From the UCLA Newsroom: Pacific Ocean’s response to greenhouse gases could extend California drought for centuries
Warming forces have caused millennia of dryness in California’s prehistory, and greenhouses gases could do the same
Clues from prehistoric droughts and arid periods in California show that today’s increasing greenhouse gas levels could lock the state into drought for centuries, according to a study led by UCLA professor Glen MacDonald.
The study, published today in the Nature.com journal Scientific Reports, looked at how natural climatic forces contributed to centuries-long and even millennia-long periods of dryness in California during the past 10,000 years. These phenomena — sun spots, a slightly different earth orbit, a decrease in volcanic activity — intermittently warmed the region through a process called radiative forcing, and recently have been joined by a new force: greenhouse gases.
As long as warming forces like greenhouse gases are present, the resulting radiative forcing can extend drought-like conditions more or less indefinitely, said MacDonald, a distinguished professor of geography and of ecology and evolutionary biology.
“Radiative forcing in the past appears to have had catastrophic effects in extending droughts,” said MacDonald, an international authority on drought and climate change. “When you have arid periods that persist for 60 years, as we did in the 12th century, or for millennia, as we did from 6,000 to 1,000 B.C., that’s not really a ‘drought.’ That aridity is the new normal.”
Researchers tracked California’s historic and prehistoric climate and water conditions by taking a sediment core in the Sierra Nevada mountains. They pulled a 2-inch-wide, 10-foot-deep cylinder of sediment from the bottom of Kirman Lake and analyzed it in third-of-an-inch sections, creating the most detailed and continuous paleoenvironmental record of California.
The team correlated their findings with other studies of California climate history, and for the first time, united all the studies and cross-referenced them with histories of the Pacific Ocean’s temperature taken from marine sediment cores and other sources.
What they found was not only that periods of increased radiative forcing could produce drought-like conditions that extended indefinitely, but that these conditions were closely tied to prolonged changes in Pacific Ocean surface temperatures.
Changes in ocean temperatures are linked to El Niño and La Niña conditions, which increase and decrease precipitation in California. Until now, no one had the long, detailed record of California’s dry periods needed to show that that aridity went hand-in-hand with changes in the prehistoric climate records of the Pacific Ocean, MacDonald said.
“Climate models today have a challenging time predicting what will happen with Pacific sea-surface temperatures in the face of climate change, and we hope that our research can improve that,” he added.
The researchers chose Kirman Lake in central-eastern California for its sensitivity to climate changes and its stable geologic history. Today, it’s a small, freshwater lake full of trout and about 16 feet deep, with a small marsh at one edge.
The team found evidence though that through the millennia Kirman Lake has grown more and less salty, dried until it was exclusively marshland and refilled again. All the while, sediment accumulated on the lake’s bottom, forming a record of lake conditions, the changing climate and the surrounding environment.
The research team spent years analyzing the core sample, which revealed California’s history layer by layer:
- charcoal deposits indicate when wildfires were more prevalent.
- layers of fossilized pollen shows eras of more pine trees or drier sagebrush.
- shells from mollusks indicate times of deeper water.
- single-celled algae and molecules of carbon and nitrogen give clues to the lake’s depth and salinity, and the abundance or waning of plant and animal life.
From 6,000 to 1,000 B.C., during a time geologists refer to as the mid-Holocene, the core sample captures a 5,000-year dry period in California that has been seen in less detail through other paleoenvironmental records. This arid period is linked to a slight variation in Earth’s orbit that increased the amount of solar energy received by the Northern Hemisphere in the summer months. California was warm and dry, while marine sediment records show the Pacific was in a La Niña-like state, likely reducing precipitation.
A similar dry period was seen from about 950 to 1250 B.C., a time known as the medieval climate anomaly. Increased radiative forcing and warming at this time is connected to decreased volcanic activity and increased sunspots. Again, La Niña appears to have reigned in the Pacific Ocean.
“We suspected we would see the millennia of aridity during the mid-Holocene at Kirman Lake, but we were surprised to see a very clear record of the medieval climate anomaly as well,” MacDonald said. “It was very cool to see the lake was sensitive on the scale of not just thousands of years, but also something that lasted just a few centuries.”
Even more exciting to the researchers was a brief shift in the record toward moister conditions around 2,200 B.C. In the middle of thousands of years of mid-Holocene dryness, Kirman Lake suddenly became moister again, MacDonald said, while simultaneously the Pacific Ocean record switched to more El Niño-like conditions.
