Study: Large volcanic eruptions cause drought in eastern China

Santorini Landsat.jpg
The “Minoan eruption” Satellite image of Thera, November 21, 2000 May have led to collapse of a Chinese Dynasty. See below.

Via AGU, and the “science is settled” department, once again we learn things we didn’t know about climate.

In most cases, the annual East Asian Monsoon brings heavy rains and widespread flooding to southeast China and drought conditions to the northeast. At various points throughout history, however, large volcanic eruptions have upset the regular behavior of the monsoon.

Sulfate aerosols injected high into the atmosphere by powerful eruptions can lower the land-sea temperature contrast that powers the monsoon circulation. How this altered aerosol forcing affects precipitation is not entirely clear, however, as climate models do not always agree with observations of the nature and scale of the effect.

Using two independent records of historical volcanic activity along with two different measures of rainfall, including one 3,000-year long record derived from local flood and drought observations, Zhuo et al. analyzes how large volcanic eruptions changed the conditions on the ground for the period 1368 to 1911. Understanding the effect of sulfate aerosols on monsoon behavior is particularly important now, as researchers explore aerosol seeding as a means of climate engineering.

The authors find that large Northern Hemispheric volcanic eruptions cause strong droughts in much of eastern China. The drought begins in the north in the second or third summer following an eruption and slowly moves southward over the next 2 to 3 years. They find that the severity of the drought scales with the amount of aerosol injected into the atmosphere, and that it takes 4 to 5 years for precipitation to recover. The drying pattern agrees with observations from three large modern eruptions.

China’s northeast is the country’s major grain-producing region. The results suggest that any geoengineering schemes meant to mimic the effect of a large volcanic eruption could potentially trigger devastating consequences for China’s food supply.


The paper:

Proxy evidence for China’s monsoon precipitation response to volcanic aerosols over the past seven centuries


The effect of volcanic aerosols on China’s monsoon precipitation over the past 700 years has been studied using two independently compiled histories of volcanism combined with the Monsoon Asia Drought Atlas. For both reconstructions, four categories of eruptions are distinguished based on the character of their Northern Hemisphere (NH) injection; then Superposed Epoch Analysis (SEA) with a 10,000 Monte Carlo resampling procedure is undertaken for each category and also each individual grid. Results show a statistically significant (at 90% confidence level) drying trend over mainland China from year 1 to year 4 after the eruptions, and the more sulfate aerosol that is injected into the NH stratosphere, the more severe this drying trend. In comparison, a minor wetting trend is observed in the years following Southern Hemisphere-only injections. Results from spatial distribution of the SEA show (1) a southward movement of the significant dry areas in eastern China from year 0 to year 2 after volcanic perturbations that are either equal to or double the size of the 1991 Mount Pinatubo eruption (15 T sulfate aerosols in NH) and (2) northeast and northwest China experienced substantial droughts in years 2 to 5. These results are in good agreement with a SEA analysis of the Chinese Historical Drought Disaster Index compiled from historical meteorological records. Our findings illustrate the important role stratospheric aerosols have played in altering China’s precipitation during the summer monsoon season and can shed new light on the possible effects that stratospheric geoengineering may have on China’s precipitation.


From Wikiepdia:

A volcanic winter from an eruption in the late 17th century BCE has been claimed by some researchers to correlate with entries in Chinese records documenting the collapse of the Xia dynasty in China. According to the Bamboo Annals, the collapse of the dynasty and the rise of the Shang dynasty, approximately dated to 1618 BCE, were accompanied by “yellow fog, a dim sun, then three suns, frost in July, famine, and the withering of all five cereals”.

Source: Foster, KP, Ritner, RK, and Foster, BR (1996). “Texts, Storms, and the Thera Eruption”. Journal of Near Eastern Studies 55 (1): 1–14. doi:10.1086/373781.

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August 5, 2014 2:44 pm

…climate models do not always agree with observations…
Heresy! Burn him at the hockey stake!
disclaimer: just kidding 😉

James Ard
August 5, 2014 2:56 pm

Is it just me or does the idea of climate geoengineering scare the hell out of you? I mean, what could possibly go wrong?

