Last week we were treated to the ridiculous story about Genghis Khan having an impact (or apparently not enough) with his impact on humanity. This week, a “new interpretation”; it’s the Romans and Christopher Columbus who are the ghosts of climate injustices past by daring to enable use of forest resources. I got quite the chuckle from this part, emphasis mine:
Ignoring the progress in agriculture, the preceding models implied that the same area of land is required to feed a European living in the fifth century as in the 20th century. This is why scientists struggled in trying to estimate the amount of CO2 produced by man before the industrial era. The work of Jed Kaplan’s team now enables us – for the first time – to travel back thru time.
Wow, time travel! Here is the press release in full:
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Man has been provoking climate change for thousands of years!
24.01.11 – The Roman Conquest, the Black Death and the discovery of America – by modifying the nature of the forests – have had a significant impact on the environment. These are the findings of EPFL scientists who have researched our long history of emitting carbon into the environment.
“Humans didn’t wait for the industrial revolution to provoke environment and climate change. They have been having an influence for at least 8000 years.” Jed Kaplan is putting forward a new interpretation of the history of man and his environment. This SNSF professor at EPFL and his colleague Kristen Krumhardt have developed a model that demonstrates the link between population increase and deforestation. The method enables a fairly precise estimate of human-origin carbon emissions before the advent of industrialization.
The story of our influence on the climate began with the first farmers. At that time, the prevailing technology didn’t allow an optimal use of the soil. “For each individual, it was necessary to clear a very large area of forest”, explains Jed Kaplan. However, with time, irrigation, better tools, seeds and fertilizer became more effficient. This development was a critical factor, which would partially counterbalance the increase in population, and contain the impact of human pressure on the natural environment.
Animation commented by Jed Kaplan
Agriculture – the story of a race for productivity
The relationship between population levels and agricultural land-use is therefore not simply proportional, as was formerly believed. In the Middle Ages, Europe had fewer forests than today, although since then the population has increased more than five fold. “The real innovation in our research has indeed been the taking into account of the improvements in farming techniques. Standard models simply state that the bigger the population, the more forest is cleared; but this doesn’t correspond to the historical reality.
Ignoring the progress in agriculture, the preceding models implied that the same area of land is required to feed a European living in the fifth century as in the 20th century. This is why scientists struggled in trying to estimate the amount of CO2 produced by man before the industrial era. The work of Jed Kaplan’s team now enables us – for the first time – to travel back thru time.
The influence of the Roman Empire and the Black Death on the climate
The results of this research tell a very different story from that which has been circulating up until now. They show, for example, a first major boom in carbon emissions already 2000 years before our era, corresponding to the expansion of civilizations in China and around the mediterranean.
Certain historical events, almost invisible in the preceding models, show up strongly in the data produced by the scientists. A good example is the re-growth of the forests as a consequence of the fall of the Roman Empire. The Black Death, a plague which resulted in the death of more than a third of the European population, also led to a fall in carbon emissions.
From the decline of the American indians to the minor ice age
Lastly, a significant decrease in emissions began in the 16th century – the one which would herald the minor ice age. Jed Kaplan has an audacious hypothesis to explain the dip in the data curve: “Thanks to the reports of the early explorers, we know that the forests were less abundant on the American continent. Then the settlers gradually eliminated the indigenous population.” Threatened with extinction, these populations effectively deserted the forested areas, which – by taking up the carbon in the atmosphere – in turn set off the legendary frosts of the 19th century. “Of course, it’s only a hypothesis”, he concludes, “but given the data we have gathered, it’s entirely plausible”.
Jed Kaplan’s model is not in contradiction with the previous ones on one critical point: the enormous increase in emissions from the beginning of the industrial era, and the massive use of fossil fuels. “We are just saying that our influence on the climate began a lot earlier than we thought. In 6000 BC, we were already accumulating significant quantities of carbon in the atmosphere, even though it was nothing compared to the situation today”, adds the scientist. A conclusion that could turn out to be critical in the future for the improved evaluation of the decisive impact of the forests on the climate.
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This story was released via Eurekalaert. The study authors: Prof. Jed Kaplan and Kristen Krumhardt have interesting bios.
Here’s the abstract:
Holocene carbon emissions as a result of anthropogenic land cover change
Kaplan, Jed Oliver ; Krumhardt, Kristen ; Ellis, E. C. ; Ruddiman, W. F. ; Lemmen, C. ; Goldewijk, K. K.
In: The Holocene, 2010
Date: 2010
Humans have altered the Earth’s land surface since the Paleolithic mainly by clearing woody vegetation first to improve hunting and gathering opportunities, and later to provide agricultural cropland. In the Holocene, agriculture was established on nearly all continents and led to widespread modification of terrestrial ecosystems. To quantify the role that humans played in the global carbon cycle over the Holocene, we developed a new, annually resolved inventory of anthropogenic land cover change from 8000 years ago to the beginning of large-scale industrialization (ad 1850). This inventory is based on a simple relationship between population and land use observed in several European countries over preindustrial time. Using this data set, and an alternative scenario based on the HYDE 3.1 land use data base, we forced the LPJ DGVM in a series of continuous simulations to evaluate the impacts of ALCC on terrestrial carbon storage during the preindustrial Holocene. Our model setup allowed us to quantify the importance of land degradation caused by repeated episodes of land use followed by abandonment. By 3 ka BP, cumulative carbon emissions caused by anthropogenic land cover change in our new scenario ranged between 84 and 102 Pg, translating to c. 7 ppm of atmospheric CO2. By ad 1850, emissions were 325–357 Pg in the new scenario, in contrast to 137–189 Pg when driven by HYDE. Regional events that resulted in local emissions or uptake of carbon were often balanced by contrasting patterns in other parts of the world. While we cannot close the carbon budget in the current study, simulated cumulative anthropogenic emissions over the preindustrial Holocene are consistent with the ice core record of atmospheric d13CO2 and support the hypothesis that anthropogenic activities led to the stabilization of atmospheric CO2 concentrations at a level that made the world substantially warmer than it otherwise would be.
Keyword(s): agricultural intensification, anthropogenic land cover change, dynamic global vegetation model, global carbon cycle, Holocene CO2, prehistory
Reference: EPFL-ARTICLE-161674
Full paper:
Poor things, they are trying so hard to explain temps rising before SUV’s
The start was good then i got to the word models, when will they learn. I could not read anymore. The statement ignoring the advancements in agriculture, farms in euro. in the 5th century could feed today’s euro. just boggles the mind they would say such CRAP.
““We are just saying that our influence on the climate began a lot earlier than we thought. In 6000 BC, we were already accumulating significant quantities of carbon in the atmosphere, even though it was nothing compared to the situation today”, adds the scientist. A conclusion that could turn out to be critical in the future for the improved evaluation of the decisive impact of the forests on the climate.”
I suppose a little evidence of all that is too much to be expected of a “scientist”.
The find a decrease in carbon emmissions following the plagues of the midle ages?
Let me get this straight a 30% decrease in population and the have discovered that the carbon emmisions of the survivors decreased. Somebody paid for this study?
I seem to recall a couple of other studies out recently that also linked a change in climate to the plagues as well, something about clooler wet summers, lower crop production as a result. Lower crop production, bad nutrition a concentration of vermin and people in the urban areas no public health science to speak of can you say plague.
This whole study seems to have decided that they result of the study will be X now go justify the result with some theories.
Are they serious or just plain barking?
They’re a strange breed these environmentalists. They take examples of widllife & nature like Darmoor, Exmoor, Yorkshie moors, etc, yet these areas of outstanding beauty were actually created by man clearing the land of trees to creat arable land. Yet if you suggested that we replant the entire area with native trees there would be an outcry of anti-environment! You can’t win!
It was worse back then than we thought
I suspect Mr. Peabody and Sherman are seeking more funding for their Way-Back Machine.
….we developed a new, annually resolved inventory of anthropogenic land cover change from 8000 years ago to the beginning of large-scale industrialization (ad 1850).