“This change at 2,200 B.C. was a global phenomenon,” MacDonald said. “It’s associated with the collapse of the Old Kingdom in Egypt. It’s linked to the decline of the Akkadian Empire in Mesopotamia and similar Bronze Age societal disruptions in India and China. It was amazing to find evidence of it in our own backyard.”
That blip in the record was a reminder that El Niño and La Niña weather patterns have global repercussions. It also confirmed the accuracy and sensitivity of Kirman Lake’s record, and the strong link between the ocean and California’s weather.
All this has consequences for California, the researchers said. Drought-like conditions can last indefinitely as long as increased warming, or radiative forcing, is present. And greenhouse gases are currently expected to increase.
“In a century or so, we might see a retreat of forest lands, and an expansion of sagebrush, grasslands and deserts,” MacDonald said. “We would expect temperatures to get higher, and rainfall and snowfall would decrease. Fire activity could increase, and lakes would get shallower, with some becoming marshy or drying up.”
California might remain an agricultural state, thanks to irrigation and engineering, though productivity might decrease and crops might change, said MacDonald, who emphasized that while the past is no guarantee of the future, in this case it does provide cause for concern.
“I think we would find a way to keep our cities going through prolonged drought, but we’re not going to engineer a way to conserve or preserve the ecosystems of the state,” MacDonald said. “We can’t save our huge expanses of oak woodlands, or our pine and fir forests, or high-elevation alpine ecosystems with irrigation projects like we might our orchards and gardens. I worry that we will see very different wildlands by the end of this century.”
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The study:
Prolonged California aridity linked to climate warming and Pacific sea surface temperature
Glen M. MacDonald, Katrina A. Moser, Amy M. Bloom, Aaron P. Potito, David F. Porinchu, James R. Holmquist, Julia Hughes & Konstantine V. Kremenetski
Scientific Reports 6, Article number: 33325 (2016) doi:10.1038/srep33325
Abstract:
California has experienced a dry 21st century capped by severe drought from 2012 through 2015 prompting questions about hydroclimatic sensitivity to anthropogenic climate change and implications for the future. We address these questions using a Holocene lake sediment record of hydrologic change from the Sierra Nevada Mountains coupled with marine sediment records from the Pacific. These data provide evidence of a persistent relationship between past climate warming, Pacific sea surface temperature (SST) shifts and centennial to millennial episodes of California aridity. The link is most evident during the thermal-maximum of the mid-Holocene (~8 to 3 ka; ka = 1,000 calendar years before present) and during the Medieval Climate Anomaly (MCA) (~1 ka to 0.7 ka). In both cases, climate warming corresponded with cooling of the eastern tropical Pacific despite differences in the factors producing increased radiative forcing. The magnitude of prolonged eastern Pacific cooling was modest, similar to observed La Niña excursions of 1o to 2 °C. Given differences with current radiative forcing it remains uncertain if the Pacific will react in a similar manner in the 21st century, but should it follow apparent past behavior more intense and prolonged aridity in California would result.
The full paper is here, and is open access: http://www.nature.com/articles/srep33325
Certainly, California has experienced megadroughts before. During the most recent one, we covered a study that showed they were quite common:
Source: Cook et al, 2007 and L.A. Times. https://wattsupwiththat.files.wordpress.com/2014/08/nadrought.pdf
But the most important statement in their study is this one:
Given differences with current radiative forcing it remains uncertain if the Pacific will react in a similar manner in the 21st century…
That’s very true, we just don’t know. Some people claim we’ll see more precipitation and we’ll be in a more El Niño like state rather than La Niña. Just a few months ago we heard this in a story we covered:
Global warming will increase rainfall in some of the world’s driest areas over land, with not only the wet getting wetter but the dry getting wetter as well.
Only Nature knows for sure, and I’m not talking about the journal.
I imagine Tim Flannery will be on the plane ready to deliver some prophecies of doom at LAX and assorted expensive hotels. I’m guessing he would be as wrong for you as he was for us.
“Could”-the old weasel word. It proves nothing-mere conjecture. Almost anything “could” happen, making this scare mongering to deceive the sheeple and justify the hidden agenda of the left.
HiT….”Could”-the old weasel word. So Right. Stopped reading the “article”(really propaganda) when I saw that in the title.
How does this 5,000 year drought work? Does a high pressure system sit over California for 5,000 years to make this happen? If so, how does *that* work?
Half of California in drought and the other half flooded as the polar ice melts and the ocean levels rise. The ultimate scary prediction.
PS Don’t forget to send us your money so we can study this further.
The long since absence moisture in Tulare Lake; the largest lake west of the Mississippi River, was not cause by CO2.
