Arctic sea ice loss could dry out California

December 5, 2017, Lawrence Livermore National Laboratory
Extent of Arctic sea ice in September 2016 versus the 1981-2010 average minimum extent (gold line). Through satellite images, researchers have observed a steep decline in the average extent of Arctic sea ice for every month of the year. Credit: NASA

Arctic sea ice loss of the magnitude expected in the next few decades could impact California's rainfall and exacerbate future droughts, according to new research led by Lawrence Livermore National Laboratory (LLNL) scientists.

The dramatic loss of Arctic sea ice cover observed over the satellite era is expected to continue throughout the 21st century. Over the next few decades, the Arctic Ocean is projected to become ice-free during the summer. A new study by Ivana Cvijanovic and colleagues from LLNL and University of California, Berkeley shows that substantial loss of Arctic sea ice could have significant far-field effects, and is likely to impact the amount of precipitation California receives. The research appears in the Dec. 5 edition of Nature Communications.

The study identifies a new link between Arctic sea ice loss and the development of an atmospheric ridging system in the North Pacific. This atmospheric feature also played a central role in the 2012-2016 California drought and is known for steering precipitation-rich storms northward, into Alaska and Canada, and away from California. The team found that sea ice changes can lead to convection changes over the tropical Pacific. These convection changes can in turn drive the formation of an atmospheric ridge in the North Pacific, resulting in significant drying over California.

"On average, when considering the 20-year mean, we find a 10-15 percent decrease in California's rainfall. However, some individual years could become much drier, and others wetter," Cvijanovic said.

Schematics of the teleconnection through which Arctic sea-ice changes drive precipitation decrease over California. Arctic sea-ice loss induced high-latitude changes first propagate into tropics, triggering tropical circulation and convection responses. Decreased convection and decreased upper level divergence in the tropical Pacific then drive a northward propagating Rossby wavetrain, with anticyclonic flow forming in the North Pacific. This ridge is responsible for steering the wet tropical air masses away from California. Credit: Kathy Seibert/LLNL

The study does not attribute the 2012-2016 drought to Arctic sea ice loss. However, the simulations indicate that the sea-ice driven precipitation changes resemble the global rainfall patterns observed during that drought, leaving the possibility that Arctic sea-ice loss could have played a role in the recent drought.

"The recent California drought appears to be a good illustration of what the sea-ice driven precipitation decline could look like," she explained.

California's winter precipitation has decreased over the last two decades, with the 2012-2016 being one of the most severe on record. The impacts of reduced rainfall have been intensified by high temperatures that have enhanced evaporation. Several studies suggest that recent Californian droughts have a manmade component arising from increased temperatures, with the likelihood of such warming-enhanced droughts expected to increase in the future.

"Our study identifies one more pathway by which human activities could affect the occurrence of future droughts over California—through human-induced Arctic sea ice decline," Cvijanovic said. "While more research should be done, we should be aware that an increasing number of studies, including this one, suggest that the of Arctic sea ice cover is not only a problem for remote Arctic communities, but could affect millions of people worldwide. Arctic could affect us, right here in California."

Explore further: Influence of sea-ice loss on Arctic warming is shaped by temperatures in the Pacific Ocean

More information: Ivana Cvijanovic et al. Future loss of Arctic sea-ice cover could drive a substantial decrease in California's rainfall, Nature Communications (2017). DOI: 10.1038/s41467-017-01907-4

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Dec 05, 2017
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4.2 / 5 (5) Dec 05, 2017
To be clear, our weather over here in California changed dramatically and overnight with El Nino.

That's a very valid point, considering this article had absolutely nothing to do with El Nino. /sarc
By that same point, my trees wiggle when the wind picks up. Crazy how fast that can happen too!
Dec 05, 2017
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4 / 5 (5) Dec 05, 2017
It very much has everything to do with the alarmism that is today happening in the climate sciences: Despite all of the warnings about man affecting the climate, it was the NATURAL variation which pulled us out of our recent drought.

So the best plan is to do nothing and allow nature's randomness and variation to fix any climate issue that may or may not be caused/amplified/affected by humans? got it. Good science right there.
not rated yet Dec 05, 2017
Well with the new tax bill CA is losing its local and state deductions. Residents will be leaving in droves.

Which is good because wildfires driven by drought will extend the sonoran desert up the coast. Earthquakes will finish the job and the US will be glad to acknowledge the Reconquista.

Salvage will be the principle industry for this new estado.
So the best plan is to do nothing and allow nature's randomness and variation to fix any climate issue
Yes, the same way it turned the vast savannahs of north central africa into the sahara.
3 / 5 (4) Dec 05, 2017
Despite all of the warnings about man affecting the climate
Are you disputing that man is affecting the climate? If yes - you have to present an alternative explanation for the recent warming trend - which so far no NATURAL cause has been found. If no - then I am not sure what your point is. We know there are natural variations - milankovich cycles, feedback loops, El Nino, El Nina, amo/pdo cycles etc. etc. Should we stop studying the subject at this point - or let science take it's course?
Dec 06, 2017
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Dec 06, 2017
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4.5 / 5 (2) Dec 06, 2017
Re: "So the best plan is to do nothing ..."

Yes, the best plan is to stop pretending like we can predict the future. Just as you cannot predict how you yourself will die...

If i have cancer, I should not have any medical procedures done, since nature will inevitably fix it for me, right?
3.7 / 5 (3) Dec 06, 2017
The dire predictions were bogus
As you point out - the dire predictions you speak of were in the "newspapers." I don't get my science news from the newspapers. You and Donald Trump do that. Climate change is not a boogeyman for me. I do understand the dire possible ramifications of our increasing populations, pollution, habitat destruction, and climate change. It is just stupid for us to put our heads in the sand - and not understand the possible consequences. There is good scientific reason to be concerned about what is happening on our planet. Here is one example - with lots of science - http://www.resili...ollapse/ Please show us one example of a scientific paper that tells us there is nothing to worry about - from an evidence based - scientific perspective.
3 / 5 (2) Dec 06, 2017
Follow up Reeve. I asked if you are disputing that man is affecting the climate. Crickets chirping. The point being - that if you are making that assertion - then you need to give us the alternative explanation for the current warming trend. If you are not making that assertion - then you seem to have no point.
3 / 5 (2) Dec 07, 2017
I guess you haven't been watching the news these past few days Reeve. California just had one of the hottest summers on record. Now we are in the rainy season - and they have received about 5% of the normal rainfall. Are you willing to reimburse people for their destroyed lives? Sounds reasonable to me that deniers should be held accountable for obstructing the process of learning about our world.

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