Allowable 'carbon budget' most likely overestimated

From Eurekalert and the it’s worse than we thought department.

Public Release: 24-Jul-2017

Penn State

While most climate scientists, including the Intergovernmental Panel on Climate Change, implicitly define “pre-industrial” to be in the late 1800’s, a true non-industrially influenced baseline is probably further in the past, according to an international team of researchers who are concerned because it affects the available carbon budget for meeting the 2 degrees Celsius (3.6 degrees Fahrenheit) warming limit agreed to in the Paris Conference of 2015.

“The IPCC research community uses a definition of preindustrial that is likely underestimating the warming that has already taken place,” said Michael Mann, distinguished professor of atmospheric science and director, Earth System Science Center, Penn State. “That means we have less carbon to burn than we previously thought, if we are to avert the most dangerous changes in climate.”

The researchers explored a variety of date ranges for defining a “pre-industrial” baseline and the likelihood that, compared to those baselines, the global temperature averages could be held to 2 degrees C (3.6 degrees F) or to the preferred 1.5 degrees C (1.7 degrees F). They report their results today (July 24) in Nature Climate Change.

“When the IPCC says that we’ve warmed 1 degree C (1.8 degrees F) relative to pre-industrial, that’s probably incorrect,” said Mann. “It’s likely as much as 1.2 degrees C (2.16 degrees F).”

Because greenhouse gas concentrations have been increasing since 1750 it would be preferable to define a baseline prior to then, but actual instrumental measurements of temperature did not exist before the 1800s. There are also natural phenomena that preclude defining a single unique value for pre-industrial average global temperature.

“What period do you choose?” said study lead author Andrew Schurer, research associate in the School of Geosciences, University of Edinburgh. “Temperatures change due to natural factors such as volcanoes and fluctuations in the sun. If we choose the period 1600 to 1700 we get a different baseline temperature, for example, than if we choose 1500 to 1600.”

The researchers estimated the temperature baseline using simulations from the Coupled Model Intercomparison Project Phase 5, the current suite of models used for climate change research. They used a mixture of simulated sea-surface temperatures and surface-air temperatures to mimic actual global temperature observations. They also used three different scenarios for future carbon emissions that assume varying levels of aggressiveness in combating climate change.

They found that assuming the traditional late 19th-century baseline and using the highest future emissions scenario, by the middle of this century, the temperature rise will likely be about 4 degrees C (5 degrees F). With a moderate emissions scenario, the researchers found that keeping below 2 degrees C was still unlikely. Only the most aggressive scenario for reducing carbon emissions is likely to keep the temperature rise to 2 degrees C or less.

The researchers then considered all possible century-long periods for defining a baseline from 1401 to 1800 and used 23 simulations with seven different models. They found that anywhere from 0.02 to 0.21 degrees C (0.036 to 0.378 degrees F) warming took place prior to the late 19th-century period conventionally used as a baseline. Depending on which interval is chosen, the baseline could differ by almost nothing to a fifth of a degree C.

“A widely used metric for climate change mitigation is how much carbon we can still burn and remain below 2 degrees C,” said Mann. “It’s what we call the ‘carbon budget.'”

A pre-industrial baseline that truly contained no human-caused warming would alter the amount of carbon that could be put into the atmosphere. Measured in gigatons of carbon, to account for the 0.2 degrees C likely unaccounted for in previous estimates of human-caused warming, we would need to burn 40 percent less carbon to remain below the 2 degree C threshold, according to Mann.

“Either the Paris targets have to be revised,” said Mann. “Or, alternatively, we decide that the existing targets really were meant to describe only the warming since the late 19th century.”

If nothing else, Mann says that the community needs to be far more precise in defining what baselines are being used in setting targets.


Also working on the project were Gabriele C. Hegerl, professor of geosciences and Simon F. B. Tett, professor of geosciences; both at the University of Edinburgh, UK and Ed Hawkins, professor of climate science, Department of Meteorology, University of Reading, UK.

