Study claims: Global warming induced by “Ancient Farmers” may have staved off ice-age

Ancient farmers spared us from glaciers but profoundly changed Earth’s climate

UNIVERSITY OF WISCONSIN-MADISON

MADISON – Millenia ago, ancient farmers cleared land to plant wheat and maize, potatoes and squash. They flooded fields to grow rice. They began to raise livestock. And unknowingly, they may have been fundamentally altering the climate of the Earth.

A study published in the journal Scientific Reports provides new evidence that ancient farming practices led to a rise in the atmospheric emission of the heat-trapping gases carbon dioxide and methane – a rise that has continued since, unlike the trend at any other time in Earth’s geologic history.

It also shows that without this human influence, by the start of the Industrial Revolution, the planet would have likely been headed for another ice age.

“Had it not been for early agriculture, Earth’s climate would be significantly cooler today,” says lead author, Stephen Vavrus, a senior scientist in the University of Wisconsin-Madison Center for Climatic Research in the Nelson Institute for Environmental Studies. “The ancient roots of farming produced enough carbon dioxide and methane to influence the environment.”

The findings are based on a sophisticated climate model that compared our current geologic time period, called the Holocene, to a similar period 800,000 years ago. They show the earlier period, called MIS19, was already 2.3 degrees Fahrenheit (1.3 C) cooler globally than the equivalent time in the Holocene, around the year 1850. This effect would have been more pronounced in the Arctic, where the model shows temperatures were 9-to-11 degrees Fahrenheit colder.

Using climate reconstructions based on ice core data, the model also showed that while MIS19 and the Holocene began with similar carbon dioxide and methane concentrations, MIS19 saw an overall steady drop in both greenhouse gases while the Holocene reversed direction 5,000 years ago, hitting peak concentrations of both gases by 1850. The researchers deliberately cut the model off at the start of the Industrial Revolution, when sources of greenhouse gas emissions became much more numerous.

For most of Earth’s 4.5-billion-year history, its climate has largely been determined by a natural phenomenon known as Milankovitch cycles, periodic changes in the shape of Earth’s orbit around the sun – which fluctuates from more circular to more elliptical – and the way Earth wobbles and tilts on its axis.

Astronomers can calculate these cycles with precision and they can also be observed in the geological and paleoecological records. The cycles influence where sunlight is distributed on the planet, leading to cold glacial periods or ice ages as well as warmer interglacial periods. The last glacial period ended roughly 12,000 years ago and Earth has since been in the Holocene, an interglacial period. The Holocene and MIS19 share similar Milankovitch cycle characteristics.

All other interglacial periods scientists have studied, including MIS19, begin with higher levels of carbon dioxide and methane, which gradually decline over thousands of years, leading to cooler conditions on Earth. Ultimately, conditions cool to a point where glaciation begins.

Fifteen years ago, study co-author William Ruddiman, emeritus paleoclimatologist at the University of Virginia, was studying methane and carbon dioxide trapped in Antarctic ice going back tens of thousands of years when he observed something unusual.

“I noticed that methane concentrations started decreasing about 10,000 years ago and then reversed direction 5,000 years ago and I also noted that carbon dioxide also started decreasing around 10,000 years ago and then reversed direction about 7,000 years ago,” says Ruddiman. “It alerted me that there was something strange about this interglaciation … the only explanation I could come up with is early agriculture, which put greenhouse gases into the atmosphere and that was the start of it all.”

Ruddiman named this the Early Anthropogenic Hypothesis and a number of studies have recently emerged suggesting its plausibility. They document widespread deforestation in Europe beginning around 6,000 years ago, the emergence of large farming settlements in China 7,000 years ago, plus the spread of rice paddies – robust sources of methane –  throughout northeast Asia by 5,000 years ago.

Ruddiman and others have also been working to test the hypothesis. He has collaborated with Vavrus, an expert in climate modeling, for many years and their newest study used the Community Climate System Model 4 to simulate what would have happened in the Holocene if not for human agriculture. It offers higher resolution than climate models the team has used previously and provides new insights into the physical processes underlying glaciation.

For instance, in a simulation of MIS19, glaciation began with strong cooling in the Arctic and subsequent expansion of sea ice and year-round snow cover. The model showed this beginning in an area known as the Canadian archipelago, which includes Baffin Island, where summer temperatures dropped by more than 5 degrees Fahrenheit.

“This is consistent with geologic evidence,” says Vavrus.

Today, the Arctic is warming. But before we laud ancient farmers for staving off a global chill, Vavrus and Ruddiman caution that this fundamental alteration to our global climate cycle is uncharted territory.

“People say (our work) sends the wrong message, but science takes you where it takes you,” says Vavrus. “Things are so far out of whack now, the last 2,000 years have been so outside the natural bounds, we are so far beyond what is natural.”

The reality is, we don’t know what happens next. And glaciers have long served as Earth’s predominant source of freshwater.

“There is pretty good agreement in the community of climate scientists that we have stopped the next glaciation for the long, foreseeable future, because even if we stopped putting carbon dioxide into the atmosphere, what we have now would linger,” says Ruddiman. “The phenomenal fact is, we have maybe stopped the major cycle of Earth’s climate and we are stuck in a warmer and warmer and warmer interglacial.”

###

h/t to WUWT reader Chris C.

The paper: https://www.nature.com/articles/s41598-018-28419-5

Glacial Inception in Marine Isotope Stage 19: An Orbital Analog for a Natural Holocene Climate

Abstract

The Marine Isotope Stage 19c (MIS19c) interglaciation is regarded as the best orbital analog to the Holocene. The close of MIS19c (~777,000 years ago) thus serves as a proxy for a contemporary climate system unaffected by humans. Our global climate model simulation driven by orbital parameters and observed greenhouse gas concentrations at the end of MIS19c is 1.3 K colder than the reference pre-industrial climate of the late Holocene (year 1850). Much stronger cooling occurs in the Arctic, where sea ice and year-round snow cover expand considerably. Inferred regions of glaciation develop across northeastern Siberia, northwestern North America, and the Canadian Archipelago. These locations are consistent with evidence from past glacial inceptions and are favored by atmospheric circulation changes that reduce ablation of snow cover and increase accumulation of snowfall. Particularly large buildups of snow depth coincide with presumed glacial nucleation sites, including Baffin Island and the northeast Canadian Archipelago. These findings suggest that present-day climate would be susceptible to glacial inception if greenhouse gas concentrations were as low as they were at the end of MIS 19c.

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171 thoughts on “Study claims: Global warming induced by “Ancient Farmers” may have staved off ice-age

  1. “Things are so far out of whack now, the last 2,000 years have been so outside the natural bounds, we are so far beyond what is natural.” If it’s not natural beginning 2000 years ago, then what is it? These so-called “objective” scientists are so afraid to state the truth about climate that they are speaking gibberish.

    • Are the climastrologists now moving from blaming the industrial revolution to blaming agriculture? I guess it does fit some of the yearnings of greenies to return us to a hunter-gather subsistence as the only way to refrain from man interfering with the weather.

      • The Neolithic farmers may have burnt down the forests, but the Paleolithic hunter-gatherers killed off the global-warming, methane-emitting flatulent megafuana.

        Whatever happened, it was bad and all the fault of evil humans.

        • Hmmm Kemosabe …
          Warm Climate BAD???
          Mile thick Glacial Ice Field over North America GOOD???
          White Man is definitely CRAZY!!!

          • A contrary proposal, for you consideration:

            https://wattsupwiththat.com/2018/07/17/oddly-quiet-sun-3-weeks-without-sunspots/#comment-2407423

            “The sun has been blank for 21 straight days–a remarkable 3 weeks without sunspots.”

            I blame global warming! When I was a boy, weather was gentler. Summers were warm but not too hot, winters were cool but not too cold. The wind blew soft upon my face. Then white man come – kill our women, rape our buffalo, burn our fossil fuels, make weather crazy, disrupt our casino business! Oops! Sorry, I was channeling my inner Amerind.

            In 2002, I predicted that natural global cooling would commence by 2020 to 2030, in an article published 1Sept2002 in the Calgary Herald. I am now leaning closer to 2020 for cooling to start, possibly even earlier. I hope to be wrong. Humanity and the environment suffer during cooling periods.

            I suggest that it is long past time for society to prepare for the possibility of moderate global cooling. This would involve:
            1. Strengthening of electrical grid systems, currently destabilized by costly, intermittent green energy schemes;
            2. Reduce energy costs by all practical means.
            3. Development of contingency plans for food production and storage, should early frosts impact harvests;
            4. Develop contingency plans should vital services be disrupted by cold weather events – such as the failure of grid power systems, blocking of transportation corridors, etc.
            5. Improve home insulation and home construction standards.

            The current mania over (fictitious) catastrophic global warming has actually brewed the “perfect storm” – energy systems have been foolishly compromised and energy costs have been needlessly increased, to fight imaginary warming in a (probably) cooling world.

            I suggest this is the prudent path for Western societies to follow. It has no downside, even if global cooling does not occur, and considerable upside if moderate cooling does commence.

            I thank you for giving this modest proposal your consideration.

            My heart soars like an eagle, my son!

            Regards to all, Allan

          • Allan writes (to much praise): “In 2002, I predicted that natural global cooling would commence by 2020 to 2030 …”

            Belief in such prophesy is a form of religion, not science.

            We had a period of natural cooling from 1950-1970, when GHGs were rising very slowly. We had another period of “natural cooling” from 1998-2013, but that was barely able to maintain a constant temperature. Even if the sun were responsible for the LIA, it produced less than 1 K of cooling. Prophecies about another LIA – even if they came true – certainly won’t save us from the much larger warming projected by AOGCMs. Fortunately, AOGCMs aren’t reliable science, and the ECS they predict depends on how they are parameterized. There is plenty of room for skepticism here.

            Meanwhile, there is no doubt that rising GHGs – as you undoubtably recognize – reduce the rate of radiative cooling to space and that the law of conservation of energy demands that this produce some warming – which is at times obscured by unforced variability in climate.

          • Unforced variability seems to have had a~ 60 year cycle at least over the past two centuries. Alan is simply invoking it continues. The warming half of the cycle~30yrs peaked out on schedule ~at the turn of the millennium and we got a Pause, much resisted and finally Karlized out of existence because we couldnt allow CO2 to be weaker than Nat Var. now could we? Also this Pause occurred despite an increase in CO2 of over 30% during its reign.