August 5, 2014 2:56 pm

Interesting. I wonder if the basic premise is duplicated in other regions with seasonal monsoons, that is, do volcanic aerosols cause similar drought effect through lower surface temps.

DC Cowboy
August 5, 2014 3:00 pm

Oh please, it’s CO2… it’s always CO2. There is no other explanation.

August 5, 2014 3:21 pm

Mark and two Cats
…climate models do not always agree with observations…
Heresy! Burn him at the hockey stake!
disclaimer: just kidding 😉

Yes, his crime was resorting to observations, when he had perfectly good models available 🙂

Bruce Cobb
August 5, 2014 3:47 pm

This isn’t manmade so can’t be climate “science”.

August 5, 2014 4:34 pm

James Ard says:
August 5, 2014 at 2:56 pm
Is it just me or does the idea of climate geoengineering scare the hell out of you? I mean, what could possibly go wrong
That makes at least two of us.

August 5, 2014 4:42 pm

The main story of climatic impacts on China that should be mentioned is the impact of drought in the Steppe and how that impacted the plains of China (and of India and Europe). Whosoever it was that occupied the northern grasslands could only survive as nomadic grazer. With the horse (chariots and then bare back and then better with saddles and stirrups) and small bows there were invincible terrorists. What they did not have was grain stores to get them through the bad times. Drought propelled them on raids south. This impact of climatic change was well recognized in the 1970s. See Legg’s Heartlands
Hubert Lamb found drought on the Steppe to be one of the most important impact of climatic change on agricultural human civilization across Eurasia. Lamb’s northern hemisphere volcanic veil index tracked back to 1600 should also be mentioned, and, with this, an article by Stephen Schneider in 1975 where he models global climate change on 3 factors, NH volcanic dust veil, solar, CO2 emissions. This article suggested that the volcanic and solar forcing were major factors in early 20th Cent warming at a time when some wanted to attribute it all to CO2 emissions.
Here are two graphs from that paper:

August 5, 2014 6:08 pm

ROM says:
August 5, 2014 at 4:34 pm
James Ard says:
August 5, 2014 at 2:56 pm
Is it just me or does the idea of climate geoengineering scare the hell out of you? I mean, what could possibly go wrong
That makes at least two of us.
I’ll third that.

August 5, 2014 7:53 pm

“James Ard says:
August 5, 2014 at 2:56 pm
Is it just me or does the idea of climate geoengineering scare the hell out of you? I mean, what could possibly go wrong
putting c02 in the air is geo engineering

August 5, 2014 7:57 pm

Steven Mosher says:
putting c02 in the air is geo engineering
So we have been geoengineering for centuries. Please identify any measurable global harm from the rise in CO2. Then I can decide if I should be frightened.

August 5, 2014 8:10 pm

When I was studying the Cretan collapse around 1300 BC, the academics in Science I think, mentioned some ancient Chinese chronicles that actually mentioned a seven year drought.
That was after the Thera or Vesuvius, I can’t remember which one. Took away half the island of Santorio. Caused tsunamis and disrupted the trade routes. Now the date has been questioned, some say 1600 BC, but Vesuvius also exploded then too, and buried bronze age villages. And Mt Ararak also buried bronze age villages.. The next one of course was 79 AD. Certainly that area is a mine of not only terrestrial volcanoes, but undersea too. I’ve mentioned this before. I’ve got the paper somewhere, but quite honestly, it was written by anonymous. But was part of the required reading. There was also a storm of earthquakes, and then droughts that hid the middle east and Egypt. Whether they are connected or not I don’t know, can’t remember but the date was around the same time give a few hundred years either way. Say 14th century BC. No red cross or crescent then. And it is believed to be responsible for the sea peoples.

August 5, 2014 8:14 pm

I should have said 1600s BC as the dates are disputed by archaeologists. But volcanoes have habit of exploding after many years of dormancy. Pliney the elder actually thought Vesuvius was a hill, not a volcano.

