Why was agriculture invented in the Holocene Epoch and not before?

[lpetrich]

I think that climate fluctuations are a much stronger hypothesis than lower CO2 concentration, because they can have a strong effect on what plants can be grown at any one site.

The authors then consider social constraints on Holocene adoptions of agriculture, stating that "perhaps 20% of the world remained as hunters and gatherers until nineteenth-century European expansion", likely referring to land area with human inhabitants. Their list:

• "First, social organization is not particularly observable by outsiders. Social institutions are enacted in a diffuse network of everyday interactions, punctuated by public rituals and ceremonies of uncertain meaning to outsiders."
• "Second, institutional innovations are more difficult to try out than technical ones. At least some minimum number of individuals must understand and subscribe to an institutional innovation for it to begin operating. Its success or failure may take a generation or more to evaluate." - while it's much easier to experiment with new crop plants.
• "Third, game theorists tell us that repeated games have many equilibria. Most likely, social systems tend to be locally stable, and when events destabilize one equilibrium, the search for a new one will be heavily constrained by history (Greif 2006)." - meaning that they are likely to be stuck in some local equilibrium state rather than a global equilibrium. Thus rejecting Panglossianism.
• "Fourth, to the extent that institutions evolve by a process of cultural group selection, rates of change will tend to have millennial timescales (Soltis, Boyd, and Richerson 1995)."

 

[lpetrich]

They then consider variations among foragers' subsistence strategies.

There are at least two dominant hunter-gatherer equilibria in the Holocene, and the dichotomy is variously styled as complex versus simple, immediate versus delayed return, and so forth. We prefer a contrast in standard ecological parlance, between energy maximizing and time minimizing hunter-gatherers, terms that refer to the two quantities that dominate quantitative treatments of foraging behavior (Bettinger 1999, 2001).

Energy maximizers spend as much time as possible in harvesting resources, while time minimizers spend as little time as possible on doing that.

Energy maximizing seems like a good way to get started with agriculture, while time minimizing is not.

 

[lpetrich]

Was Agriculture Impossible during the Pleistocene but Mandatory during the Holocene? A Climate Change Hypothesis | American Antiquity | Cambridge Core

Several independent trajectories of subsistence intensification, often leading to agriculture, began during the Holocene. No plant-rich intensifications are known from the Pleistocene, even from the late Pleistocene when human populations were otherwise quite sophisticated. Recent data from ice and ocean-core climate proxies show that last glacial climates were extremely hostile to agriculture—dry, low in atmospheric CO2, and extremely variable on quite short time scales. We hypothesize that agriculture was impossible under last-glacial conditions. The quite abrupt final amelioration of the climate was followed immediately by the beginnings of plant-intensive resource-use strategies in some areas, although the turn to plants was much later elsewhere. Almost all trajectories of subsistence intensification in the Holocene are progressive, and eventually agriculture became the dominant strategy in all but marginal environments. We hypothesize that, in the Holocene, agriculture was, in the long run, compulsory. We use a mathematical analysis to argue that the rate-limiting process for intensification trajectories must generally be the rate of innovation of subsistence technology or subsistence-related social organization. At the observed rates of innovation, population growth will always be rapid enough to sustain a high level of population pressure. Several processes appear to retard rates of cultural evolution below the maxima we observe in the most favorable cases.

They propose:

Agriculture Was Impossible During The Last Glacial.

During the last glacial, climates were variable and very dry over large areas. Atmospheric levels of CO, were low. Probably most important, last-glacial climates were characterized by high-amplitude fluctuations on time scales of a decade or less to a millennium. Because agricultural subsistence systems are vulnerable to weather extremes, and because the cultural evolution of subsistence systems making heavy, specialized, use of plant resources occurs relatively slowly, agriculture could not evolve.

then

In The Long Run, Agriculture Is Compulsory In The Holocene.

In contrast to the Pleistocene, stable Holocene climates allowed the evolution of agriculture in vast areas with relatively warm, wet climates, or access to irrigation. Prehistoric populations tended to grow rapidly to the carrying capacity set by the environment and the efficiency of the prevailing subsistence system. Local communities that discover or acquire more intensive subsistence strategies will increase in number and exert competitive pressure on smaller populations with less intensive strategies. Thus, in the Holocene, such inter-group competition a generated a competitive ratchet favoring the origin and diffusion of agriculture.

