A Colder Climate is a Drier Climate

Guest essay by David Archibald

In trying to understand how the US agricultural system will respond to lower solar activity, and thus a posited colder climate, we have to go way back. As far back as the 1970s in fact when it was still possible for academics to publish books and papers on the effects of climatic cooling. In 1977, Reid Bryson and Thomas Murray published a book entitled Climates of Hunger. The book is old enough that Stephen Schneider is credited with reviewing the manuscript, from his time as a cooling alarmist. 

In their discussion of the climate of the Corn Belt, they start with the results of the archaeological excavation of an Indian village called Mill Creek Site B which was occupied from 900 to 1400 AD. This site is in northwest Iowa in the heart of the modern Corn Belt:




To put that into context, there were possibly over one thousand Indian villages on the Great Plains from Iowa to Colorado during the Medieval Warm Period. In the early 19th century when the explorers who spearheaded the European invasion of the American heartland crossed the plains, they found no corn-farming villages. They left behind the last of the agricultural tribes as they moved out onto the grasslands – the Akira and Mandan on the Missouri and the Pawnee in eastern Kansas – not to find corn fields again until reaching the Pueblos in the southern Rockies. Remnants of the villages were uncovered in the early 20th century as layers of debris covered by wind-blown soil.

The Indians at Mill Creek farmed corn and hunted elk, deer and bison as well as other animals. This is how the excavation data plotted up relative to time:


Figure 3.3 shows the percentage of each of the major hunted species at Mill Creek Site B over the 500 years from 900 to 1400 AD. Bison eat grass and deer browse on trees. The increasing proportion of bison reflects a drying climate with trees being replaced by grass. Figure 3.4 shows that the number of animals in the diet peaked in the 12th century. Figure 3.5 shows that the number of potsherds remained high after bone counts first dropped. The authors believed that corn production and potsherds were related because pottery was needed to store, cook and serve corn. The potsherd count, if read as reflection of the total number of people in the village, indicates that the total number of people in the village did not decline immediately with the reduction in game. The numbers of bones and sherds both dropped rapidly after 1300. By 1400 there were none, and no Indians either. Farmers did not occupy the region again until the mid-19th century.

In their analysis, Reid and Bryson place a lot of emphasis on wind direction. For example Fort Winnebago in Wisconsin kept weather records from 1828 to 1845. Fort Winnebago is now the town of Portage. In 1968, Professor Wahl at the University of Wisconsin-Madison compared the temperatures recorded then with records from 100 years later. His results are shown in the following table:



In every month except March, the 1800s were cooler with the biggest differences in autumn – almost seven degrees in September. Month-by-month comparisons are more important than yearly averages because they have greater implications for food production. Spring and fall temperatures determine the length of the growing season. Calculating the effect on growing degree days (GDD), the climate in the early 1800s had 680 fewer GDD. This would reduce agricultural yield by 27% relative to a 2,500 GDD corn hybrid.

Wind direction was also different with more northerly winds in the 1800s. For Septembers, winds came from the northwest and northeast 47 percent of the time in Fort Winnebago. One hundred years later, Portage records shows winds from these directions 27% of the time. Wind direction also controls rainfall with westerly winds being drier. Reid and Bryson make a stab at calculating this effect in the following figure:



This is Figure 3.1 on page 32 of Climates of Hunger. It is a map of the United States showing July precipitation decreases to be expected with a slightly expanded flow of westerlies, based on 20 years of modern weather records. Shades areas have less rainfall when westerlies are expanded. The combination of lower temperatures and lower rainfall will be a real killer. It killed off the Indian farmers on the Great Plains.


David Archibald, a Visiting Fellow at the Institute of World Politics in Washington, D.C., is the author of Twilight of Abundance: Why Life in the 21st Century Will Be Nasty, Brutish, and Short (Regnery, 2014).

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July 7, 2014 12:07 pm

Thanks David….I always read your writings and am never disappointed. More good knowledge

ferd berple
July 7, 2014 12:07 pm

Canada is already as cold as Mars:
A temperature of -63 C (-81.4 F) was recorded in the small village of Snag on Feb. 3, 1947. That’s roughly the same temperature as the surface of Mars.

July 7, 2014 12:07 pm

The Oneota & Middle Mississippian Cultures (commonly called Mound Builders) were essentially wiped out by the Little Ice Age, after having flourished during the Medieval Warm Period.

July 7, 2014 12:14 pm

if only they hadn’t planted all that GMO corn… Damn Monsanto for destroying native cultures!

Bloke down the pub
July 7, 2014 12:15 pm

Interesting variation in temperature between 1830’s and 1930’s, and all before any tobs adjustments. If temps changed by that much now, they really would get their panties in a knot.

Gary Hagland
July 7, 2014 12:16 pm

After your first entry for the authors of the cited paper, you keep mentioning ‘Reid’ and ‘Bryson.’ Reid Bryson was one of the authors. Thomas Murray was the other. Small thing, but it might detract from an otherwise excellent article.

July 7, 2014 12:24 pm

Gary Hagland says:
July 7, 2014 at 12:16 pm
Bryson was a real climatologist:

July 7, 2014 12:32 pm

Except when it’s not.

July 7, 2014 12:33 pm

David, you write, “In trying to understand how the US agricultural system will respond to lower solar activity, and thus a posited colder climate…”.
While I appreciate the data re animal based diet based on bone fragments and grain-based diet based on pottery shards over time, I don’t see a correlation or evidence of a mechanism when you connect your solar speculation with this data in terms of it being useful with regard to your solar/cold temperature proposal.
The data could be related to nomadic overhunting, which could also drive a desire to develop an agrarian grain based diet. It’s a lot harder to pick up your pueblo and move with the herd than it is your teepee. Maybe they began clearing the land because good hunting was no longer right outside their door?
As an example, the Oregon Willamette valley was cleared for agriculture long before it was settled by Anglo-Saxon pioneers. It too likely became agrarian due to overhunting and a booming Indian population.

July 7, 2014 12:57 pm

More evidence of the Dalton Solar Minimum cold period.

July 7, 2014 1:01 pm

One item to remember is this period of below normal solar activity started in 2005 so the accumulation factor is coming into play.
Secondly it is not just solar activity within itself but the secondary effects associated with solar variability which I feel are extremely hard to predict as far as how strongly (to what degree)they may change and thus effect the climate in response to long prolonged minimum solar activity.
I strongly suspect the degree of magnitude change of the prolonged minimum solar activity combined with the duration of time of the prolonged minimum solar activity is going to have a great impact as to how EFFECTIVE the associated secondary effects associated with prolonged minimal solar activity may have on the climate. An example would be an increased in volcanic activity.To make it more complicated could thresholds come about? An example would be a changing atmospheric circulation pattern which may promote more snow cover/cloud cover and thus increase the earth’s albedo. How will the initial state of the climate play into it? An example of this would be the great amounts of excess Antarctica Sea Ice the globe has presently and how this might play out going forward under a very long period of prolonged minimum solar activity. Will climatic outcomes unknown come out of this?
Then one has to consider where the earth is in respect to Milankovitch Cycles (favorable )and how the earth’s magnetic field may enhance or moderate solar activity.
Given all of that I think at best only general trends in the climate can be forecasted going forward. I am confident enough to say in response to prolonged minimum solar activity going forward the temperature trend for the globe as a whole will be down. The question is how far down /how rapid will the decline be? I really do not have the answer because there are just to many UNKNOWNS. Further when you have unknowns in a system like the climate which is non linear, random and chaotic expect surprises.
NOTE: Ocean heat content could slow down the temperature fall at first. In regards to that I look first for more extremes in the climate due to low solar activity followed by a more pronounced drop in temperature as time goes by.
Still I believe year 2014 is the turning point for global temperatures as the maximum of solar cycle 24 comes to an end.
It can be shown that a strong correlation exist between sunspot numbers and ocean heat content. When the SIDC sunspot count is well over 40 (the long term average) like it was from 1934-2003 the energy gained from solar to the oceans is positive hence ocean heat content rises.
This is now changing with the exception of the maximum of solar cycle 24(2011-2014 early) which is on it’s way out.
I say before this decade is out AGW theory will be proven wrong while solar climate connection theory will be proven correct. I like the way things have been going thus far. I am very confident as more evidence keeps coming in.

