[env-trinity] CBB: Extreme Climate Variability may be Destabilizing West Coast Ecosystems

[Sari Sommarstrom]

Columbia Basin Bulletin


Research: Extreme Climate Variability In West May Be Destabilizing West
Coast Marine Ecosystems 
Posted on Friday, April 13, 2018 (PST) 


New research shows that extreme climate variability over the last century in
western North America may be destabilizing both marine and terrestrial
ecosystems.

 

Climate is increasingly controlling synchronous ecosystem behavior in which
species populations rise and fall together, according to the National
Science Foundation-funded study published in the journal Global Change
Biology.

 

Climate variability is of concern given that extreme events, such as
prolonged drought or heatwaves, can disproportionately impact biology,
reduce resilience and leave a lasting impact. An increase in the synchrony
of the climate could expose marine and terrestrial organisms to higher risks
of extinction, said study co-author Ivan Arismendi, an aquatic ecologist and
assistant professor at Oregon State University.

 

“There has been a tremendous amount of research on climate change, but
almost all of it has been focused on trends in average conditions, such as
rising temperatures,” Arismendi said. “However, climate is also predicted to
become more variable and very little research has addressed this issue. Our
study found that extreme variability is synchronizing processes within and
among ecosystems at a level not seen in the last 250 years.”

 

The study can be found at
<https://onlinelibrary.wiley.com/doi/10.1111/gcb.14128>
https://onlinelibrary.wiley.com/doi/10.1111/gcb.14128

 

The interdisciplinary research team, led by the University of Texas Marine
Science Institute, documented that wintertime atmospheric conditions along
the west coast of North America, known as North Pacific high, are important
to marine, terrestrial, and freshwater ecosystems in California and the
southwestern United States. A strong wintertime North Pacific High is
associated with winds that are favorable for marine productivity, but also
blocks the onshore storm track and leads to drought on land.

 

The researchers documented that the North Pacific High has become more
variable over the past century, and that these trends have been imprinted on
physical and biological indicators from the continental slope to the Sierra
Nevada and beyond. There are more dramatic and frequent swings in this
winter climate pattern, and not only has variability increased, but so too
has the synchrony among diverse ecosystems.

 

“We’ve found that land, rivers, and oceans are all strongly related to a
winter climate pattern off the western coast of North America, and that
climate pattern has become more variable over the past century,” said lead
author Bryan Black, associate professor of marine science at UT-Austin.
“This extreme variability is increasingly imprinted on these freshwater,
terrestrial, and marine systems, and this has caused them to become more
synchronous with one another with a number of implications for fisheries,
drought, snowpack, and tree growth.”

 

Indeed, tree-ring chronologies provide much longer histories than
observational records and corroborate that variability and synchrony have
risen over the past hundred years, and to levels that are as high as any
observed over the past three centuries, according to the researchers.

 

More frequent and larger changes in the North Pacific High appear to
originate from rising variability in the tropics and are linked to the
record-breaking El Niño events in 1983, 1998, and 2016 and the 2014-2015
North Pacific Ocean heat wave known as “The Blob.”

 

Arismendi is an assistant professor in the Department of Fisheries and
Wildlife in OSU’s College of Agricultural Sciences. Jason Dunham, an aquatic
ecologist at the U.S. Geologic Survey Forest and Rangeland Ecosystem Science
Center in Corvallis, is also one of the study’s co-authors.

 

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