Columbus Lowered World Temperature

European germs killed 90% of the population of the Americas in the century after 1492 causing millions of hectacres of farm land to revert to forest which increased the uptake of carbon and reduced the planetary temperature. That is the upshot of a new paper that joins together previous estimates of population decline, farm land and carbon sequestration to push the onset of the Anthropocene to before the industrial revolution.

Earth system impacts of the European arrival and Great Dying in the Americas after 1492.

Abstract: Human impacts prior to the Industrial Revolution are not well constrained. We investigate whether the decline in global atmospheric CO2 concentration by 7–10 ppm in the late 1500s and early 1600s which globally lowered surface air temperatures by 0.15C, were generated by natural forcing or were a result of the large-scale depopulation of the Americas after European arrival, subsequent land use change and secondary succession. We quantitatively review the evidence for (i) the pre-Columbian population size, (ii) their per capita land use, (iii) the post-1492 population loss, (iv) the resulting carbon uptake of the abandoned anthropogenic landscapes, and then compare these to potential natural drivers of global carbon declines of 7–10 ppm. From 119 published regional population estimates we calculate a pre-1492 CE population of 60.5 million (interquartile range, IQR 44.8–78.2 million), utilizing 1.04 ha land per capita (IQR 0.98–1.11). European epidemics removed 90% (IQR 87–92%) of the indigenous population over the next century. This resulted in secondary succession of 55.8 Mha (IQR 39.0–78.4 Mha) of abandoned land, sequestering 7.4 Pg C (IQR 4.9–10.8 Pg C), equivalent to a decline in atmospheric CO2 of 3.5 ppm (IQR 2.3–5.1 ppm CO2). Accounting for carbon cycle feedbacks plus LUC outside the Americas gives a total 5 ppm CO2 additional uptake into the land surface in the 1500s compared to the 1400s, 47–67% of the atmospheric CO2 decline. Furthermore, we show that the global carbon budget of the 1500s cannot be balanced until large-scale vegetation regeneration in the Americas is included. The Great Dying of the Indigenous Peoples of the Americas resulted in a human-driven global impact on the Earth System in the two centuries prior to the Industrial Revolution.


I've heard similar claims about the death toll Genghis Kahn made.

Now for the rest of the story: During that same period 1492-1950, those same "European germs" killed many times more immigrants than they did native Americans. It is a myth to believe that only the Indians were susceptible to those killer diseases.

50-100 million of the 3 million European immigrants were killed by European diseases???

And, no, 90% of the 3 million European immigrants were not killed by European diseases to exceed the high rate of indigenous Americans killed by European diseases.

The more likely number of native Americans in the new world in 1492 was 10 million to 20 million.

Prior to vaccines and to a lesser extent prior to antibiotics a 50% death rate for children prior to age 18 was common. I am in fact old enough that me and my siblings grew up before vaccines were available and four of my siblings did indeed die very young from "childhood" diseases. Think about that; 450 years of Americans of European descent half of whose children died. Yes indeed a lot of people died before vaccinations.

I'm not sure where you got that silly "3 million European immigrants" from. Probably you knew your argument was so weak you needed to make stuff up to bolster it.

From basic biology, it seems unlikely that the pre-columbian native-american population was limited by disease, at least not at a low value. Perhaps there was a 50% death rate before age 18, but if so, the number of children averaged at least 4, or the population would have died out.

Any organism has to be able to expand exponentially when at low densities to recover from miscellaneous disasters; otherwise they go extinct. The limitation will generally be food supply, with disease and predation playing a role only if they are density-dependent - e.g., crowding leading to faster spread of disease. That seems unlikely for 20 million people spread over two entire continents.

That was the European immigrants that had a 50% death rate before age 18. The majority of those deaths was before age 5 and they were from diseases we no vaccinate against.

The 90% figure is that the overall native population declined by 90%. That is a truly staggering number that is not at all comparable with outcomes for europeans at the time. No one is claiming that europeans were immune to diseases, but the scale quite different.

"the overall native population declined by 90%."

Let's assume it is true, probably isn't but assume for the sake of the argument that it is true. Who would be to blame? God? It appears that you choose to blame the immigrants. They didn't "invent" the diseases. Just as it would be historically correct to say that the black plague in Europe was brought there by the Huns do you think that the Huns created it in their high tech labs?

The point I was making is simply that those diseases killed indiscriminately and during the period in question actually killed more immigrants than it did natives. What the immigrants had going for them was that there was a constant stream of them coming AND that they didn't depend on shamans and willow bark to nurse them back to health.

It is the nature of those terrible diseases that as soon as any immigrants or visitors reached these shores that the natives would suffer a huge loss of life to disease.

re Blame God rather than immigrants
"God" is a hypothesis. Although it can't be disproved, many of the properties assigned to it are in clear contravention of the facts we observe in the world around us. "Terrible diseases" are a case that makes the point.
Richard Dawkins recently tweeted this quote from Charles Darwin's writings:
“I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidæ … feeding within the living bodies of caterpillars” (C Darwin, 1860).