 

[lpetrich]

They mention the Little Ice Age (400 - 150 BP / 1550 - 1800 CE), a fluctuation typical of the Holocene. "Extreme years during the Little Ice Age caused notable famines and such extremes would have been more exaggerated and more frequent during last glacial times."

Weather variation accounts for some 10% of crop losses, sometimes as high as 40%. So during the last ice age, it would have been much worse.

The article mentioned risk-reduction strategies, like opportunism for foragers. That made it difficult to get started on agriculture, because much agriculture focuses on a small number of crop plants.

"In keeping with our argument, the direct archaeological evidence suggests that people began to use intensively the technologies that underpinned agriculture only after about 15,000 B.P. (Bettinger 2000)."

That was around the Bølling-Allerød warm period, where the Earth became almost as warm as in the Holocene. It was soon followed by the Younger Dryas cold period, however, and the Holocene is now defined as beginning at the end of the Younger Dryas.

 

[Elixir]

Was Agriculture Impossible during the Pleistocene but Mandatory during the Holocene? A Climate Change Hypothesis | American Antiquity | Cambridge Core

Several independent trajectories of subsistence intensification, often leading to agriculture, began during the Holocene. No plant-rich intensifications are known from the Pleistocene, even from the late Pleistocene when human populations were otherwise quite sophisticated. Recent data from ice and ocean-core climate proxies show that last glacial climates were extremely hostile to agriculture—dry, low in atmospheric CO2, and extremely variable on quite short time scales. We hypothesize that agriculture was impossible under last-glacial conditions. The quite abrupt final amelioration of the climate was followed immediately by the beginnings of plant-intensive resource-use strategies in some areas, although the turn to plants was much later elsewhere. Almost all trajectories of subsistence intensification in the Holocene are progressive, and eventually agriculture became the dominant strategy in all but marginal environments. We hypothesize that, in the Holocene, agriculture was, in the long run, compulsory. We use a mathematical analysis to argue that the rate-limiting process for intensification trajectories must generally be the rate of innovation of subsistence technology or subsistence-related social organization. At the observed rates of innovation, population growth will always be rapid enough to sustain a high level of population pressure. Several processes appear to retard rates of cultural evolution below the maxima we observe in the most favorable cases.

They propose:

Agriculture Was Impossible During The Last Glacial.

During the last glacial, climates were variable and very dry over large areas. Atmospheric levels of CO, were low. Probably most important, last-glacial climates were characterized by high-amplitude fluctuations on time scales of a decade or less to a millennium. Because agricultural subsistence systems are vulnerable to weather extremes, and because the cultural evolution of subsistence systems making heavy, specialized, use of plant resources occurs relatively slowly, agriculture could not evolve.

then

In The Long Run, Agriculture Is Compulsory In The Holocene.

In contrast to the Pleistocene, stable Holocene climates allowed the evolution of agriculture in vast areas with relatively warm, wet climates, or access to irrigation. Prehistoric populations tended to grow rapidly to the carrying capacity set by the environment and the efficiency of the prevailing subsistence system. Local communities that discover or acquire more intensive subsistence strategies will increase in number and exert competitive pressure on smaller populations with less intensive strategies. Thus, in the Holocene, such inter-group competition a generated a competitive ratchet favoring the origin and diffusion of agriculture.

That's what I said. Or rather, meant. (That's why they get the big bucks.)

 

[lpetrich]

The authors then compared 14 sites, places where intensive foraging is known to have preceded agriculture. Dates are years BP.

Place	Intensive Foraging	Agriculture
(Centers of Domestication)
Middle East	15,000	11,500
North China	11,600	>9,000
South China	12,000?	8,000
Sub-Saharan Africa	9,000	4,500
South-central Andes	7,000	5,250
Central Mexico	7,000	5,750
Eastern US	6,000	5,250
(Controversial Centers)
New Guinea Highlands	?	9,000?
Amazonia	13,000?	9,000?
(Acquisition by Diffusion)
Northwestern Europe	12,500	7,000
Southwestern US	6,000	3,500
Japan	10,500	3,000
(Never Acquired)
California	4,000	--
Agriculture	3,500	--

The Middle East (or Near East) had the earliest emergence of intensive foraging. Was that also made difficult for most of the Pleistocene?