Matt Schilling
July 7, 2014 1:07 pm

Pamel Gray has me thinking I have misread the article. She seems to be saying “they switched from hunter gatherers to farming corn because…” But doesn’t the article say the 19th Century Europeans found NO corn? Doesn’t it say that, by the 19th Century, the indians were gone from the land they had farmed and hunted centuries earlier? I apologize in advance if I am missing something obvious here.

July 7, 2014 1:10 pm

Pamela Gray says:
July 7, 2014 at 12:33 pm
The Willamette Valley was not cleared for agriculture before the arrival of French-Indian Canadian, British & American trappers & traders & later settlers from the US.
The indigenous Chinookan & Kalapuyan peoples did however use fire to maintain more productive habitats for elk, deer & other game they hunted (although see below) & the wapato, berries, tarweed, camas, biscuitroot, yampah & other plants they gathered. They may have cultivated their staple wapato, but doing so didn’t require clearing (if that means field preparation by plow or even digging stick) the Willamette Valley. The area was however often smokier in the early 19th century than in the late 20th & early 21st, before field burning was banned in 2010.
In 1826 the Scottish botanist & explorer David Douglas (of “fir” fame) traveled fifteen days through the Willamette Valley en route to the Umpqua River. He observed that there was “not a single blade of grass except on the margins of rivulets to be seen”, because all had been burned. He was concerned that their horses would find too little fodder & that game animals had left the Valley.
Even in the last century, my dear, departed friend Carrie Sampson, daughter & mother of Walla Walla chiefs, of the Umatilla Reservation, still wielded a mean digging stick, with which she could deftly uproot even a dandelion.

July 7, 2014 1:13 pm

Matt Schilling says:
July 7, 2014 at 1:07 pm
You’ve got it right. The LIA climate change made it impossible to sustain corn farming as practiced by the Oneota Culture, hence its villages were abandoned.

July 7, 2014 1:16 pm

Pamela Gray says:
July 7, 2014 at 12:33 pm
They farmed corn throughout the whole period. The type of game upon which they relied changed as the climate dried, then became too dry to support farming at all any more.

Rud Istvan
July 7, 2014 1:23 pm

Interesting take, but at best regionally true. Tony Browns (ClimateReason) historical research on CET shows a quite different pattern so far, with much higher variability and colder plus unfavorably wetter LIA conditions in central England. Could be caused by the same general shift in wind patterns, though. Iowa is a long way from any ocean. England is not.

Steve from Rockwood
July 7, 2014 1:27 pm

They are predicting a record corn harvest in the US for 2014.

July 7, 2014 1:46 pm

Pamela Gray says:
July 7, 2014 at 12:33 pm
Pamela, while Dave doesn’t make it explicit in his article the important change is a shift from dominant Elk and Deer to Bison. Elk and Deer are browsers and prefer a relatively covered landscape (with the exception(?) of Tule Elk in California). The bison population expands as the plains grasslands grow, but that one-way linkage may be overly simple, since the increased bison herds might also cause increase in grasslands. The Society for Range Management provides a good deal of information about the interactions between range land and herd animals.

July 7, 2014 1:48 pm

Your temp series differences would fit right in with the 30+ year ‘cycle’. Starting from the beginning of the current warming period, 1976/77 and moving backwards to 1945/47 as cool, then 1946/47 to 1914/15 was warm, to 1914/15 till 1884/85 as cool, to mid 1880s to mid 1850s as warm, and then the 30+ years prior to mid 1850s as cool. That would put the years 1829 to 1842 right in the middle of a cool cycle. Another thought from looking at those numbers, is where you highlight the extra cool in September. Note that August through November also show larger differences. That immediately reminded me of what occurred last year towards the end of August, and in particular September and October of last year. In late August the night time temps noticeably dropped. Then in September, there was a sharp drop in night time temps to below freezing. By October I was seeing midnight temps in the teens and as low as 10 F. This continued into November until a change at the end of November pushed night time temps back into the 40s F and the cold wave was gone for the rest of the winter, although look at how cold the interior became last year. I am close to the Pacific coast. I now expect to see a drop in temps starting around the same time as last year from some connections between data sets that I have been looking at this year. It looks like it may well dovetail with the change in monthly temperature that you have shown up above. Autumn of last year was unusual in that regard.

July 7, 2014 1:51 pm

Reblogged this on The Next Grand Minimum and commented:
Cold air brings more drought than warm air. Why do the warmest insist that warm air and droughts are our biggest danger?

July 7, 2014 1:57 pm

Rud Istvan says:
July 7, 2014 at 1:23 pm

Your implied caution against over-generalization is well taken. But, when the region feeds as many people as the corn belt does, the consequences may be global.

July 7, 2014 2:00 pm

Figure 3.5. Number of potheads found at Mill Creek Site B…..
…I had to go back and read that again
Thanks David

July 7, 2014 2:07 pm

Duster says:
July 7, 2014 at 1:46 pm
Elk are basically grazers, but now live mostly in mountainous areas, so browse more than they’d prefer. They were originally more of a plains creature. Deer of course are indeed browsers & bison grazers. Your point is correct, as IMO the author intended.

July 7, 2014 2:23 pm

Lamb (1965) shows the MWP wetter & LIA drier in Merrie Olde. I hope that Tony will come along to enlighten us.
96 AD 800-1000
97- 98 1000-1100
98-100 1100-1150
100-106 1150-1200
100-104 1200-1250
100-106 1250-1300
98-101 1300-1350
97- 98 1350-1400
95 1400-1450
95 1450-1500
97 1500-1550
93- 94 1550-1600
93- 94 1600-1650
92- 93 1650-1700 a
96- 97 1700-1750 a
94 1750-1800
96 1800-1850
97 1850-1900
99 1900-1950
Rainfalls from 1740 averages taken from NICHOLAS and GLASSPOOLE (1931) and Meteorological Office records. Rainfalls before 1740 averages derived from decade values of the summer wetness/dryness index and from the adjusted average values of annual mean and winter temperature, as explained in the text, using regression equations.
a Values given for the temperatures 1650-1700 and rainfalls 1700-1750 incorporate instrument
measurements for part of the period and the margins of error (as indicated in Fig.4 and 5) are
reduced in consequence.
I simplified the table by taking out the seasonal breakdown. I would urge going to the original, since the amount of high summer rainfall varies substantially.