And that means what? It does not change the point. Blame god, blame luck/chance, blame mother nature, whatever. The point still remains that the native population of the America's was a disaster in waiting until that inevitable day when some immigrant from the rest of the world brought disease to the new world. It is naïve at best and stupid at worst to blame that immigrant. Now, you could build an argument that the natives were to blame because they should have built a wall...

Yes, that is the reality.
Hold a Christmas Eve party, and one of the guests decides to come even though she has a cold. Then a percentage of the guests there are impregnated with it, and if they are similarly inconsiderate when they go to New Year's Eve parties the same things happens again. Then when any children present at any of these parties go back to school...
But as Charles Darwin wrote all those years ago,
“I cannot persuade myself that a beneficent & omnipotent God would have designedly created ...

The chap who wants to build a wall believes he has God on his side. Personally I somewhat doubt it, on the basis that "god" is a failed hypothesis.

European germs is an impact to the existing equilibrium state. The rate of death from childhood diseases is basically irrelevant, unless it changed significantly when Europeans arrived.

We know from evidence that European germs didn't only kill the young and very old they hit the entire population. Some diseases, eg some influenza variants, are actually more dangerous for fit young adults though I don't know if that applies in this case.

You are missing the point. The point is that in the same time period in question far more European immigrants died from the diseases. There is a general misunderstanding and misinformation that more Native Americans died from these diseases and that isn't true. Those disease were equal opportunity killers.

What matters more is deaths per capita. Percentage wise the Natives saw something like a genocide.

The Guardian (UK) covers the same story somewhat more militantly.

This is framed to sound like intentional genocide.

“European colonization of the Americas resulted in the killing of so many native people that it transformed the environment and caused the Earth’s climate to cool down, new research has found.

Settlers killed off huge numbers of people in conflicts and also by spreading disease, which reduced the indigenous population by 90% in the century following Christopher Columbus’s initial journey to the Americas and Caribbean in 1492.“

“European colonization of the Americas"

Colonization is such an innocuous term, especially compared to the reality, conquest.

"... and also by spreading disease"

Lede buried.

Yeah, the conquest part was workable mainly because disease had wiped out so many of the natives.

The diseases wiped out many of the European immigrants to. To ignore that is to ignore a basic fact about pre-vaccination health problems.

Sure some Europeans died too. But not at the same rate since they had partial resistance to the diseases.

In the book "1491", which describes the world (especially America) before the arrival of Columbus, Charles Mann (the author) explains that there was probably no way to avoid the decimation of the American natives once they got in touch with Europeans due to the diseases brought that they carried. Save for perpetual quarantine of the whole continent, there is nothing that could have been done to prevent mass deaths, especially in a world were germ theory had not yet been developed.

Still, there's something very smugly satisfying about blaming Columbus, and taking away his holiday, wouldn't you agree?

Columbus discovered what?

A thousand nations on the order of a hundred million people, the population as large or larger than Europe!

Is that what Columbus Day celebrates?

Clearly he was not the one who discovered the path to India, but he thought he found an undiscovered part of India, thus the hundred million people he found are called Indians today.

Nor did he discover new land, and he knew it because he returned with people who were thought to be from India, or Asia. Even after deciding the land was not India or Asia, clearly it had already been discovered.

What Columbus discovered was a route to travel, navigation instructions. Based on that information, a map maker drew and published some maps to already well know land to a hundred million people. From his maps came the name of the lland, sorta like Apple is associated with smart phones others built a decade earlier incrementally toward an evolving goal laid out by Gene Roddenberry and crew in Star Trek.

Columbus Day celebrates Europeans becoming as smart as the hundred million people who knew about the land they lived on. Every child born spends years of days doing what Columbus Day celebrates.

On a lighter note, Maxwell Smart had a cell phone in his shoe when Star Trek was still on the drawing board.

You tell 'em, hun!

"...there was probably no way to avoid the decimation of the American natives once they got in touch with Europeans..."

To paraphrase there was no way to avoid decimation of American natives once they got in touch with anybody....

Contact with non-native peoples was an inevitability. It was going to happen with the rate at which population and technology were changing. If not 1492 then 1645 or 1712 or whenever. If not the Spaniards or Europeans then the Chinese or Arab traders or polynesians.

These likely alternative historical outcomes are not politically correct however. Neither is the acknowledgment that native civilizations - existing essentially in a geographic vacuum on a planet with 30% land mass - were essentially doomed to - at least a minimum - radical change.

We in the modern world continue to fight over this endlessly with some kind of thinking that allows us to acknowledge that discovery of this continent would have been better - not worse- under any other perceivable scenario. It happened. It was inevitable. Yes, It could have been worse.

Let's turn the page if we don't mind.

Hypothetical inevitability aside, in our timeline Europeans intentionally gave smallpox contaminated blankets to the natives.
I can understand wanting to turn the page on that but you have to prove that you've read it first.

The smallpox blanket is a myth.

Not completely - 'The Indians destroyed several of the smaller British forts, but Fort Pitt (present-day Pittsburgh, Pa.) held out under the command of Captain Simeon Ecuyer, a 22-year veteran Swiss mercenary in the British service. Ecuyer, whose native language was French, also spoke German, the predominant language of his native Switzerland; the British had retained him because many settlers in Pennsylvania also spoke German. Smallpox had broken out among the British garrison, and during a parley on June 24, 1763, Ecuyer gave besieging Lenape warriors several items taken from smallpox patients. “We gave them two blankets and a handkerchief out of the smallpox hospital,” Captain William Trent of the garrison militia wrote in his journal. “I hope it will have the desired effect.”'