———–
Large scale industrialization occurred well before 1850: Manchester was renowned for its blackened skies by the 1820s. The switch to coal-fired steam engines pre-dates the 1769 Watts engine with fairly extensive use of the Newcomen engine by 1750 for collieries, public water-works and blast furnaces. Also, the switch to coal predates 1600, and London skies and buildings were blackened by the domestic use of coal for cooking and heating. By 1800 at least 50% of air pollution was generated by domestic fires, and massive population increases meant this was a not a trivial quantity of smoke generated. Also, surely, according to their model, the increased C02 caused by deforestation, which re-emerged as a major problem by 1300 in Europe, with growing populations etc before the Black Death, should have triggered warming, not the plummeting of temperatures that occurred in the 14th century. This self-same deforestation led to the widespread use of sea coal – and then mined coal – in England from the 13th century onward. So the generation of CO2 likely did not slow much even following the Black Death – especially as the resultant increased wealth from re-distribution of property led to higher standards of living. I wonder if these researchers have looked at the historical literature?
Has anyone factored in the naturally occurring forest fires that humans have been putting out in the latter half of the 20th century?
Sounds like he’s saying the ‘Black Death’ was a good thing because it led to a fall in human carbon emissions in that era. These ‘scientists’ are truly pathetic. There’s a saying that things go from bad to worse to hilarious. Climate science has definitely gotten to the hilarious point. But it’s still annoying because I’ll bet this ‘study’ was paid for by taxpayer funds. Only governments would fund this kind of nonsense.
What you people don’t understand is that all science researchers, no matter what field, are jumping on the global warming bandwagon in a wild feeding frenzy of funds. Here is where some of the research funding went.
Warmer Northern Hemisphere winters because of global warming
Colder Northern Hemisphere winters because of global warming
Global warming to slow down the Earth’s rotation
Global warming to speed up the Earth’s rotation
North Atlantic Ocean has become less salty
North Atlantic Ocean has become more salty
Avalanches may increase
Avalanches may reduce
Plants move uphill due to global warming
Plants move downhill due to global warming
Declining coral calcification on the Great Barrier Reef due to global warming
Increasing coral calcification on the Great Barrier Reef due to global warming
Look on the bright side, we’ve lived at least 8000 years without doing anything about AGW.
Are they really suggesting that a decrease in CO2 emissions by humans brought on the Little Ice Age?
“a significant decrease in emissions began in the 16th century – the one which would herald the minor ice age.”
Are they completely ignorant of the work of Knut Angstrom, Chamberlin, and others that determined a hundred years ago that the roll of CO2 was way over estimated?
Following their logic, I suppose one might conclude that the introduction of the Chevy Volt caused the bitter cold this winter in New England and Europe.
Unbridled ridicule of these clowns would be too kind.
Yes, and so have beavers. But for some reason, humans are evil and beavers are good.
If man was influencing (by influencing, I mean somewhat significantly, not a very very tiny amount which could be possible) the climate for 8000 years, that indicates to me that it’s very sensitive to our influence. Given that the world population today is many times greater than it was 8000 years ago and that we are using technology that didn’t exist back then, I would expect our influence on the climate to be many times greater than it was 8000 years ago. I’m not sure I’m seeing this…
led to the stabilization of atmospheric CO2 concentrations at a level that made the world substantially warmer than it otherwise would be.
So, if one were to believe this paper (…yeah, right…), human CO2 emissions probably saved the planet from entering a new ice age – isn’t that great? Because: the general temperature trend during the last 8000 years has been a downward slope. If it would have been “substantially” colder without humans messing with forests, that downward slope would have been a lot steeper, and the “little ice age” could very well have turned into a real glacial phase.
Jimbo: Great collection of links :-D!
All life on Earth interacts with and influences the climate.
All geological functions, like tectonics and the weathering of rocks and erosion, interacts with and influences the climate.
How much longer will we be subjected to the Capt. Obvious level of climate science ‘discoveries’ that are used to sell global climate disruption?
It’s all the bacteria’s fault. From ABC, Australia:
http://www.abc.net.au/science/articles/2010/02/09/2814540.htm?topic=
“Finnish researchers have called for a revision of climate change estimates after their findings showed emissions from soil would contribute more to climate warming than previously thought.”
Scientists, it would seem, can prove anything catastrophic. And they wonder why we distrust them. http://www.bbc.co.uk/programmes/b00y4yql
The sad thing is, all this distrust will probably cause us to throw the baby with the bathwater. [trimmed by request]
This is what happens when scientists swallow the idea that co2 is climate control king. If it is the only influence that affects climate then we have to fit into historical climate somehow. Anyhow… Poor blighters.
Jimbo says:
January 24, 2011 at 7:50 am
Jimbo hit the nail on the head. It is no surprise that the preponderance of global warming research press releases is highly correlated to the huge increases in funding seen world-wide over the past ten years. When the money dries up (as it inevitably will), so will the press releases…
In particular, look for some MAJOR downsizing of climate funding in the US over the next two years…
This really is complete nonsense. This is proof that the current models are totally wrong, the fact you can use them to conjecture something so ridculous.
Jimbo says:
January 24, 2011 at 7:50 am
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priceless Jimbo
They do have a small point about Man producing carbon in some quantities before some magic date in the 1850s as the transition to steam did not happen as with the click of a switch. One only has to look at the poorer parts of Asia to get an idea of the carbon output from fires and from the relatively primitive industrial power sources there, but I suspect their idea of reality is more imaginative than real. Reading accounts of Wellington’s campaigns in the Peninsula Wars reminds one of the human and animal numbers required to maintain just one foot soldier in the large armies on the march and in battle, which must also have produced more than a little carbon.
It might be an idea if one of these computer gamers got a job on an up-to-date mixed farming enterprise, then they would find out just how little (not how much) land is actually required now to sustain x numbers of humans. And they postulate that medieval man’s carbon use diminished after plague had swept through a population – who ever would have imagined that! Visiting Sienna, for example, and seeing the great religious building projects that were stopped dead in their tracks and left incomplete in the intervening centuries is a reminder of the effects of a sudden 50% depopulation by plague.
From the release: “‘Thanks to the reports of the early explorers, we know that the forests were less abundant on the American continent. Then the settlers gradually eliminated the indigenous population.’ Threatened with extinction, these populations effectively deserted the forested areas, which – by taking up the carbon in the atmosphere – in turn set off the legendary frosts of the 19th century.”
Am I reading this correctly and the authors are saying displacement of native american aboriginal populations caused the LIA..?
This study reads more like fictional narrative than scientific research. The entire argument of the paper—that changes in world population and extent of agricultural land use cause climate change because of their impact on carbon dioxide levels—is not supported by evidence. CO2 levels have been increasing the past 8000 years; however, the pre-historical temperature record dating back 8000 years shows long term cooling, not warming.
Cutting down trees has little effect on atmospheric CO2 concentrations but a significant effect on the hydrological cycle. Atmospheric CO2 changes follow the hydrological cycle which is controlling temperature.
I hate the way the AGW propaganda can take a grain of truth and transform it into a monumental lie. The earth’s biomass does modify climate towards the optimum. This is fundamental. However, Man is only a small part, of the biomass, that is constantly influencing climate towards the ideal required for this same biomass. Without these influences, the planet would be a barren planet. It is like calling a pregnant woman fat. GK
This article is so full of half truths and dodgy deductions that any serious scientific mind will simply ignore it. However, politicians and greenies are another matter altogether.
I am feeling very deprived – how can I get my snout in the same grants’ trough as the authors of this stuff?
Has anyone yet written a “Milking the Climate Grants’ Trough for Dummies?” If so, where can I get a copy?
This study seems like a way of patching over the hole left in the CAGW narrative left by the demise of Mann’s hockey stick.
You know a woman caused all this when she ate that apple. It seems to me we are all here now because of that apple and the advances in farming, mining, manufacturing and science. Who, in their right mind, would want to go back to the time when at age 21 you were an old timer?
Land degradation caused by repeated land use then abandonment and the inability to close the carbon budget in the study is a lot and the study may turn out to be worthwhile but the implication that man and CO2 has been a damaging influence on the earth from the get go is a stretch.
Everything in the earth and atmosphere is in constant motion and change as is the universe. Change brought by man has been good in terms of way of life and ability. At some point man will have to either leave the earth for good or cease to exist and that cannot be done, without CO2, by man that has not yet discovered fire. Thank God for women. And the apple.
I don’t mind models, as long as they look like Elle Macpherson.
A great example of a ridiculous study.
Why is it somehow tree cutting is the focus as opposed to irrigation/dam building?
And how many of those trees were cut down for fuel as opposed to building ships and houses?
And more importantly, why does this matter?
The CO2 involved by anyone’s definition is insignificant.
The only positive to this is that at least THIS study wasn’t paid for by the Obama Stimulus.
I wonder if the authors considered that the increase in agriculuture productivity in the 20th Century came about because of the CO2 increase.