            The good news, he’s doubled down on his forecast so he has the cojones to have it judged within a couple of dozen months, nothe endless goal post shifting with deadlines missed over the past 40yrs and projections off by 300% and the catastrophe rescheduled for after we’ve all died off. If the performance of the Team is judged good by your lights, you are a most accommodating fellow indeed.

            Oh and look up the LeChatelier principle on wiki to see how the laws of thermodynamics are NOT violated. While you are at it, may I suggest a thorough study of enthalpy, energy, work heat and temperature since we are talking about thermo. Maybe elementary botany too. Energy from the sun is currently being stored in the Great Greening of the planet, an endothermic (cooling) process that is irrelevant to your linear dependency on radiative physics and its certainty of raising temperature. There is a lot of comfort I guess in being part of the 97% but little certainty.

          • By conservation of energy, he is just stating that for a system to be in balance, the energy in must equal the energy out.

          • So far, those times that warming from rising GHG’s is obscured by natural variability could just happen to coincide with all the times we have data. But eventually, it may show up as the dominant factor. According to Cook et al 2013, almost 2% of published papers with an opinion on the cause of warming agree this is already the case.

          • Frank wrote:
            “Prophecies about another LIA – even if they came true – certainly won’t save us from the much larger warming projected by AOGCMs.”

            Frank, with respect:
            If you believe your above statement, then you must believe that manmade global warming will overwhelm natural variability and the world will get warmer. I disagree. I think that natural variability will overwhelm CO2-driven warming and the world will become cooler, probably like the moderate cooling that started circa 1940 and ended with the Great Pacific Climate Shift in 1977.

            I really hope you are correct and I am wrong – but I doubt it!

            Here is why I hope you are correct:

            1. Climate Sensitivity to Increasing Atmospheric CO2 is Low – Only About 1C/doubling

            Christy and McNider (2017) estimate climate sensitivity at 1.1C/doubling for UAH Lower Tropospheric (LT) temperatures.

            Lewis and Curry (2018) estimate climate sensitivity at 1.6C/doubling for ECS and 1.3C/doubling for TCR, using Hatcrut4 surface temperatures (ST). These surface temperatures probably have a significant warming bias due to poor siting of measurements, UHI effects, other land use changes, etc.

            Both analyses are “full-earth-scale”, which have the least room for errors.

            Both are “UPPER BOUND” estimates of sensitivity, derived by assuming that ~ALL* warming is due to increasing atmospheric CO2. It is possible, in fact probable, that less of the warming is driven by CO2, and most of it is natural variation.
            (*Note – Christy and McNider make allowance for major volcanoes El Chichon in 1982 and Pinatubo in 1991+)

            The slightly higher sensitivity values in Curry and Lewis are due to the higher warming estimates of Hadcrut4 surface temperatures versus UAH LT temperatures.

            Practically speaking, however, these sensitivity estimates are similar, about 1C/doubling. and are far too low to support any runaway or catastrophic manmade global warming.

            Higher estimates of climate sensitivity have no credibility. There is no real global warming crisis.

            Increased atmospheric CO2, from whatever cause will at most drive minor, net-beneficial global warming, and significantly increased plant and crop yields.

            Conclusion: The total impact if increasing atmospheric CO2 is hugely beneficial to humanity and the environment. Any scientist or politician who contradicts this statement is destructive, acting against the well-being of humanity and the environment.

            2. Earth is Clearly Colder-Than-Optimum for Humanity and the Environment

            Earth is significantly colder-than-optimum for humanity and the environment. Twenty times more people die from cold than die from heat – about 2 million Excess Winter Deaths every year worldwide.*

            In the USA, Excess Winter Deaths average about one hundred thousand souls per year, equivalent to two 9-11’s per week for 17 weeks every year!

            Even more startling is the preliminary estimate of Excess Winter Deaths in the UK – about 48,000 this past winter! The UK suffered about HALF the average annual Excess Winter Deaths of the USA, but the UK has only ONE-FIFTH the USA’s population. High energy prices, or “Heat or Eat” as it is termed in the UK, is becoming a significant cause of premature deaths of the elderly and the poor.

            Anti-fracking groups in the UK, many of whom are phony-green Marxist fronts, have cost Britain dearly in lost billions of pounds sterling and hundreds of thousands of needlessly-shortened lives.

            Conclusion: Excess Winter Deaths are increased by foolish green energy policies like mandatory wind and solar power in the grid, which produce little useful (dispatchable) energy and drive up energy costs, preferentially killing off the elderly and the poor.

            A few more thoughts:

            3. Global warming Alarmism is Anti-Human and Anti-Environment

            False global warming alarmism causes the enormous human suffering and death in the developing world, where green fanaticism has prevented the installation of cheap, reliable, abundant energy systems.

            This is frustrating, because some of us knew that the global warming scam was false nonsense as early as ~1985, based on the evidence available then. Since that time, the evidence against global warming fraud has grown more and more credible, and yet this multi-trillion dollar-per-year scam continues.

            We published in 2002 that the global warming crisis did not exist in reality, and that green energy schemes would not be adequate to replace fossil fuels. Both these statements are now proven to be correct, for anyone who objectively examines the evidence.

            Conclusion: Anyone who continues to support global warming alarmism and schemes to abate fossil fuels is seriously deluded at best, and more correctly is guilty of crimes against humanity. The overwhelming evidence is that increasing atmospheric CO2 will lead to improved plant and crop growth, and any resulting warming will be mild and beneficial.

            4. Green Extremists are the Great Killers of Our Age

            Green extremism started with the banning of DDT from ~1972 to ~2002. The ban on DDT DOUBLED the number of deaths from malaria, more than half of which were children age 4 and under whose deaths peaked at almost 1 million per year – just babies –and half of these deaths were easily preventable.

            Add to this the numbers of deaths due to the global warming scam and the “phony war” against increasing atmospheric CO2 and the total green death toll is in the tens of millions, similar to the number of needless deaths caused in the 20th Century by leftist icons Hitler, Stalin or Mao.

            Conclusion: Leftist Green extremists are the greatest killers of our time – rivaling the death tolls of the greatest sociopathic killers of the 20th Century. Those who fail to learn from history are condemned to repeat it.

            Regrets, Allan
            _______________________________

            * Reference:
            COLD WEATHER KILLS 20 TIMES AS MANY PEOPLE AS HOT WEATHER
            By Joseph D’Aleo and Allan MacRae, September 4, 2015
            https://friendsofsciencecalgary.files.wordpress.com/2015/09/cold-weather-kills-macrae-daleo-4sept2015-final.pdf

          • Lastly, Allan raised the question of the optimal temperature for the planet.

            Who knows? The economists seem to think the 20th-century’s rise of 1 K has brought us to near optimum. The fanatic Green’s want to limit that rise to 1.5 K. I would be politer, but your characterization of them as Green Killers isn’t absurd.

            Some simple principles: Change is usually costly; it certainly puts stress on both the environment and people. People in temperate zones seem to prefer a little warmer, but the temperate zones are far more economically productive today. Productivity is good, affluence and technology trump climate every day. Texas is 10 K warmer on the average than North Dakota. Spend money on growing our economy and improving technology first.

            Sea level rose 120 m and temperature about 6 K with the end of the last ice age. It is stupid to expect rising temperature to not have a major effect on sea level. As ice caps retreat poleward, that 20 m/K average change at equilibrium will undoubtably shrink, but it won’t go to zero. The more important question is how fast will the change occur. The GIS survived a couple of millennia of the Holocene climate optimum. No one should care if Arctic sea ice disappears in for a month or two in late summer. If humanity can’t figure out how to keep Antarctica from melting in a few millennia, technological progress will have ceased and we will be facing far more serious problems.

            Anyone who thinks developing countries are going to limit their CO2 emissions needs to think again. Like China, they think (correctly) that cheap energy is going to improve their standard of living, and their richer descendants will be able deal with the resulting climate change. Anyone who thinks the developed world is going to pay the developing world not to emit CO2 also needs to think again. If ECS is high, I’d bet on technology over human nature. We won’t burn that coal if there is a cheaper answer. More and safer nuclear power can help a great deal.

          • Frank,

            The Holocene Optimum was globally perhaps two to four degrees C warmer than now. More than that in polar regions, of course, less in temperate zones and less yet in the tropics.

            That means three to five degrees warmer than AD 1850. The higher end of that range would produce more sea level rise, which need not be disastrous, but could be expensive. But I’d agree that given where so many cities are now, the warmest possible range of the HCO might not today be optimal.

            But it’s impossible for CO2 to achieve that much warming, especially as burning all fossil fuels over the next century or two would at most boost photosynthesis feed stock in the air to only around 600 ppm, still far below optimum for C3 plants.

            Earth’s long-term temperature is still falling. Sooner or later, another glacial advance is coming. For the sake of the planet, tens of thousands of years would be better than mere thousands. IMO hundreds aren’t in the cards.

          • John: I respectfully suggest that your Holocene Optimum temperature data (+2 to +4 degC higher than today) is for the Arctic, not the whole global. Arctic temperature is relevant to melting of the GIS. Trees on both continents grew on the shores of the Arctic Ocean at this time and orbital mechanics provided the greatest irradiation during Arctic summer. (Today the greatest irradiation is during Antarctic summer). Ice cores are problematic temperature proxies for the whole globe because they are local proxies, either Arctic or Antarctic. There are huge differences between Arctic and Antarctic during the last termination and Greenland showed enormous temperature spikes during the last ice age.

            The best global temperature proxy is a composite of ocean sediment cores from a variety of locations. Unfortunately, such cores don’t have annual resolution (50 year average temperature is typical) and dating can be problematic. Ocean temperatures less than land and land variation is greatest at the poles. Marcott (2013) published the first reconstruction of Holocene ocean temperature. Steve McIntyre correctly poked quite a few holes in the recent portion (blade) of this hockey stick (which I recommend ignoring), but the Holocene Climate Optimum may be reasonable. Marcott’s work says ocean temperatures fell 0.5 K from the HCO peak to the LIA and have recovered since. Many reconstruction methods suppress the dynamic range of changes, so directly comparing the red and blue curves might be problematic. However, I think this is more reliable than the numbers you present above, without references.

            https://s-media-cache-ak0.pinimg.com/736x/72/9a/e5/729ae5833429eba7a17d8abc61d2597d.jpg

          • Hi Gary,

            The Calgary Herald Editorial Board has probably since been dominated by warmist minions, and the article would not get published.