July 7, 2014 2:24 pm

Rud Istvan says:
July 7, 2014 at 1:23 pm
Reply above was to Rud.

KRJ Pietersen
July 7, 2014 2:26 pm

The disappearance of the settled farming communities would likely be explained by the transformation of the Comanches into fearsome horseback warriors after their acquisition and subsequent mastery of horsemanship sometime during the late seventeenth century. This, as I understand the history of the Great Plains, was the greatest transformation on the plains up to the appearance in large numbers of Europeans (or European Americans) some 150 years or more later. The Comanche were known for wanting to fight everyone, and particularly despised non-horse cultures.
I’d be of the view that it was Comanche humans, not climate, that put paid to settled agriculture on the Plains in the period discussed in this article, although, of course, I could be wrong.

July 7, 2014 2:32 pm

KRJ Pietersen says:
July 7, 2014 at 2:26 pm
I assume you’re kidding. If so, pretty funny.
Comanches didn’t get horses until c. 1640 at the earliest (probably later), & never came anywhere near Iowa.

July 7, 2014 2:53 pm

Speculation: Figure 3.3 is “percentage” of bones found. Notice in figure 3.4 that the “number” of bones found is nearly equal between deer and bison, suggesting that both species may have been fairly equally represented compared to elk. It could also suggest that bison tasted better. I’ve had all three. Bison is pretty damn good. So is elk. Deer is good if it is butchered off the bone, fat, and sinew properly. That the elk population decreased so dramatically is interesting. Elk are very sensitive to wolf depredation, and wolves prefer elk over deer for sure. However, overall, it still could be related to overhunting. Too many people, not enough wildlife. At the very least, the decreasing population of all three game species appears to have nothing to do with solar issues. Unless you are willing to disregard the reconstructed solar record.

Adam from Kansas
July 7, 2014 2:57 pm

One thing this article doesn’t take into account is how today’s higher Co2 levels may actually allow the type of farming in a colder, drier climate that wasn’t possible before.
A new Little Ice Age in this sense may not definitively lead to an agricultural collapse as long as modern society keeps belting out carbon.

KRJ Pietersen
July 7, 2014 3:00 pm

milodonharlani says:
July 7, 2014 at 2:32 pm
You haven’t read the main article very carefully. It talks about the disappearance of the settled agricultural peoples during the period sometime after evidence of their existence in the period 900 to 1400 AD to their non-existence when the Europeans (European Americans) arrived. So their disappearance during that gap, in other words.
As I said in my post, “the transformation of the Comanches into fearsome horseback warriors after their acquisition and subsequent mastery of horsemanship sometime during the late seventeenth century”. You didn’t read this very carefully either.
And yes, it’s well known that the Comanche were present in Iowa across the period of the 17th to the 19th century.
Time to do some more reading, my friend.

July 7, 2014 3:21 pm

KRJ Pietersen says:
July 7, 2014 at 3:00 pm
I see you weren’t kidding.
I have already done my reading, my archaeology & my talking to Comanches & members of similar tribes. Also winning money in their casino at Lawton near Ft. Sill.
I not only read the blog post but long ago the book upon which it is based. Evidence for the Iowa farming settlements disappears c. AD 1400, long before there were any horses in North America (they having gone extinct here thousands of years earlier). Iowa Indians didn’t get horses until about 300 years later.
It is not only not well known, but definitely known that there were never any Comanches living in Iowa. The Iowa “Padouca” mentioned in your link are not Apaches or Comanches. This might help explain your & the link authors’ errors. You indeed have some reading to do:
Grinnell, G. (1920). Who Were the Padouca? American Anthropologist, 22 (3), 248-260 DOI: 10.1525/aa.1920.22.3.02a00050
Michelson, T. (1921). Who Were the Padouca? American Anthropologist, 23 (1), 101-101 DOI: 10.1525/aa.1921.23.1.02a00120
Secoy, F. (1951). The Identity of the “Paduca”; An Ethnohistorical Analysis American Anthropologist, 53 (4), 525-542 DOI: 10.1525/aa.1951.53.4.02a00060
The Comanche were originally Shoshonan people, living along the Upper Platte River in Wyoming. After they got horses (usually estimated around 1680), they migrated south, drove out the Apaches & occupied a territory in eastern New Mexico, southeastern Colorado, southwestern Kansas, western Oklahoma & most of northwest Texas.
The Mississippian cultures which crashed so dramatically at the end of the Medieval Warm Period were victims of colder climate, not horse-mounted raiders. Some more reading for you:

kadaka (KD Knoebel)
July 7, 2014 3:24 pm

In trying to understand how the US agricultural system will respond to lower solar activity…
It must first be understood the effects of central government mis-management in DC will clearly outweigh the effects of any minuscule variation of solar output.
Farming was transformed into favoring corn production by the ethanol mandate. Tomorrow the Occupant in Chief may determine this agricultural product is too energy wasteful thus promoting climate change so he will immediately do some action to disfavor it.
And there is always the standard favoring with subsidies of crops to produce favorable votes from the representatives of the states who produce those crops.
Don’t forget the state level screw-ups. When talking about a drier climate, note how water and soil policies decided upon and enacted by career bureaucrats can easily wreck agriculture for years and drive farmers bankrupt.
Thus the article is at best an intellectual exercise, examining a “what if” without possibly-idiotic government intervention thus is far from the reality.
Besides, how would the US government respond to long-term cooling when they are certain it is only a short-term reduction in warming that will soon speed up again? It’s only been almost a few decades, maybe. Why can’t there be three or four or five decades of this less-warming before it comes roaring back without unified global governmental intervention preventing it?

July 7, 2014 3:28 pm

Pamela Gray says:
July 7, 2014 at 2:53 pm
Game didn’t decrease. It switched from more browsing deer in the area to more bison. Bison range expanded during the LIA because of the spread of grassland into previously forested areas.
There was not overhunting from human population growth because there weren’t enough people to kill all the bison. Quite the opposite. The human population in the area fell because they were reliant on farming as well as hunting.
The population of North America plummeted because of the Little Ice Age, which is associated with weakened solar activity, whether you like that fact or not. The population crash is not a controversial conclusion. See link to Cahokia above, or any work on the subject. The Mound Builder cultures were wiped out in the upper Mississippi region.
I used to raise bison & still hunt deer & elk, not that that matters.

KRJ Pietersen
July 7, 2014 3:43 pm

milodonharlani says:
July 7, 2014 at 3:21 pm
Cahokia is on the Mississippi in Illinois facing across to Missouri, so I fail to see how it links to your assertions about iowa.
However, I’m sure you are right in everything you say, and I withdraw quietly. I do. I’m not interested in fighting somebody on the internet.

July 7, 2014 3:47 pm

KRJ Pietersen says:
July 7, 2014 at 3:43 pm
Cahokia was the biggest known city of the Mississippian Culture, to which the farmers in Iowa belonged. The whole vast cultural complex crashed at the same time, because the climate got too cold. Needless to say, Comanches did not belong to this culture, living far away from either Iowa, Illinois or Missouri (St. Louis also has big mounds).
If you really want to learn about Comanches, I highly recommend this excellent history:
It’s the best book on the subject I’ve ever read.

