114.6.7(六) Samedi 7 juin 2025
A September heat wave switching into a
snowstorm over one day in the Rocky Mountains. Winter snowfall suddenly melting
and saturating fields of dormant crops, before refreezing and encasing them in
damaging ice. Early spring warmth prompting plants to blossom followed by a cold
snap that freezes and drops their petals.
Rapid temperature change events like these
have increased in frequency and intensity over recent decades, a new study
found.
The transition periods for these abrupt temperature
shifts have also shortened, according to the study, published Tuesday in the journal
Nature Communications.
Because the quick changes in temperature give
communities and ecosystems little chance to respond, they may pose greater challenges
than heat waves or cold snaps alone, said Wei Zhang, an assistant professor of
climate science at Utah State University and one of the lead authors of the
study.
The researchers warned these temperature
flips could have damaging effects on people and natural environments, including
destruction of crops, harm to ecosystems and strains on power infrastructure.
And low-income countries, where there is less access to weather forecasting and
infrastructure is less resilient, are more vulnerable.
The researchers examined temperature data
from 1961 to 2023 to identify global patterns in sudden weather shifts, where
temperatures in an area either jumped from cold temperatures to warm or plunged
from warm to cold within five days. They found that instances of these flips
increased in more than 60% of regions they surveyed.
The largest increased in frequency were observed
in South America, West Europe, Africa, and South and Southeast Asia. Some
areas, including the polar regions, showed different behavior and experienced few
events.
While the climates mechanisms driving
changes to these temperature-flip events are not yet fully understood, Zhang said,
there is a significant trend showing that these events are becoming more frequent,
stronger and quicker in many areas of the globe.
Sudden temperature changes can disrupt the
growth of plants, posing challenges for agriculture.
In natural environments, plant loss from these flip events could set off a series of other consequences, like less available food for animals, Zhang said. Another risk from back-to-back severe temperatures is increased pressure on power systems, which can cause people to lose heat or air conditioning during dangerous temperatures. (Christina Kelso)
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