I find this to be an interesting graph. For several reasons. We’ll go through them one at a time. There will be several mentions of bits of history that we’ve talked about before. If I get time I may put in links to the particular articles, but for now you get to use the search box or the ‘by topic’ categories on the right side of the page… Random quoted text will be from a wiki about a given empire or event.
First up, some general points.
1) Our last 500 years of temperatures have been extraordinarily stable. This graph ends in 1950 (as it takes time for ice on the surface to seal and form a usable layer) and it was modestly warm in the 1934-50 range. Folks quibble over the question of ‘was 1934 the hottest or 1998’; for our purposes, all we care about is that it was ‘about the same’. So look at that little 500 year tail on the dog. Darned near flat compared to the rest of the graph. 1500 AD to date covers the rise out of the little ice age. Something that we frequently talk about as a major temperature swing. It isn’t, in the context of 11,000 years.
2) There is no “Hockey Stick” here. We have a generally ’rounding over’ series that was higher in the past and is slowly turning into a downtrend from about 1000 BC ( 3000 BP ) to date. Run your eye from peak to peak and visually add in the hoop over the top, the upper bound trend arc.
3) Things were incredibly volatile in the past. There are spikes and drops of 2 C regularly and some over 3 C in 50 to 100 year (or less) ranges. While there were civilizations that rose in good times and fell in cold times in sync with those spikes. I think “this matters”. We HAVE climate change, and even catastrophic climate change. It just isn’t caused by people and it has nothing to do with CO2. It happens, and has happened, all on its own. You can find the start of The Dark Ages at that first big plunge about 1500 BP / 500 AD when The Roman Warm Period ends. There is the rise and fall of the Akkadian Empire from 3000 BC to 2145 BC (5000 BP to 4145 BP) “Urban populations there had peaked already by 2,600 BC ” which is that peak rising just after 5000 BP on the graph.
The water table in this region was very high, and replenished regularly—by winter storms in the headwaters of the Tigris and Euphrates from October to March, and from snow-melt from March to July. Flood levels, that had been stable from about 3,000 to 2,600 BC, had started falling, and by the Akkadian period were a half-meter to a meter lower than recorded previously.
That is 5,000 BP to 4600 BP. So there was a period of good rains, then things began drying. By 4600 BP the population had peaked. The Akkadian empire takes over and rises during the warming and then collapses in the next dip.
4) It was much warmer in the past. On many occasions. Remember that this is the Greenland temperature. All that worry about how Greenland is going to melt away due to our “unprecedented” warming? Well, I count 3 peaks of about 2.5 C higher than ‘now’ and almost the entirety of the graph is above ‘now’. We’re in a cold time, not a warm time. Yes, the Little Ice Age was colder. So?
5) There have been some VERY sharp cold spikes in the past. One of them could ruin your whole day. They tend to land on periods of history that were commonly called “Pessimums”. The warm times were commonly called “optimums” (as times were good then for people.) See the Roman Era Optimum leading into that peak at 2000 BP (then that Christ guy came along and the whole Republic has some issues on that dip, warming after to about 400 AD when the Roman Optimum ended, and the Roman Empire with it…)
6) The right margin shows a dramatic rise out of the 12,000 BP or so range. We know that Golbeki Tepe was built during a very much colder time. Clearly that society was fairly advanced (at least they new how to carve rock well). It looks like The Flood will date from about that time, when the glacial ice sheets were melting under very fast warming.
7) Something interesting happened 8.2 kiloyears ago (it’s called the 8.2 Kiloyear Event).
8) Civilization was disrupted from that 12,000 BP prior civilization until about 4,000 BC, or 6,000 BP on the graph. The volatility is greatest, with the most massive swings and the the least stable runs, during that 12,000 BP to 6,000 BP window. Hard to recover when you have just had a global flood, ice sheet collapse, undoubtedly disrupted weather systems, and no stability. At that 6,000 to 5,000 BP window of stability, human history as we know it begins.