But if you read the article, calling such a story mainly myth is completely justified, and the effects of that documented example do not seem to large (especially compared to what occurred before that case with French allied Native Americans plundering a captured fort a couple of years beforehand.

However, one should also note this - 'Ecuyer’s attempt to spread smallpox among the hostile Indians was in no way disapproved. While Colonel Henry Bouquet was preparing to lead a British expedition to relieve Fort Pitt, Amherst sent him a note on June 29: “Could it not be contrived to send the smallpox among the disaffected tribes of Indians? We must on this occasion use every stratagem in our power to reduce them.”

Bouquet, another Franco-Swiss mercenary recruited because he spoke German, wrote back on June 13, “I will try to inoculate the bastards with some blankets that may fall into their hands, and take care not to get the disease myself.” Amherst replied on July 16, advocating exposure to smallpox “by means of blankets, as well as every other method that can serve to extirpate this execrable race.”'

Let us just say that the idea that at lest some white Europeans wanted to exterminate (a more modern term than extirpate) Native Americans is far from myth.

There are much earlier reports of biological warfare in Europe, in this case Muslims attacking Christians, from 1346:

"the Mongol army hurled plague-infected cadavers into the besieged Crimean city of Caffa, thereby transmitting the disease to the inhabitants; and that fleeing survivors of the siege spread plague from Caffa to the Mediterranean Basin."

Yeah, there were no small pox blankets. Also small pox is not transmitted in that way it is usually caught by being close to someone with small pox and inhaling the air. There is an irony though, in the discussion of chemical weapons. It was the Indians who did that when they would put a dead animal in the water source for the immigrants.

'there were no small pox blankets'

Well, except for an actual quote, that is - '“We gave them two blankets and a handkerchief out of the smallpox hospital,” Captain William Trent of the garrison militia wrote in his journal.' Again, mainly a myth, but yes, there is one documented case of 'smallpox blankets.'

'Also small pox is not transmitted in that way'

Strangely, as noted in the article, that was not the belief of those actually planning to use smallpox blankets, to repeat the quote in case you overlooked it - 'Bouquet, another Franco-Swiss mercenary recruited because he spoke German, wrote back on June 13, “I will try to inoculate the bastards with some blankets that may fall into their hands, and take care not to get the disease myself.” Considering that those people had much more experience with smallpos than we do, I will trust their experience in this regard, based as it was on many centuries of accumulated practical knowledge.

'in the discussion of chemical weapons'

Interestingly, though one assumes you will likely read with the same care as already demonstrated, the Indians were merely using a thousands year old European trick, as noted below.

yeet and yet,
because of the essential nature of the small pox it would have spread with or without blanket/hankies.
it is an objective sorta virus

and in 2019 let us help you
avoid these suppurating sores,
these itchy rashes

'it is an objective sorta virus'

So is TB. However, the connection between clothing of smallpox victims and the spreading of the disease was known, and was intentionally employed.

'avoid these suppurating sores,
these itchy rashes'

Better let Anon know, as this is distinctly underinformed - 'Also small pox is not transmitted in that way it is usually caught by being close to someone with small pox and inhaling the air.'

tb notta gonna be a virus
tb gonna be a mycobacterium

"Considering that those people had much more experience with smallpox than we do, I will trust their experience in this regard, based as it was on many centuries of accumulated practical knowledge."

How many centuries of experience with influenza do you reckon that people in the U.S. and around the world had when the flu pandemic of 1918 hit? Yet people still wore garlic necklaces, surrounded themselves with horse manure and onions, and performed eucalyptus oil enemas.

'How many centuries of experience with influenza do you reckon that people in the U.S. and around the world had when the flu pandemic of 1918 hit?'

I believe you are not making a distinction between how to transmit a disease based on centuries of experience, and trying to prevent or cure a disease.

Obviously, someone in the 1760s was unfamiliar with the germ theory of disease, however they were intimately familiar with smallpox. Including the fact that essentially everyone was pockmarked after surviving exposure to the disease. The pockmarks or 'pocks' are where the ending of the work smallpox comes from.

Of course, chickenpox is caused by another virus family entirely, showing how even in an age with a better understanding of disease, we still cling to older words based on an incorrect foundation.

Absolutely - much like the old tactic of throwing dead animals into a stream or well.

As noted here - 'Even before 300 BC, Persian, Greek, and Roman literature quote examples of the use of animal cadavers to contaminate wells and other sources of water. And as early as the sixth century BC, poisons were administered to enemy water supplies. Animal cadavers were used as substitute for poisons during the Greek and Roman eras, using human corpses. The Assyrians in 500 BC were also famous in poisoning enemy wells with rye ergot fungus causing hallucinations to target opponents.'