            The warmist minions are a strange breed – they typically have a soft degree in the humanities from some junior college, specializing in English, Sociology, Psychology, Gender Studies, Witchcraft, etc. and have no clue about the Scientific Method.

            Still, the typical warmist minion will scream their belief in manmade global warming catastrophism and climate change hysteria – all based on what they heard from their idiot friends on Facebook and Twitter or over a “Venti, Soy, Semi-Caf, No Foam Latte” at Starbucks – and they will verbally or physically assault anyone who disagrees with their imbecilic position.

            The following brief treatise on the Scientific Method is presented for the benefit of all the warmist minions out there. If they read it, it will be the most scholarly work they have done on global warming and climate change in their entire lives – but even this 3-minute treatise will probably be too long and complicated for them.

            Best personal regards, Allan
            _______________________________

            ON THE SCIENTIFIC METHOD:

            Richard Feynman on The Scientific Method (1964)
            https://youtu.be/0KmimDq4cSU

            at 0:39/9:58: ”If it disagrees with experiment, it’s wrong.”
            At 4:01/9:58: “You can always prove any definite theory wrong.”
            At 6:09/9:58: “By having a vague theory, it’s possible to get either result.”

            THIS IS THE “CLIMATE CHANGE” ALARMISTS’ DECEITFUL STRATEGY:
            “By having a vague theory, it’s possible to get either result.” – Richard Feynman
            “A theory that is not refutable by any conceivable event is non-scientific.” – Karl Popper.

            The “Climate Change” hypothesis is so vague, and changes so often, that it is not falsifiable and not scientific. It should be rejected as unscientific nonsense.

            The “Manmade Runaway Global Warming” hypothesis is at least falsifiable, and IT HAS BEEN ADEQUATELY FALSIFIED:

            1. By the ~37-year global cooling period from ~1940 to 1977;

            2. By “the Pause”, when temperature did not significantly increase for almost two decades, despite increasing atmospheric CO2 concentrations;

            3. By the absence of runaway global warming over geologic time, despite much higher CO2 concentrations;

            4. By the fact that equatorial Pacific sea surface temperatures have not increased significantly since ~1982, and corresponding air temperatures increased largely due to the dissipation of the cooling impact of two century-scale volcanoes – El Chichon in 1982 and Pinatubo in 1991+;

            5. By the fact that CO2 trends lags temperature trends by ~9 months in the modern data record, and by ~~800 years in the ice core record, and the undeniable reality that the future cannot cause the past.

            Global warming and climate change alarmism, in a few decades at most, will be regarded as a mass delusion, and its leaders and its followers will be widely regarded as scoundrels and imbeciles.

            In summary, there is no real dangerous global warming or wilder weather crisis. In fact, increasing atmospheric CO2 certainly improves plant and crop yields, and may cause some mild global warming, which will be net-beneficial to humanity and the environment.
            _______________________________

          • Allan: Your comments on Feynman and the scientific method are missing some useful information. To my knowledge (and I did some checking), Feynman never incorporated the problem of deterministic chaos into his physics. On our planet, the mixed layer of the ocean (that is in equilibrium with the atmosphere and surface temperature) rest on top of an average of 2 km of a much colder deep ocean. Chaotic fluctuations in the ocean currents that exchange of heat between the deep ocean can have a significant impact on surface temperature with no change in fluxes across the TOA. ENSO is the simplest example of such “internal variability”.

            Consequently, the 37-year cooling period, the recent Pause, and the periods of rapid warming that surrounded these events can’t disprove (or prove) any theory of global warming, because such events can occur in the absence of an external forcing such GHG’s, changes in solar activity, or changes in orbital parameters. We find evidence of such unforced (or possibly naturally-forced variability in ice and ocean sediment cores. It isn’t likely that such variability exceeds 1 K, but how much less is difficult to establish. ENSO – high frequency internal variability – has reached an amplitude of almost 0.5 K, but we don’t have reliable information on how big low frequency variation can be. During the last ice age, temperatures in Greenland briefly rose 10 K! – almost certainly because ocean currents chaotically brought more heat to that region.

            Internal variability makes our planet a lousy experimental system for testing the consequences of radiative forcing. Fortunately, WE DON”T NEED TO TEST OUR THEORIES on a planet with a chaotic climate. We have no doubt that the law of conservation of energy applies to our planet and that if more radiation goes out across the TOA than comes in, our planet must warm – somewhere. Our theories about the interactions of thermal infrared and GHGs have been tested in the laboratory for a century. Those theories and the absorption coefficients we have carefully measured in the laboratory correctly predict the spectral intensity of the radiation escaping to space and returning to the surface as DLR. There is NO DOUBT that rising GHGs will slow down the rate at which heat escapes from our planet by ABOUT 3.6 W/m2 following an instantaneous doubling of CO2. We don’t need to do the experiment.

            The real question is how much more LWR will the planet emit and SWR the planet reflect for every degree it warms. That is the climate feedback parameter (the reciprocal of ECS) expressed in W/m2/K. The climate feedback parameter depends on feedbacks that are poorly understood, but we can place some sensible limitations on its value. It isn’t likely to be greater than 3 W/m2/K (ECS around 1) or close to 0 than 1 W/m2/K (ECS 3 rather than infinity). It is impossible to suppress all warming because an ECS of 0.5 requires 6 W/m2/K. The reciprocal relationship make zero impossible.

            So AGW IS A LOUSY THEORY in the sense that it can’t be experimentally tested until forced warming greater than possible warming due to unforced variability. All of the evidence that allegedly falsifies the hypothesis can be written off as unforced variability. No warming in the Equatorial Pacific? No problem! Chaotic increase upwelling of cold water off Peru. Pauses? AMO. PDO and aerosols.

            The FAR candidly acknowledged the problem that forced warming and unforced or naturally forced warming were expected to be comparable. Later reports relied on AOGCMs to demonstrate that unforced variability is only 0.1 K, and ignored the problem that these models were not capable of properly representing known modes of high frequency unforced variability such as ENSO, QBO (until they used finer grid cells in the upper atmosphere), and the Madden-Julian oscillation, nor lower frequency (and therefore more poorly characterized) phenomena such as AMO and PDO.

            Antarctic ice cores don’t tell us anything about the lag between warming and rising CO2. The slow rate of snow accumulation means that the uncertainty in the age difference between snow (future ice) and the air that gets trapped in that snow is now understood to be several millennia. 800 years is obsolete. The rate of snow accumulation is Greenland is much higher, but warming didn’t begin there for at least 4 millennia after warming began in Antarctica and CO2 began rising. Today we have lots of warming in Greenland and none in Antartica. The end of the last ice age tells us NOTHING useful about GHG-mediated warming. The only logical reason for an increase in CO2 at the end of the last ice age is that it was released from the deep ocean – and overturning of the deep ocean takes about a millennia.

            AGW is a consequence of two phenomena that have been well established in the laboratory: 1) a reduction in radiative cooling to space by rising GHGs and 2) conservation of energy. These aren’t likely to be experimentally invalidated. The laboratory parameters for the interaction of thermal infrared and GHGs have been validated by measuring real world OLR and DLR, the latter under a variety of conditions.

          • Actually, the cause is anthropogenic sunspot depletion brought about by all the solar energy panels installed by humans.

            (Yes, I know this is nothing more than scientific sounding gibberish but it makes as much sense as the great cult of global warming.)

          • Allan
            News alert, it has started cooling already. One of the last identifiers is the 2 meter temperature.
            A good prediction.
            Regards.

          • Allan replied (respectfully for which I’m grateful): “If you believe your above statement, then you must believe that manmade global warming will overwhelm natural variability and the world will get warmer.”

            But Allan didn’t understand my main argument. If climate sensitivity is as high as the IPCC fears, then neither naturally-forced variability or unforced variability will “save” us from severe consequences. Nothing in the Holocene record of variability has the potential to save us. If climate sensitivity is as low as Allan hopes (1 K/doubling), then our future won’t depend on whether his prophecies about a weakening sun are correct or not.

            So the ONLY relevant question is: What is climate sensitivity? The sun is a distraction.

            (I’ll reply separately to some of his other comments.)

          • In replying to my comment, Allan then discussed climate sensitivity, perhaps agreeing with me that climate sensitivity is the most important topic.

            Allan writes: “Climate Sensitivity to Increasing Atmospheric CO2 is Low – Only About 1C/doubling.”

            This is probably too low. I’ll fully endorse Lewis and Curry (2015) at 1.6 K and Otto (2013, which included Lewis) at 2.0 K, but both have confidence intervals that don’t exclude the IPCC’s central estimate of 3.3, but they do cast doubt on AOGCMs with ECS above 4 K/doubling. Your estimate of 1 K is actually closer to the edge of these confidence intervals than the IPCC’s. The confidence interval in LC15 is widened by uncertainty in aerosol forcing and limited ocean temperature data 130 years ago. Otto et al used 1970-2010, in a period with much better defined temperature change and negligible (measured) change in aerosols. If we can agree upon an EBM central estimate for ECS of 1.8 K, that would be great.

            However, I believe there is at least equal chance that unforced variability has decreased observed warming (decreasing estimates of ECS), rather than increased it. Significant anthropogenic forcing began around 1950, the after 1.5 centuries of some sort of natural variability that brought us out of the LIA. Unfortunately, it is more plausible (to me) that natural or unforced variability has artificially increased, not decreased, EBM estimates of ECS. Fortunately, the consistency of EBM estimates from a large number of periods allows me to hope that this contribution from unforced variability is negligible.

            The problems with drifting satellites has (IMO) pushed UAH and RSS to the bottom of my reliability estimates. Since UAH bases their correction on radiosonde data, the reliability of their low warming rate is now no better than the radiosonde warming rate. I have to believe the surface record of warming, with all of its flaws, must be better than radiosonde data, especially when that data shows no enhanced warming at higher altitudes (and therefore no negative lapse rate feedback). And BEST has destroyed most of my faith that UHI are an important factor in even the land record. Homogenization of other records is worth only about 0.2 K of warming, mostly in the early part of the record which wasn’t used by Otto. ERSST3 vs ERSST4 didn’t change overall warming much, just smoothed out a little of the Pause.