9) Sumer begins about 4500 to 4100 BC ( 6500 BP to 6100 BP). Just when we get that bit of stability. The earliest farming seems to start about 5000 BC in that area. Just after that 7000 BP spike of warmth and the stability shelf that follows it. It would be hard to farm in the violent swings before that (not impossible, just a bit hard) and much easier afterwards. With few surviving people after the flood collapse, hunting would the easy. I suspect that the warm 8000 BP to 7000 BP (despite one spike down) would have given time for populations to grow and villages to expand to the point where starting to farm would make sense. Sumer was top dog in the area until about 2200 BC / 4200 BP when the Akkadians took over (right after that ‘dip’ at about 4600 BP.
10) That dip at 4600 BP is called the Piora Oscillation “The cause or causes of the Piora Oscillation are debated. A Greenland ice core, GISP2, shows a sulfate spike and methane trough c. 3250 BC, suggesting an unusual occurrence — either a volcanic eruption or a meteor or an asteroid impact event. Other authorities associate the Piora Oscillation with other comparable events, like the 8.2 kiloyear event, that recur in climate history, as part of a larger 1500-year climate cycle.” Ötzi the Iceman fell in about 5300 BP, just as THAT warm peak turned into this drop, covering him in ice for the next 5000 years.
10) At about 4,600 BP / 2,600 BC we get the Egyptian Old Kingdom. That happens on that nice warm rise just as we head out of the 5,000 BP dip (they seem to grow through the Piora Oscillation, then flower to empire in the aftermath of Sumer falling). Just as we rise out of that dip: “Old Kingdom is the name given to the period in the 3rd millennium BC when Egypt attained its first continuous peak of civilization in complexity and achievement” So things were a bit disrupted before that. Oh, yeah, the dip… They end in the next dip about 4200 BP. That’s not a very good time “The First Intermediate Period, often described as a “dark period” in ancient Egyptian history, spanned approximately one hundred years after the end of the Old Kingdom from ca. 2181-2055 BC.”
11) What happens in the nice warming ramp about 1500 BC? Say about 3700 BP to 3400 BP? This nice list of empires says “1500 BC Olmec” and “1700 BC Shang Dynasty”. In 1400 BC 3400 BP it has “c. 1400 BC: Expansion and Contraction of Mesopotamian Empires” and the chart does have a bit of wobble about then. What about that peak at about 4200 BP / 2200 BC? Anything interesting? “2205 BC: Early Chinese Civilization” Hmmm…. On a ‘someday list’ is to do a much more complete map of empires against that graph. For now it’s pretty clear that the classical empires fall on the down spikes, new ones form on the rising warm periods. Instability is bad, stability is better.
12) The Dark Ages and the Little Ice Age were no great shakes for our civilization. IMHO, the only thing that saved us was that long flat stable time from about 1300 when the Renaissance could develop, then our modern warming when we could turn that into an industrial age.
The 8.2 Kiloyear Event
With all that interesting history to map onto those wobbles, why look at the 8.2 Kiloyear Event? Isn’t the Iron Age Cold Epoch or Iron Age Pessimum in about 2900 to 2300 BP more interesting? We have some history from then and folks were doing interesting things with new metals technologies. It has the Hittite Empire leading into it along with the arrival of the mysterious Sea People about the time of the fall into the entry of that cold period. The Sea People collapsed several empires and were only stopped by Egypt (barely). Yes, that cold period is another chaotic one with lots of interesting collapses of empires. But I’m going to save that one for another day.
What interests me about the 8.2 Killoyear Event is that it is so “clean”. Relatively warm ahead of it, one giant plunge, then a recovery.
What does the wiki say?
The 8.2 kiloyear event is the term that climatologists have adopted for a sudden decrease in global temperatures that occurred approximately 8,200 years before the present, or c. 6,200 BC, and which lasted for the next two to four centuries. Milder than the Younger Dryas cold spell that preceded it, but more severe than the Little Ice Age that would follow, the 8.2 kiloyear cooling was a significant exception to general trends of the Holocene climatic optimum. During the event, atmospheric methane concentration decreased by 80 ppb or 15% emission reduction by cooling and drying at a hemispheric scale.