August 5, 2014 8:51 pm

Take away lesson here;
More dim sun means less dim sum

August 5, 2014 9:30 pm

Regarding sulphate aerosols, my understanding of Svensmark’s theory is that sulphur compounds are converted into sulphuric acid by ultra violet radiation, and the sulphuric acid seeds the water vapour in the air to produce clouds. The clouds will then reduce the temperature.

August 5, 2014 9:42 pm

James, Rom and whomever else I 4th, 5th (my wife), 6th my son, that stuff scares the heck out of me although I have read numerous reports it is already being done .(Chinese prior to the Summer Games , Jones Town in the USA).

August 5, 2014 10:38 pm

The bottom line is that people who live near Vesuvius can not insure their properties. And there is bugger all we can do to stop a volcanic eruption. The Ash when first laid is very harmful to plants not only covering them, but the high corrosive components. Only prior alerts can help people move away. Seems in the Vesuvius area only 600,000 can be removed quickly, so the rest of the 2 million will have to take the chances and run!

August 5, 2014 10:44 pm

Wonder if an aggregation of coal mines releasing coal dust has the same effect.?

August 5, 2014 11:20 pm

I don’t know about that Jack, but surface coal fires in India, Indonesia and especially China, pollute the air. Actually the water they use to wash coal is one of the best organic fertilizers you can get. Very expensive too. It is pure carbon.

August 6, 2014 1:06 am

The eruptions most likely to affect us are the long dirty basaltic ones like Laki/Grimsvotn starting mid-1783. (2010’s Iceland eruption was tiny compared to Laki, but the effects were major.) A Laki will give you more probs than a Krakatoa or Tambora, and there’s no reason why it can’t happen again soon. Wasn’t there an even more toxic spout in Iceland in the 10th century? Might feel pretty silly wiping volcanic sludge from acres of solar panels after closing down those nukes and coal plants.
It’s odd that volcanism is not at the centre of “climate studies”. After all, under 1783-5 atmospheric conditions making jet trails to Paris, Kyoto, Cancun and Rio would be impossible.

August 6, 2014 3:39 am

Mosher: CO2 does wonders for Earth. It’s on par with cow manure for farmland. Crops love cow manure and Earth loves CO2. Is weather any different in 2014 than it was 64 years ago in 1950. Nope. Even you (Mosher) know there is no difference. Tornadoes, Hurricanes, etc. You (Mosher) can’t find any difference from 1950 to 2014, why you think you have to resort to the Scary Religion game of repent or the future will be bad is rather sad. Reality tells us the Earth doesn’t create Hurricanes or Tornadoes because of more CO2 in the atmosphere, only in the fantasy Model world can we find Earth taking vengeance for an increase of CO2. We get it, you hate coal and oil. Well, use your brain to create a new energy source instead of playing Priest of CO2. It’s been a rather cool Summer in my neck of the woods (haven’t really needed to use the AC) and was a freezing winter, I like my heat in the winter so let me have mine. You can go without fossil fuel heat in the winter. Just put on another blanket in -20 F weather.

August 6, 2014 3:46 am

“I should have said 1600s BC as the dates are disputed by archaeologists. But volcanoes have habit of exploding after many years of dormancy. Pliney the elder actually thought Vesuvius was a hill, not a volcano.”
Egypts 10 plagues and the exodus? And of course God was behind all extreme events at that time. And extreme events they had, Black Sea and Thera(Atlantis?)

August 6, 2014 6:04 am

I have reached the point that I automatically distrust any document that uses the phrases “statistically significant” and “Monte Carlo” or the word “trend” in a ‘statistical’ context – if is doesn’t come from Steve McIntyre. 10,000 trial runs of a model average out to exactly one model that produces results which are not replicable.
I am no statistician myself, but I know enough about mathematics and measurements that I can tell a competent statistician from a hack.
All they really have here are *alleged* correlations (no direct causation) based on a single anecdote (the concidental Pinatubo eruption preceding the 93 to 96 China drought), and they had to use two different volcanic chronologies (Royal Ann and Bing cherries) to get that much.
They are saying the vulcanism causes droughts – because they are looking at droughts.
They also say the in the southern hemisphere eruption trigger ‘minor wetting trends.’
There is no indication that they gave consideration to the different types of vulcanism and the differing nature of the respective ejecta (ash vs gas vs magma), which vary with individual volcanoes.
If they were looking at heat waves or cold spells or monsoons, they would find a link there as well.
Hasty generalizations based on anecdotal evidence are eminently publishable.