          • Continuing by reply to Allan on ECS (which seem to be posting out of order): Your estimate of 1 K/doubling implies that net feedbacks are zero (or technically slightly positive). This is unlikely to be true.

            There is very likely that rising temperature will increase absolutely humidity, but relative humidity does not need to remain constant. Rising water vapor (like any other GHG) will slow radiative cooling to space (positive feedback) and reduce the lapse rate – producing more warming at higher altitudes than at the surface (negative feedback). However much water vapor increases, there is no doubt that its positive feedback on radiative cooling dominates negative feedback through lapse rate. So we expect some positive feedback from rising water vapor.

            We can observe that positive feedback via CERES when the larger landmass in the NH causes GMST (not GMST anomaly) to rise 3.5 K during summer in the NH. From clear skies, we observe an increase of 8 W/m2 in OLR arising from clear skies – -2.2 W/m2/K or an ECS of 1.8 W/m2. 1.1 W/m2 is almost exactly what models predict for WV+LR feedback and for the seasonal cycle in LWR feedback from clear skies.

            In fact, CERES also shows about -2.2 W/m2/K for the whole planet, meaning that models are wrong there is no additional positive LWR feedback from clouds. And it also shows that models do a horrible (and mutually inconsistent job of reproducing seasonal changes in SWR (which are NOT linear with Ts.) Now, I’m forced to admit that seasonal warming (+10 K on average in the NH and -3 K on the average in the SH, little change in the tropics) is not the same phenomena as global warming. AOGCMs do however produce the same WV+LR feedback for both.

            http://www.pnas.org/content/110/19/7568.full (IMO, most useful climate science paper ever published, because it shows that positive LWR feedbacks exist, but that AOGCM can’t reproduce feedbacks properly!)

            If CERES is correct about an LWR feedback of -2.2 W/m2/K, then you need about -1 W/m2/K of negative SWR feedback to get to an ECS of 1.2 K/doubling and the IPCC needs +1 W/m2/K of positive feedback to produce an ECS of 3 or more. The planet currently reflects about 100 W/m2 of SWR back to space. so a 1 W/m2/K is a massive 1%/K change in reflection. Rising air masses produce cloudy skies and subsiding air masses produce clear skies. To a first approximation, it isn’t obvious why the fraction of cloudy skies should change. Marine boundary layer clouds don’t depend on convection, they are a wild card. Surface albedo is likely to decrease from reduced coverage of seasonal snow and sea ice.

            So I think the best estimate for ECS is 1.8 K/doubling, and both 1 and 3 K/doubling are on the outer limits of believability. (Burning all of the coal on the planet might not be the greatest idea.)

          • Frank,

            As you may know, Manabe’s was one of the two ECS guesses used by Charney to derive the “canonical” 3 K central “estimate” in 1979. Manabe’s was 2 K and Hansen’s was 4 K.

            Unlike Dr. Manabe, I don’t consider the outputs of worse than worthless, GIGO computer models to be “data”. The models have repeatedly been shown to run way too hot. Not surprisingly, since their assumptions are unphysical. We don’t know enough about climate to model it, and even if we did, we lack the computing power accurately to model such important factors as clouds. “Parameterization” is just a Latinate term for “making stuff up”.

            On a largely homoestatic water world, I don’t know why you would rule out net negative feedbacks. Earth can and does switch from hothouse to icehouse mode on the scale of millions to hundreds of million years, and within icehouse intervals between glacial to interglacial episodes on the scale of tens to hundreds of thousands of years. But at least within interglacial phases, climate appears self-regulating to a large extent. Hence positive and negative feedbacks must mainly balance out.

            The Holocene Climatic Optimum was globally at most four degrees C warmer than now, but probably less. The Little Ice Age and Dark Ages Cool Periods were at most some two degrees C cooler than now, for a maximal Holocene range of six degrees C, but likely less. A reasonable guess is a range of three K, from 2 K warmer during the HCO peak to a low of 1 K cooler during the LIA. Such stability implies no runaway feedbacks.

            There is no guarantee that albedo will decline in future. The Holocene has been in a long-term cooling trend for at least 3000 years. While Arctic sea ice declined during the dedicated satellite record since its near-20th century high in 1979, it has been growing since its record low in 2012. Antarctic sea ice, which has a far greater effect on albedo, grew from 1979 to 2014. Snow cover has been increasing in recent years.

            Rising CO2 was associated with pronounced global cooling for more than 30 years from the 1940s until the PDO flip of 1977, then with slight warming for some 20 years, until the super El Nino of 1998 or shortly before it, followed by another ~20 years of flat GASTA (in so far as such a thing can be measured), until the 2016 super El Nino. For the past over 2.5 years, Earth has been cooling off from the Feb 2016 El Nino peak.

            IMO the cooked book surface “data” sets are packs of lies.

            No way is ECS anywhere near 4.5 K. It might be as high as 1.5 to 2.0 K, but less than that is more likely. If negative and positive feedbacks cancel each other out, then it’s 1.1-1.2 K.

            Who can say when “equilibrium” might come? We don’t even know all the CO2 sinks. Earth’s photosynthesizers have been soaking up the extra plant food like crazy, noticeably greening the planet, thanks to humans’ having so generously given them free lunches.

            Accepting that Earth has warmed by 1 K since c. AD 1850 (which it hasn’t), under an ~130 ppm increase in the essential trace gas CO2, then ECS can’t be as high as 2 K per doubling, since the effect is logarithmic. Another 150 ppm (560-410) shouldn’t produce as much warming as the first 130 ppm increase from the “pre-industrial” level of 280.

            Your own central guess of 1.8 K per doubling is IMO plausible, but your upper bound of 3.0 isn’t. A range of 1.0 to 2.0 K is defensible, since net negative feedbacks from evaporative cooling, clouds and other factors, watery and not, can’t be ruled out in the present state of our lack of good observations of the complex climate system, and explanations thereof. A central figure of 1.5-1.6 K may well result from observations in AD 2100.

          • John: Yes I know that Manabe’s first AOGCM had an ECS of 2 K/doubling and Hansen’s was 4 K. It may be that many subsequent researchers were (conciously or unconciously) influenced when tuning models to chose among equally good choices to produce models with ECS somewhere between.

            However, the Manabe (2013) paper is not about model tuning, it is about how well models reproduce OBSERVATIONS, the LARGE feedbacks (LWR, SWR, clears skies, all skies, difference between all skies and clear skies caused by cloud feedback) in response to large SEASONAL changes in absolute temperature. The 8 W/m2 seasonal change observed every year is twice the forcing from a doubling of CO2 that will take more than a century to develop, so we can measure seasonal responses with far greater accuracy than anything due to rising GHGs. And Manabe shows that models do a lousy – an mutually inconsistent – job of reproducing the seasonal feedbacks we observe … except for LWR from clear skies. Look at the plots – you’ve never seen such tight data from climate science anywhere else.

            El Ninos are due to chaotic fluctuations in wind and ocean currents. From my perspective, reduced upwelling of cold water off Peru and subsiding of warm water in the Western Pacific is what produces warming. This internal (unforced) variability has nothing to do with the imbalance at the TOA associated with the slow warming from rising GHGs.

            I discussed the HCO elsewhere.

      • That’s right. It seems like they have assigned themselves the task of splainin’ away how it could be that ancient temperatures fluctuated without the fossil fuel burning of the industrial age, while staying within the orthodoxy that greenhouse gases drive everything.

        As I understand their “theory”, interglacials begin with a set amount of GHGs, and that warms the planet. Then the GHGs gradually decline until the next glaciation. The declining GHGs drive cooler and cooler temperatures. So how does the big bolus of GHGs show up to start the interglacial? Deus ex machina apparently. (Nobody knows, send research money?)

        What lunacy! Consistent with CAGW orthodoxy, as usual they have the causation backwards. Of course there is a correlation between CO2 and temperature. Warmer temperatures driven by Milankovitch cycles cause the oceans to release dissolved CO2, due to the fact that the solubility in water decreases with temperature. As the same natural factors drive temperatures to cool, the oceans absorb CO2, due to increasing solubility of CO2. Thus CO2 follows temperature with a lag.

        I’m not denying that rising GHG levels modestly accelerate warming or that falling GHG levels accelerate cooling, it’s just that these are minor second order effects that are not driving the main warming or cooling effect.

        Just as the burning of fossil fuels by human activity has increased atmospheric CO2 concentration above equilibrium with the oceans, land use changes at the dawn of agriculture may have had measurable effects on methane emissions. The extra GHG may have had a small warming effect, just as CO2 from fossil fuels has had a small beneficial warming effect. These things are not driving climate and are strongly limited by emergent phenomena (clouds, thunderstorms, etc). They will not save us from the next ice age (unfortunately).

        It’s remarkable that they reference Milankovitch cycles, yet still insist on GHGs driving temperature. It’s almost as if the goal is to reassure wavering co-religionists that the Milankovitch stuff they may have read about in heretical writings by climate deniers are nothing to worry about.

        • My guess is they are softening us up for re-introduction of the modified hockey stick and being able to explain the warming through GHG since the little ice age. What is not to like. They can’t win with science so best to re-write history.

    • They are trying to blame the invention of agriculture on the climate of the last 10K years. I guess, then, the taming of fire was the beginning of the end. I would also blame the current Interglacial Period for allowing agriculture to be invented. It’s actually, thus, the fault of evolution that it set mankind up to be able to develop agriculture if the conditions were right. Damn nature and it’s horrible laws. We are doomed, for sure. We now have to ban nature and all its practices.

      • Worse than that! it was the original original sin. It caused the forests to shrink and the savannas to grow. That in turn caused the displaced primates to move into the grass lands and walk upright thereby freeing their hands to become dexterous… and evil!

        “four feet good! two feet bad!”
        Animal Farm

        A rose by any other name…

    • Almost certainly, ancient alien astronauts introduced agriculture to forestall global cooling.

      Hey! It’s “… the only explanation I could come up with “

      • Remember, sophisticated does NOT mean clever or intricate, it simply means corrupt & adulterated! So these puter models are corrupt & adulterated, presumably to produce the predetermined outcome they want!

  2. Take your pick. Bullocks. BS. Balderdash. Blithering gibberish.

    Ruddiman’s fantasy was rightly rejected as sheer lunacy when he first hatched the cockamamie “hypothesis”, and it has only gotten less plausible with time.

    The Holocene would have been preternaturally shorter than most interglacials had it ended about the time that agriculture started.