Hrm, speculate much?
I’m guessing the Roman and Medieval Warm Periods are about to be rehabilitated once they think they can sell them as being anthropogenic. Nero drove a Volvo while Rome burned, you know?
And we are paying for this unutterable crap?
These pscientists need to try getting a real job!
If you do a little bit of research on “Terra Preta” you will see that the pre-Colombians burnt A LOT of wood to fabricate it. As a start here is the entry in Wiki:
“Terra preta soils are of pre-Columbian nature and were created by humans between 450 BC and AD 950.[5][6] The soil’s depth can reach 2 meters (7 ft). Thousands of years after its creation it has been reported to regenerate itself at the rate of 1 centimeters (0.4 in) per year.”
“Terra preta soils are found mainly in Amazonia, where Sombroek et al.[10] estimate that they cover at least 0.1 to 0.3%, or 6,300 to 18,900 square kilometres (2,400 to 7,300 sq mi) of low forested Amazonia[2]); but others estimate this surface at 10.0% or more (twice the area of Great Britain).”
There was a lot of people back then. They were not controlling the weather… they had GODS that were in charge of that. And their GODS demanded human sacrifices not CO2.
It seems that the faith-based scientists are demanding human sacrifices again to control the weather.
Regarding ” Jimbo says: January 24, 2011 at 7:50 am ”
I looked up the articles Jimbo linked to. They do not in fact contradict each other. They often focused on different regions, zones or time periods.
“Provoking”?
Um… Doesn’t that require a sentient respondent or something?
“This SNSF professor at EPFL and his colleague Kristen Krumhardt have developed a model that demonstrates the link between population increase and deforestation.”
This is not necessarily true in all scenarios, I.E. population increase = deforestation, for example from Answers.com “Johannesburg, South Africa has over ten million trees and it is now the biggest man-made forest in the world.” other sources cite the largest man-made forest in the world is in northern Nebraska where the once treeless plains are now teeming with trees. See us evil carbonators can be useful to Mother Gia on occasion.
What, no mention of Norman Borlaug (1914 – 2009), 1970 Nobel Peace Prize laureate (when that still meant something), father of the cereal-crop Green Revolution responsible for ending global famines, preserving several hundred million human lives?
AGW catastrophists, climate hysterics, demonstrate a Thanatist psychopathology akin to Muslim terrorists’ nihilistic “death more than life” ethos of willful self-destruction. From Paul Ehrlich to John Holdren, latterly James Hansen and Keith Farnish, these Luddite sociopaths rage against humanity’s well-being, sabotage global energy economies with the express purpose of “eliminating” nine-tenths or more of Earth’s existing human population.
We see in this a mindset recalling early 20th Century anarchists’ eager anticipation of 1914 (see Joseph Conrad, “Under Western Eyes”). To the extent this “culture of death” implants itself in naive polities, so civil discourse perishes, communo-fascist elites vitiate popular governance in furtherance of self-destructive ends.
In the long run, only ideas matter. But ignore historical reality, betray youth for but a generation, and (as Yeats put it) “all is ruin once again.” Either broad polities decisively repudiate the Green Gang of Briffa, Hansen, Jones, Mann, Trenberth et al. or Warmists’ extraordinarily hate-filled, vicious agenda will encompass mega-deaths as Pleistocene Ice Time returns.
So if we look at ice cores, they show a drop in atmospheric CO2 just before the LIA?
Oh, and if the LIA was caused by decreased global atmospheric CO2, are we now conceding that the LIA was a global phenomenon?
“deforestation”
yeah right, like they never had forest fires back then
Even now, we fight those fires with everything we have, and they still burn millions of acres
Only serves to highlight the notion of carbon as the original sin in the church of AGW.
There is little difference between what a tree does and what corn does. Both use CO2 etc to grow. The size and time frame of growth is different. So if vegetables don’t count in CO2 output impact why should trees?
Well, I suppose we could all just stop farming…….that would fix things.
Utter fraud. Read the whole paper.
According to the data presented, atmospheric concentrations of CO2 varied within the range 280ppm +/- 5ppm from 1000 BC to AD 1850.
Anyone who thinks that less than +/-2% variation in atmospheric CO2 is going to have a measurable effect on climate, i.e. significant climate change, has simply got to be nuts. “Of course, it’s only a hypothesis”, he concludes, “but given the data we have gathered, it’s entirely plausible”. No it’s not even remotely plausible.
Going back to 8000 years before present there is shown a rise of 20ppm to the supposed pre-industrial 280ppm. Jed Kaplan says:
“simulated cumulative anthropogenic emissions…support the hypothesis that anthropogenic activities led to the stabilization of atmospheric CO2 concentrations at a level that made the world substantially warmer than it otherwise would be.”
What, a paltry 20ppm? Oh, and as for this 20ppm, where did it come from? Kaplan has now jumped on the AGW bandwagon, but what did he and his colleagues say in a previous recent paper?
“We conclude that a range of mechanisms most likely contributed to the 20 ppmv CO2 rise between 8000 years BP and the preindustrial, including calcite compensation, SST changes, coral reef build up and, to a minor extent, C uptake and release through changes in the terrestrial biosphere”
Anthropogenic didn’t even get a mention.
So, until last year the 20ppm could be accounted for almost wholly by natural means. Now it can all be attributed to man, who made the world “substantially warmer”.
Somebody’s lying.
What complete and utter tripe….
I want them to tell us what CO2 levels would be without the “pollution” caused by man in pre-industrial times. Would it even be enough to sustain plant life?
In 1850 CO2 levels were already pretty low (280 ppm?). If their theory is correct, that we’ve been influencing CO2 levels for at least 8000 years, then we’d have to have been adding around 1 ppm of CO2 to the atmosphere per century since any inputs much higher than that would mean was CO2 below the level required for plant life.
Only if you’re a blithering idiot. Or an environmental journalist. [But I repeat myself.]
How could any sentient adult — however much in the thrall of the AGW superstition — possibly take this delusional pseudoscience seriously?
“Yes, and so have beavers. But for some reason, humans are evil and beavers are good.”
Hard to know where to start with this one! But humans who like beavers are good.
KPO says:
January 24, 2011 at 9:27 am
During the time of Napoleon in France, they planted lots of trees, oaks mainly, because they needed them to built ships and also make drums for the whiskey, rum and of course wine. He made a law that no trees younger than 150 years old could be cut. The law was never changed. Because if that France’s area is 25% forested, twice the total of 1806.
This information comes from a whiskey company’s website.
http://www.bruichladdich.com/latestnewsarticles/16firstgrowth.htm
Jed and Kristen’s Excellent Adventure.
No Way!
Yes, Way!
The HYDE 3 database is very cool. Get ready folks because it’s being used in Ar5
Must kill all the nasty Hue-Mons and turn this into the PLANET OF THE APES!
So much for ‘renewables’
Omigawd – so the depopulated forests in America took much more CO2, which made people freeze? And that is supposed to even be ‘plausible”?
I think that ‘scientist’ has been reading too much Tolkien…
Does anyone really think that cutting down mature trees, and not replacing them, does NOT add to the amount of CO2 in the atmosphere?
You can argue what effect it had on global temperatures until the cows come home but surely everyone can agree that burning trees and not replacing them with something that ties up just as much carbon just has to add more CO2 to the mix?
And they had the audacity to breathe too.
John Blake says:
January 24, 2011 at 9:33 am
AGW catastrophists, climate hysterics, demonstrate a Thanatist psychopathology akin to Muslim terrorists’ nihilistic “death more than life” ethos of willful self-destruction.
Right on! When the Progressives = Regressives were begging and demanding that we “understand” the Islamofascists’ evil, it became obvious that they were actually inviting the rest of us to understand Them as well, in effect, as the Islamofascists’ deathworshipping groupist soul Bro’s, equally in opposition to life and the advancement of Humanity via the free-thought of the individual human mind: instead, for the “dead-ender” Progressives it is, “Give them Totalitarianism’s population control of the infidels and the plague-like masses, its suicidal-homocidalism, and its enslavement, or give them death!” CAGW “Science” is just another means toward those malignant, de-evolutionary ends.
The kneejerk viciousness of the responses here does not impress and does not reflect well on the commenters.