And of course, when it comes to warfare, the Europeans have always been quite advanced. As this example a couple of centuries before the spread of the plague shows - 'In 1155 AD, Emperor Barbarossa broadened the scope of biological warfare by using the dead and decomposing bodies of soldiers as well as animals to poison wells during the battle of Tortona, Italy.' And that Frederick I, Holy Roman Emperor, died during the Third Crusade in 1190 just shows that Christians were fully capable of attacking Muslims - and winning. to a major extent.

You don't need any understanding of the germ theory of disease to be able to use biological warfare.

@Engineer, yeah, the weasel-y bits here are that this was anything to do with a planned campaign of genocide by Europeans or organised at any scale beyond local wars and skirmishes.

That some commander or other under Britain or another force may have thought it was a good idea, that's pretty likely. The enemy is trying to kill you, and there are no rules of war, people do what they can.

The other weasel-y bit is to suggest further that this is due to flithy dishonourable European practices or something. Like natives were above fouling or poisoning a water supply of their enemies in a desperate situation, even if they never wrote it down in diaries full of cursive.

The smallpox blanket isn't a myth.

Myth or not, it is basically irrelevant to the horrific sweep of disease through the native population.
These are small isolated events in a much bigger process.

I'm a little leery of the reasons these stories are so attractive given their marginal significance. The bigger story, common to isolated native populations everywhere, is that new diseases entered the population "accidentally" with the European arrivals with a high level of lethality. Disease was not an element of a planned genocide. It just worked out that way. Attitudes varied but the colonisers basically believed they were moving into "terra nullis" - unowned land only occupied by natives, a view that appears bizarre to us now.

There is ZERO evidence that small pox blankets were ever used. Both quotes brought in this discussion are suspect, one being entirely rhetorical ("we should do it") and the other just drops a line in a journal with no other verification or witness. There are infinitely more occasions in which Forrest Demons were encountered, but we don't quite rely on those reports, now do we.

First, nothing you just said addresses the point i was trying to make.

Second, even if it did happen, nothing like that was outside the pervue of antagonistic practice even among Europeans themselves within the old world (use of diseased animals, poisoning water supplies, use of plague "spys", etc.). Indian tribes and Europeans were - at times - antagonistic to each other and within the context of the period this would not have been seen as outside any scopes, especially considering practices against non-christians (let's not forget muslims got the same treatment and, oh yeah, vice versa).

Still yet none of this addresses similar acts of "extermination" practised by native peoples both against Europeans and among themselves, even in pre-columbian times.

It sounds cruel, but the point i was making was their time was up. They were a stone age people living in a garden of eden naturally protected by barriers that were artificially being broken down, even before Columbus discovered America. Even today similar undiscovered people live essentially at the benefaction of modern governments that put considerable effort to keep them from being contacted for this very same reason.

The world turns but we don't feel it move. Neither did they.

'They were a stone age people'

No, a number of South American societies were not 'stone age'.

Borderline. Their general technology and culture was inferior to anything the ancient Greeks had. Maybe they were a close match for the first city states of 6,000 BCE.

Depends - they seem to have not had much interest in using metallurgy to develop ever more effective weapons. Nonetheless, to describe them as stone age is thoroughly incorrect.

And one should note this - 'The earliest known powder metallurgy, and earliest working of platinum in the world, was apparently developed by the cultures of Esmeraldas (NW Ecuador) at some point before the Spanish Conquest.'

Their general technology and culture was inferior

In what way was their culture inferior? How is the inferiority/superiority of cultures determined?

As far as technology is concerned, it's frequently mentioned that the residents of the new world had never put the wheel to practical use while it had been common in the other hemisphere for millenia. At the same time, the concept of the screw had been known in ancient Greece but wasn't usefully employed by Europeans until the early stages of the Industrial Revolution.

@chuck, unless you really do believe that all cultures are equal (and this include FGM practitioners and illiterates and people who violently reject science and so forth), you should probably interrogate this idea from the perspective of "Why do we both believe this idea?" not "You must justify to me why you believe this idea!".

Perhaps by "FGM" you mean "female genital mutilation". If so, does that practice have any relationship to male genital mutilation or "circumcision", a procedure found in cultures that generally consider themselves superior to others?

You're getting into the weeds of the specifics here, when the real question I posed is whether you really believe in a sort of culture-neutral "I don't believe any group has a better or worse culture" stance. I don't really care about moving onto discussing this specific practice, and I think you should easily understand it's a derail of the worst kind to do so!

The statement was made that the cultures of the new world were inferior to those of the old world when contact between the two was made. The response was how is that inferiority or superiority determined and measured? In 1492 there were plenty of illiterate, unwashed Spaniards living in huts with their sheep. It's doubtful that Cortez, an uneducated mercenary from Extremadura, was more intellectually sophisticated than Montezuma or the other leading Aztecs he put to the sword.

Your question specifically was "How is the inferiority/superiority of cultures determined?" as if it were some odd thing that no one would think of doing, hence my challenge to you on that basis.

If we're going to talk specifics on technology, it's pretty clear that their economy, engineering and materials science was pretty comparable to early civilizations, slightly ahead in some ways, behind in others. Lots of impressive things in the architectural and general building large stone structures department. No metallurgy, no glass, simple pottery, not much chemistry, little mathematics and science, no ship construction, unsophisticated textile manufactures, not much sophistication in trade, no Axial Age philosophical thinkers and no philosophical religion at all, etc, etc.