    • If, as some think, agriculture began in South China some 13.5 Ka, with rice farming, then maybe it was methane from the paddies which staved off the regrowth of NH ice sheets.

      Nah, just as likely that lack of woolly rhino and mammoth flatulence ended the Holocene Climate Optimum.

  3. How many farmers were there 5,000 years ago? how many acres did they cultivate? And this caused a change in the earth’s climate? Come on guys, Whose blowing smoke up my bum?

      • The same ones the Martians are using to cause global warming there. ‘Twas my best laugh of the day–thanks!

        Jim

      • None, they were using Domesticated Wooly Mammoth to pull their Stone Ploughs to till the soil. The Domesticated Mammoth produced far more Flatus per Pachy Acre Tilled than modern methods do today.

    • how many acres did they cultivate? ….

      Only about 4% is even possible….so probably 1/100th percent back then

    • Presently termites out mass humans by a factor of ten. I might assume that the earth’s termite population probably always has been a far larger multiple of human population as all of our technological creations have allowed us to increase our population rather quickly. I will hazard a guess our technological advancement is better than termites’.
      Take away all of our technological creations, that the early civilizations did not have and the only output would be respiration. So the sole difference between us and termites would be who breathed more. Well, the termites are still currently out ahead of us by a factor of ten.

      I wonder how much methane output was altered when shallow swampland was converted to shallow rice paddies? Or, when wild grass lands were converted to single crop grass lands?

      • Micro-Fauna and Micro-Flora each out weight all other Fauna and Flora by multiple times. Their contributions to the Carbon Cycle and use of Carbon Dioxide is massive, as well as the Methane and Oxygen they contribute. A warm climate for both Flora and Fauna Microbes increases their reproduction and cooling temperatures reduce them. They live in every environment from Ice to extreme heat according to their species.

        We humans may have some effect on the environment locally that changes the environment, but its effects on the global scale is miniscule. We simply do not compare with the rest of the environments contributions.

        Which means that all of the Alarmism is an artificial narrative against humanities advancement and capitalism that’s become political.

  4. “People say (our work) sends the wrong message, but science takes you where it takes you,” says Vavrus. ”

    Who are these “people.” Name names. Such people should not receive public money or sit on editorial boards.

  5. Minoan Warm Period? …. Minotaur farts?

    Damned agriculture. It must’ve been horrendous being warm back then.

      • Poor misguided Mark. You deny the science, despite the clear correlation? All farmers know that bumper crops cause warm moist conditions. Failed crops have often been shown to cause droughts. Exactly the same thing as rising CO2 causes temperature to rise or the rooster crowing causes the sun to rise.

  6. Over the last thirty years, we have become used to insane Global Warming theories, but this “Ancient Farmers” one is well beyond previously established boundaries of stupidity and ridiculousness.

  7. So, a few stone age farmers prevented those mile thick glaciers from covering North America?

    Who would have thunk that?

    Currently, AFAIK, humans account for about 3% of the CO2 which enters the atmosphere each year. What percentage of CO2 entering the atmosphere was due to human activity during the stone age?

    Everybody knows that water vapor is the greenhouse gas which counts.

    • “Peta of Newark
      The self importance and hubris of these people is just galactic.

      I’ve looked and looked and looked and failed to find a thing I found ages ago.
      It was a real experiment conducted in a field in South West Scotland. I remember it because it would have been barely 45 minutes drive from my old place.
      Basically a farmer had ploughed a tired old pasture field and was going to leave it ‘fallow’ for 12 months
      Researchers took the opportunity to plant some CO2 flux meters in the field for the 12 months.
      As it happened and due to the less than clement weather in that part of the world, the meters were running for 2 years.
      Just sitting on some bare ploughed field. at 55+ degrees North.
      They recorded that for both of the 2 years, that bare soil was releasing 10 tonnes per acre per year of CO2
      Does ‘World Farmland’ extend to 1,200 million acres, roughly.
      Work it out. Compare to fossil emissions….
      No matter until you see this, (something I did properly bookmark and is *still* there. Nice.)
      http://flux.aos.wisc.edu/~adesai/documents/Desai-AFM-Multisite.pdf

      It describes how they did the reverse experiment – looking to see how much CO2 an actively growing and mixed tree-age forest, at reasonable latitude, absorbed.

      Just eyeballing their Fig 2, I’d guess that their forest was soaking up about 5 grams of carbon per square metre per day over the 3 months of summer. Nil otherwise.
      I get that to be just shy of 5 tonnes of CO2 per acre per year- which stacks up *perfectly* with a figure someone here quoted about Douglas Fir forest growing on Oregon.
      I calculated then that it would need 720 acres of Douglas Fir to soak up 1 hour’s worth of output from the wood-burning exercise currently going on inside Drax Power Station. Even before they get all of Drax burning wood and thus quadruple that figure.

      See the ‘problem’…
      Acre for acre, ploughed dirt is releasing twice as much CO2 as forest is absorbing – the *difference* amounting to 1,200 million acres at 5 tonnes per acre = 60+ gigatons annually”
      HIS ANSWER SHOULD HAVE BEEN 6 NOT 60.

      “(From my experience of livestock farming and grazed dirt and what our (now disappeared) contributor – RGB@Duke – used to say= ‘Goats make deserts’…..
      (A desert being defined as a place with low to zero soil organic content)
      …I would assert that grazed farmland is producing just as much CO2 as ploughed farmland)

      In light of that, are Fossil Fuels a problem – is there anything to worry about or get into a blind panic about, as is patently happening now amongst scientists and politicos…….

      PS I take ‘farmland’ to be 10% of entire Earth surface, hence= 10% of 5E14 square metres”

      NOT TRUE SEE BELOW FOR ACTUAL FARMLAND

      ***************************************************************************
      After this the analysis is by Alan Tomalty
      Actually when you consider the 1.5 billion cows which produce methane and the fact that there is 17% more farmland than we thought(discovered by satellite studies) in a report November 2017. and the fact that the IPCC underestimated the amount of CO2 given off by a ploughed field , the % is 6.667.
      !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

      This number is derived by global warming equivalent gases emitted of 15 GT carbon equivalent by agriculture, deforestation and fossil fuels including cement making / divided by /total emitted to atmosphere of 225 GT carbon equivalent See below.

      https://www.producer.com/2017/11/worlds-farmland-total-bigger-expected/
      Satellite figures show 17 % more farmland they they thought.
      The answer is 4.62 billion acres are farmland.

      After a crop started growing the soil would not release as much CO2. However you are correct that the IPCC is surely underestimating the land use component of CO2 emission to atmosphere. Mankind is now emitting over 10 GT of carbon or 36.7 GT of CO2 per year. The US DOE has vastly underestimated the landuse component and the IPCC just blindly copies as usual.
      According to Peta of Newark’s calcs his number should have been 6 not 60 . However with the true total of farmland at 4.62 billion acres at 5 tonnes CO2 net per acre emission , the total would be 23.1 billion tons of CO2 or 6.29 GT of carbon because of farmland. However some of that farmland is orchards and never gets ploughed. % of orchards in Europe is 0.25% so subtract .1 to give you 23 GT of CO2 or 6.267 GT of carbon .

      However Peta of Newark’s premise is correct. Since the IPCC says land use is 29% of total that means per year actual farmland (IPCC figure ) emits 2.9 GT of carbon or 10.643 GT of CO2. However your figure is 6.267 GT of carbon or 23 GT of CO2. Even just adding 17% more farmland and disregarding your figures for a moment, would give 3.393 Gt of carbon(revised IPCC figure) or 12.45 GT CO2(revised IPCC figure) which is 1.81GT CO2 more which is 0.493 GT of carbon more . That represents a revised IPCC figure which is 4.93% higher for all sources of mankind emissions.

      However adding PETA of Newark revised figures to this revelation we get 6.267 – 2.9 = 3.367 GT Carbon more or 12.357 GT CO2 more. Your figures give 33.67 % more . Some of that is because of the 17% more farmland and some of it is because of your figure of net 5 tonnes CO2 emission per acre per year is obviously way more than what the IPCC says.

      Alan Tomalty
      If Peta of Newark is correct. See his and my post near the bottom . Then there is a big hole in the carbon cycle. It amounts to 3.367 GT of carbon or 12.357 GT CO2. Plus there is another 1 GT carbon or 3.67 GT CO2 that mankind has increased over the past couple of years that the carbon cycle diagrams have not incorporated. Thus there is now a missing amount of ~ 4.36 GT of carbon or ~16 GT CO2. Where has it gone? The oceans maybe , but the IPCC likes to say that the oceans and atmosphere are perfectly balanced in a trade of CO2. This is a lot of CO2 ; over 33% of all of mankind’s emissions per year. The net emissions from all sources to the atmosphere are still 4 GT carbon or 14.68 GT CO2 but that figure is showing no increase in % over time. For the last 10years ; It is now 0.617% higher than a year ago which was 0.484% higher than previous year which was 0.745% higher than previous year which was 0.753% higher than previous year which was 0.549% higher than previous year which was 0.512% higher than previous year which was 0.669% higher than previous year which was 0.494% higher than previous year which was 0.601% higher than previous year which was 0.526% higher than previous year. The alarmists will look at that data and say the graph shows a slight trend upwards. Perhaps, but if that is their idea of CAGW, then spare me the marmalade.

      1 ReplySeptember 7, 2018 5:51 am
      Alan Tomalty
      Another thought. Cows according to the IPCC are thought to cause 18 % of global warming all by themselves because of the methane release. So we have 11.8 Gt carbon equivalent of emissions before the revised figures of Peta of Newark and myself are taken into account. If you add in the new land use figure for farming of 6.267 GT carbon plus the 1.8 GT carbon for the cows to the 10 GT carbon listed in IPCC figures you then have a total of over 18 GT carbon of which 8.067 is agricultural caused which is 44.6 % of global warming emissions. Yup the farm sector is the highest man made emitter followed by fossil fuel burning and then cement making. So does this mean we ban farming or at least put a carbon price tax on farms?? I can see all the farmers lining up now to lynch every climate scientist they can get their hands on. I have to admit I would be hard pressed to attempt to stop them.

  8. Trolling for dollars with all the key word “warmer and warmer and warmer interglacial”
    “Computer Models”
    “800,000 years ago”
    To believe man can alter nature is the height of stupidity and arrogant.