The theory proposed Kaplan et al. is that human impacts on the historical environment included continental-scale landscape burning. That is, anthropogenic fire drove a significant percentage of the terrestrial carbon cycle. When massive hemoclysms (human population crashes) occurred in history, the sudden dehumanization of landscapes eliminated, for a time, anthropogenic fire. During those hiatuses, plants continued to grow and carbon fixation continued apace, but CO2 emissions declined because people weren’t burning off the land so frequently or so broadly.
There are three parts to this theory. First, that historically human beings had a significant impact on the carbon cycle. Second, that a massive and rapid population crashes occurred in pre-history. Third, that the subsequent, albeit temporary, alteration of the carbon cycle (to increased fixation, decreased emissions) affected global climate.
The first two parts are cutting edge new findings in anthropology, landscape geography, and historical ecology. The evidence is strong, as are the inferences.
The third part is based on GCMs, and may be weak. Many papers here maintain that CO2 has no effect whatsoever on global climate. However, some papers by frequent posters here do so maintain, and project the sensitivity at different levels, from slight to more than slight.
[snip]
It is fair and reasonable to question the effects of CO2 on climate. As a climate realist myself, I find the CO2 theories lacking.
But it is not reasonable to deny that huge human population crashes occurred in the past.
I have read at WUWT on numerous occasions posters claiming that deforestation is rampant today, and that must be the cause of global warming, not CO2. That kind of grasping for excuses is as much pseudo-post-normal science as anything, because there are more trees per acre and more acres with trees on the planet today than at anytime during the Holocene.
The reason there are more trees today is that continental-scale anthropogenic fire has disappeared over the last 500 years. The terrestrial carbon cycle has indeed changed significantly. In western US forests the biomass loading is 5 to 10 times what it was 200 years ago, and many more times the loadings of 500 years ago when much of landscape was anthropogenic prairie and savanna, not forest at all.
Did the elimination of anthropogenic fire change the climate? I venture to say not. But I don’t deny the human-induced changes in the carbon cycle over the last 500 years.
Again, it is fair to question the effects of CO2, but it is not “skepticism” to reject whole cloth historical human influences on the environment. That’s denial.
Since Hyde 3 has land use and population going back to 10000BC it will interesting to see what difference, if any, it makes to GCM hindcasts that have land use models.
In the video they try to make us believe that except for Greenland, the rest of the land was all covered with forests. Another example of science that only shows the wanted results using deception.
What they appear to be saying is that evil man can’t live on this planet without drastically affecting it.
tonyb
Is Jed Kaplan related to Hans Christian Andersen?
This obsession with “carbon” and “greenhouse gases” is psychopathic. [snip]
As Daffy Duck would likely say… ‘this is just getting silly….’
Hey, not so fast! The ancient Greeks deforested their land turning lush mountain sides into barren rocky outcrops chopping down trees to build their ships. The Venetians deforested the Dalmatian coast to get the wood for the piles on which their city is founded. I think mankind (like every living being) has a carbon footprint existing in a dynamic interaction with the world about it. However, unlike other living beings, we can actually study the interaction and grow in understanding of our place in the world. No doubt, our attempts to study are world are coloured by our current cultural com political baggage. It’s not a good reason to fling manure (which has its own carbon footprint 🙂 ).
This is not a new idea at all. On books.google.com you can find an English book published in the early 19th century (or late 18th century) where the author claimed the climate of England was changed right after the Romans settled there and introduced agriculture. The forests were turned into fields and the climate of England went from a warmer climate that supported vineyards to the colder, damper climate they had in the 18th to 19th century.
I couldn’t find the book again or I would have provided give the link.
Re the animation: I cannot help but notice Egypt remains deep green and unchanged thoughout the run.
Also, that caveat “natural vegatation” below the map. Natural vegatation for a desert is “sparse”, yet remains colored green. Apparently “no-data” gets a green, too: Look at central Australia.
Based upon this one piece of fiction, the originator of that cartoon, Jed Kaplan, is not to be believed in any future or past work.
Louise says:
January 24, 2011 at 11:23 am
“Does anyone really think that cutting down mature trees, and not replacing them, does NOT add to the amount of CO2 in the atmosphere?
You can argue what effect it had on global temperatures until the cows come home but surely everyone can agree that burning trees and not replacing them with something that ties up just as much carbon just has to add more CO2 to the mix?”
Mature trees do not sequester carbon at nearly the rate that young trees sequester it.
If the trees are cut and used to build homes, tools, ships, wagons, etc, then it is likely a net carbon loss because, despite your assumption, trees can and do grow back without people actively planting them.
Alternatively, one could argue that when people gather firewood, esp. in primitive societies, they will gather what is easiest – dead branches on the forest floor which are slowly decomposing and releasing their CO2. Yes, burning them would speed up this process, but it may also prevent forest fires to a certain extent with clearing of flammable dead brush from the forests.
Of course, if plant life is considered good then we can wonder what the effect of killing 100 million or so large herbivores (i.e. Bison) in the 1800s. We can wonder till the buffalo come home about these things, but it is all conjecture and useless bullshit.
There they go again.
Programming their (sexual) fantasies to create a model which does what they want. This is not science!
“Lastly, a significant decrease in emissions began in the 16th century – the one which would herald the minor ice age. Jed Kaplan has an audacious hypothesis to explain the dip in the data curve: “Thanks to the reports of the early explorers, we know that the forests were less abundant on the American continent. Then the settlers gradually eliminated the indigenous population.” Threatened with extinction, these populations effectively deserted the forested areas, which – by taking up the carbon in the atmosphere – in turn set off the legendary frosts of the 19th century. “Of course, it’s only a hypothesis”, he concludes, “but given the data we have gathered, it’s entirely plausible”.”
The history of the indigenous populations of the Americas starting in 1492 is not a happy one. Disease, conquistadors (even in North America–e.g. Hernando de Soto), loss of lands to European settlers and Americans. But I’ve not read many books that posit a large, stable population through the 16th century, followed by a gradual elimination of the population (and reforestation?), that suddenly spiked somehow to bring on the Little Ice Age in the 19th century. The general theory is more like plague, war and the difficulties of enslavement carrying off multitudes (causing likely North American reforestation), followed by an increase in population, followed by encroachment of whites, who cut down forests for agriculture and wood-fire until the discovery of coal.
If this guy is looking to blame the LIA on evil Westerners, he should revise his theory and apply it to Africa. The whole slavery industry actually did depopulate vast swaths of Africa at approximately the right time. And it probably did result in reforestation since farms would have been easy targets for raiding parties. He could blame little up-and-down swings in temperature on little historical events that cause more/less agriculture. It could actually work.
This reminds me of another study that went into the past and made amazing “discoveries” about historical events and ancient history. It was called “Chariots of the Gods”. As I recall, the end result of that one was SciFi as well…
Mike D. says:
January 24, 2011 at 12:01 pm
The kneejerk viciousness of the responses here does not impress and does not reflect well on the commenters.
————–
I have been reading WUWT more or less faithfully for two years and cannot recall any – repeat, any – sceptic basing his argument that deforestation is the cause of global warming. Most of us are too well-read and aware that in North America and Europe, at least, forest extents are greater than they have been in the past 200 years (North America) or over 1000 years (Europe).
By the way, how do you distinguish between the effects of anthropogenic and natural forest fires? Since the implementation of ecosystems-based forestry in the 1980s in the US (which forbids forest clearing, and has reduced the extent of timber harvesting drastically), and anti-scrub clearing measures in Australia, forest fires, including those caused by lightning strikes, have been more extensive and damaging.
Great animation. Very interesting.
Read somewhere that if you took all the humans born in the last 5,000 years and stood them side by side they would cover an area the size of Wales (8,023 square miles maths anyone ? ) Anyway whatever, we still not have the physically or brain power to make it rain or stop raining in Australia, perhaps the Australian Government should contact Prof. Giro Gearloose , Danold Duck has his address he could change the fancy desalination plants into water evaporators
I just love it! So, …. Until about 100 years ago, Australia was a green paradise covered in forests! Gee, Bourke and Wills were obviously deluded when they thought that they were dying in the desert! This guy has obviously never flown, driven or walked over the vast red-brown plateaus of Central Australia! Six hours in a plane from Sydney to Broome would help clear his mind! What source of public money is funding this self-indulgent nonsense.
ntesdorf
vigilantfish says: …how do you distinguish between the effects of anthropogenic and natural forest fires?
Anthropogenic fires were frequent, seasonal, and purposeful. They were set in specific locations, including lowlands. Purposeful landscape fire has been the key way that humanity has altered ecosystems during our entire existence, and were set for survival and sustenance reasons. Anthropogenic fires induced prairies, savannas, and open and park-like forests. Frequent burning eliminated most trees, but those that survived lived to very old ages.