July 7, 2014 3:49 pm

If you read the history of Europe, the appearance of the horse led to the disappearance of smaller villages and the creation of larger, more easily defended towns. These later sites were eventually destroyed too, but it took centuries. It didn’t happen all at once.
I read this in a book, The Horse, The Wheel, and Language. So, it must be true, as I remember it.
It might have been tough to raid on horseback without much water or forage. The Mongols rode mares, and drank the mares milk on the march. I don’t recall the Indians doing this.
But, it is true, I regret to say. You have to read old books to get an honest view of climate history. We live in a dark age.

July 7, 2014 3:51 pm

The overall number of deer, elk, and bison bones uncovered in the area decreased from their peak shortly after 1000 AD to their rapid significant fall by 1200 AD, and then a trailing off from there. The solar period you are interested in occurred more than a few 100 years after that fall in the number of bones found (1645-1715). Did they not like meat anymore? What made them clearly significantly reduce their consumption of meat if you use the number of bones as evidence?

KRJ Pietersen
July 7, 2014 3:56 pm

milodonharlani says:
July 7, 2014 at 3:47 pm
I read it last year. All the best.

Ulric Lyons
July 7, 2014 4:02 pm

US drought is strongly associated with warm AMO phases:
“Key role of the Atlantic Multidecadal Oscillation in 20th century drought and wet periods over the Great Plains”
The next warming of the AMO should be from just after this sunspot maximum, to around 2024/25:

July 7, 2014 4:04 pm

My main question during all of this for the past 10 years is: “What’s the downside?”
Sure if it goes to high too long then we’ve got local problems but overall things should be gradual allowing population movement and technology to counter act the worst events.
I’m expecting more cooling this winter. The last one wasn’t too bad but it was hard in some places due to increased heating costs. Not an increase in snow here (SE PA) so impact was low as far as threats to life and commerce.
Doubt they can convince me that warmth is bad.

July 7, 2014 4:06 pm

Milo, Indians surely did farm the Willamette Valley. Just not in the way you understand. The distinction is this: farming what is there versus planting and farming what was not there. Indians did the former, white settlers did the latter. But farming it surely was. And it was extensive.

July 7, 2014 4:07 pm

Pamela Gray says:
July 7, 2014 at 3:51 pm
The number of bones found correlates with human population decline. It’s all right there in Bryson’s great book:
The change in species frequency correlates with the progressive drying out of the region.
I’m interested in all the solar periods associated with cooling & warming, & not just in the MWP & LIA, for that matter. Decreasing solar activity didn’t come more than a few hundreds of years after the collapse (appropriate term in this case) of the Mound Builders. Before the Spörer (c. AD 1460-1550) & Maunder Minima came the Wolf Minimum (c. 1280-1350), still during the MWP because there was a last gasp warm pulse between the Wolf & Spörer before the LIA. There’s also a bit of lag, since it takes a while for the full effect of reduced UV radiation & magnetic field to be felt in oceanic circulation.
Iowa & the rest of the Oneota zone were naturally affected by climatic deterioration sooner than Cahokia & the lower Mississippi zone. Different areas were hit by the onset of worsening climate at different times in the transition period, c. 1300 to 1500, not just in North America, but globally.

July 7, 2014 4:10 pm

not exactly what’s being pushed in Australia today:
8 July: ABC: Margot O’Neill: Warm water likely to accelerate Antarctic ice melt and sea level rises, Australian scientists find
Scientists from the University of New South Wales (UNSW) have modelled how shifting wind patterns can drag warm water currents right up to the base of the giant ice shelves.
“What you usually have is cold water sitting next to the ice shelves at about minus 2 degrees Celsius and then warm water further out,” said Paul Spence from the Climate Change Research Centre at UNSW…
The University of Hawaii’s Professor Axel Timmerman, who has seen the research paper, says the melting of some unstable ice sheets might be irreversible…
The Australian Antarctic Division’s Tas van Ommen says the effects of a rapidly transforming Antarctica are now likely to be felt this century…

July 7, 2014 4:18 pm

Pamela Gray says:
July 7, 2014 at 4:06 pm
Your link merely says what I already pointed out. If you want to call burning clearing, then OK. But that’s not agriculture. Its cultivation. Anthropology & archaeology make the distinction between shifting or settled cultivation & agriculture, which involves domestication & usually sodbusting. The WV Indians didn’t domesticate any of the local plants they may have selectively cultivated, which in the case of wapato simply means sticking it in some mud along the shore of a watercourse.
Pyroculture is a good name for the practice, but would include the Plains Indians burning grasslands, as well, which is not generally considered agriculture. The only domestic animal they had of course was the dog. Mexican Indians had turkeys & South American Indians had llamas & alpacas, along with cities.
Unless some finds have been made since I studied the subject, IMO Willamette Valley Indians also lacked pottery, although some ceramics have been found in the southern Oregon coast sites & the basin & range region in the southeast (Lake, Harney & Malheur Counties). I could be wrong about this.
Basically, the region was so abundant that there was no need for agriculture. Hunting & gathering, with possibly some cultivation (planting wapato), sufficed.

July 7, 2014 4:23 pm

KRJ Pietersen says:
July 7, 2014 at 3:56 pm
Then it’s surprising you imagined that the Comanches made it to Iowa.

July 7, 2014 4:31 pm

Joel says:
July 7, 2014 at 3:49 pm
There were horses in Europe before there were humans. Maybe you refer to the breeding of draft or war horses, or the invention of the horse collar.
No American Indian raiders covered as much territory as the Mongols, or in such numbers, so they could ride mares, geldings or stallions. Nor did they develop comparable war bows (& arrows requiring metallurgy) or saddles. They were however able to shoot bison from horseback at close range.

July 7, 2014 4:33 pm

The Wahl study was a landmark. I
have found much additional independent data confirming
these results for the 1800’s.

Ulric Lyons
July 7, 2014 4:34 pm

milodonharlani says:
“I’m interested in all the solar periods associated with cooling & warming, & not just in the MWP & LIA, for that matter.”
There were persistent drought conditions across the great plains during the solar minimum in the 1880/1890’s.

July 7, 2014 4:49 pm

Ulric Lyons says:
July 7, 2014 at 4:34 pm
IMO cold & drought are often linked. Cold air holds less moisture than warm air. The polar regions are cold deserts. Glacial phases of Ice Ages are generally drier as well as colder than interglacials, such as now.
I too find correlations between solar activity & climatic parameters such as precipitation & drought, as has been noted for about a century, at least. Monsoonal flows seem particularly noticeably affected.

KRJ Pietersen
July 7, 2014 4:50 pm

milodonharlani says:
July 7, 2014 at 4:23 pm
Plenty of other posters here are taking issue with you, so there’s no reason for me to add fuel to the fire. As I have explicitly said, I’m sure you are right. You need to focus on the others calling you out. I’ve excused myself from this fight. Good luck 🙂

July 7, 2014 4:54 pm

Do we know if UV radiation from the sun changed from 900 to 1400 AD

kadaka (KD Knoebel)
July 7, 2014 5:05 pm

From milodonharlani on July 7, 2014 at 4:18 pm:

Unless some finds have been made since I studied the subject, IMO Willamette Valley Indians also lacked pottery, although some ceramics have been found in the southern Oregon coast sites & the basin & range region in the southeast (Lake, Harney & Malheur Counties). I could be wrong about this.