    To an outsider, the most significant innovation in the global warming controversy is the overt reliance that is being placed on models. Back in the days of nuclear winter, computer models were invoked to add weight to a conclusion: “These results are derived with the help of a computer model.” But now, large-scale computer models are seen as generating data in themselves. No longer are models judged by how well they reproduce data from the real world—increasingly, models provide the data. As if they were themselves a reality. And indeed they are, when we are projecting forward. There can be no observational data about the year 2100. There are only model runs.
    This fascination with computer models is something I understand very well. Richard Feynman called it a disease. I fear he is right. Because only if you spend a lot of time looking at a computer screen can you arrive at the complex point where the global warming debate now stands.
    Michael Crichton: State of Fear

      • Well, yes. Actually I have. Barry Obama was on TV today, running his mouth. And then there’s Michael Mann, Nancy Pelosi, Al Gore, Dick Durbin, Bill McKibben, Michael Moore of course….. well, really the list is too long to detail, for a species that is supposed to be extinct.

        • Lol, J Mac! I saw that dodo Obama yesterday too, standing there telling one lie after another.

          Now that Barack is back in public, some reporter needs to ask him about the attempt on the part of Democrats to prevent Trump from winning the election and undermining Trump after he was elected. What did you know, and when did you know it, Barack?

          The people involved in this Democrat sedition are all Obama’s people. Are we supposed to believe that everyone in his administration was involved except him? That’s what he wants us to think, but I have a feeling the truth is going to come out and Barack isn’t going to like it. My guess is Barack orchestrated all of it. Ordered it done in collusion with Hillary and the Russians.

          Trump is going to declassify pertinent documents any day now and we will all get a much clearer view of the criminality that took place during the Obama administration to deny Trump the presidency.

          Obama was the Worst President Evah!, and now he’s the worst ex-President Evah!

          Would love to have a forum where I could rebut every lie in his speech. I used to do that a lot on Usenet, back in the “good ole days”.

          • One constant with Democrat presidents, once they leave office, they never go away.

            It’s almost as if they suffer if they ever leave the limelight.

        • Yeah, saw that too. With the starry-eyed acolytes in the audience.

          I also noticed he accuses Trump of doing what he did:

          1) Promoting fear (Obama promoted fear of climate change)
          2) Pitting one group against another (accusing skeptics of being deniers)

          • Obama declared that he didn’t need to work with Republicans because “He won”.
            Now he wants to condemn Republicans for failing to “work with” Democrats. (Of course by “work with” he means, do what we tell you to do”.)
            When Obama was president, he declared that he was the president of “His people”, meaning, those who supported him only.
            Now he condemns Republicans for being divisive.

            If you want to know what a liberal is planning on doing, just look at what he is accusing others of.

        • How about North Africa then? Two thousand years ago it was the grain basket of the Roman Empire now due to soil erosion caused by human mismanagement it is infertile and a desert. Or Australia where tens of thousands of years of burning by Aborigines have profoundly changed the climate and vegetation.

  9. A usual idiot alert is the use of “robust” to describe findings. This is code for “we have no data so we have to sell our findings with rhetoric. The phrase “plus the spread of rice paddies – robust sources of methane” might be an idiot double red alarm. OED defines robust as strong and healthy which implies nothing about abundance. They just had to get in the obligatory modeller’s robust, however ludicrous the usage.

  10. Lets face facts .
    CO2 is not the control knob of the worlds climate and never has been and never will be.
    The small areas of cultivation thousands of years ago and the cutting and burning of forests would have had absolutely no effect on the global climate .
    All the warmth that reaches this earth comes from the Sun, that round yellow thing that rises every morning in the East and sets every night in the West .
    When these or any other scientists can tell us what caused the ice ages and how the ice ages came to an end and how we are to know when to expect the next ice age they might have something to tell us .
    This paper is a Joke ..This is the sort of thing that high school students could come up with .
    Graham

    • OFFS —we’re talking about anthropogenic climate change here, not a regionalized change in climate patterns caused by Mother Nature and natural variations.

      “The Neolithic Revolution” involved no more than a few hundred thousand human beings who COULD NOT have generated enough CO2 to increase atmospheric concentrations, let alone temperatures

      One article even makes this utterly and literally bat-s#it-crazy statement:

      “A clean and pure pristine primeval planet earth existed for a billion years in natural perfection, wholeness, and wholesomeness – unpolluted, untainted, untarnished and uncorrupted in the perfection of the harmony of nature. The geology, biology, and climatology were in a state of perfection. The climate was stable and unchanging with no extreme weather. Living creatures both plants and animals lived in peace and tranquility as essential elements of nature itself. There was no ozone depletion, no climate change, no skin cancer, no hurricanes and no species extinction from bad weather. Modern day ecofearology is a yearning for this humanless state of nature – a yearning for a return to what the planet was like before humans came along.”

      That’s right, perfection — no Siberian or Deccan traps. No asteroids. No five big extinction events. No changes in weather patterns due to plate tectonics. No environmental pressures that would lead to evolution. No changes in solar luminence that would affect temperatures on Earth.

      Yeah….that’s science, all right —–snort!

      But wait–there’s more!

      “Then the devil appeared in the form of humans who came on spaceships from outer space. Humans are not part of nature but an external force alien to nature and an abomination. They will soon turn this heavenly planet into a living hell with human activity because their nature is to consume and destroy.

      At first the alien humans were relatively harmless living off the land as hunter gatherers in harmony with nature.”

      So humans came to Earth on spaceships—and then abandoned their superior technologies to live as hunter-gatherers!!!!

      Whew!

      • “A clean and pure pristine primeval planet earth existed for a billion years in natural perfection, wholeness, and wholesomeness – unpolluted, untainted, untarnished and uncorrupted in the perfection of the harmony of nature. The geology, biology, and climatology were in a state of perfection. The climate was stable and unchanging with no extreme weather. Living creatures both plants and animals lived in peace and tranquility as essential elements of nature itself. There was no ozone depletion, no climate change, no skin cancer, no hurricanes and no species extinction from bad weather. Modern day ecofearology is a yearning for this humanless state of nature – a yearning for a return to what the planet was like before humans came along.”

        Anna, I’m not sure where you got that quote, but it seems you have been taken in by somebody’s failure to include /sarc (sounds like one of my rants, actually, except that I generally multiply the age of the earth by two and say that things were perfect for nine billion years before the evil humans came along)

        Certainly the biggest tell is the use of the term “ecofearology”

        The wingnuts do seem to believe most of that crap, but it is exaggerated a bit for effect.

  11. How embarrassing for the UW-Madison, my alma mater. Reid Bryson must be spinning.

    “All this argument is the temperature going up or not, it’s absurd,” Bryson continues. “Of course it’s going up. It has gone up since the early 1800s, before the Industrial Revolution, because we’re coming out of the Little Ice Age, not because we’re putting more carbon dioxide into the air.”

    • >>
      . . . UW-Madison, my alma mater.
      <<

      I’ll see your alma mater and raise you mine: University of Washington. I’ve seen some pretty stupid stuff coming out of there lately.

      Jim

      • EVERYONE

        WRITE YOUR UNIVERSITIES SAYING THAT YOU WILL NOT DONATE ONE MORE DIME UNTIL THEY CEASE SPONSORING GLOBAL WARMING ALARMIST FRAUD. DO IT TODAY!

        These phony green academics cause enormous harm to humanity and the environment.

        Skyrocketing energy costs have increased fuel poverty and contributed to about two million Excess Winter Deaths per year worldwide. Millions of other premature deaths can also be attributed to energy poverty, particularly in the developing world.

        The big green machine drove the 30-year effective ban on DDT from 1972 to 2002, doubling deaths from malaria, most of whom were children 4 and under – just babies for Christ’s sake! After DDT was re-introduced. malaria deaths declined.

        https://www.facebook.com/photo.php?fbid=1566107003466856&set=a.1012901982120697.1073741826.100002027142240&type=3&theater

        THE GREENS ARE THE GREAT KILLERS OF OUR AGE.

        Green energy is not only bad for humanity, it is harmful to the environment. From wind power slicing up birds and bats to clear-cutting the rainforest in SE Asia and the Amazon for biofuels to draining the vital Ogalalla aquifer in the USA to grow corn for fuel ethanol, almost every green energy scheme is a really terrible idea, both economically and environmentally.

        It is difficult to believe how terribly wrong our universities have been on green alarmist nonsense, until you realize THEY ALL MADE MONEY PROMOTING IT.

        Reference:
        COLD WEATHER KILLS 20 TIMES AS MANY PEOPLE AS HOT WEATHER
        By Joseph D’Aleo and Allan MacRae, September 4, 2015
        https://friendsofsciencecalgary.files.wordpress.com/2015/09/cold-weather-kills-macrae-daleo-4sept2015-final.pdf

        • Everything you just wrote including the numbers of death was done intentionally to cause those deaths. Green Progressivism is just another name for fascism. They don’t even care that you object to it. It’s all for Gaia, the mother of all Gods, after all.

  12. I warned all of you about the increasing attention to the past. Michael Mann has given his troops the orders. Attack the past. He who controls the past controls controls the future. He who controls the present controls the past.

    You will see one of these studies every week and they will increase until Mann has completely deconstructed the past.

    • Mann doesn’t exactly have street creds much anymore around here. Most of the population doesn’t know who he is and would care less after they were told about him. This paper will most likely wind up in the trash bin of university papers.

  13. “The findings are based on a sophisticated climate mod…” SKRITTCHCHHH.

    The manure keeps getting deeper by the week.

  14. What Hubris.

    To presume any human capacity to transform climate prior the industrial revolution, we’re no more relevant than termites.

  15. Actually about 8–10, 000 years ago the Holocene Optimum engendered the advent of agriculture and the planet has been cooling ever since, in a roller coaster ride, but always downward. These guys really need to consider that a trace gas, even at three times today’s concentration cannot drive climate. It’s a trace gas, has very limited IR absorption ability, and cannot warm the atmosphere in any detectable way. The water cycle, a huge global heat engine, is responsible for moving 85% of the daily solar energy budget, transporting energy from the surface to altitude. The demonization of CO2 is a huge joke being played on the gullible.