Lightning fires are infrequent, generally occur during summer (hot dry weather), and generally start on ridgetops or other high places. Infrequency leads to biomass build-up, and lightning fires tend to be more severe because of the larger fuel loadings. Without frequent human fires to reduce fuels, lightning fires tend to be stand-replacing; that is, they kill all the trees. No trees grow to very old ages. Often fire-type brush replaces forests and prairies.
For example, many areas of the Southwest and California were subjected to anthropogenic fire for millennia. Those led to the open, park-like forests of old-growth ponderosa pine, punctuated by open meadows, encountered by the early Euro-American explorers to that region. But in the absence of the former frequent, tending fires set by the indigenous residents, biomass accumulated. Modern fires in those areas kill all the trees and convert the burned areas to chaparral.
Without frequent anthropogenic fire, forest development pathways are altered. Short-lived thickets of trees and brushfields result. Old-growth trees do not develop. Shade-tolerant species such as true firs tend to dominate, and shade-intolerants such as ponderosa pine are all but eliminated. Meadow and prairie areas become overgrown with brush and small trees. Savannas are invaded by trees and the former dominant species die out.
It may not be obvious to all, but a trained eye can readily detect the differences between anthropogenic and lightning fire regimes.
Here’s an interesting little ‘trick’ to show Warmists. It’s a visual representation of how much C02 is in the atmosphere.
Step 1. Work out how many pixels are on your computer screen by accessing the display data on your computer. For example my imac has a display 1200×1920 =2,304 000
Step 2. Say that there is presently 400ppm CO2 in the atmosphere (let’s give them the benefit of the doubt, you’ll see why in a second)
Step 3. Divide 2,304 000 by 1,000 000 and multipy by 400. This will give you a number of pixels which represent the proportion of CO2 in relation to the total atmosphere i.e. the number of pixels which are on your screen. In my case 2.3×400=920
Step 4. Get the square root of 920 using a scientific calculator. Approximately 30×30.
Step 5. (This is the clever bit, thanks son!) Go onto google images advanced search and search for images 30 by 30 pixels…then down load one.
Now sit back and stare at the tiny square on your screen. Hmnnn.
Let your eyes wander over the vast emptyness that surrounds it, then ask your self if you really believe for one second that what is OBVIOUSLY a ‘trace’ gas could destablize an open chaotic system like the atmosphere. If you’re really keen, generate a second image based on the percentage increase of CO2 in the atmosphere over the last century…you will barely be able to see it!
Finally, try asking a Warmist this question. If the heat amplifying/trapping properties of CO2 are so immense that a tiny puff of it can destablize the entire earths atmosphere, then surely we can use the pure gas to trap/amplify heat in solar type arrays. Why has no one done this?
This weird belief in the magical heat amplifying properties of CO2 must be shown up for the garbage that it is. Pass this on if you like. I’ve made it my screen saver!
Finally I understand. When early settlers saw less forests, that is evidence. When Vikings are found in Greenland permafrost, that’s an anecdote.
Of course the main problem in all of this is not the discussion of forest extent – it’s the Co2 concentrations. 280 +/- 2ppm is about the change in co2 per year in modern times. So if the climate is that sensitive, we should be seeing a year-on-year reaction to that sensitivity as atmospheric co2 climbs and climbs.
Obviously this is some background to try and pin blame for climate change back to prior to 1850. After hectoring the public about coal fired power and SUVs, I don’t think they’re going to buy the fact that pre-industrial mankind was also causing changes, having virtually only wood fires and ruminants to cause emissions.
I have a hypothesis.
These academic types, whilst sitting around having a social drink at the University Bar come up with a couple of ideas, they apply for a grant with the words Climate Change attached to it and bingo bango bongo you have yourself another paper to add to your CV.
And the way the IPCC reports are compiled, (more than a third of the AR4 was references pages) almost any paper about CC gets cited, so now there is a citation to bolster the validity of the paper.
Everybody wins, except the taxpayer.
Then please deal with the following:
http://www.nature.com/nature/journal/v399/n6735/abs/399452a0.html
http://dx.doi.org/10.1029/2009JD013568
Furthermore are you saying that ALL “do not in fact contradict each other”???
Mike D. says:
January 24, 2011 at 12:01 pm
The kneejerk viciousness of the responses here does not impress and does not reflect well on the commenters….
….Again, it is fair to question the effects of CO2, but it is not “skepticism” to reject whole cloth historical human influences on the environment. That’s denial.
Huh, “denial”? As for me, I just can’t wait for the next Environmentalist engineered Catastrophic Conflagration resulting from the pathological obsession the alleged Environmentalists have with Forestation and the phobia they project against the human race; which usually manages to wipe out the very things the “Environmentalists” are allegedly trying to save; while, if the Conflagration occurs where I live, it will also burn down my house along with the adjacent Wilderness; but which would probably make it all worthwhile for the Environmentalists, especially since it is me who is in “denial”, not them!
Then from the Press Release:
Ignoring the progress in agriculture, the preceding models implied that the same area of land is required to feed a European living in the fifth century as in the 20th century.
My apologies, but I’m not going to pay attention to any discipline that only recently figured this out via its “cutting edge” Anthropology, except to protect myself from it. The Press Release reads like those “self-annointed” of the “cutting edge” would be much better advised to start watching “Dora the Explorer” immediately in hopes of possibly catching up with the First Graders, instead of trying to “save the world” from its completely infantile, Fairy Tale CO2CAGW Boogieman.
Slowly the green warriors are morphing their quest from to protect our environment to a frontal attack of human civilization. They are Charlatans.
http://notrickszone.com/2011/01/24/potsdam-institute-for-climate-impact-research-is-a-house-filled-with-charlatans/
Where will this end?
http://green-agenda.com and the magnificent Vaclav Klaus, the current President of the Czech Republic and author of the book ‘Blue Planet in Green Shackles
They know exactly what’s ahead of us.
Jimbo,
I have noticed your great references many times. Excellent and informative.
Jimbo – You da man!
Baa Humbug says:
January 24, 2011 at 2:49 pm
I have a hypothesis.
These academic types, whilst sitting around having a social drink at the University Bar come up with a couple of ideas, they apply for a grant with the words Climate Change attached to it and bingo bango bongo you have yourself another paper to add to your CV.
And the way the IPCC reports are compiled, (more than a third of the AR4 was references pages) almost any paper about CC gets cited, so now there is a citation to bolster the validity of the paper.
Everybody wins, except the taxpayer.”
You’re more on the mark than you even know!!!! Many a grant idea were generated by my advisor and me in precisely this way (although not in the field of climate change)
This sits very well with Trenberth’s “reversed null hypothesis”.
I have thought about it and in the end, I have to agree that we should be trying to falsify the hypothesis that “mankind has no effect” on the environment. Humans are embedded in the environment, and we have been altering the environment for a long time. Could CO2 have risen as a result of the vast forests that have been cleared? All that carbon from those vast forests went into the atmosphere.
Similarly, the change in albedo and transpiration of land that was forest and is now crop land must make changes to weather patterns, and consistent changes to weather patterns are changes to climate.
I am very sceptical about the “measurements” of temperature both recent and ancient (via proxies etc) and about the importance of CO2 as a “forcer”, and I personally believe that the Sun and celestial forces are probably more important, but it seems vaguely arrogant to place our long human history “outside of the environment” when looking at what is going on.
Yes, follow Trenberth’s lead, because then we can get down to the finer hypotheses that allow us to truly discern the impact of an ever expanding population on the weather. What are we doing that does have an impact? Is that impact a problem or simply part of the never ending process of man using the environment to improve our living conditions?
JPeden says: As for me, I just can’t wait for the next Environmentalist engineered Catastrophic Conflagration resulting from the pathological obsession the alleged Environmentalists have with Forestation and the phobia they project against the human race; which usually manages to wipe out the very things the “Environmentalists” are allegedly trying to save; while, if the Conflagration occurs where I live, it will also burn down my house along with the adjacent Wilderness; but which would probably make it all worthwhile for the Environmentalists…
Exactly. The enviro religion is predicated on the Euro-centric Pristine Myth, that all land was “wilderness” before the Euro’s arrived. Designated wilderness, by law, is supposed to be:
“…primeval character and influence, without permanent improvements or human habitation, which is protected and managed so as to preserve its natural conditions and which… generally appears to have been affected primarily by the forces of nature, with the imprint of man’s work substantially unnoticeable.”