Have you never heard of air drying clays? There was a piece recently on the local Home and Backyard show, people still use it to make plates and other dinnerware.
Clay is ubiquitous, practically anywhere you can dig down so many feet and find a layer. If you ever come across an old portable coal forge with the cast iron pan carrying the warning “Clay Before Use”, they don’t want fireclay, just a layer of common clay to protect the metal.
So you dig it up, shape it, dry it, use it. It’s not a durable as fired pottery, but still usable.
And afterwards, you discard it out in the open, it gets wet, maybe buried in moist ground. Why would you not expect it to break down, get soft again, and leave no trace for the future archaeologists to find?
Here’s an example listing of a commercial offering, it’s very easy to find some:

Mexican Pottery Clay
A self-hardening clay that has a rich red color similar to Mexican or Indian Pottery. Little or no decoration is necessary. May be shaped by hand or thrown on the wheel. When dry, modeled objects are hard and durable without firing. Decorate with acrylic colors.

July 7, 2014 5:27 pm

kadaka (KD Knoebel) says:
July 7, 2014 at 5:05 pm
There is certainly clay in the Willamette Valley, so air drying is a theoretical possibility, however 18th & 19th century explorers, trappers, traders & settlers did not report seeing any kind of indigenous ceramics among the inhabitants of the Valley or in the larger NW Coast Indian cultural province.
They used stone, wood & basketry. Nowadays Indian artists put clay inside some baskets, but that’s not reported by 18th or 19th century observers whose accounts I’ve read.

July 7, 2014 5:40 pm

PS: You are aware, are you not, that it’s rainy nine months out of the year in the Willamette Valley, so the climate is less conducive to use of air dried plates & bowls than Mexico? And that wood & stone are abundant there?

July 7, 2014 5:42 pm

Australia’s having its own “polar vortex” winter at the moment, a lot milder than America’s winter, but we’re getting unaccustomed lashings of snow and freezing rain. Even up in the North, on the edge of the tropics where I live, its cold. We’ve been running the heaters full time, and its still chilly.
So I guess the cold weather gets drier after all the moisture drops out of the atmosphere as snow.

kadaka (KD Knoebel)
July 7, 2014 6:33 pm

From milodonharlani on July 7, 2014 at 5:40 pm:

PS: You are aware, are you not, that it’s rainy nine months out of the year in the Willamette Valley, so the climate is less conducive to use of air dried plates & bowls than Mexico?

They are using air dried clay objects in Pennsylvania, now, which is not as arid as Mexico. Your link says those Indians made plank houses. Obviously if they can be kept indoors then rain is not a problem.
Nor would it be expected for rain to be a great issue. If the air-dried clay vessel is suitable for storing water for a while, then why would rain be expected to harm it? Degradation is a longer-term issue.
Just how primitive are these tribesmen? Didn’t they have fires to keep warm, suitable for drying out nearby clothes and pottery?

July 7, 2014 6:46 pm

kadaka (KD Knoebel) says:
July 7, 2014 at 6:33 pm
Of course they could have made air dried clay objects indoors, but they frequently lived, cooked & ate out of doors, although less so during winter, of course. The main reason why pottery of any kind was not observed among NW Coast tribes is because they had so much wood of the highest quality.
Western red cedar was used not only to make houses, but bowls, plates & spoons, as well as its roots for basketry. Bark was also commonly used for cooking & eating. You’re free to assume that NW Coast Indians used air dried clay objects, but there is no evidence to that effect, & indeed, why would they, living as they did among such abundance? Same reason why they didn’t farm (besides of course lacking suitable domesticated crops), when sticking wapato in the mud for starch & gathering berries for sugar & vitamins works so well & you can practically walk across the spawning salmon which jump into your net at the falls, catches so easily smoked with alder wood. After cooking, you can eat them off a piece of bark, which you then throw away or burn.
In short, there is no reason to assume ceramics of any kind nor to suppose they made it.

Farmer Gez
July 7, 2014 6:53 pm

Non farmers may not recognise the possibility of a plant pathogen that could have caused the local cultivars of corn to be non viable for sustenance. It happens all the time and our modern plant scientists fight a never ending battle against mutated pathogens. In the past people just starved or found new food. Nature doesn’t care if we thrive or die.

Steve P
July 7, 2014 6:53 pm

milodonharlani says:
July 7, 2014 at 3:47 pm
KRJ Pietersen says:
July 7, 2014 at 3:56 pm
On Amazon, 57 of 1088 reviewers gave Empire of the Summer Moon one star. After reading a few of those poor reviews, I wouldn’t spend the time or money on the book, but perhaps those who have read it would care to address the 1 star reviewer’s criticisms, which point to sensationalism, hyperbole, and “excessive use of superlatives.” i.e. “the most powerful tribe in American history.”
From the first 1 star review on Amazon, link above:

I’m not really liking this book. I’m seeing a lot of generalizations and a lot of very charged language that undercuts any positive points Gwynne might be trying to make about the Comanches. He even blunders with the history of other tribes.

And another:

Mr. Gwynne is clearly not one to let the truth get in the way of a good story.


July 7, 2014 7:11 pm

Steve P says:
July 7, 2014 at 6:53 pm
Many object to the way he portrays Comanche life, which never the less is accurate.
Maybe there was a more powerful tribe in the 19th century, but how many not only stopped the advance of European civilization in the US, but actually rolled back the frontier, resisting the power of Mexico, Texas & the federal government for decades?
But of course feel free to pass.

July 7, 2014 7:17 pm

Farmer Gez says:
July 7, 2014 at 6:53 pm
Possible, but less likely with less highly bred strains & in isolated areas. Corn continued flourishing in areas less affected by the climate changes observed in the proxy data for the period. Nor did farmers return with new strains from elsewhere during the next centuries, as the climate got even worse.

Gene L
July 7, 2014 7:56 pm

Not sure if this is relevant. Charles C. Mann postulates in his book “1491: New Revelations of the Americas Before Columbus” that about 80-90% of the Indians died off around 1500 because of introduction of European domestic animals like pigs. Pigs were quickly adopted and spread faster than the Spanish. Unfortunately they carried the usual range of Old World disease. And the fact that the animals and people lived in close proximity contagion was fast and deadly.
He also postulates that as the number and size of villages grew the Indians began herding Bison. Both to make hunting more efficient and to keep the Bison from overrunning the villages. If true could be another reason for the increase in Bison.

gary gulrud
July 7, 2014 9:54 pm

Thank you, David, for taking up this little gem of anthropology and Global Cooling as it impinges on my homeland. I’m a little jealous, as no doubt the anklebiters are, at how seamlessly you move between disciplines with your deceptively simple style of expression in English.
It was obvious last winter, the Arctic cap of air had not shifted over the Canadian Shield from Siberia, rather it had expanded. This is more, IMHO, than a simple confluence of PDO and AMO in the negative phase, which coincidence persisted 5 years or so in the 1930’s. The states of Kansas, Oklahoma, and the panhandle of Texas are already drier than during the Dust Bowl.
milodonharlani says:
July 7, 2014 at 4:18 pm
I had not picked up on this distinction between agriculture and cultivation before now. Thanks for knowing whereof you speak. The paucity of same has grown tiresome hereabouts.