Their culture I can't be bothered to get into right now. It's fairly possible Cortez was more intellectually sophisticated than Moctezuma, simple from the kind of culture that he lived in, where more sophisticated ideas were about and known. Further rather than being completely "uneducated", he was a lesser noble who was "At the age of 14 ... sent to study Latin under an uncle in Salamanca", who was on what was at the time the beginning of a legal career track following his education. So he could well have had some access to more sophisticated ideas than Moctezuma. We don't have any reliable dialogues between the two men to compare of course.

Their culture I can't be bothered to get into right now.

Interesting rhetorical device, "I can't be bothered". The fact is that you know nothing about the sophistication of 16th century Meso-American thought. The Mayas, for instance, had a grasp of complex mathematics and a calendar that covered many centuries of time. Trade was highly developed. Rating their culture below that of the conquistadors is to simply assume that the Spanish culture is the standard by which others must be measured.

They were inferior.

They worked fewer materials to less effect. They had inferior technology and construction across all fields of endeavor. Their agronomy was lower efficiency. They captured less energy from their environment. They produced far less information per capita. They had lesser and less-efficient administration. Their mathematics was inferior. Their astronomy was inferior. Their art, and forms of art, were less varied. Their culture was not influential on other cultures, and was easily superseded by the culture of their conquerors. They produced no novel or enduring scientific discoveries. They produced no novel or enduring philosophy or theology. They had non-existent financial systems. Their trade was lower by value, volume, and distance on an absolute and per-capita basis. They had less specialisation and social diversity. They were poorer, on a per-capita basis. They were more violent. But their weapons and modes of warfare were inferior too.

They were inferior.

A strong assertion (too strong for me), but on the facts you're closer to correct here than chuckleberry, at any rate.

The problem with "they were going to die anyway, no harm in hurrying the process along" should be obvious if you apply it to your own mortality.

By 1700, indigenous populations were no more susceptible to disease than immigrant Europeans or the children of immigrants.

What followed was intentional extermination that had started by 1600 and increased steadily in what is now the US based on an ideology of God's plan, white supremacy, or whatever you call it. We hace a wave of leaders fueling and fueled by a populism.

Killing indigenous peoplle is alive today. The new Brazilian president ran on killing indigenous peoples so white people, globalists, can take and pillage their land. He was elected by people in part in opposition to globalism, just like Trump.

His policies make no logical sense. Does Trump realky want and end to globalism? That would mean he can not build resorts outside the US or have guests in his US resorts from outside the US.

Likewise, the only reason to take the rain forests granted to indigenous Brazilians is for exports of first the very high priced lumber, then to export cattle, and the current fad ag monoculture product. The US Latin America policy was, is, driven by ag monoculture, one genetic line of bananas, of rubber plants, coca, ...

As I recall, he discussed this very same cooling idea in his follow up book, 1493, too. Color me a tad skeptical, but still....those were good books.

and yet now theres a free/cheap effective vaccine for most of this stuff
that the npr has made people fraught about
so jeff mate, what do you think is going on here?
is this real/fakeloop is n. offerman actually a robot
the biology dept. awaits your reply

The important finding is the uptake of carbon as the result of population decline and reforestation. Today, deforestation continues to reduce the uptake of carbon even as the emission of carbon accelerates. A the population grows and the world shrinks the risk of a pandemic that kills a significant percentage of the world population increases, thereby repeating the pattern of reforestation and the uptake of carbon. Death is the planet's friend, mass death the planet's best friend.

The planet does not care. It is a hunk of rock.

Life cares. Maybe all life, for some expansive definition of "care". But life is in no danger. Indeed, a warmer world would very likely have more life.

Death cult rhetoric is not an amusing way of showing how sophisticated and edgy you are. It shows something else entirely.

To back up the statement you should show that either speciation has accelerated faster than extinction, or that biomass itself is increasing valuable spell.

Otherwise it is just handwaving.

My cautionary link would be:

Higher levels of CO2 promote photosynthesis, while also providing greater resistance to drought (leaf stomata don't have to open as much to let in CO2, reducing loss of water). This is very well-accepted science. The resulting increase in plant growth is going to increase the overall amount of life.

Realistic amounts of warming aren't going to really have drastic effects, but suppose they did - with ice caps in Greenland and Antarctica melting away. The increase in land area available for flora and fauna would obviously increase biomass. There would be loss of land area from sea-level rise, but this would be accompanied by an increase in ocean habitat.

Warming itself tends to lead to increased biomass, as on can see by comparing how prolific polar lands are to more tropical lands. There's no sign that tropical regions are reaching any sort of limit past which warmer temperatures decrease productivity. And in any case, a central prediction regarding CO2-driven warming is that it will be greater in polar regions than in tropical regions.

Current observations doe indeed indicate that there is a "greening" of the earth (eg, in the Sahel).

I understand the plausibility, but I thought that field experiments showed a muted effect.

New study undercuts favorite climate myth ‘more CO2 is good for plants’


The impact of CO2. The global rise in the levels of CO2 is good for trees, bad for grasses and terrible for corals

Given time of course the Earth will recover from extinction events, but that doesn't mean for the next few centuries will necessarily be pleasant from the standpoint of biodiversity.