The National Science Foundation, the European Research Council; Natural Environmental Research Council, UK; National Centre for Atmospheric Science, UK; Wolfson Society; and the Royal Society, UK supported this research.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

217 thoughts on “Allowable 'carbon budget' most likely overestimated

  1. With the oceans starting to cool, it is an ABSOLUTE NECESSITY that the world continues to release carbon deposits from coal and oil into the carbon cycle.
    ALL LIFE on the planet depends on this.
    Those scientifically illiterate FOOLS trying to reduce CO2 output must be stopped before they cause irreparable damage.
    This CO2-HATRED we see around the world is the absolute peak of IGNORANT SUPERSTITION.

    • More like moving the starting line. According to Mann the industrial age started before we had industry, even before the steam engine was invented. Must have been all the coal fired forges at the smithies.

      • He probably figured out a new math formula he can run some cherry picked data through to deliver whatever output he already had written on a paper that was already in a sealed envelope. The difference between a cheap magician and a fraud lies in the cost so Mikey Mann is no cheap magician!

      • You understand him correctly. He can do this now because his team along with NOAA and NASA have reduced the historical temperatures (back to the late 1800’s and early 1900’s by 0.5 Deg C or more). Therefore, he can then claim the extra rise of 0.5 degrees, which supports his new claim: “When the IPCC says that we’ve warmed 1 degree C (1.8 degrees F) relative to pre-industrial, that’s probably incorrect,” said Mann. “It’s likely as much as 1.2 degrees C (2.16 degrees F).”
        Sneaky how Mann can now make these claims when the real historical (unmodified) shows very little global temperature change since 1900.

      • 2000 big whoop.
        20 million might have been enough to have a noticeable impact on CO2 levels.

      • Thomas Savery patented the first steam engine in 1698. Five years later the great storm of 1703 hit southern England. This is obviously no coincidence – the first use of fossil fuel for industrial purposes caused a massive climate change. It’s worse than we thought! /sarc

    • “said Michael Mann, distinguished professor of atmospheric science and director, Earth System Science Center, Penn State.”
      The first three words are probably enough to throw the whole thing in the bin.
      The rest of the quote means we can throw ESSC and probably Penn State in the bin too.

    • Sweet Bob.
      Mann will choose the middle of the last coldest period as a reference to start the temperature base line.
      I remember some friends taking LSD in the early seventies, even when they were totally out of it they had a greater grasp on reality than these baboons.

  2. “That means we have less carbon to burn than we previously thought, if we are to avert the most dangerous changes in climate.”
    Michael Mann, noted litigant and climate huckster.
    Translation, “We’re all gonna die. Send money now”.

    I thought that the CO2 released by Human Beings prior to 1950 had no effect on temperatures at all. That all of human influence happened after the 1950’s. Perhaps the baseline should be set from 1935 to 1985 instead.
    Or maybe we should go all the way back to the Roman Climate Optimum, Man was most certainly adding CO2 for cooking back then.
    Humans have been adding CO2 into the Biosphere for as long as Homo Sapiens have been around.
    I guess it is time yet again to move the start line back so you aren’t accused of moving the goal posts foreward (again)

      • Barbarian
        thank you, my abiding belief.
        We are releasing naturally, but accidentally sequestered CO2.
        Coincidental that man happened along just when CO2 was at it’s lowest point ever, threatening to extinguish all life, and we discovered the means to make fire, eventually discover fossil fuels, thereby liberating the planet from petrification.
        Divine intervention perhaps? But I’m not a believer, so just the most amazing coincidence the planet has ever witnessed.

      • Yep, it couldn’t be “fossil fuel” otherwise. Apparently Mann is attempting to squeeze every last milliwatt out of human releases that he can. The end of course is arguing that the entire holocene has been affected by AGW and that it has simply been increasing with time, population and technology. The argument has already been advanced however.

      • Reply to HotScots reply to Barbarian, absolutely correct, I have a laminated graph of the Co2 levels over the Geological timeframe, (I keep it in the car and every time I come across a loony-doomsayer-97%er out it comes and I ask them what they think about that?) and we are as you say at the lowest Co2 levels in geologic history other than the boundary between the Carboniferous and Permian epochs when concentrations became dangerously low then as well. On that occasion all life was saved by a bacteria that ‘miraculously’ appeared in the peat that released massive amounts of Co2. WTFH is that? We have seemingly miraculously been saved twice from the same fate…a dangerously low, below 400ppm Co2 concentration….
        Cheers guys, put a laminated Co2 graph in your cars glovebox, you will have no end of fun with it, the gift that keeps right on giving. The unhomogenized Co2 graph…history written in stone! And absolute proof that there can be no runaway greenhouse effect, with the geologic Co2 average concentrations of about 2,200ppm and has been higher than 8,000ppm and no greenhouse effect then.