 

[lpetrich]

Two lines of evidence that point to independent domestication in each center:

• "First, the domesticates taken up in each center are distinctive and no evidence of domesticates from other centers turns up early in any of the sequences."
• "Second, archaeology suggests that none of the centers had agricultural neighbors at the time that their initial domestications were undertaken."

So there were at least 7 centers of origin of agriculture and likely at least 9. Intensive foraging typically preceded agriculture by a few thousand years, and in some cases, was pre-Holocene. But even the oldest intensive foraging goes back only as far as the  Bølling–Allerød warming period, about 14,690 to 12,890 BP.

The authors conclude that species variety is not a very good indicator of intensiveness of foraging.

For all these reasons, quantitative features of subsistence technology are a better index of Pleistocene resource intensification than species used. We believe that the dramatic increase in the quantity and range of small chipped stone and groundstone tools only after 15,000 B.P. signals the beginning of the pattern of intensification that led to agriculture.

The authors also note

The exact sequence of events also varies quite widely. For example, in the Near East, sedentism pre- ceded agriculture, at least in the Levantine Natufian sequence, but in Mesoamerica crops seem to have bcen added to a hunting-and-gathering system that was dispersed and long remained rather mobile (MacNeish 1991:27-29).

So agriculture was not all-or-nothing, and it was preceded by halfway-agriculture systems.

 

[lpetrich]

More Intensive Technologies Tend to Spread

One successful and durable agricultural origin in the last glacial on any sizeable land mass would have been sufficient to produce a highly visible archaeological record, to judge from events in the Holocene. Once well-established agricultural systems existed in the Holocene, they expanded at the expense of hunting-and-gathering neighbors at appreciable rates (Bellwood 1996).

In conclusion,

Those who are familiar with the Pleistocene often remark that the Holocene is just the "present inter- glacial." The return of climate variation on the scale that characterized the last glacial is quite likely if current ideas about the Milankovich driving forces of the Pleistocene are correct. Sustaining agriculture under conditions of much higher amplitude, high-frequency environmental variation than farmers currently cope with would be a considerable technical challenge. At the very best, lower CO, concentrations and lower average precipitation suggest that world average agricultural output would fall considerably.

Then mentioning global warming caused by emission of CO2 from burning fossil fuels. Would that stave off the return of the glaciers?

Nevertheless, the intrinsic instability of the Pleistocene climate system, and the degree to which agriculture is likely dependent upon the Holocene stable period should give one pause (Broecker1997).

So we are in danger of ruining a great interglacial period by spewing lots of CO2 into the air.

 

[lpetrich]

From the Cover: Current perspectives and the future of domestication studies - PMC - that paper as a webpage.

I searched in Google Scholar for +Eemian +agriculture and while I got some hits, the agriculture that they discussed was all Holocene agriculture. I could not find any discussions of why our ancestors back then had not invented agriculture.

So I looked for comparisons of Eemian and Holocene climate stability.

Eemian climate fluctuations observed in a European pollen record | Nature

RECENT ice-core data from Greenland1,2 suggest that the climate during the last interglacial period (the Eemian) was more unstable than that of the Holocene (about 10,000 years ago to the present), being characterized in particular by a series of cold episodes each lasting about 70 to 750 years. Subsequent analysis of a second Greenland ice core3,4, however, failed to corroborate the details of these Eemian climate fluctuations, a result that may be attributable to the effects of ice flow4. To resolve this discrepancy, it is imperative to seek alternative sources of information about the Eemian climate. Here we present climate reconstructions from pollen data from the annually laminated Eemian lake-sediment record at Bispingen5 and from the Eemian and Holocene peat records at La Grande Pile6. The former record indicates that an initially warm period of 2,900 yr was followed by cooling and a series of colder episodes, one of which had winter temperatures comparable to those at the end of the preceding cold stage. The latter records show greater climate instability during the Eemian than the Holocene. These results are in broad agreement with those from the GRIP ice core, but contrast both with the GISP2 core3,4 and with recent high-resolution marine records from the North Atlantic7,8.