A Crooks of Adelaide
July 7, 2014 10:50 pm

I’m reading this and wondering what ever happened to the precautionary principle?
I guess there’s precautions and precautions.

July 7, 2014 11:31 pm

Didn’t the dustbowl and severe drought happen in the 1930s when it was warmer? I suppose it might also depend on which part of the interior you are.
My guess is that with global warming, the interior US will be either drier, wetter, or about the same. Same if it cools.

July 8, 2014 12:46 am

Few people appreciates role of the Earth’s magnetic field in changes in the circulation.
Of course, these changes are closely related to the activity of the solar magnetic field. Much about it knows Vukcevic. Regards.
Measurements have been made of the Earth’s magnetic field more or less continuously since about 1840. Some measurements even go back to the 1500s, for example at Greenwich in London. If we look at the trend in the strength of the magnetic field over this time (for example the so-called ‘dipole moment’ shown in the graph below) we can see a downward trend. Indeed projecting this forward in time would suggest zero dipole moment in about 1500-1600 years time. This is one reason why some people believe the field may be in the early stages of a reversal. We also know from studies of the magnetisation of minerals in ancient clay pots that the Earth’s magnetic field was approximately twice as strong in Roman times as it is now.

Kelvin Vaughan
July 8, 2014 1:39 am

Perhaps an ice age occours when the tropics heat up and the Hadley cells extend all the way to the poles depositing the moisture at the poles as the air decends and brings the cold air back down over the Northern latitudes…

Ulric Lyons
July 8, 2014 3:11 am

milodonharlani says:
July 7, 2014 at 4:49 pm
“IMO cold & drought are often linked. Cold air holds less moisture than warm air. The polar regions are cold deserts. Glacial phases of Ice Ages are generally drier as well as colder than interglacials, such as now.”
Generally yes:
Though through the colder parts of solar minima precipitation will increase in some areas as the atmospheric circulation patterns shift, and with increases in El Nino and positive Indian Dipole events.

July 8, 2014 3:35 am

Eric Worrall says:
July 7, 2014 at 5:42 pm
Australia’s having its own “polar vortex” winter at the moment, a lot milder than America’s winter, but we’re getting unaccustomed lashings of snow and freezing rain. Even up in the North, on the edge of the tropics where I live, its cold. We’ve been running the heaters full time, and its still chilly.
So I guess the cold weather gets drier after all the moisture drops out of the atmosphere as snow.
Hi Eric, yeah mate in Qld emailed it was 6c where he lives this am.
I saw that Warwick got to -6C this am as well
even WA has copped some fairly bitter cold, stranding hikers etc,
we’re having reported to 100k winds hitting Vic this evening, along with icy cold n rain.
it is winter though:_0
unlike the usa asia and eu copping snow hail etc in summer!

July 8, 2014 4:25 am

“That would put the years 1829 to 1842 right in the middle of a cool cycle. ”
I agree. AMO was in deep trough or cold 1790-1850 and PDO was fluctuating but negative as well during the period in question. , Studies done by McCabe et al 2004 showed that this combination of negative AMO and negative PDO results in droughts of 6 years or more in the area under discussion and central US . The last time we had this combination was 1965-1975 and again 1895-1915. Both of these periods were cold as well

Ulric Lyons
July 8, 2014 5:19 am

David Archibald wrote:
“In their analysis, Reid and Bryson place a lot of emphasis on wind direction. For example Fort Winnebago in Wisconsin kept weather records from 1828 to 1845.”
It was notably cooler 1836-1845 in CET: http://climexp.knmi.nl/data/tcet.dat
That run of cold events should repeat 179 years later from Autumn 2015 to 2024.

July 8, 2014 5:24 am

A Crooks of Adelaide says:
July 7, 2014 at 10:50 pm
I’m reading this and wondering what ever happened to the precautionary principle?
I guess there’s precautions and precautions.

I suppose that would depend on your definition of The Precautionary Principle.
Isn’t that the requirement that we should take mandatory and immediate global totalitarian dictatorial actions now that will kill millions of innocents each year between now and 2100 and cause billions more people to suffer trillions of harm and suffering extreme pain and disruption while only enriching elite dictators and bureaucrats worldwide by restricting energy use and artificially increasing its price and availability to take actions that will not reduce the possible chance of a beneficial 2-3 degree increase in global temperatures?
Is that the precautionary principle you demand? or is there a different one that offers some chance of global improvement other than increasing reliable energy availability and reducing its cost?

Rhys Jaggar
July 8, 2014 5:37 am

One is minded to suggest that ‘drier’ is not necessarily bad, if the evaporation of moisture from soil is suitably reduced in cooler climates, if the destruction of crops through hailstorms etc is reduced in high summer and if the snowmelt from mountains occurs over a longer period in spring, thereby supplying moisture during the growing season more effectively than in hotter climates.
There is also the issue of holistic geographical realignment of crop growing centres across the USA to obtain a new reality.
Has anyone done any rigorous, reputable and defendible research on that??

July 8, 2014 5:40 am

I might add that this past winter also had negative AMO and negative PDO . Both may be negative during the next several decades .AMO cycles are variable but they can be negative up to 60 years as we saw 1790-1850. Past negative AMO cycles were 1900-1926 and again 1964-1995. PDO negative cycles are closer to 30 years like 1944-1976 and . AMO has peaked and may go negative in an extended way during this decade and PDO has been negative since 2007. except for a few months recently. So the period of 1829-1842 that David selected could be a sign of what lies ahead as well for the next several decades , not necessarily due to the sun but possibly due to the natural variability of the ocean cycles l

J. Keith Johnson
July 8, 2014 6:39 am

milodonharlani says:
July 7, 2014 at 12:07 pm
The Oneota & Middle Mississippian Cultures (commonly called Mound Builders) were essentially wiped out by the Little Ice Age, after having flourished during the Medieval Warm Period.
milodonharlani, I live less than two hours away from Moundville, AL, which is a major archeological site for the Mississippian Culture. Several weeks ago I had the opportunity to visit the site and tour both the mounds and newly renovated museum. The displays at the museum indicated that the area around the mounds was protected by a stockade type fence, and the information plaque attached to it asked the question, “From what or whom was the fence protecting the citizens of Moundville?” Evidently the folks from UA in Tuscaloosa don’t know either.
By the time the European’s arrived this culture had disintegrated and the five civilized tribes were left to their own devices. Where I live now (Fulton, AL) there were two of these tribes (Choctaw and Creek) who existed in relative peace with one another, and there are many evidences of their occupation here just waiting to be discovered. I’m very interested in learning more about the Mississippian Culture but have neither the time nor the money to attend classes at UA. Could you please contact me off-list (jkjcfii@yahoo.com) if you have any recommended resources concerning this Culture?