It was cause by people smoking something else, who dug a ditch and connected Tulare Lake to the San Joachin River and drained it out through SF Bay into the Pacific Ocean.
They actually were after the land on the bottom of the lake; not to look for fossil munchkins; but to have some more land to build some stuff on.
So they built the Lemore Naval Air Station on it, as well as the City of Hanford.
Yes some people don’t like water when they can swap it for Land.
Didn’t they make a movie about trying to get land in exchange for water ??
G
Somewhere in California there’s a two inch diameter area that won’t see raindrops for 5000 years.
And when the pdo changes again, they’ll be wailing about permanent flooding!
Have they given up on Australia? For decades Australia was the poster child of climate change drought devastation and this poor child has now been abandoned for someone new? How sad.
As the historical graph shows, the Medieval Warm Period wasn’t wetter in CA, although the temperature was up, along with most if not all the world, while the LIA was.
So much for the main assumed feedback effect in IPCC science fiction.
It is God’s burning judgment on the evil ways of the Californians.
Huh?
Deut.11:
[11] but the land which you are going over to possess is a land of hills and valleys, which drinks water by the rain from heaven,
[12] a land which the LORD your God cares for; the eyes of the LORD your God are always upon it, from the beginning of the year to the end of the year.
[13]”And if you will obey my commandments which I command you this day, to love the LORD your God, and to serve him with all your heart and with all your soul,
[14] he will give the rain for your land in its season, the early rain and the later rain, that you may gather in your grain and your wine and your oil.
[15] And he will give grass in your fields for your cattle, and you shall eat and be full.
[16] Take heed lest your heart be deceived, and you turn aside and serve other gods and worship them,
[17] and the anger of the LORD be kindled against you, and he shut up the heavens, so that there be no rain, and the land yield no fruit, and you perish quickly off the good land which the LORD gives you.
Yes, well, California is not Utah, no doubt of that.
Next chapter in Deuteronomy:
“do not inquire after their gods, saying, ‘How did these nations serve their gods? I also will do likewise.’ You shall not worship the Lord your God in that way; for every abomination to the Lord which He hates they have done to their gods; for they burn even their sons and daughters in the fire to their gods.”
But the climate change we have been experiencing is caused by the sun and the oceans over which Mankind has no control. Despite all the hype, there is no real evidence that CO2 has any effect on climate. The AGW conjecture depends upon a postulated radiant greenhouse effect caused by the LWIR absorption properties of so called greenhouse gases. There is no real evidence that such a radiant greenhouse effect exists in a greenhouse, on earth, or anywhere in the solar system even Venus.
Meanwhile they are working mighty hard to drive rural voters and agriculture related “deplorables” from their state.
Raw Video: Trump Talks Water Crisis In Fresno, Says There Isn’t A Drought
Sorry Joel, but it is NOT about farms or fish; neither of which is a large part of California’s economy (although both are big by some standards)
The real water thieves are the people with those vast Socal desert wastelands, who want to turn their 10 cents an acre scrubbery into Oases for future armies of golfers, who they can con into buying a “home” in some place that even the buzzards don’t want to live.
The central Valley arable land farmers can get water to irrigate ALL of the land that they want to have in production of their crops, but they want to get that water for next to free if they can, so they choose of their own free will to allow good farm land next to Hiway 5 go feral, and become a dusty desert, to make their point to gullible California voters.
But just beyond those tumbleweed groves, they can grow whatever they want. They usually operate by limiting the water to some orchard, that is currently growing some out of favor species, so they get insurance which will pay to pull those trees, and scrap them and plant what seems to be the latest organic yuppie food crop that is more profitable.
So some of those farmers are quite happy to see the whole Monterey Bay Ecology, that depends on the SF BAY and its river delta systems for the nurseries of the Monterey Bay species, go under, if they can get cheaper water at below market prices.
Where I live, and people farm, who like farming; they get by as they have always done, by being intelligent in their cop rotations and soil conservation, and sometimes choosing crops which are less water wasting.
G
Water in California has been a political issue for a very long time, with no free market as such since the 19th Century. Mostly, water formerly attached to land, with various rights depending on who was upriver or in the same groundwater basin. The other problem was government water projects, which never tried market discipline either. Throw the greens interfereing with other water rights with no sense of the worth of what they were trying to preserve, and the whole jerry rigged system breaks down.
If they are going to do that then they should stop all use of Sierra based rivers south of the San Joaquin so as to reestablish Lake Tulare to be the great lake and fishery that it once was. All human population should be removed from the San Joaquin valley and surrounding mountains and the whole area turned into a wilderness wildlife preserve. The states high speed rail system is contrary to the California wilderness concept.
