From the DOE/PACIFIC NORTHWEST NATIONAL LABORATORY
El Nino and global warming work together to bring more extreme weather
RICHLAND, Wash. – In the future, the Pacific Ocean’s temperature cycles could disrupt more than just December fishing. A study published in Nature Communications suggests that the weather patterns known as El Nino and La Nina could lead to at least a doubling of extreme droughts and floods in California later this century.
The study shows more frequent extreme events are likely to occur. Other research shows the Golden State’s average precipitation increasing gradually, but not enough to account for the occurrence of extreme events. A better understanding of what gives rise to El Nino and La Nina cycles — together known as El Nino-Southern Oscillation — might help California predict and prepare for more frequent droughts and floods in the coming century.
“Wet and dry years in California are linked to El Nino and La Nina. That relationship is getting stronger,” said atmospheric scientist Jin-Ho Yoon of the Department of Energy’s Pacific Northwest National Laboratory. “Our study shows that ENSO will be exhibiting increasing control over California weather.”
Rain’s range
California is experiencing one of the most severe droughts in its history, but it’s not clear if a warmer world will make droughts worse, more frequent or perhaps even improve the situation. After all, warmer air can hold more water, and some research suggests global warming could increase California’s average rain and snowfall.
However, research also suggests future rain will come down more as light drizzles and heavy deluges and less as moderate rainfall. Yoon and colleagues from PNNL and Utah State University in Logan, Utah, wondered if droughts might follow a similar pattern.
To find out, the researchers looked at what happens to California in global climate models. They simulated two periods of time: 1920 to 2005 using historical measurements; and 2006 to 2080 using conditions in which very few efforts are made to reduce greenhouse gas emissions. They chose this future scenario to examine the most extreme case.
To understand how well the simulations worked, they used two tactics to show reproducibility: In one tactic, they used a compilation of 38 different models. In the other, they re-ran a single model 30 times. The more similar the results, the more sure the researchers were of the finding.
Weather pendulum
The models showed that in the future, assuming emissions continue to increase, California seasons will exhibit more excessively wet and excessively dry events. These results suggest that the frequency of droughts could double and floods could triple between the early 20th century and late 21st century.
“By 2100, we see more — and more extreme — events. Flooding and droughts will be more severe than they are currently,” said Yoon.
But why? Yoon suspected the El Nino-Southern Oscillation. Every two to seven years, El Nino comes in and warms up the tropical Pacific Ocean a few degrees, increasing winter rain and snowpack in California. On a similar schedule, La Nina cools things off. Both disrupt regular weather in many regions around the globe.
To explore El Nino’s connection to California precipitation, Yoon and colleagues ran a climate model with and without El Nino. In both simulations, they ramped up the concentration of carbon dioxide by 1 percent every year for 150 years. In just one of the runs, they removed El Nino’s cyclical contribution by programming the sea surface temperatures to reflect only steady warming.
Without El Nino and La Nina, the frequency of extreme precipitation in California stayed constant for the simulation’s century and a half. With ENSO, simulated California experienced wide swings in rainfall by the end of the period.
The results suggest that even though researchers expect rain and snowfall to increase as the climate warms, the manner in which the water hits California could be highly variable.
The El Nino-Southern Oscillation is still a bit of a mystery, said Yoon. Scientists only know El Nino and La Nina years, named for the Spanish terms for boy and girl, are coming by sea surface temperatures and other weather hints. Studies that investigate what controls the unruly children could help scientists predict unruly weather in the future.
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This work was supported by the Department of Energy Office of Science.
Reference: Jin-Ho Yoon, S.-Y. Simon Wang, Robert R. Gillies, Ben Kravitz, Lawrence Hipps, and Philip J. Rasch. Increasing water cycle extremes in California and relation to ENSO cycle under global warming, Nature Communications, Oct. 21, 2015, DOI: 10.1038/ncomms9657.
Call me a pedant, but only a model could fit a frequent drought and and a frequent flood into the same year, or even the same decade.
It’s a new thing called a “droughtflood”.
Britain CLAIMED to be preparing to invade mainland Europe from Essex and Suffolk in 1944. The claim was made to German spies. Can’t for the life of me understand why Omaha beach was in Normandy…….