Once again we have drying during a cold spike. When it is cold, don’t expect a lot of rain fed agriculture. It was also worse than the Little Ice Age. Duration of a couple of centuries is not so nice either. These cold spikes tend to last a couple of hundred years, much as did the Little Ice Age.
The strongest evidence for the event comes from the North Atlantic region; the disruption in climate shows clearly in Greenland ice cores and in sedimentary and other records of the temporal and tropical North Atlantic. It is less evident in ice cores from Antarctica and in South American indices. The effects of the cold snap were global, however, most notably in changes in sea level during the relevant era.
Things are worst in the Northern Hemisphere, but the whole world goes when it goes. The wiki goes into speculation about melt water pulses and thermohaline circulation disruption, but when I look at the sea level rise graphs, it looks like the ice age melt is pretty much over by 8200 BP and it’s on a generally straight rise reaching the round off to near flat of the current era. So I’m not seeing much reason to buy that line:
If it were melt water related, why did all the prior melt water not cause one? Hmmm?
Estimates of the cooling vary and depend somewhat on the interpretation of the proxy data, but drops of around 1 to 5 °C (1 to 11 °F) have been reported. In Greenland, the event started at 8175 Before Present, and the cooling was 3.3 °C (decadal average) in less than ~20 years, and the coldest period lasted for about 60 years, and the total duration was about 150 years.
Hmmm… that 60 year number is familiar. As is the 150 years. Those are rather near certain solar cycle values. Sort of like having one of those periodic “barycenter retrograde moments” and having things skip a beat or two.
Some Spike Counting
For this exorcise, we’re going to do a bit of spike ‘cherry picking’ and / or counting. There is a known 1470 year cycle of Bond Events and DO events. One is a periodic spike up, the other the periodic spike down that seems to be the counter point. DO events are during glacials, Bond Events during interglacials (like the entire chart up top). In another posting I have speculated about periodic “Half Bond Events” when we were looking at just the sweep of history. There seemed to be empire collapses on about the 700 year marks, too.
So the game here is to start from that 8.2 Kiloyear Event that is just so clean, and look 700 years to each side for a ‘blip’ down. Not a big spike, just a middling bit. Then move forward to the next big spike on about a 1500 year marker and repeat. 700 years to each side.
Do you see what I see?
There tends to be a “dip” like a small shelf in the trend on each side, at about that 700 year point. Much clearer in some times than in others, but clearly there. It’s not just a 1500 year dip, it’s more like a 750 year cycle on top of a 1500 year cycle. Sometimes with a reinforcement, sometimes making a ‘kink’ in the rise or fall. The three deepest dips come on about 3000 year centers, so there might even be a higher order harmonic to deal with. 1200 BP, 4800 BP, 8200 BP as I eyeball the graph. 3600 and 3400 year spacings. Add 3500 to 8200 and you get 11,700 BP. What happened then?
The Younger Dryas stadial, also referred to as the Big Freeze, was a geologically brief (1,300 ± 70 years) period of cold climatic conditions and drought between approximately 12.8 and 11.5 ka BP, or 12,800 and 11,500 years before present. The Younger Dryas stadial is thought to have been caused by the collapse of the North American ice sheets, although rival theories have been proposed.
Well, I don’t have a ‘rival theory’ but I do seem to have some ‘predictive power’. Yes, I know, not enough sample size to have statistical validity. Still… 11.7 vs “11.5” is pretty good shooting. Use that 3400 number instead and you get 11.6 that is just about dead on, given the error bands on these dates.
To me, I think it is well worth saying that the next “big down” is most probably going to come about 3400 years from that Dark Ages time of about 800 AD. Call it 4200 AD. I’m not going to lose much sleep over that, but it is most likely going to be our entry point into the next ice age glacial. It will be a down tick of great force, and we will have gotten far enough along in the orbital cycles that the north pole ought to freeze over and not thaw out again. That then starts the ice accumulation feed back that ends with a mile of ice over New York…
The entry into the 1200 BP or about 800 AD misery of the Dark Ages was in 535 AD give or take a couple of years. That means it could be as soon as 3935 AD, or 1925 years from now, that the entry starts. Still not going to lose any sleep, but might want to send the great great great grand kids to Brazil..