But the fact is nearly every acre (with the exception of mountain peaks) in North America (and all the other continents save Antarctica) has been trammeled and imprinted by thousands of years of human habitation and impact. Anthropogenic fire and anthropogenic predation have altered vegetation and wildlife populations enormously. All our old-growth forests, oak savannas, prairies, canebrakes, etc. arose via human manipulations.
There is no pristine virgin wilderness. It’s a myth, a pernicious myth that eliminates human stewardship and leads to catastrophic fires that leap across legal boundaries and cause enormous devastation including to cities. Or in the case of the putative Amazon “wilderness”, to poverty and usurpations inflicted on the residents of today.
That’s why I make the effort to educate climate realists on historical human impacts to the environment. We are all environmental realists at the core, whether the emphasis is climate, vegetation, ranching, farming, wildlife management, water management, property rights, etc. We need to use our scientific skepticism wisely, as a tool of the Scientific Method, and apply it across disciplines.
You might be surprised to find out that the environmental realists who study ancient human influences on the environment are your natural allies. They are skeptical of the enviro religion and attempt to apply rigorous science within their disciplines.
The CO2 Myth is also pernicious, and creeps into all branches of environmental science these days. But it’s presence does not necessarily mean that all environmental science is corrupt. We have to separate the wheat from the chaff. It troubles me to see kneejerk Ludditism and anti-science from this crowd, whom I want to respect as discerning students of environmental science.
Mike D. says:
January 24, 2011 at 12:01 pm
….Again, it is fair to question the effects of CO2, but it is not “skepticism” to reject whole cloth historical human influences on the environment. That’s denial.
————–
My query about anthropogenic forest fires and natural ones did not refer to the obvious differences in effects on the ground of intended and controlled fires vs unintended ones – it referred to the amount of CO2 generated, which was the point of your initial comment.
Nobody here denies that humans have an effect on the environment – eg that Roman copper smelting resulted in copper, arsenic and other particles in the Greenland ice cores, or that Chinese demand for carbon for ink resulted in severe deforestation for 200 miles around the Southern Song dynasty capital Hangzhou in the 10th century. The focus here, as always, is in regards to the proportion of CO2 generated by human activity in the past. If the environment is indeed that sensitive to the relatively minor perturbations of atmospheric CO2 caused by a world population that was a fraction of the current population size, why are we only witnessing supposed temperature increases that fall within the range of instrumentation error of historical measurements? See:
http://wattsupwiththat.com/2011/01/22/the-metrology-of-thermometers/
vigilantfish says: I have been reading WUWT more or less faithfully for two years and cannot recall any – repeat, any – sceptic basing his argument that deforestation is the cause of global warming.
Look harder. Here it is in this thread:
Surfer Dave says: Could CO2 have risen as a result of the vast forests that have been cleared? All that carbon from those vast forests went into the atmosphere.
There you go. It isn’t fossil fuel use; it’s the clearing of vast forests. Except that there are more forested acres today than at any other time during the Holocene.
We need to be scientific. That means in all scientific disciplines.
vigilantfish says: If the environment is indeed that sensitive to the relatively minor perturbations of atmospheric CO2 caused by a world population that was a fraction of the current population size, why are we only witnessing supposed temperature increases that fall within the range of instrumentation error of historical measurements?
You are conflating separate hypotheses, which I elucidated in my original post above.
1. Is it possible that a few human beings, far fewer than are alive today, could have altered the terrestrial carbon cycle?
Yes. Via continental-scale landscape burning.
2. And when those few human beings, say 50 million or so, were wiped out rather rapidly by exotic diseases, would the burning have moderated for awhile?
Yes. Leading to temporary reduction in atmospheric CO2.
3. Do relatively small perturbations in CO2 drive global temperatures?
No. I don’t think so. The sensitivity to CO2 is very small. But that does not negate or argue against the answers to #1 and #2.
But let’s go a step further:
3. Could a very few human beings armed with firesticks have altered the Earth’s albedo on a continental scale? Could the soot from millions of acres burned by humans every year have altered the albedo even in areas far from the actual fires?
There’s a very good possibility that’s exactly what happened.
4. Could alterations in the Earth’s terrestrial albedo affect global temperatures?
I think so, to some degree. What do you think?
Why not take this ridiculous line of argument back 60,000 years? The aborigines of Australia arrived on this land around 60,000 years ago and have been using fire in a number of ways (i.e. burning the bush to generate regrowth* and for land management purposes)… see, for example:
http://www.nma.gov.au/libraries/attachments/schools/resources/fire_in_australia/fire_in_australia_part_four/files/8296/fire_colour%20p4.pdf
We’d better start looking for signs of the Australian Aboriginal impact in the ice cores…
(Yes, there may have been a slight tone of sarcasm there…)
* For fun look up karrikinolides – interesting stuff that!
On another thread dealing with CO2, “Climate Sensitivity”, and mean global Temperature rise, I attempted to show that the available credible atmospheric CO2 record (measured) and the concurrent record of “Mean Global Temperature” presumably either surface or lower Troposphere (2 metres high ?) can not be proven to be related by any logarithmic function. I showed that for the change for 315 ppm CO2 in 1957/8 to the present 390.6 a ratio of 1.24, the slope difference between a linear curve fit, and a logarithmic curve fist is only about 105; yet this number is supposed to have a 3:1 range of values according to IPCC numbers (and typical climate data). Thus I argued that no credible experimental verification for the concept of a “Climate Sensitivity” implying a fixed Temperature rise for each doubling of atmospheric CO2 abundance, exists.
I have also stated in the past, that no theoretical basis for such a relationship exists either. Others have claimed that such a relationship derives from “Beer’s Law”, or the “Beer -Lambert Law”.
Under that name, the law seems to be a product of chemical texts.
In the field of Optics, and related issues such as Optical absorption, the law is commonly stated in its exponential form.
For a given thickness of an absorbing Optical medium, the Transmission is given by T = exp (-alpha.t) where T is the transmission (<1) and (t) is the thickness of the absorbing sample; alpha being the absorption coeffcient.
The concept is simple, If a given light source is transmitted say 90% (not counting surface reflection losses), in say 1.0 mm of a given optical glass or sample; that fraction is asumed to be linear with signal amplitude, so two such identical pieces of glass would transmit 90% of 90% or 81% of the total, and three pieces 72.9%. This can be checked by optical contacting several such pieces of glass, to remove the intermediate surface reflections, and measuring the combined transmission. This is Beers Law as it is applied to optical media.
Well why not to LWIR absorbing CO2 containing atmosphere.
Well for a start, Beer's Law is simply not valid; it violates the First Law of Thermodynamics; which says:- energy is conserved; it cannot be created or destroyed. (closed system)
So I input a beam of 1 Watt per square metre into my glass plate, and only 1/2 Watt per square metre comes out the other side; Exp (-alpha.t) = 0.5 for this sample. So half of my input energy simply vanished from the universe, and is no more. Well that's a bummer ! And a violation of the First Law.
Years ago when doing Photo-Luminescence experiments on epitaxial Gallium Arsenide Phosphide layers, we used to use a red Ne-Ne laser (632.8 nm wavelength) to excite epi layers that were 60/40 As/P and were supposed to emit red light peaking at about 645 nm; that being the "brightest " (visually) color. Longer wavelengths lost eye sensitivity, and shorter wavelengths were less power efficient as LEDs. The problem was that the laser wavelength was awfully close to the desired output and very much stronger, so it tended to corrupt the LED material photoluminescence spectrum.
So I got the bright idea (and the money) to replace the He-Ne laser with a nifty He-Cd laser emitting a 441.6 blue line; nowhere near the LED wavelength. So all I had to do was put a sharp cut Schott Optical glass color filter in between the specimen and the photomultiplier tube, and filter out the blue laser line. The filter specs said it would attenuate the blue laser by over five orders of magnitude. Well it did; not a jot of blue light was visible coming out of that filter; BUT, lookie there, the laser was apparently also emitting a yellow line, because in a dark room, I could see a yellow beam coming out of the filter, Well a yellow cut sharp filter took care of that yellow light and also the blue laser light; but now the laser was also emitting an orange light. No matter how I moved through the Schott Optical glass selection, I just kept getting large amounts of transmitted light at longer wavelengths. Moreover scanning the barefoot laser without the filter showed there was no yellow, or orange or red light being emitted from that laser. The problem is that those Schott sharp cut filter glasses all fluoresce, and the missing laser energy that was absorbed by the glass, is largely re-emitted at some longer wavelength; and eventually it would emerge as heat.