Ulric Lyons
July 8, 2014 9:25 am

herkimer says:
“AMO cycles are variable but they can be negative up to 60 years as we saw 1790-1850.”
I don’t believe it, there are ship logs that report very reduced Arctic sea ice extent in the 1810’s, that would happen during a warm AMO.
“AMO has peaked and may go negative in an extended way during this decade..”
It hasn’t even done 20 years yet, and with the expected increase in negative NAO through the next decade, the AMO will be bouncing right back up again:

July 8, 2014 9:52 am

Pamela Gray says:
July 7, 2014 at 2:53 pm

The percentage of bones of various species is deceptive because elk, deer and bison are all considerably different in size. Thus if you reckon a deer as one-third the mass of a bison, and equal proportion of bones would at the simplest, reflect less importance of deer in the diet and that “at its simplest” is a gross over simplification. The other point is that unless you are dealing with forest bison, which are still grazers, the preferred habitats are different, so minimally the change in species reflects a change in hunting behaviour. There is an active and very disputatious debate about how to estimate meat acquisition in archaeological sites based upon bone recovery. There are a number of different “utility indexes” that have been proposed but all have problems. There are a lot of imponderables and questions tied to the issue since bone size may affect how survivable the bone will be once buried. Large animals taken a way from camp were parted out and much of the skeleton discarded before transport. But several bones have high utility for tools or a marrow extraction and so could be transported anyway. Smaller animals might be carried back whole. The upshot is that while it is often possible to tell what animals were hunted by the creators of an archaeological deposit, it is a far more difficult to determine how important individual species were.
Considering over-hunting, in North America elk and deer were typically taken either individually or in drives where they could be corralled, killed and butchered. In Nevada antelope, jackrabbits and grasshoppers were taken the same way. Bison, prior to the horse were apparently often hunted by fire drives and “jumps” that lead effectively to the animals killing themselves. There are “jumps” or kill sites several thousand years old where less than half the animals that died were butchered. The hunters had to start at the top of a ravine full of dead animals and process as many as they could before decay ran them off. After the horse was introduced, bison hunting changed character with hunters pursuing herds but killing more individual animals. It would be very difficult to estimate accurately the “pressure” that the different forms of hunting would have on the herds. However, the fact remains that the preferred environments differ between bison and elk and deer.

July 8, 2014 10:08 am

urlic lyons
I did not talk about a warm AMO around 1810 . I talked about a negative AMO 1790-1850
AMO went positive about 1995 and by 2020 will be 25 years . There is nothing sacred about 20 years, just a statistical mean figure . The actual warm AMO periods are all over the place . You and I may have different opinions when it will shift to negative again and that is ok. We may both be wrong too. I just happen to judge that it will happen this decade .Yes it does bounce around but the sustained trend can be negative like 1900-1926

James at 48
July 8, 2014 11:29 am

In particular, summers that are cooler-than-normal in the interior of NOAM are dry summers. No thermal lows, no monsoons, and, for frontal systems, weaker intrusion of cT and mT from the south.

Ulric Lyons
July 8, 2014 12:30 pm

herkimer says:
“There is nothing sacred about 20 years, just a statistical mean figure .”
I was saying that it would be unusual for the AMO to stay positive for only 20 years, and I have a few lines of reasoning that suggest the AMO should go positive again 2016-2024. I don’t see any clear reasoning behind your judgement.

July 8, 2014 4:35 pm

I’m still waiting for the increased humidity. Are we sure our climastrologists know how warm or cold it was in the past?

Abstract – February 2000
Henri D. Grissino Mayer et. al. – The Holocene –
….Century scale climate forcing of fire regimes in the American Southwest
Following a centuries-long dry period with high fire frequency (c. AD 1400-1790), annual precipitation increased, fire frequency decreased, and the season of fire shifted from predominantly midsummer to late spring….
Abstract – 1994
‘Little Ice Age’ aridity in the North American Great Plains: a high-resolution reconstruction of salinity fluctuations from Devils Lake, North Dakota, USA
…..A high-resolution reconstruction of salinity fluctuations in Devils Lake, North Dakota, based on fossil diatoms, ostracode-shell geochemistry, and bulk-carbonate geochemistry, indicates that saline conditions prevailed throughout much of the recent past. These results suggest an arid climate in the northern Great Plains throughout the ‘Little Ice Age’…..
Abstract – 2011
Humid medieval warm period recorded by magnetic characteristics of sediments from Gonghai Lake, Shanxi, North China

July 8, 2014 5:00 pm

@ herkimer…it is the Sun. It has always been the Sun that sets the signature into the oceans. Your example of a negative AMO in 1900/26. Look what happens afterwards in the CONUS where temps go to all time highs in the 30s and 40s. Look at how the Dalton fits in with the 1790/1850 period. Using Dr Svalgaards elegant ssn chart I note that between cycle 17 to cycle 18 the length of the base of the minimum shortened from around 4+ years down to 2 +/- years for the following 6 solar cycles. This changed with the last solar minimum which went back to the 4 year length pattern. The 4 year base for a solar minimum looks like it is linked to a cooler time here on Earth. Would the 6 prior solar cycles show 6 cycles of cooler solar effects? I don’t know as Dr Svalgaards chart starts in 1875 and shows 4 cycles of a 4 year base for the minimum prior to the 6, two year base minimums. I partially recognize this from the standpoint of the 9 year Pac Northwest flood cycle that somehow morphs closer to 12 years after 6 cycles. It was my basic knowledge of the 9 year flood pattern that made the first connection as I started down the path of the climate change debate and started looking at charts and graphs. That stimulated my thoughts. Are we now headed for 3 or 5 more 4 year base minimums and thus 33 to 55 approx more years of a cooler period? The 19/20 year offset between PDO and AMO also sticks and connects with other aspects of the story. In any 60+ year cycle there will be shifts within that cycle. The CET clearly shows how that works. There are 1/2 patterns around 15+ years and 1/4 patterns around 7/8 years. The globe on the whole does similar although regions meld and influence each other also, but it is all driven by solar influences from the incoming energy or lack of that drives the climate system, with the oceans being the storage system for the globe. The entire solar system likely modulates the interactions through solar influencing.

July 8, 2014 5:07 pm

Interesting sidelight is mention of use of fire by tribal people’s.
There is archaeological data from the area of Port Angeles WA, across the Strait of Juan de Fuca from Victoria BC, indicating that tribal people there used fire to create and maintainmeadows to increase interface periphery and to foster growth of edible plants. (Animals live and feed in interface not in forests.)
There are also anecdotal reports of tribal people burning underbrush near Sooke BC, on the other side of the Strait, to suppress undergrowth.
Camus lilly roots and deer were big in their diet.
Today environmentalists treat “Garry Oak meadows” as mystical, ignoring they are human creations. (The natural state of Garry Oak (aka white oak south of that line on maps that trees don’t read) is forest, typically supplanted by Douglas Fir as people say happened in the area called Metchosin on the Strait west of Victoria in the past 150 years.) So environmentalists are trying to preserve something that is doubly not natural.

July 8, 2014 5:11 pm

J. Keith Johnson says:
July 8, 2014 at 6:39 am
OK, I will.

July 8, 2014 5:26 pm

goldminor says:
July 8, 2014 at 5:00 pm
IMO the Pineapple Express & Chinook-induced winter floods in the PNW are definitely cyclic, related to PDO phase. I noticed this in 1995/6, recalling 1964/65 & being told by my parents & grandparents about previous occurrences.