What about that 700 ish and 1470 period and half period? OK, 535 and 700 gives 1235. Anything interesting in the 1200s?
has quite a laundry list of empires killing each other off. From Mongols and Huns to Crusades and Holy Roman Empires. Don’t know as that is definitive of anything.
Has a nice list of things, including this one:
1. Eleanor of Provence (Queen-Consort to Henry III) was frustrated by ‘bad weather’ (dates not known, but has to be late summer / early autumn 1264) in her attempt to bring troops to the aid of her husband’s cause. The Queen’s fleet was trapped by frequent spells of high wind at Sluis, Flanders (modern-day Netherlands, near the Belgian border) before it could cross to the Kent coast. According to Lamb, the 13th century experienced the highest number (by some margin) of “severe sea floods” along North Sea & English Channel coasts. Although the climate across NW Europe was still generally benign (indeed, the peak of warmth of the Medieval Age may have occurred in this century), from the middle of the 13th century, an increase in ‘unsettled’ weather events has been detected by some researchers; the first signs of the descent into the ‘Little Ice Age’. It is indeed possible that the increased storminess was concentrated in the second half of the 13th century, so it was unfortunate that Eleanor attempted the passage of the Dover Strait at this time. (Lamb)
Ending of warmth turning into a lot of unsettled and flooding. Wait a minute, that sounds rather like this last decade or so… Could we be needing just a bit longer future horizon to see what is to come, rather than what is now?
As our period could be up to 750 years, what about a peak into the 14th Century. The wiki for the Little Ice Age says:
1250 for when Atlantic pack ice began to grow
1300 for when warm summers stopped being dependable in Northern Europe
1315 for the rains and Great Famine of 1315-1317
Oh Dear. So if we add another 750 years onto those dates, we would get
2000 for when Atlantic pack ice began to grow
2050 for when warm summers stopped being dependable in Northern Europe
2065 for the rains and Great Famine of 2065-2067
I note in passing that if we add 1500 to 535 we get 2035 AD as the latest likely entry point and 1470 + 535 = 2005 AD as the early start.
This would be for a Bond Event spacing from the last big dip, not a 1/2 Bond Event, but also not on one of those 3000 year Big Dips…
My reading on this is pretty simple. I think we had The Last Big One at the entry to The Dark Ages and it pretty much screwed things up for a few hundred years. That would make The Little Ice Age a 1/2 Bond Event (thus answering the question of “was it a Bond Event?” with a pretty good “No”.) This matters as many folks argue from the point that “it was really cold so it MUST have been the Bond Event”.
I think this misses the context. It misses the cycles of 3000 years and the Half Bond 700 years. (Dare we call them Smith Events? ;-)
It misses our slow decline from the Holocene Optimum into ever lower optimums. So much so that the Modern Optimum hardly shows on the Ice Core at all (and Greenland is colder than it was when the Vikings landed there (on that peak about 1000 BP). We had a lower Little Ice Age compared to the prior 1/2 Bond event of about the time of Christ, even though it was only a 1/2 Bond Event, due to the lateness of the hour in this interglacial. That would imply that THIS Bond Event, that I’ve taken to calling Bond Event Zero (c) will likely be worse than the last one we had. The Dark Ages. It ought to be worse than the Little Ice Age too. It ought to have made the first stirrings of the turn about 2005, and be well underway about 2035. That this is in agreement with the projected depths of the present Solar Grand Minimum does not give me cheer…
This is how I see the world. I take some interesting things, I connect them to other interesting things, patterns are puzzled out, and the patterns extended (with a bit of pulling to and fro for checking possible range and edge conditions). It is a system that works pretty well. Not perfectly. But well enough.
At this point I’m hoping for all I’m worth that CO2 is a magic gas than can bring global warming. We’re going to need it, and lots of it. But I’m also pretty sure that it doesn’t do much. Convection dominates. Ice wins.
Being an incurable optimist, though, I do have to take some solace in the idea that it will likely be 20 years of modestly slow cooling. It will take time to cool the oceans and change the trend. The entry to a dip is not the bottom. That is 150 years in the future. Long after my time is done. 20 years means my kids need to think in terms of Los Angeles and Phoenix, not Anchorage and Denver. And maybe I need to think in terms of Miami or Santiago ;-) But hardly end of the world stuff.