Intra-interglacial cold events: an Eemian-Holocene comparison - Maslinetal1998.pdf

Abstract: Rapid oscillations between warm and cold climates have been found in the oxygen isotope record of the Greenland Ice-core Project (GRIP) ice core during the Eemian/Marine oxygen Isotope Stage (MIS) 5e. In contrast, the variability in Greenland Ice Sheet Project 2 (GISP2) ice core is significantly different and some Atlantic deep-sea records suggest no such climate variations. We present here a high-resolution (50-300 years) set of marine proxies from the low-latitude east Atlantic margin (ODP Site 658), which suggest that in general the Eemian was climatically very similar to the Holocene. We, however, observe that the upwelling intensity off the West African coast was greatly reduced during the early Eemian, corresponding to the very mild climate observed in the European lake records. We observe that MIS 5e contains one significant short cold spell (<400 years), which is marked by a reduction of upper North Atlantic deep water ventilation. We suggest this cold event may correlate with the cold interval found in the European terrestrial records. The cause of the intra-Eemian event was likely to be the freshening and cooling observed in the Norwegian Sea. This brief cold spell, however, did not affect the overall stability of MIS 5e, and moreover it has an analogue event in the Holocene 'Sub-Boreal' period. Marine and terrestrial records thus seem to be incompatible with those of the GRIP ice core record, supporting the suggestion that the GRIP record has been altered by ice tectonics.

Tepsankumpu revisited — pollen evidence of stable Eemian climates in Finnish Lapland - SAARNISTO - 1999 - Boreas - Wiley Online Library

Several till-covered organic deposits, principally lake gyttja, in Finnish Lapland have been correlated with the last (i.e. Eemian) interglacial on the basis of their lithostratigraphic position and pollen stratigraphy. Most of the sequences are short, but together with three longer sequences from Finnish Lapland and one from Swedish Lapland (Leveäniemi) they provide a complete picture of Eemian vegetational and climatic development. The Tepsankumpu site was revisited, and the till-covered thick freshwater gyttja deposit was studied in detail for pollen in order to search for signals of rapid climatic fluctuations postulated for the earlier part of the Eemian on the basis of Greenland ice core studies. The Eemian pollen stratigraphy in Finnish Lapland closely resembles the Holocene pollen stratigraphy of the area. The abundance of spruce and alder pollen suggests, however, more northerly limits for forest vegetation zones during the Eemian than during the Holocene. Oak also grew closer to Lapland, indicating a wanner climate than during the Holocene climatic optimum. The Tepsankumpu pollen stratigraphy indicates climatic stability over the entire time-span it covers, i.e. the major part of the interglacial. This finding is in conflict with results from Greenland GRIP ice core studies and interpretations of some Continental European Eemian pollen diagrams.

So the Eemian was much like the Holocene. But it was initially warm and gradually cooled. One has to ask why the Holocene did not also do that.

Agriculture's influence on climate during the Holocene - ScienceDirect

This paper summarizes the variations of trace gas behaviour and climate during the Holocene (approximately the last 10,000 years), with reference to the last four ice age cycles. The industrial era, commonly regarded as commencing during the 18th century, is one noted when atmospheric greenhouse gas increases due to burning of fossil fuels and land use changes have been attributed to increases in global average near-surface temperatures, particularly in the latter part of the 20th century. However, analysis by Ruddiman has noted that in the Holocene during the period of civil society, the changes in atmospheric greenhouse gases have been anomalous compared with the geological record of the last 400,000 years. During this period, both carbon dioxide (CO2) and methane (CH4) increased, probably as a result of the introduction of agrarian agriculture and land clearing in Eurasia. These, and other land use changes because of agrarian rural activities, may have caused a subtle forcing of climate, preventing climate cooling which might have been expected because of natural forcing. If future evidence supports the Ruddiman hypothesis, then agricultural and forestry activities during the period of civil society may have been exerting an influence on climate for, at least, the last 8000 years.

So our agriculture has been keeping our planet warm.

 

[lpetrich]

Late Holocene climate: Natural or anthropogenic? - Ruddiman - 2016 - Reviews of Geophysics - Wiley Online Library

For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2.

• Holocene ice core and ocean sediment trends are anomalous compared to previous interglaciations
• Paleoecology and archaeology show that early farmers emitted large amounts of CO2 and CH4
• Large early agricultural emissions are consistent with geochemical constraints

It's a long paper, discussing a lot of evidence, so I'll skip to the end.