  16. Boy these people are really stretching it to find away to say mankind is the bad guy. Forget the Industrial Revolution. The mere fact we farmed long ago started to overwhelm this “fragile” earth environment. To think those poor farmer staved off a possible ice age. Seems to me that was a food thing. That might have killed us off and were would we be today. (Not here most likely). You have to give these environmentists credit for their creativity. Once again computer models reveal all the wonderous information. These guys would be lost without the computer.

    • The logic of their conclusion is that we will still get global warming if we ban fossil fuels and return to subsistence farming. So what’s the bother?

      • But they are indicating that even the Subsistence Farming by a global populace of 45M of some 5,000 – 10,000 years ago was still sufficient to cause human induced Climate Change. I think they want to reduce our population to around a million privileged few Hunter Gatherers as more than that is modeled to still cause climate change.

      • The Khmer Vert want us to go further back still – back to hunter-gatherer existence. They want to reverse both the industrial and the agricultural revolutions. Together with the elimination of a 99.9% surplus of human beings.

  17. What utter nonsense! (1) Early humans were so few and their effect on the amount of CO2 they put into the atmosphere was so miniscule that it could not have seriously affected climate. (2) Both Ruddiman and Vavus completely ignore the fact that CO2 ALWAYS lags warming in ice cores and could not therefore be the cause of warming. The same is true of short term CO2 and warming–CO2 ALWAYS LAGS WARMING. WARMING CAUSES INCREASE IN CO2, NOT THE OTHER WAY AROUND.

    The Ruddiman concept is beyond ridiculous because of the two facts above. How any competent scientist could ignore such conclusive evidence against CO2 causing Ice Ages to end is incredulous.

  18. Global population 5,000 years ago is estimated at 45 million. This population cleared some forest and started farming, and this was enough to warm the climate?

    And we (some of us anyway, and the number seems to be increasing) are debating whether our current population of billions and our massive industrialization and gigatonnes of CO2 emissions is responsible for about 1°C of warming in 150 years?

    Right.

    Climate logic in action!

  19. “There is pretty good agreement in the community of climate scientists that we have stopped the next glaciation for the long, foreseeable future…”

    It’s not a good idea to challenge mother nature. Just when you think you have her tamed, she decides to put you in your place.

  20. “These opposing trends are consistent with the prediction from the Early Anthropogenic Hypothesis (EAH) that MIS1 values would have continued falling if not for early agriculture, as they did in other recent interglacials14”

    CO2 always was and always is a well mixed gas. How could humans spread out over Africa produce enough of anything especially CO2 to affect anything considering they were all hunter gatherers before 8500 BC?. It is well documented that agriculture as practiced by humans started around 8500 BC. (Neolithic period) in the Mediteranean Fertile Crescent area. There were less than 5 million in population of the world at that time.

    One of the studies referenced in this study was a study by one of the coauthors Ruddiman. I quote him in his previous study.
    “In recent millennia, the estimated warming caused by these early gas emissions reached a global-mean value of ∼ 0.8 °C and roughly 2 °C at high latitudes, large enough to have stopped a glaciation of northeastern Canada predicted by two kinds of climatic models. ”

    This climate scientist should have all his funding taken away and he should be enlisted in a special deprogramming regime whereby scientists who stop believing in reality in favour of their models; get help.

  21. The researchers deliberately cut the model off at the start of the Industrial Revolution, when sources of greenhouse gas emissions became much more numerous.

    Well of course they did. For a few million humans with no industrial capacity at all, and no use of fossil fuels to materially affect the temperature of the earth, sensitivity to GHG’s would have to be enormous. If they’d allowed the model to continue to run through to the present with sensitivity modeled that high, the modeled temperatures for the present would be high by (WAG) dozens of degrees. They’d have looked like total idiots.

    So they cut them off at 1850 to hide, dare I say it, “the rise”?

  22. I got the following from a google search:

    “In the Devils Hole, Nevada, paleoclimate record, the last four interglacials lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stands.”

    If the current interglacial has lasted less than 12,000 years, why would anyone conclude that farming has had anything to do with prolonging it? What was it that made the previous interglacials last over 20,000 years, alien visitors stopping by to grow more supplies before continuing on with their long-distance travels?

    I’m tired of climate scientists loading the dice when programming computer models, knowing there are too many unknowns to simulate the earth’s climate in any kind of precision. Then they claim the models have verified their understanding of the climate when they spit out exactly what they programmed them to do.

    • In the early days of the climate hysteria, paleoclimate data quoted by skeptics, was perhaps the biggest threat to the anthropogenic global warming theory – well established facts that they couldn’t explain. At first they ignored the paleo data (probably because they’d never seen it before). Now the climate establishment is all over paleoclimatology, trying to shoehorn it into the “CO2 rules them all” hypothesis. They are learning stuff, and getting more sophisticated as they go, and we see references to insolation and Milankovich cycles. But in terms of producing any evidence that the climate has been dramatically affected by human activity, they aren’t doing very well. This study certainly doesn’t help them; it just makes the idea of anthropogenic forcing look silly.

    • It’s not possible to ban the past, Mike. The past will continue to change whether we like it or not. Only the future is certain. /sarc

  23. There ya go…..
    The potatoes, rice and squash are what done it. They caused prehistoric global warming.
    Currently, it is the CO2 feted arugula, soy beans, and estrogen driven soy boy gynecomastia that’s forcing global warming.
    Next time it will be due to planetary gender reassignment: Men are from Mars, or Venus, or Neptune, by Jove! /s

    I like to make fun of it but this climate change scam is getting bat shit crazy. Says Vavrus “Things are so far out of whack now, the last 2,000 years have been so outside the natural bounds, we are so far beyond what is natural.” Boy, and Howdy! The ironic truth of Varvus’ so-far-out-of-whack declarations illustrate just how far disconnected from reality the climate change ‘sophisticated model’ based schizophrenia has progressed in the minds of the afflicted. The exhaled breath of every animal on the planet is now classified as ‘pollution’, as is the essential food of all plant life. I fear the dark ages of unreasoning are upon us once more.

    • “I like to make fun of it but this climate change scam is getting bat shit crazy.” Well said. I really think all of this should be transferred to the science fiction arena, under models run amok and the crazies that follow them. There’s virtually only fiction in any of this at this point. No science at all.

  24. anywhere there is water and a mild temperature then things will grow. It does not need human farmers. Where did all the coal beds come from, busy busy humans of course.

    MJE

  25. “The reality is, we don’t know what happens next. And glaciers have long served as Earth’s predominant source of freshwater.”

    This seems a bit off. It’s true that a majority of freshwater volume is currently trapped in glaciers and ice caps, and during glaciations the percentage would be much higher. But as a *source* of freshwater for human use the vast stocks frozen in Greenland and Antartica might as well not exist at all, their contribution to the water cycle is just to calve into the ocean. Most countries have essentially no glacial melt at all, the freshwater coming from some combination of groundwater, rain, and melted *seasonal* snow/ice. Even in places like India glacial melt is not a “predominant” source of freshwater. For example, I found an analysis of the Baspa River basin (originates in Himalyas) showing 81.2% of flow from snowmelt, 11.4% from rainfall, and just 7.4% from icemelt.

    Further, in order for the stored freshwater in glaciers to provide *any* net contribution to liquid freshwater, they must be melting! A glacier that releases no more fresh water in the summer than it captures in winter isn’t providing anything at all, just processing snow in a different fashion. A glacier that is growing is actually *removing* fresh water that would otherwise have been available.

    • Well it does usually even out river flow over the year by releasing meltwater during the often dry summer. Not in India/China though, where most rain comes with the summer monsoon and winter is the dry season. There the glaciers are indeed completely irrelevant as water sources.

  26. Unfortunately, I believe I’ve been infected by the latest mutation of the Feynman virus. He said (in essence): “if the data disagree with your theory, then the theory is wrong.”

    So the theory is this: CO2 goes up, temperature goes up. So far, so good?

    Okay. Therefore, if there were ever a time when CO2 levels were significantly higher than they are now, and the temperatures were significantly LOWER than they are now, then that would prove the CO2 cannot be a primary driver of temperature, right?

    To my knowledge this has happened at least twice . . . wait for it . . . during ice ages. So game, set, and match.

    Further, data also show that CO2 trails temperature. So unless those CO2 molecules have little tiny time machines . . .

    Oh, I know: the real explanation is that those early farmers had diesel-powered oxen.

    • Richard, Let me intervene here before you have to hear from RyanS or one of the other trollBots. Haven’t you heard that the sun was a dim bulb back in the Ordovician? It was barely brighter than our dusk at their high noon. And oh, by the way, the CO2 levels were not that high anyway. Look pal, the past will be conformed to our theories. Resistance is futile!

        • It will probably get reported that as the snow gets compressed into Firn, before becoming the next layer of Glacial Ice, a percentage of the CO2 gets compressed out and what remains is what is measured. CO2 levels of the past were likely higher than what CO2 trapped in ice would indicate.
          CO2 really needs a more likeable Facebook account so it can get better Firnded. UnFirnding it is a detriment to measurements.

    • If temperature goes up first, then CO2 follows, and then temp drops again as CO2 is still going up, that also disproves the hypothesis.

      • Not necessarily. Ocean outgassing/absorption is not the only source/sink. Volcanic action could also drive higher CO2 even in a cooling environment. Human activity has driven CO2 above equilibrium levels. Ocean currents, upwelling, etc. can be a factor. It’s a complex system. But in general, CO2 is mostly going to rise after ocean temperatures rise and drop after ocean temperatures drop.

  27. These “scientists” will soon go the whole hog and “find” evidence that actually the world got out of the ice age because of neolithic farmers interfering with nature. Move over, Milankovitch.

  28. “Things are so far out of whack now, the last 2,000 years have been so outside the natural bounds, we are so far beyond what is natural.” Translation: Human beings on earth are not natural. That leaves us being aliens dropped here from somewhere afar. Funny, I don’t remember learning that in any classes I ever took, but it must be true because these climate scientists said it was and so did their models.

  29. I was actually looking forward to something discussing the actual advent of agriculture, how humans harnessed specific plant species, the evolution of growing and harvesting techniques, so on and so forth. And yet again it is just a jumble of crap based on crap computer models and pre-concieved political bias. Oh well, guess we could go to a movie, it raining and whatnot.

  30. “Inferred regions of glaciation develop across northeastern Siberia, northwestern North America, and the Canadian Archipelago. ”

    This study can thus safely be disregarded, like essentially all such studies of glacial inception based on GCM:s. They always model a huge icecap in Northeastern Siberia, where there never was one. Probably because they are unable to model precipitation realistically.