The biggest issues will be for China and India. The monsoons tend to slack off during Bond Events.
The North Atlantic ice-rafting events happen to correlate with most weak events of the Asian monsoon over the past 9,000 years, as well as with most aridification events in the Middle East. Also, there is widespread evidence that a ≈1,500 yr climate oscillation caused changes in vegetation communities across all of North America.
While I’m not liking the look of that ‘vegetation changes in North America’, it’s the monsoons failing that will cause Asia to go ballistic ( I suspect, literally) and ‘most aridification’ in the Middle East is not going to go well with a Muslim Population that is mostly young and reaching the capacity limit of the water supplies already. (While it would all be completely survivable if folks started building nuclear powered desalinization plants and planting greenhouses right now, that is just not going to happen. They are too busy vilifying nuclear power and shooting each other.)
No, I’m pretty sure that will be the trigger for massive food riots from Libya to Bangladesh. With at least 3 nuclear armed states now, and likely 4 or 5 by then, the results will not be good. We can likely look to the weather events of the Little Ice Age and the Dark Ages for some pointers as to what will happen in China, Europe, and the Levant. IIRC, there were ice chunks floating past Constantinople…
The southern hemisphere will likely do much better. More water moderation of the climate. Equatorial countries too (modulo the likely drought conditions that will increase).
What ought we be doing? The world ought to be preparing a couple of year food storage. There were recorded periods of a year or two of repeated crop failures. Instead we are going to global ‘just in time’ delivery from the field and criminalizing over a week of food on hand. The result will inevitably be massive starvation. The world is NOT stable, nor is the weather. Both history and the graph up top say so. We ought to be building nuclear power plants and desalinizing plants for places with marginal water supply. We ought to be building local greenhouses for food production even in cold times and with the ability to run those greenhouses with electric lights if things are dark (as they were during the Dark Ages). We are not.
But it’s not all bad news. Recently the world has become awash in natural gas. Fast to produce. Fast to make generators to use it. A greenhouse can be made in a couple of weeks and takes little more than cheap plastic. Cold frames even easier and faster. Desalinizing technology is easy and available. Heck, you can get reverse osmosis water filters for home use. When things get bad, we have the ability to move fast and fix it.
Of a more mixed status is that we will have Canaries in the Coal Mine. Those countries that get jerked around first and hardest. Those with the most unstable weather and societies. Unfortunately, Northern Europe is in one of those climate locations. Fortunately, they have a fairly bright social structure that has come through this before (though, I note, with a few revolutions… “let them eat cake”…) The Levant looks like it take a water hit, and for major events so does Egypt. One can only hope they can turn oil and oil money into water and food.
Russia is already preparing. They understand the issue, so I think they will do OK. Not well, but OK. A couple of their more southern neighbors may not fare so well… North Korea is toast, so will likely take South Korea with them (unless China steps in and makes them a nice new province…). Japan will be fine. Much of their life comes from the sea and they are a creative people. Industry will suffer, but Japan will be ‘late to the party’ on bad times. Oceana may hardly notice. Excess food production and plenty of warmth with all that lovely water to isolate and buffer… but will South East Asia be stable enough to leave them in peace? That’s the mixed bit.
The truly bad bits will be Africa (where deserts become worse and famines rule), and the monsoon dependent areas in Pakistan, India, etc. There is just no way to make enough food and water happen fast enough. Especially with no preparation underway. China typically has a dynasty fall during these events. I’d expect it again. Life and civilization goes on. Likely the One Child generation will be the inheritors of a country built out for twice as many people. Good timing that. Grief, yes. Food problems? No. With all the power plants they are building they will have plenty of power to keep warm. Plenty of plastics for greenhouses and desalinizers. The rest of us will have to forgo our usual plastic junk from China for a while ;-)
That’s what I see from this. Somewhere about 2035 to 2040, sorrow in the monsoon belt and war in the Levant. Oddly not too different than it has always been… We have time to avoid that. I wish we would use it wisely.