I guess if you take the dark view that we are just bees on the windshield of the universe, none of it matters.

I guess I messed up my first link.

From a quick glance, the article seems to be citing studies showing that some particular species/varieties of plants growing in temperate zones (eg, France) don't do as well in heat spells. This isn't surprising - plants are adapted to the climate where they grow, and tend to do badly when conditions depart greatly from the norm where they are. But I don't see the evidence that France, say, would have less biomass if it were warmer - there are plenty of places now warmer than France with healthy plant growth.

I asked you up top for studies showing Improvement.

In response you have given plausible argument, but then waved away three negative sources.

I think now I would like to see those studies showing actual improvement.

Well, you waved away the observations that the world is getting greener, so I think we've reached equilibrium here.

You don't really expect me to write a real literature review in a blog comment, do you? And I hope you don't think an article in the Guardian is a real literature review...

Truly that comment is the soul of the internet.

Will higher CO2 levels increase the time the sun shines in polar latitudes?

Or even in New Hampshire where I live and make growing crops like in Indiana where i grew up possible?

Ideology does not change the laws of nature.

You're right that nothing will change how insolation varies with latitude. But temperature does affect whether the sun that shines is of any use - it's not when it's -40C.

Latitude is not the explanation of why crops grow better in Indiana than in New Hampshire. Crops grow very well in places like Manitoba that are north of New Hampshire. I'd look to soil as the explanation...

Did any sitting US Senator assist in the writing of this report?

File under "Academic Absurdity Of The Week." CC: "How Civilizations Collapse."

Who paid for it?

mebbe the federal dept. of postmodern cultural climatology studies?

No, the climate modeling guys can do math, but the postmodernists know that algebra is just a conspiracy of western logocentric toxic masculinity and avoid it.

That explains it.

I had believed algebra's was a backhanded ploy used by Asians and white nationalists to keep out of STEM careers me, females and minorities.

Speaking of authentic charity, planting trees is probably better than sponsoring a conference.

Yes, planting trees is probably better than sponsoring a conference. I usually have a chuckle when I read of conferences calling delegates from around the world on subjects such as renewable energy or climate change. It is a bit like the old TW3 satire joke of holding a banquet for donors of a charity providing famine relief.

By the by: in positing "land-use change" the authors assume (by Alex's description) early inhabitants to have formerly devoted "millions of hectares" to farming and cultivation.

Do tell.

A further by-the-by: these researchers DO KNOW that the First Arrivals would have been obliged to clear those millions and millions of hectares of farm land. How were these feats managed? Equine mammals were not (re-)introduced to North America until the 16th century, so what draft animals might native engineers have enlisted for toppling trees and clearing out root systems in a timely manner? (I have heard a US Forest Service firefighter remark that Native American practices in setting fires to clear vast swaths of forest were often not well-managed and led to much needless burning.) Otherwise: any evidence of enslavement in order to clear millions of hectares of (formerly) old-growth forests?

'How were these feats managed?'

Fire, mainly. Though possibly describing these methods would be more helpful - 'The old American civilizations, like the Inca, Maya, and Aztecs, also used this old agricultural technique.

Large families or clans wandering in the lush woodlands long continued to be the most common form of society through human prehistory. Axes to fell trees and sickles for harvesting grain were the only tools people might bring with them. All other tools were made from materials they found at the site, such as fire stakes of birch, long rods (Vanko), and harrows made of spruce tops. The extended family conquered the lush virgin forest, burned and cultivated their carefully selected swidden plots, sowed one or more crops, and then proceeded on to forests that had been noted in their wanderings. In the temperate zone, the forest regenerated in the course of a lifetime. So swidden was repeated several times in the same area over the years.'

People had been sculpting landscapes for human use for tens of thousands of years before the domestication of any bovine or equine mammals.

Seems like all that pre-Columbian slashing-and-burning would complicate these recent estimates, computations, and calculations concerning carbon release and carbon capture both. What might those widespread practices alone (intermittent here and there, repetitive in many another locale) have contributed to global carbon release in the centuries and millennia prior to c. 1500 CE?

The use of uncontrolled burning to level millions of hectares of forestland (admittedly, with vastly different kinds of flora from continent to continent and region to region) would have been virtually continuous among migrating North Americans, we might think, less so presumably among settled peoples of Mesoamerica and South America's Andes.

This posited "human die-off" in the New World would have occurred barely a century after the Old World career of Timur the Conqueror, whose campaigns yet other academics aver led to the slaughter of almost 5% of the ENTIRE GLOBAL POPULATION. What climate consequences might fourteenth century-CE Asia have posed, with or without New World contributions over a century later?

'Seems like all that pre-Columbian slashing-and-burning would complicate these recent estimates'

Sure - but do not think of Amazonian style slash and burn being the only style employed.

'This posited "human die-off" in the New World '

The Spanish and Catholic Church did document this collapse in the areas they controlled, you realize. There is nothing posited about it, though one is welcome to quibble over whether it was 87.8 or 91.1 or 83.9 percent of the population found in the Americas in 1491.