August 6, 2014 10:22 am

Steven Mosher [August 5, 2014 at 7:53 pm] says:
putting c02 in the air is geo engineering

And in that one short sentence Mosher exposes himself and his ilk as the non-scientist(s) we all suspected or already knew.
That statement is a conclusion, or better yet, a belief system like a religion. When they start fron this conclusion or religion and then work backwards how is there any real surprise when data gets tampered with or rejected with models used instead? Is it surprising at all that they chisel away the historical climate ups and downs to create a flat hockey stick?
Besides absolute impartiality, division of labor is also a key component of true Science, or any fact finding system. Having completely different persons playing cop, investigator, judge, jury, and executioner is self-evident logic, yet in what passes for science today we allow people like Mosher with their admitted conclusions to go near the raw data. Agenda driven special interests with their thumbs on the scale telling everyone what the item weighs and then also what we need to do about it ( yep, raise your taxes naturally ). Steve, that single sentence tells everyone that you should never be allowed in the same room as scientific data, or an ice core, or a weather station, or even with a computer that has access to the historical data. You want to be on the agenda pursuing side of policy matters? Stop playing scientist.
Of course Mosher’s religious belief that putting c02 in the air is geo engineering is itself patently foolish on its face. It is Humanity Nihilism which places man as an intruder in this garden of eden and whatever we do is not unlike a synthetic virus sent down by aliens. It also means that they actually believe in a steady-state for Earth, like a museum that must be frozen in time while the human beings here should rightly walk around in cleanroom gear careful not to ‘contaminate’. This leads to a comedy of conflicting beliefs for them such as a lightning bolt causing a forest fire that sends up CO2 as being perfectly natural. Or an Asteroid that wipes the place clean for millions of years is also just peachy. These religious nuts must have been told by their God that it is now at this particular point in time, 2014 or maybe 1860 AD, is the precise state of conditions that their God wanted preserved. These are the levels of CO2 and O2 and N2 and sea levels and PH that he has commanded.
Like it or not, humans are as natural as snail darters and redwoods. What we do is as natural as what they do, or an Asteroid does. Whether CO2 is in the ground or in the air is meaningless in both the big and small scheme of things. We can always argue whether we should do some particular thing, and we do it all the time, but trying to take man out of the natural order is downright creepy and paves the way for dangerous avenues where people die in the name of a sick religion. Oh wait we’ve been there already with tyrants using pet ‘scientists’ to rationalize their agenda. That could never happen again could it?

Tom O
August 6, 2014 1:12 pm

” Steven Mosher says:
August 5, 2014 at 7:53 pm
“James Ard says:
August 5, 2014 at 2:56 pm
Is it just me or does the idea of climate geoengineering scare the hell out of you? I mean, what could possibly go wrong
putting c02 in the air is geo engineering ”
I got to admit, Steven, some times you say the dumbest things. Thanks for reminding me of something though. I used to love the sound of song birds in the spring, and now, thanks to the AGW crowd, all I can think of is “those damn polluters are at it again,” and now with Mosher’s comment, I will be thinking “Damn. More of that featherbrained geoengineering!”