So the problem with Beer's law; is that it is not a complete description of what is going on. Yes it will attenuate via absorption the input signal; but the absorbed energy doesn't disappear like Beer's law suggests; it simply re-emerges at some other wavelengths and eventually even as heat.
Well that is exactly what CO2 in the atmospehre does. The CO2 can absorb radiant energy at several wavelength bands for example 2.7, and 4.0 and 15 microns; but it doesn't destroy that energy, it simply passes it on to the ordinary and much more plentiful atmospheric gases as thermal agitation of the molecules.
Well the problem is that in turn, that heated atmospehric gas, also emits a thermal radiation spectrum, and it typically is in the same wavelength range that the CO2 absorbed from the ground in the first place; and so CO2 can also absorb some of that spectrum, which will be partly transmitted upwards towards space, and partly downwards towards the earth surface. So multiple emissions, and thermalizations and re-emissions occur, and because of the Temperature and pressure lapse rate in the atmosphere, the upward path to escape is slightly favored over the downward path to the surface, because of changes in the Doppler and pressure broadening of the multiple spectral lines that make up the CO2 band spectrum.
So the GHG absorption of surface emitted LWIR energy does not simply follow Beer's law; which would mandate that energy be destroyed.
Consequently there is no theoretical basis either, for a belief in a logarithmic relationship between mean global surface or lower tropo Temperature, and the CO2 or other GHG abundance. In any case the very surface emission itself is a strong (4th power) function of surface Temperature, and that purportedly is the driving source that powers the CO2 absorption which warms the atmosphere.
So absent either experimental data or a theoretical model that favors a logarithmic relationship between CO2 abundance, and mean global Temperature; it would seem to me to be adviasble to stop teaching new generations of climatism 101 students, that unproven dogma. You can always tell when some newbie drops into WUWT (welcome one and all); they sooner or later will traipse out that Temperature changes with the log of the CO2. Well it doesn't and it isn't supposed to either.
You have to love the video’s color scheme. The whole world (including the deserts and arid mountain peaks) was green before we burned it up.
Well, I answered my own question above, about CO2 and the Little Ice Age. The Law Dome Antarctica ice core shows a decline of about 5 ppm atmospheric CO2 around 1600, and according to the Wiki article on the LIA, some researchers have attributed some LIA cooling to reforestation-induced CO2 uptake (to me the CO2 decline appears too little and too late, but YMMV).
If I’m reading the full article correctly, however, the authors don’t explicitly attribute LIA cooling to increased forest uptake of CO2, only mentioning the LIA once as occurring at about the same time as the population decline. The press release, however, explicitly makes the connection.
The article does seem to say that humans have added a +20-25 ppm “baseline” to natural CO2 levels, making this part of the Holocene “much warmer” than it would otherwise be. I think they’re giving too much credit to a small (hypothesized) increment of CO2, but again YMMV.
BTW, I didn’t realize it’s news that agricultural productivity has risen through human history; it seems pretty obvious on the face of it.
Mike D. says:
January 24, 2011 at 4:47 pm
My response to your questions is not in order.
2. And when those few human beings, say 50 million or so, were wiped out rather rapidly by exotic diseases, would the burning have moderated for awhile?
Yes. Leading to temporary reduction in atmospheric CO2.
I hate to resort to Wikipedia, but since I taught this stuff I know based on ‘other’ authority that Homo sapiens and Homo Neandertalis , the first species to use fire, emerged along the evolutionary tree between 2 and 1 million years ago. Therefore any ash from 50 million years ago, the period of the Paleocene-Eocene Thermal Maximum, would have been entirely naturally generated. I suppose we can leave the question of whether human beings are a part of nature or not for another day.
http://en.wikipedia.org/wiki/Timeline_of_human_evolution
1. Is it possible that a few human beings, far fewer than are alive today, could have altered the terrestrial carbon cycle?
Yes. Via continental-scale landscape burning.
I hope not – I doubt that the very few human beings in ancient periods could burn forests on a continental scale. They must have localized fires as much as possible, because forest fires are deadly if out of control. I wonder if our human ancestors were adventitious and used areas already burned by natural fires for their first forays into agriculture, which occurred between 12,000 and 10,000 B.C. UNESCO, which is not noted for its accuracy in any estimate I have ever seen (it tends to exaggerate, in my experience) estimates the world population at 5 million. Of that population, the vast majority was likely hunter-gatherers around 10,000 B.C. – agriculture came later in the Americas and China. Hunter-gatherers do not, to my knowledge, indulge in burning landscapes to create arable land. I know that the North American Indians did so to improve hunting territory before contact, but they also practiced agriculture on varying scales, depending on tribe and location. I doubt that the scale of burning by humans in any period would be great enough to show up as significantly different amounts of ash of CO in ice cores from the normal background. Indeed that was the conclusion (Sort of) of researchers who studied evidence of biomass burning in the Southern Hemisphere over the past 650 years.
http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&SESSION=&RCN=32884
“In fact, the ice core revealed that total atmospheric CO concentrations dwindled by around 25% between the mid 1300s and the 1600s, before recovering completely by the late 1800s. Meanwhile, studies of the oxygen isotope signatures in the CO show that biomass burning varied widely over the centuries.”
“‘While [our result] is consistent with previous findings, there is still a common misperception that biomass burning rates are much higher today than in the past,’ noted Professor Mak. ‘This is significant since many researchers assume that human-induced biomass burning is much greater than “naturally” occurring biomass burning. While this may still be the case – there were people around in the 18th century – the fact that today’s rates of [southern hemisphere] biomass burning seem to be lower than one to two centuries ago calls for a re-evaluation of sources.”
3. Do relatively small perturbations in CO2 drive global temperatures?
No. I don’t think so. The sensitivity to CO2 is very small. But that does not negate or argue against the answers to #1 and #2.
If the small but growing populations of the past increased the burn levels that in many periods are indistinguishable from natural burns then it is unlikely that human activities alone altered the CO2 levels. You are arguing against the CAGW argument here, as their standard argument is that CO2 alone is responsible for the supposed climate anomalies of the past 60 years. It appears that even they don’t think human industrial and domestic combustion was significant enough to affect the climate prior to 1950. Why do you want to make this argument?
If climate is more Co2- sensitive than even the standard CAGW theories argue for, which appears to be the argument put forth by the authors of “Holocene carbon emissions as a result of anthropogenic land cover change” then it would mean that the CAGW arguments that our climate has progressed naturally and normally until the last 60 years, when human CO2 took over and started global warming, are meaningless (which they are, anyway). It would mean that the human signal has been in the past indistinguishable from the natural signal, and that CO2 has not been a significant driver of climate change, as even when CO2 levels were increasing, the temperatures dropped (eg. Little Ice Age) — see “Southern Hemisphere” article cited above.
But let’s go a step further:
3. Could a very few human beings armed with firesticks have altered the Earth’s albedo on a continental scale? Could the soot from millions of acres burned by humans every year have altered the albedo even in areas far from the actual fires?
There’s a very good possibility that’s exactly what happened.
See answer to your question #2 above. I doubt there are any studies on the extent of annual burning, although it was practiced mainly in the tropics in swidden (slash and burn) farming in Asia. I have just realized I have no knowledge of the farming practices, if such existed — beyond animal herding — of sub-Saharan Africans. In the northern temperate climates, rotational burns would not have to be frequent, as it would take longer for forests to grow back, and the aim was to create glades and expanses of shrublands to encourage deer and other prey animal populations. In Europe, the wood was most likely usually cut down for fuel and building, and swidden farming was mostly practiced in Scandinavia and Eastern Europe, where the fallow periods between raising crops and burning down the growth that results from the fallow period was generally from 40 to 60 years. There are just too many variables to easily answer your question, but one would think that if the amounts of soot were significant enough to affect the albedo, then they would show up in ice cores. Also, probably most of the burning in the northern hemisphere would occur in the spring – and the ashes would just get washed into the soil from rainfall, thus not affecting snowcover -which is what I assume you mean in asking this question, rather than cloud albedo — significantly.
4. Could alterations in the Earth’s terrestrial albedo affect global temperatures?
I think so, to some degree. What do you think?
Yes.
Whew – this was an attempt to begin to rise to the Moshpit’s standards, and it did take awhile. However, I am not an expert on any of this stuff. Some of it just crosses my path in studying the history of technology.