  31. My problem with all of this is these people are counting how many angels can fit on the head of a pin. They are talking in tenths of a degree with wide error bands; who does that? It’s not real, it’s fake, as in fake science. They are worrying ‘no change’ to take a direction and cry uncle.

  32. Ancient farmers spared us from glaciers but profoundly changed Earth’s climate

    Ridiculous, laughable, useless and misleading “research”. Now, maybe, we are having a small effect on temperatures in cities.

    • I’ve noticed that once some folks get advanced education in a particular field, they assume they are experts in whatever subject is being discussed. It’s fun to look up what they say and show them when the actual facts disagree.

  33. Wow! What a load of academigog double-spewed garbage!
    If you can’t dazzle ’em with brilliance, baffle ’em with bullsh1t.

  34. Irrigation added lots of Water Vapour into the air over a very large area. Of course it’s going to affect the climate. I believe irrigation for agriculture is more important than just agriculture when talking about these things. Agriculture by itself doesn’t change all that much, putting rivers worth of water into the air does.

  35. The farmers dunnit. Yeah, that’s the ticket. Actually, I believe ol’ Flim Flam Flannery proposed the idea in his book, The Weather Makers.

  36. No, boys and girls. Total poppycock. The entire human population was only ~5 million 8000yrs ago and the Anatolia farmers would make up some fraction of that. If they have warmed the planet a couple of degrees to stave off an ice age, Iowa all by itself could do the same.

    Am I right in saying that a huge problem with climate science is the gradeschool understanding of effective proportions, scales, magnitudes? I’ve judged highschool science fairs and found these weaknesses, but perhaps not as frequently as I have in climate science. An engineering estimate of the effect of the farmers of Anatolia is that it would be undetctable.

  37. The only difference between now and 800K years ago was a very small increase in CO2 and methane?

    If that tiny rise was sufficient to raise the temperature 2.3C, the modern rise should have increased temperatures by 10 times as much. At the very least.

    • What about the period 400K ago? Similar Milankovitch criteria with low eccentricity causing that interglacial to be a longer one also. Did that period not match their narrative so they left it out?

  38. They need to have this established as its more proof that CO2, the emissions of white male capitalists, need to be banned and their political and economic system ended and changed over to socialism.

    Surprised they haven’t spent more time, money, and created more studies on showing how sensitive the climate is to planet killing maggots</strike. humans. They know they need this 'scientific' link, wouldn't be surprised to see more similar studies in the next 5 years coming out.

  39. …says Vavrus. “Things are so far out of whack now, the last 2,000 years have been so outside the natural bounds, we are so far beyond what is natural.”

    I’m mystified by this reference to 2,000 years ago, as if humans had been doing nothing, zilch, nada, zip, zero for the 10,000 tgo 16,000 years prior to that. Since there is MORE than enough archaeological evidence to show that humans moved out of the hunter-gatherer state long before 2,000 years ago, I find it difficul to take this seriously.

    Why does he say “the last 2,000 years”, as if the Anno Domini period is the be-all and end-all for civilization?

    Per Food Timeline, flour, bread and soup were in common use 12,000 years ago, circa 10,000 BCE. http://www.foodtimeline.org/

    “Remnants of wild emmer in early civilization sites date to the late Paleolithic Age 17,000 BC (Zohary and Hopf 1993). Cultivated emmer emerged as the predominant wheat along with barley as the principal cereals utilized by civilizations in the late Mesolithic, and early Neolithic Ages 10,000 BC (Helmqvist 1955; Harlan 1981; Zohary and Hopf 1993). Cultivated emmer dispersion and use by early civilizations greatly exceeded that of einkorn. Due to the addition of the BB genome cultivated emmer could be grown in a wider range of environments including regions having high growing season temperatures. Cultivated emmer became the dominant wheat throughout the Near and Far East, Europe, and Northern Africa from the Neolithic (Stone Age) through the Bronze Age 10,000-4,000 BC. Emmer utilization continued through the Bronze Age 4,000-1,000 BC, during which the naked wheats, primarily the tetraploid species slowly displaced emmer. However, emmer continued to be popular in isolated regions such as south central Russia into the early 1900s. Presently emmer remains an important crop in Ethiopia and a minor crop in India and Italy (Harlan 1981; Perrino and Hammer 1982).”

    The use of wild grains such as rice, emmer and einkorn began 19,000 years ago. Cultivation of these crops began as much as 12,000 years ago. It is unclear what leads this researcher to imply that something done by humans is interfering with or exacerbating a natural cycle. I’m not sure what his purpose was, other than to imply that all progress since 0.00AD is bad. Well, it is NOT bad. There was plenty of progress before 0.00AD, which he seems to have ignored, and it is rather odd for him to say that humans have done something that implies damage to the planet while ignoring the repeated, recorded episodes of extreme cold.

    I doubt that our influence on this planet consists of much more than creating large masses of plastic stuff, and creating fatbergs in London’s sewer system.

    I don’t get it. The weather last year and this year at the same time are below average in temperature and above average in rainfall, and this trend has been increasing slowly since the winter 2010-2011. All it means to me is stock the pantry and freezer, and make sure the furnace gets its autumn checkup.

  40. “The findings are based on a sophisticated climate model that compared our current geologic time period, called the Holocene, to a similar period 800,000 years ago. ”
    Why 800,000 years ago when the uncertainty in the proxy would be closer to 1.3K than 100,000 years ago or any of the 3 warmer interglacials according to ice-cores going back 450,000.
    If I was more cynical I would suggest that this was the 6th or 7th attempt to find data that fitted their theory.

    • Robert,

      Maybe, but the interglacials of MIS 19 and MIS 11 are often cited as the nearest Milankovitch simulacra to the Holocene.

      https://www.sciencedirect.com/science/article/pii/S027737911500150X

      Interglacial analogues of the Holocene and its natural near future

      Unfortunately this paper suffers from CO2itis, but it does rightly point out that the interglacial of MIS 11 lasted a long, long time. Which fact wouldn’t be good for Ruddiman’s hypothesis. Hence, go with MIS 19!

      MIS 11 appears to have been the warmest and longest lasting interglacial of the last 500,000 years. If the Holocene turns out to be like MIS 11, Earth might experience natural “catastrophic global warming”, with loss of much of the Southern Dome of the Greenland Ice Sheet.

  41. “And unknowingly, they may have been fundamentally altering the climate of the Earth.”

    Ahhhh, there it is once again . . . that hard science phrase “may have been”. How about getting back to me when you have a science-based conclusion supported by data, instead of speculation supported by nonsense.

    I simply don’t have time for such BS.

  42. “It also shows that without this human influence, by the start of the Industrial Revolution, the planet would have likely been headed for another ice age.”

    I’m curious, has anyone put forth a truly plausible mechanism that explains the “Ice Age”? And by plausible, I’m referring to evidence based.

  43. Seems to me the modelers are just trying to come up with more reasons why their models didn’t work when they were doing hind casting… had to come up with some more excuses that it isn’t the model that’s bad… just that the data we are putting into it is bad.

  44. “I noticed that methane concentrations started decreasing about 10,000 years ago and then reversed direction 5,000 years ago”
    Which means that the earth must have been cooling even more since the end of the previous ice-age since the GHG level determine temperature, of course.
    Funny how the evidence isn’t there for such a simple application of logic to GHG/temperature correlation!
    Just as well we have models.

  45. I Think it is much more likely that a nearly infinite number of bugs and bacteria responding to natural cycles that are billions of years older than any nearly insignificant effect of hypothesized manmade farming cextrapolate the results they purport to extrapolate.

  46. “Global warming induced by “Ancient Farmers” may have staved off ice-age” It must be true because computer models tells us so. Now that’s funny. LOL

  47. In short, until we greatly increase our understanding of the workings of our closest star , our solar system and it’s history , and our galaxy , every single one of these hypothesis will have huge holes of uncertainty which preclude accurately predicting the Earth’s future climate .Predicting the future of any extremely complex chaotic system assumes knowledge of all variables influencing the system. Glaring assumptions inherent in all these models is 1) We understand how the energy output from the Sun ( and possibly the energy input into the Sun, yeah -we do not know it’s inner workings )in all it’s manifested forms, influences our Planet 2) the past energy input into the Earth has not varied to any large degree from what’s presently observed(if even understood) , and the future, with respect to these external forces, will not vary from the present. We should be humble , the predictive power of these models, for the foreseeable future , will remain very low .

  48. That fact that this type of garbage gets published shows that “Peer Review” does not work and has been compromised. You write a paper about anything causing you want, and as long as you tie it to AGW you’ll get published. Absolute nonsense.

  49. Possibly the authors would be happier if the earth was in a glaciation period? During the last one most of Canada and the northern part of the US were under 1/2 mile of ice. Would they like that better?

  50. And another thing! The temperature data determined from ice cores at Antarctica and Greenland don’t correlate with atmospheric CO2. Over the last 6000 years CO2 went up but temperature went down.

  51. Maybe I missed something* but it appears to be “the models show this … the models show that …” Is there any actual measurement of anything in here or is this more of the “science can be done with computers” stuff** that implies the real world has no significance.

    *If I missed the real world references it’s because I can only take so much of “it’s the models, stupid” before giving up because I know which side of the writing the stupid is on.

    ** avoiding more accurate but less objectionable words.

  52. “The findings are based on a sophisticated climate model that compared our current geologic time period, called the Holocene, to a similar period 800,000 years ago. They show the earlier period, called MIS19, was already 2.3 degrees Fahrenheit (1.3 C) cooler globally than the equivalent time in the Holocene, around the year 1850. ”

    Models are useful. But models based on estimates, guesses, supposition, and proxies are just sophisticated guesses. They are not facts, and treating them as such is foolhardy at best.

    There is nothing wrong with building castles in the clouds.

    The trouble starts when you try to move in.

    P. Dolan

  53. Earth’s climate would have been much cooler today, says Stephen Vavrus, senior scientist at the University of Wisconsin-Madison Center for Climatic Research at the Nelson Institute for Environmental Studies Ancient roots of farming produced enough carbon dioxide and methane to influence the environment. ”
    ________________________________________________

    Correct knowledge with wrong reasoning:

    Not carbon dioxide and methane were the triggers, but the change of albedo from that of an ice ball to that of a green planet.

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