4.4 Conclusions

The late Holocene stands apart from equivalent intervals in other interglaciations of the last 800,000 years by registering greenhouse gas increases instead of decreases and in showing regional temperature stability in most regions instead of a shift toward glacial conditions (section 2). These anomalous responses implicate anthropogenic interference in the climate system. Independent ground truth estimates of CH4 and CO2 emissions sufficient to account for substantial parts of these inferred anomalies come from syntheses of archaeological and paleoecological data and from land use modeling (section 3). After more than a decade of debate over whether late Holocene climate was natural or anthropogenic, the convergence of evidence from these several branches of scientific inquiry points to a major anthropogenic influence.

Concluding that our agriculture has kept us warm by emitting greenhouse gases: CO2 and CH4.

That paper lists these origins of agriculture with approximate dates:

• 12,000 - 8,200 BP -- Fertile Crescent, N China, S Mexico, N Andes, S Amazonia
• 8,200 - 4,200 BP -- W Africa, E Africa, India, S China, Japan, New Guinea, E US, S Andes

 

[rousseau]

Most ancient histories I own describe the early climactic conditions of the Holocene as pretty conducive to the growth of plant-life, even moreso than is the case today. Abundant resources for survival, easier cultivation, increased population pressures etc.

Maybe it's not so much that agriculture was invented during the Holocene, but rather it flourished during the period.

 

[Jarhyn]

Most ancient histories I own describe the early climactic conditions of the Holocene as pretty conducive to the growth of plant-life, even moreso than is the case today. Abundant resources for survival, easier cultivation, increased population pressures etc.

Maybe it's not so much that agriculture was invented during the Holocene, but rather it flourished during the period.

Also, agriculture is something that relies in many ways on language and structural advancement as well.

Hunting/gathering when there are few people and enough land is a lot less bother than farming.

If things keep changing or the tools to hold the knowledge aren't available, that just washes away quickly with time and the death of those who know the magic.

 

[bilby]

Agriculture also isn't a pure dichotomy.

A nomadic hunter gatherer might make sure to scatter the seeds of the fruit he found, in the hope that the next year, there will be more fruit to be found.

Is he farming?

 

[Jarhyn]

Agriculture also isn't a pure dichotomy.

A nomadic hunter gatherer might make sure to scatter the seeds of the fruit he found, in the hope that the next year, there will be more fruit to be found.

Is he farming?

Or they may greedily and unskillfully eat the whole damn thing and shit somewhere nearby later. Or just toss the seed or stone or core as they walk away.

Are they farming?

 

[bilby]

Agriculture also isn't a pure dichotomy.

A nomadic hunter gatherer might make sure to scatter the seeds of the fruit he found, in the hope that the next year, there will be more fruit to be found.

Is he farming?

Or they may greedily and unskillfully eat the whole damn thing and shit somewhere nearby later. Or just toss the seed or stone or core as they walk away.

Are they farming?

In that case, far less so. But it's clearly a spectrum, not an either-or proposition.

 

[rousseau]

Most ancient histories I own describe the early climactic conditions of the Holocene as pretty conducive to the growth of plant-life, even moreso than is the case today. Abundant resources for survival, easier cultivation, increased population pressures etc.

Maybe it's not so much that agriculture was invented during the Holocene, but rather it flourished during the period.

Also, agriculture is something that relies in many ways on language and structural advancement as well.

Hunting/gathering when there are few people and enough land is a lot less bother than farming.

If things keep changing or the tools to hold the knowledge aren't available, that just washes away quickly with time and the death of those who know the magic.

Yea there was likely a cultural element there as well. To me it looks like most revolutions entail a massive change in energy intensification, which is energy extracted per unit of land. In the case of the Holocene it'd be hard to overstate how much more energy became available, not just for us, but for every form of life.

So the ability to cultivate was likely there before-hand, and possibly some small scale cultivation that would be impossible to prove, but the ultimate cause of social and ecological change during the Holocene was climate.

It's along the lines of what Bilby's saying, it doesn't have to be a dichotomy. More broadly than agriculture we saw a huge increase in energy availability, which gave rise to far more specialization.