So climate change has been taking place without us for millions of years, but now we’re in charge? Last I heard water vapor was a “greenhouse gas” and it doesn’t have a net warming effect. Without water vapor the earth would be much hotter. How can they claim the opposite? It makes no sense at all.
We are to ignore the causes for changes in the past , and now focus entirely upon manually induced CO2? Of course we should. Forgot the past, we’re in charge now!
There is no proxy for radiative forcing. McDonald argues only from an incorrect first principle that all warming results from such forcing. Yet he links the droughts to Nina conditions. Ninas also result from radiative forcing? Doubtful.
Kim Cobb et al (2013) drilled corals and found that the strongest Ninos in the last 7000 years were during the little ice age.
Now we have a unified theory. Ninas cause droughts and Ninos cause ice ages, and they are both caused by radiative forcing. What could possibly be wrong here?
The scientific evidence does not support alarm over global warming. Global warming is not unprecedented, either in rate or in magnitude. While global warming may lead to sea level rises, melting continental ice will avail arable farmland; an increasingly diminishing commodity that is of greater benefit to humanity than some over-priced waterfront real-estate. Global warming will result in the retreat of deserts further extending arable farmland. Global warming will also result in biological radiation making it easier for us to conserve the biodiversity many of us are so fond of. Increasing atmospheric carbon dioxide is not a cause of global warming and is either an indirect product of warming or a product of deforestation. The evidence clearly shows that global warming brings about the opposite of mass extinction. We are currently near the bottom limit of global mean temperatures [and CO2] on Earth, and global warming can only bring us closer to what are more normal temperatures for planet earth.
http://climate.geologist-1011.net/
Couldn’t have said it better myself.
In a state lying on a tectonic boundary, riven by faults, filled with volcanoes:
These researchers have located a small pristine lake, so pure and innocent that cores dug here reveal an incredibly detailed history of California.
Why do I doubt this incredibly simplistic depiction of a lake frequently shaken, dried, swampland, beaver infested, and perhaps not stirred?
I believe these folks need serious psychological help! They’ve been associating with Lewserandownsky too much.
i rather would have expected a conclusion that says that drought conditions are rather the norm then exceptions for California.
but i guess that would cause a catastrophic melt of the climate scare and an unseen mega… euhm gigadrought of $$$$ for them….
Back in 1969 my brother, who had moved to SoCal, invited me out to visit and while their tried to convince me to move there myself. But I told him that it was a frickin desert and I had no desire to live in a brown, dry climate.
Little did he know that a group of bureaucratic Marxists would come along someday and enlist ALGORE to blame my brother and his ilk for those desert conditions.
At least now he can rest easy knowing that the desert conditions existed 9,960 years before he settled there. Whew! I know he was worried about having to taking the blame for global warming.
Here is the takeaway quote from the study:
“Based on current observational data and models, warming or cooling of the eastern pacific remains possible and could either mitigate or exacerbate aridity in California.”
The science is indeed settled.
“What they found was not only that periods of increased radiative forcing could produce drought-like conditions..”
I thought Geologists teach that dry periods become hotter because of less evaporation, not the other way around as the article states
“Claim: ‘greenhouse gases could extend California drought for centuries’”
CO2 has only increased since measurements started in the 1950s. There is no mechanism by which CO2 could do anything but continue its impact into the future. Man will never decrease or even slow the growth of CO2. If CO2 is the cause of anything other than increasing crop yields, we are headed for certain death. I doubt anyone believes that, it is pure nonsense, and 700 million years of geologic record proves it.
“could” – binned.
It seems that this study is likely to look good from the failure of the El Nino this year which means more drought for the next few years.
In the graph there seems to an overall wetter trend with roughly a 130 year fluctuation within it, just as the Wolfe, Maunder and Sporer were about 130 years apart.
“Even more exciting to the researchers was a brief shift in the record toward moister conditions around 2,200 B.C. In the middle of thousands of years of mid-Holocene dryness, Kirman Lake suddenly became moister again, MacDonald said, while simultaneously the Pacific Ocean record switched to more El Niño-like conditions… All this has consequences for California, the researchers said. Drought-like conditions can last indefinitely as long as increased warming, or radiative forcing, is present. ”
Wouldn’t increased radiative forcing mean a warmer Pacific, more El Ninos and more rain?
All right, I give up. If drought is going to drive more dope-smoking liberal Californians over to Colorado, I’m willing to dedicate more money to do what we can to ameliorate the drought. Oh god … please … no more of those out-of-touch losers. Please.