We stared into our crystal ball and it showed us that lots of Very Bad Things will happen. Be afraid. Oh, and send money.
Do these writers not understand that I have to pay good money to a utility company to haul away my garbage? Please stop stuffing more stuff into my trash bin.
We don’t know (as this article) what causes ENSO cycles, but yet we can say with great confidence El Nino’s and global warming will both contribute in future? NONSENSE
Below gives us a better understanding in what causes ENSO cycles.
http://i772.photobucket.com/albums/yy8/SciMattG/SunSpots_v_NINO3.4Minrem_zpsjazoxqcs.png
While there is apparently an unknown cause there is also an unknown outcome, but above highlights an 85.7% presence that is difficult to ignore. We have only had global warming mainly due to increasing and stronger El Nino’s during the satellite era. When these had stopped becoming more frequent or as strong, global temperatures behaved with them, hence the pause. Only way it may resume again would be because of another continuous medium and strong El Nino. Relying on El Nino’s for global warming will have great limitations in future. This study shows nothing about the unknowns in the model, other than the conclusion seems to have been decided beforehand.
ENSO is driven by solar energy and nature’s way of building and releasing this Tropical Ocean energy in two different favorable phases known as La Nina and El Nino. Solar energy, global warming and ENSO are virtually the same thing in this context and the claim in this article is exactly circular reasoning.
ENSO also contributes significantly towards the Gulf Stream, where this energy moved northwards via the AMOC directly linked with the AMO and warms or cools the Arctic Ocean especially. Therefore if the ENSO has no/little contribution towards global temperatures then why does removing the AMO lead to a flat trend in global temperature?
http://i772.photobucket.com/albums/yy8/SciMattG/RSS%20Global_v_RemovedAMO2_zpsssrgab0r.png
The fact that the AMO shows this provides the scientific evidence that ENSO has had a significant contribution towards global temperatures.
I challenge them to show scientific evidence that global warming had nothing to do with ENSO because the fact is it has. The global temperature rises up and down to the behavior of ENSO and is by far the major driver during the satellite era with far better observation techniques. With fewer La Nina’s global temperatures dip less often and with fewer El Nino’s global temperatures rise less often.
http://i772.photobucket.com/albums/yy8/SciMattG/RSS%20Global_v1997-01removal_zpszk83g0xi.png
Summary
Speculations from a model with circular reasoning, based on ocean mechanism they admit hardly know anything about. The irony global warming will cause worse floods and droughts when almost entirely dependent on ENSO.
The study is specious as increased forcing of the climate increases La Nina and reduces El Nino, it cannot increase the intensity of both.
A solar minimum begins in the 2090’s, which will increase El Nino and make California wetter, as the next ten years of this solar minimum will.
I agree 100%. The reason is that we now define a drought as a function of how it affects the human population. With an increase of population over the next 75 to 85 years you will put more demand on the precipitation, causing a shortage which will be a drought. The next thing to look at is today’s flood compared to the a flood in the future. The population will continue to accumulate in low lying areas and streams and rivers will occupy the flood plains at some time- more flooding. Also, if you look at the horrid management or our headwaters areas (ie. a forest policy that sets up for catastrophic fires and invasive weeds) we end up with typical rains causing untypical runoff. We keep looking at how nature affects the human and comparing to the past. How many more people are living is states that are subject to hurricanes than since Camille? The same storm we had 60 years ago; hurricane, tornado, downpour, or blizzard, now impacts many more people.
Claim:
“By 2100, we see more — and more extreme — events.”
Explanation:
If I can kick this down the road for the next century, I can give employment to my children, and to my children’s children.
R
Seems like a pretty easy problem to solve with the proper infrastructure, like building a dam or two to catch some of the excessive rain for use during the dry periods. And we have 85 years to do it!
And in 2101 California will break off from the US mainland, float south, and attach itself to Mexico.
No one in Mexico will notice because the official language of California since 2075 will have been Spanish
As usual, this horrific climate projection was brought to you using RCP 8.5 — the coal-burning, slow tech growth, high population growth scenario.
Note that the authors do not even attempt to justify their use of RCP 8.5, even by the typical hand-waving to it as a “business as usual” scenario. They present it as the future, without any relevant information or context.
http://www.nature.com/ncomms/2015/151021/ncomms9657/full/ncomms9657.html