August 6, 2014 1:20 pm

I did a long search of historical drought / famine a while back. Essentially, it happens during cold phases. Some modest, some dramatic; always the same cycles…
China tends to get it bad in cold times. Every “long time” of about 1000 to 1500 years (but with some 750 year minor points and even a 1/2 that about 360-375 year pattern) we get cold bad times. Especially Egypt gets whacked on the long cycle. The fall of the Akkadian Empire along with the Old Kingdom / New Kingdom transition.
This isn’t just supported by history books. It is supported by sand / dust layers in the dirt. By layers of death in the ground.
So this paper finds a specific: Volcanoes cool things, and China has drought.
Now generalize….
Things COOL, and lots of folks get drought, leading to famine, death, and economic collapse, followed by political upheaval and the fall of dynasties. It has happened repeatedly throughout history. Some major (like the Old Kingdom / New Kingdom transition) and some minor (like a famine in China). Some others major, but not quite fully taking down the major Empire. In 535 AD a cold dark cycle hit. The Western Roman Empire fell and the Dark Ages began. In the east, the Eastern Roman Empire surived (eventually to become Byzantium). They made it all the way to the Little Ice Age …
Why am I, a person of mixed English, German and Irish ancestry over here in North America? Because during an early cold fall, my Saxon ancesters moved to England. During another, my Irish ancesters abandonded a cold and starving Europe and moved here. And in another, my German ancesters moved south from the coast, then off to the west. Each time leaving cold and starvation behind, and moving to warmth and plenty.
The Migration Era Pessimum was called that due to it being a pessimistic time due to the cold. ( The Wiki has now been purged of the name ‘pessimum’ after it was pointed out…) The folks on those Asian steppes always run south and west when the cold returns. That is why Hungarians are in the middle of Europe. That is why Ostrogoths wandered past Rome and on as Visigoths headed down to Spain (and on to North Africa).
In warm times, people expand north and east in Eurasia. In cold times, they run south and west. It pulses all through history. (Though the Slavs moved north and east, then hung onto the land as the cold came). For America, that movement got on boats and came to a new continent. It contiued even here. In “The Year WIthout A Summer” or “1800 and Froze To Death”, farms in New Endland were abandoned as folks headed south and west into Oklahoma in a great land rush. My family ended up in Iowa in slighly warmer times and stayed through the Dust Bowl hot times… then ‘moved on’ to California a bit after the Grapes Of Wrath …
That the folks who preach catastrophic unprecidented “Climate Change” seem clueless about this is a bit daft of them… We are in unprecidented stable and pleasant times. What historically was called an “Optimum”. A warm optimum. (And a lot of Mexicans are moving north and east…) It is not the warmth that is a problem. It is when the cold returns. As it always does…

John Of Cloverdale WA, Australia
August 7, 2014 3:59 am

One thing to do in life is visit Santorini and enjoy the view on the ancient crator rim as you sip the local wine (Boutari) . But go in late spring and early summer. I also recommend visiting Crete to imagine how the Minoans lived in an agreeable warm climate before Thera blew and destroyed their civilization. One can look further back in human history when the Indonesian supervolcano erupted and changed the destiny of mankind. It just shows us how the dynamic earth may decide to burp in the future and once again have an destructive effect on mankind. And we are worrying about a degree or so temperature rise over a century. How pathetic we are.

August 7, 2014 7:02 pm

Steve Mosher
Do you not understand the posted study?
It puts cooling as the cause of crop failure/famine. What do you think? Should this be rejected? It has great implications for the whole school that adheres to the viewpoint “CO2 is bad” If this is right then you are not.

August 7, 2014 8:57 pm

John nice post. Actually there is a bit of controversy about when and how the Minoan civilization collapsed, as there discrepancies in the archaeological record. One thing for sure though, is Thera was the main hub for trading and an earthquake did a lot of damage decades before the eruption, they were rebuilding then. I’ve passed Crete on my way to Cyprus in the sixties. It has very high mountains. The time of the eruption would depend on the month. As the Cretan fleet only went out at times when the same men were not required for agriculture and inter-trade items. So the fleet may have been else where or just harbored. There was little ash deposits, and only on the side of the island facing Thera and was not deep. It would have killed off seedlings but would not have harmed fully grown crops or trees. (Olives, fruit etc). It seems, that Thera eruption was four times the force of Krakatoa, but depending on the wind the ash cloud may have largely missed Crete and other nearby land falls. There is evidence that some sea did go inland though, but Knossis is placed very high and maybe not effected by the Tsunami directly. But all sea life in the area would have been effected. But it would have left the main hub for trading under the sea. And maybe they switched to Mycenia as their main trading posts.

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