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You can’t help but feel sorry for these guys. The money to do this kind of useless research is definitely drying up. Reading this, I have serious doubts if these people will be able to feed themselves or their families when access to the government trough is shut off.
On Small Problem for their timelines…
We don’t really have a clue how far back the history of civilization goes. We’ve found nicely carved monumental scale rocks from about 12,000 BP. Yes, during the tail end of the last ice age….
So, how you gonna deal with the fact that Canada was under ICE when people were busy building civilization and cooking meat on wood fires and cutting down trees?
http://chiefio.wordpress.com/2011/01/06/gobekli-tepe/
Did all the CO2 sequestered in the new forests as the Ice Sheet retreated result in sudden global cooling? Oh, wait…
Also, minor problem… it was warmer 6000 years ago than now. So, with all this human induced tree destruction, things have gotten colder? Oh dear…
That’s the problem of trying to do a non-fit match of an increasing thrend (CO2) to a very long term decreasing trend with major cyclical ripples in it. You can get some things to match, the the total never can line up right.
What excellent proof CO2 does not make global warming. So carbon emissions were rose during the warm periods—the Roman Warming and the Medieval Warming. Just as now.
If CO2 is the cause of GW then how come the cold periods happened and why were they so cold? CO2? The whole globe couldn’t have a temperature inversion as in Frost Falls.
Perhaps the cold periods had something to do with the Wolf Minimum (1280-1350) and the Sporer Minumum (1460-1550) and the Maunder Minimum (1645-1715). The weather was so bad during The Little Ice Age, the Church of Rome authorised witch hunts—after all, the continuous bad weather had to be caused by “Satan’s agents on Earth.”
Dr. Landscheidt thinks we may be heading for another Maunder Minimum about 2030: see New Little Ice Age instead of Global Warming.
Cheerful article.
@Jimbo: Brilliant! Excellent! Magnifico! Thiiis is the ooone! 🙂
“I doubt that the very few human beings in ancient periods could burn forests on a continental scale.”
Australian Aborigines changed the entire ecosystem, continent-wide, leaving only fire-friendly trees like eucalypts in a previously much more diverse ancient Australia forest spread. Pines were wiped out eg.
Angry Exile says:
January 24, 2011 at 9:14 am
I’m guessing the Roman and Medieval Warm Periods are about to be rehabilitated once they think they can sell them as being anthropogenic. Nero drove a Volvo while Rome burned, you know?
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Nero was not much of a risk-averse, safety-first kind of guy. I’m thinking a Hummer.
This may have been pointed out already, I’ve not time to read the comments now, but is it not odd how over the past 8K years, humans have ever increased CO2 emissions, yet the climate has cooled over the same period? WUWT?
http://i45.tinypic.com/2yo1hsy.jpg (from some crummy US gov’t science website)
Mike D. says:
January 24, 2011 at 2:20 pm
vigilantfish says: …how do you distinguish between the effects of anthropogenic and natural forest fires?
Anthropogenic fires were frequent, seasonal, and purposeful. They were set in specific locations, including lowlands. Purposeful landscape fire has been the key way that humanity has altered ecosystems during our entire existence, and were set for survival and sustenance reasons. Anthropogenic fires induced prairies, savannas, and open and park-like forests. Frequent burning eliminated most trees, but those that survived lived to very old ages.
Lightning fires are infrequent, generally occur during summer (hot dry weather), and generally start on ridgetops or other high places. Infrequency leads to biomass build-up, and lightning fires tend to be more severe because of the larger fuel loadings. Without frequent human fires to reduce fuels, lightning fires tend to be stand-replacing; that is, they kill all the trees. No trees grow to very old ages. Often fire-type brush replaces forests and prairies.
For example, many areas of the Southwest and California were subjected to anthropogenic fire for millennia. Those led to the open, park-like forests of old-growth ponderosa pine, punctuated by open meadows, encountered by the early Euro-American explorers to that region. But in the absence of the former frequent, tending fires set by the indigenous residents, biomass accumulated. Modern fires in those areas kill all the trees and convert the burned areas to chaparral.
Without frequent anthropogenic fire, forest development pathways are altered. Short-lived thickets of trees and brushfields result. Old-growth trees do not develop. Shade-tolerant species such as true firs tend to dominate, and shade-intolerants such as ponderosa pine are all but eliminated. Meadow and prairie areas become overgrown with brush and small trees. Savannas are invaded by trees and the former dominant species die out.
It may not be obvious to all, but a trained eye can readily detect the differences between anthropogenic and lightning fire regimes.
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Honestly, I don’t know where to begin after reading this gobbledygook. I can only speak about Australia, a place where devastating bushfires are almost an annual event, and where uber-fires which kill hundreds of people in settled areas have happened more than once in 210 years of European occupation of this sparsely populated continent.
Before, and since, European settlement, the two sources of fire were anthropogenic (Aboriginal fires to clear land for hunting) and natural (lightning strikes and possibly other sources of combustion). The man-made component was limited by the low number of indigenous people and their small geographical range. They tended to stay in the same area and burn the same area, over thousands of years.
The naturally caused fires were, and are, more frequent in the high country. Yet, it is there that the oldest trees are found. The predominant species, eucalypts, are not only adapted to fire, many of them require it to reproduce – and that goes for many of the other species in fire prone areas as well. The heat of a bushfire opens the seed pods, which can sit on the forest floor for decades.
After a big fire, many of the old trees, which look dead, start resprouting leaves within weeks.
Sport, you and your ‘trained eye’ know nothing about fire ecology in Australia. Perhaps your views are more valid for the rest of the world – I will leave that to others who know something about it. But, let me stress again the size of the Australian continent, and the tiny number of people (less than 500,000 pre European settlement about 200 years ago). We are now up to 22 million, and like Californians, have little control over naturally occurring bushfires.
Mike D. says:
January 24, 2011 at 2:20 pm
Actually, lightening strike forest fires aren’t unique to ridges. Quite a few in Australia are not much above sea-level. One fire, at a neighbour’s property, was caused by lightening, on river flats. Luckily it was spotted and dealt with in time to save the neighbour’s home and shedding, not to mention cattle.
I really would like to refer to the speech made by President Vaclav Klaus in october 2010 and what he said about climate change.
So in short, the climate change doctrine and the environmental movement are the new Communism and the environmentalist’s want a human empty planet.
That’s exactly the crap we’re going to hear much more about the next years.
Better to ignore it or provide every wacko who comes up with such ideas with a gun so they can shoot themselves.
We have found a clear indication that Europe is preparing for energy rationing and even prohibition. President Klaus has warned us about this:
http://www.europol.europa.eu/publications/Scenarios/Organised_crime_in_energy_supply.pdf
http://wattsupwiththat.com/2010/10/20/president-vaclav-havel-climate-control-or-freedom/
One thing I do not see having been raised above is the use of fire for hunting. As well as driving herds of animals off cliffs, fire were ignited up wind of animals with hunters downwind waiting for the fleeing animals.
The main take-away I get after reading this is “humans=evil”. If, as their premise suggests, even medieval man is responsible for such drastic climate change as MWP and LIA, the ONLY remaining logical method to prevent anthropogenic climate change of any sort would be the extermination of all mankind.
This is actually a good study as it reveals many things. The first thing it reveals is the ignorance of the authors. In order to accept their hypothesis, one has to agree that man is “extra-terrestrial” and therefore any actions man has on the environment is against nature or natural cycles. I find this hypothesis fascinating as I am a big fan of Arthur C. Clarke and “2001: A Space Odyssey”.
The second revelation revealed is that this study now opens the door for the AGW group to admit to the existance of the MWP. Something that a “vast consensus” of scientists have agreed for a long time really did exist. Now they can admit to it, without destroying their premise. Of course the Hockey stick will have to undergo a minor revision, but I am sure we can all start talking about the “Kayak Oar” that will replace it.
johanna;
Eucalypts are unique, as is the environment they’re suited for. Other areas that make the mistake of transplanting them learn that fast.
Just my 2c worth. Dr Pielke Snr has been talking about Land Use Change and it’s effect on (at least local) climate. Disregarding CO2 issues completely, he has written that UHI, change of land from forest or, I believe, prairie to farmed land has distinct impact on the environment. Of course he has been pooh-poohed by the ‘Team’, so doesn’t this actually support his hypothesis? Cetainly supports it better than any CO2 change as climate change mediator.