry-hot extremes. Science Advances, 2020; 6 (39): eaaz4571
    DOI: 10.1126/ sciadv.aaz4571 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2020/09/200928152922.htm

    --- up 5 weeks, 6 hours, 50 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)