It's interesting that you, and many others, deny that a large die-off of the new world population could have occurred, an historical event proven by extensive research, while other many others, perhaps yourself included, are vehement about the future destruction that's inevitable because of a small change in supposed "global" temperatures.

Not just research - there are records in terms of the Spanish Empire and the Catholic Church.

Not to mention the reality that due to the collapse in numbers of the local labor force, the Spanish (and others afterwards) needed to import slave labor.

I don't deny that American populations were ravaged following contact with European colonials and conquerors: I quibble with the specific claims made by the folks whose report Alex cited (the particulars of their claims regarding land use probably more than population studies they cite), so I would be better prepared to entertain their claims if they would dutifully apply their methodologies and analyses to the career of Timur the Conqueror, whose rampages a century earlier killed at least as many Asians in less than a half century as Americans died of disease and conquest over succeeding centuries.

Says WKPD: " Although in northern Europe one crop was usually harvested before grass was allowed to grow ..." I wonder which parts of northern Europe. The best landscape historian I have read points out that you can't do slash and burn agriculture with British broadleaf woodland, and I imagine that applies too to neighbouring bits of the continent wherever the tree species are identical.

@dick : +1

...referenced paper is primarily idle speculation not fact

disease, warfare, and Mother Nature ravaged native populations long before Europeans showed up

...and everybody started out in the plains of Africa

Mother Nature has a 100% kill rate no matter what historical circumstance transpire anywhere

Diseases like smallpox and TB were utterly devastating in the Americas. Something that can be seen by Spanish accounts (along with fairly good records after the Americas became integrated into both the Spanish Empire and the Catholic Church) of how their native labor/convert population collapsed. Which led to the importation of slaves to replace that lost labor force, one should note.

"Mother Nature has a 100% kill rate no matter what historical circumstance transpire anywhere"

Someone should have used that defense in Nuremberg.

Since the defendants were trying to avoid being hanged for their crimes, I'm not sure this argument would have had the desired effect....

Thank you, Columbus!

So this is how America falls, 1492 version.

'of the abandoned anthropogenic landscapes'

Yet, the Europeans were likely able to quickly reverse much of that 'abandonment.' Sugar and tobacco were instantly profitable, even without imported slave labor. After the importation of slaves, it was necessary to feed them too, of course.

There is no question that a century can play a major role in changing an anthropogenic landscape, as demonstrated by Northern Virginia following its transformation after the Civil War. Basically all of the forest that was found in 1960 - and was then cut down to 'develop' the Northern Virginia suburbs - was farmland in 1860.

A fact nicely illustrated by the controversy that arose when the National Park Service developed plans to return the Manassas Battlefield to resemble its 'original' condition. A plan that involved this - 'Fast-growing Prince William and Fairfax counties are now so heavily developed that green space and large trees have become comparatively scarce in many areas. Locals fear that few mature trees will be left unless development is checked and strict tree protection ordinances are enforced.

Given that area residents have become very protective of the remaining mature trees, it was a foregone conclusion that there would be a public outcry when the National Park Service made plans to cut down numerous trees at the Manassas National Battlefield Park in order to restore some of the most important historic sightlines. Many trees have been removed already, but some residents and county officials continue to grumble that the Park Service has let the need for historical authenticity trump the need for mature trees and the many benefits they produce.'

Odd to think that now one could actually quantify Til Hazel's contribution to increasing atmospheric CO2 by comparing the forested areas of Northern Virginia in 1950 and today.

In addition to creating the happy motoring framework that so marks Northern Virginia, obviously. And changing an area that had a distinctive character to the sort of place that Kunstler writes about in the Geography of Nowhere.

Europeans did not begin to settle areas north of the Gulf of Mexico until the 1600s- over a century after initial contact. They didn't start settling west of the Appalachians until around 1800 (New Orleans and Santa Fe being exceptions)

Interesting article. Sorry, no agenda to promote.

Go back further to the end of the ice age. What happens when humans begin proto-farming, no plow seeding of the ice line north as the earth warmed?

The opposite, humans would have accelerated the uptake of co2, reduced the rate of co2 expansion right at the ice age change. Using the same mmethodoly we would find that humans engaged in global cooling 11,000 years ago, caused the Younger-Dryas event and left the earth in the unstable holocene period.

We are long over due for an ice age.

Europeans, Asians, and Africans got pretty lucky in terms of the Columbian Exchange - aside from maybe Syphilis, there were no Smallpox-esque mega-death plagues that came out of the Americas and spread across the rest of the world with similar fatalities.

It could have happened, too. The usual explanation why it didn't was that the indigenous population in the Americas didn't have domesticated animals, but Smallpox actually jumped from a rodent IIRC.

Politics pretending to be science. Sad.

Indians had not invented the plow. They cleared land by burning. Burning creates CO2. So, ending mass burning would have offset forest growth, no?

If anything, this reinforce their point; think a bit - the theory is that the growth of forest reduced the CO2 in the atmosphere; if mass burning was also reduced, then even less CO2.

Slash and burn actually sequesters carbon. I'm not sure what net result is, but there's the reason the Amazon is so fertile (carbon rich):

Seems like an odd model, as if the rest of the world was steady state at the same time.