July 8, 2014 5:28 pm

ulric lyons
Predicting an exact date for a change in an AMO period is bit of crap shoot at the best. No one has got it right yet?
Unlike the PDO, numerical models have been unable to predict AMO cycles with any accuracy. There are only about 130-150 years of data based on instrument data which are too few samples for conventional statistical approaches. With aid of multi –century proxy reconstruction, a longer period of 424 years was used by Enfield and Cid –Serrano to develop an approach as described in their paper called, The Probabilistic Projection of Climate Risk. Their histogram of zero crossing intervals from a set of five re-sampled and smoothed version of Gray et al(2004) index together with the maximum-likelihood [MLE] gamma distribution fit to the histogram, showed that the largest frequency of regime interval was around 10 –20 years
An analysis of the Atlantic multi-decadal Oscillation(AMO ) Index or North Atlantic Ocean SST Reconstruction shows that the index or SST had major temperature dips( up to -1.7 C) every 100 years or so , namely600-1620,1720,1820,1910-1920
Best guess is by approx. 2020 another dip( future?)
see papers and article
Also see article by Bob TISDALE
http://i47.tinypic.com/ekkhuc.pngAMO Reconstruction
I really have nothing more to add.
[Thank you. .mod]

July 8, 2014 5:32 pm

Gene L says:
July 7, 2014 at 7:56 pm
Prairie Indians did light grass fires to encourage new growth, more nutritious for bison. But this IMO isn’t “agriculture”, but managing natural resources by hunters & gatherers. There is also a school of thought among archaeologists & cultural anthropologists that the Magdalenian Culture of Upper Paleolithic Europe may have “herded” reindeer in a manner similar to the Lapps (Sami) today. Horses too might have been managed to some extent by these advanced Stone Age people.

July 8, 2014 5:38 pm

I got over my love affair of solar cycles after a lot of analysis and many blogs . I have no desire to reopen it . To me the ocean currents /enso/ atmosphere coupling is much more rational .

July 8, 2014 5:47 pm

gary gulrud says:
July 7, 2014 at 9:54 pm
For Dust Bowl, please see next comment.
You’re welcome re cultivation & agriculture. My point is that there isn’t always a hard & fast, bright line between hunting & gathering cultures & “agricultural” ones. It’s more of a continuum, but detailing where a group lies on that spectrum needs careful use of language, IMO. Technically, agriculture requires domestication & more elaborate field preparation than sticking a naturally occurring food or fiber plant in a place where it’s not growing but could. Often also artificial watering in some way, but not necessarily.
As per my comment above, many H&G cultures also practice some form of natural resource management short of cultivation or pastoral keeping of livestock (besides dogs). But IMO the practices of Willamette Valley Indians & the whole NW Coast Cultural Zone were far from any reasonable definition of farming or agriculture, which of course was practiced elsewhere in pre-Columbian North America. The Pacific Coast however was largely H&G, thanks to the abundant natural resources both of the NW & California’s valleys. The long grass prairie & SW were farmed in periods of favorable climate & abandoned in inclement times.
The NW Coast peoples had among the most complex societies in pre-Columbian N. America, to include coastal whaling, large boat & structure construction & wonderful woodcarving, but could support this complexity without agriculture, due to the great natural abundance. It was also a commercial product (including slavery) society, but lots of less complex cultures practice trading, although not with conspicuous consumption on the potlatch scale. They even had a sort of incipient metallurgy, hammering naturally-occurring fairly pure copper.

July 8, 2014 5:51 pm

Ulric Lyons says:
July 8, 2014 at 3:11 am
My comment was originally longer, with caveats for continental v. coastal regions, etc, but of course you’re right that given the nature of the atmosphere, colder is surely not always drier.
Despite some cold winters, for instance, the 1930s in the US were generally hotter than now, yet that’s when we had the Dust Bowl, made worse by unwise farming practices. The history of the Plains is largely driven by climatic cycles of moisture & drought, warm & cold, but not always rain & heat together.

July 8, 2014 6:08 pm

Speaking of North American Indian agriculture, IMO the greatest achievement in prehistoric plant domestication (certainly for grains) was corn (maize, choclo, etc). Corn is also interesting because its genome is virtually indistinguishable from its wild variety, the grass teosinte. The enormous difference in appearance between the two varieties is thus almost entirely epigenetic, ie in when & how the genes are expressed & turned on or off. Mesoamericans also breed up domestic varieties of a lot of other crops now common. Plus of course turkeys.
The domestication of the potato (in bewildering & humorous variety, most not seen outside South America) by Andean Indians must also rank high on the scale, but is a lesser achievement than corn, IMO.

Ulric Lyons
July 8, 2014 6:16 pm

The tree ring based AMO reconstruction shows the late 1500’s warm, which was very cold in the CET reconstruction, warm in Maunder, and warm in the Gleissberg Minimum in the late 1800’s, but gets colder 1807-1817 in the coldest part of Dalton, also colder in the cold period in CET of 1836-1845. I think that the proxy is in error in those two periods.

Ulric Lyons
July 8, 2014 6:27 pm

milodonharlani says:
“..given the nature of the atmosphere, colder is surely not always drier.”
England tends to be wetter when cooler in summer, and when warmer in winter, there’s not much trend, or sign of an AMO signal:

July 9, 2014 5:53 am

I think that the proxy is in error in those two periods.”
Yes I agree. The period 1650-1700 and 1850-1880 in particular seem in question . I checked these against the Greenland ice core records and they also indicated cold periods during these two periods where as the AMO proxy graph shows warming.

July 9, 2014 8:11 am

Though I am inclined to agree with the premise, it is hard to take a science article seriously when the author does not know that the x- axis is the independent variable and the y- axis is the dependent variable. Those graphs are a mess.

Ulric Lyons
July 9, 2014 10:40 am

herkimer says:
“The period 1650-1700 and 1850-1880 in particular seem in question . I checked these against the Greenland ice core records and they also indicated cold periods during these two periods where as the AMO proxy graph shows warming.”
There’s no point in referring to Greenland temperatures as they usually go in the opposite direction to CET, e.g. from the coldest part of Maunder around 1690 Greenland cools towards 1730, and warms again around 1740, which is the coldest year on CET. And just before that from 1650-1654 was very warm in the UK:

July 9, 2014 11:27 am

Ulric Lyons says:
July 8, 2014 at 6:27 pm
As I can also report from experience there in the 1970s.
Thanks for the link.

July 9, 2014 11:59 am

Uric Lyons
I just rechecked the MOE INDEX in the WOODFORTREES blog and compared it with the NORTH ATLANTIC PROXY graph for the period 1850-1900 and found them quite close . I don’t see any significant discrepancy here.anymore The part 1850-1700 of Maunder minimum still remains a mystery. There were 5 major volcanic eruptions ( level 5 and higher)) between 1660 and 1680 which may account PARTLY for the cold air temperatures but warm SST

July 12, 2014 8:41 pm

I have for years been informing Warmists and Alarmists that droughts are from cooling and drying; if you want wet air, warm it up! Ironic one of their predictions may finally come true — caused by the contrary of their model mash-inations!

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