As well, what does the archaeology say? Where are these hectacres of abandoned land? Do direct estimates of abandoned land and forest re-growth match what they're talking about at all? That would be a check on their model.

It seems a bit wrong to say "Well, the model says there must have been cultivated land and forest somewhere, don't expect us to provide direct evidence!"

Also, how do we compare with other plague events. For instance - - "The Black Death is estimated to have killed 30–60% of Europe's total population. In total, the plague may have reduced the world population from an estimated 450 million" (1346 high) "down to 350–375 million in the 14th century. It took 200 years for the world population to recover to its previous level. "

Where's the carbon dip and warming dip from that? What about the plague of Justinian with 50 million dead?

These are both megadeath events that are as serious or more so (their estimate for this megadeath with 50 million). So what gives? Are Eurasians just so efficient at farming that no land was lost from cultivation, or what?

Interestingly, Angus Maddison estimated the population of the Americas at 20.2 million in 1500 ad. He estimates the population decline to 10.5 million by 1600. Serious estimates put tbe population of Inca and Aztec empires at 4 and 6 million, respectively.

Saying that the Americas had 65 million people in 1492 with 90% reduction to 1592? What? That's ludicrous. Where were these 65 million people? The native populations of Brazil and US combined was about 3.5 million in 1500, there were 4 million people in the Andean region plus 8 million in Mexico and Central America, total about 18 million. Add a couple of million for the hunter gatherers elsewhere.

Oh, I see they use some highly questionable estimates for Central Mexico, Yucatan and the Andes. For Central Mexico they assume a population of ca. 25 million over an area of 500,000 square kilometers, which would imply it was more densely populated than any major region in the old world in 1500. Considering the vastly superior agricultural technology used in China and Europe at the time, who could not support the same level of population densities, such claims appear quite ludicrous: in 1500 ad the British Islands had 4.4 million people living in half of the area and there is much higher density of archaeological ruins dated from the 15th and 16th centuries in the British Islands than in central Mexico.

Serious estimates put the population of central Mexico at 6 million which implies in a slightly lower density as the Western European average in 1500 AD.

. Considering the vastly superior agricultural technology used in China and Europe at the time,

Tomatoes, maize, potatoes, squash, and other common agricultural products that have become staples all over the world originated and were developed in the New World, by supposedly inferior agriculturalists.

Rafael, in the spirit of my comment just above, fully agree with need for some archaeological backing and archaeogenetic backing for what they propose and severely skeptical in the meantime.

Would add though, Eurasian populations may have been suppressed quite a lot by disease, even when they had apparently better agricultural technology. Americas got all their Eurasian plagues at once, while Eurasia had this happen in a number of waves, and that would suppress things every time.

Hence possibly one of the reasons for higher scale of monumental civilization in the Americas relative to their general level of technology, which technology was in a general sense lower than in Eurasia and in some ways also than in West Africa. Monumental civilization depending on getting large numbers of people together under the command of some god-king to pull and move stone about.

Charles Mann made the exact same case in his book 1493 several years ago. Albeit with less rigor.

The first immigrants (Indians) were colonized, conquered, and killed off because they had a poorly defined and inconsistently enforced immigration policy.

They didn't have a wall.

Let that be a lesson for you.

I cannot understand the framing at all: "...key evidence in the calls for the drop in atmospheric CO2 at 1610 CE to mark the onset of the Anthropocene epoch". But the argument is that atmospheric change was caused by the reduction of human activity, implying previous human activity in the Americas had previously affected carbon dioxide levels. Which is an argument for a much earlier date for the start of the Anthrpocene - whenever American human land use started having significant effects.

The only way to reconcile the argument with the conclusion seems to be the authors not considering precolumbian Americans to be human?

Blame it all on the white race. That's what academics do when not blaming the US.

Wow. Amazing to see the pro-genocide wing of Marginal Revolution in full force today. Didn't realize libertarians harbored such views before this post.

Once you acknowledge the word genocide, next thing you'll be asking yourself what happened to the other 10% and if some form of restitution might be owed.

I have to wonder if the Democratic-Socialists' Green New Deal aims to do a similar thing.

I want to talk about global warming. Forget about the population and disease issue. The core argument is that the collapse of western hemisphere population meant that there was vast biomass growth that followed, which absorbed CO2 from the atmosphere and so cooled the planet fast and far enough to trigger a Little Ice Age. Amazing if true.

Clear implications for us. Can we produce a comparable explosion in biomass to absorb CO2 but without a 90% population decline? That is the clear implication of the science authors.

Perhaps seeding the ocean with iron dust would do it by stimulating plankton growth. Reforesting Ethiopia would help (ahem). America has done a good job with reforesting since 1900 but we could do more.

We could grow forests, cut them down, store and preserve the wood, and grow more forests. Wood takes out of the air what coal puts into it.

We might want to build nuclear power facilities to generate electricity.

"We could grow forests, cut them down, store and preserve the wood, and grow more forests. Wood takes out of the air what coal puts into it."

That's a really expensive way to make coal. It would be far cheaper to just not mine coal in the first place.

Biochar You can burn crop residue and waste paper via pyrolysis leaving the carbon behind it a stable state.

So what's it going to be: globalism, or environmental stewardship?

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