    • The beauty of this is that it supports natural warming for an even longer period of time before CO2 got large enough to make a difference. Somehow the warmists are failing to see they are once again shooting themselves in the foot.

  4. Considering that the 2 degrees C was pulled out of the air, if not one’s nether regions, who really cares? The climate in the Medieval warm was probably over the 2 degree goal, and no dread things happened.

    • It’s really a window into their thought processes isn’t it. To them, it’s the number that matters, not the effect.

      • I’m starting to think that the mentality they must have is that a well-crafted bulshit story might as well be the truth, and thus will morph into the truth if repeated often enough.
        They just have to get the hang of the well-crafted part.

      • Gnome
        They have to make stuff up in an attempt to remain relevant.
        What they don’t realize is this type of garbage decreases their relevance at an ever increasing rate.
        It would be interesting to be a fly on the wall listening to this drivel being discussed.

    • Didn’t Phil Jones claim to be the source of the ‘2 degrees’ meme? And didn’t he say he just made it up out of thin air?
      As it is obvious to everyone that ‘2 degrees’ has no meaning at all about anything other than the difference between a bad winter and a slightly less bad winter (is it warmer in summer anywhere?) i just can’t get excited about Mann’s silly targets.
      Revising a silly target for no reason at all – he doesn’t give one – is as unproductive as changing teats on a bull and expecting a different flavour.
      Since Hansen quit Mann has become more strange.

    • The Medieval may or may not have been over the 2C mark. However the Roman and Minoan warm periods were well over that mark, and the Holocene Optimum blew through and waved good bye.

  5. Co2 from volcanoes is a relatively small proportion of modern day co2 but back in the preindustrial age it is likely to have been a substantially larger factor than mans emissions.
    Bearing in mind the length of time it is supposed to build up in the atmosphere the accumulated amounts fiom the previous few centuries prior to the industrial age must be significantly greater than our influence

    • There are no accumulated amounts of CO2. Its half-life in the atmosphere is about 5 years, which means Co2 is quite dynamic and responds to current conditions. The fact that CO2 has been increasing linearly in the atmosphere and our emissions have been going up logarithmically shows that we are having no effect on global CO2 concentrations. That’s the ball game.
      No effect even with our emissions and, thus, who cares what CO2 can do, it is not our fault and we have no control over it. ADAPT is the key word to repeat over and over now.

      • Higley
        In addition to the increase not following the rate of human-sourced CO2, the seasonal variation has been increasing, as attested by Keeling ‘hisself’.
        The seasonal variation is far more in ppm than AG emissions showing that biomass on land and in sea is a larger source of variation. By that I mean if the biomass growth rate doubled it would more than swallow all AG CO2 without any net increase in concentration. Just slowing down the plants in about 1/2 of the world raises the CO2 about 6ppm, right? 7ppm? Something like that.
        It seems to me we shall soon enough be at equilibrium with AG emissions from fossil sources entirely taken up by increased photosynthesis. And at what concentration? Not enough to keep us out of the next ice age.

      • Correct that CO2 never accumulates in the atmosphere. Standard biogeochemical carbon cycle. Deep sources and sinks are hundreds or thousands of times larger than atmospheric CO2.
        There are several overlapping time periods for how quickly CO2 exchanges into the large surface sinks/sources which are not exactly balanced.
        Annual turnover is about 25 percent, but that is just exchanged with shallow surface sources/sinks, such as the ocean surface and annual biology. This fast turnover tends to stay balanced, but there are exceptions.
        The key long time period carbon sinks remove about 5 percent of all atmospheric CO2 in a year. CO2 in this exchange pool never returns to the atmosphere, but is mostly replaced by a similarly sized pool of deep sources, biological and deep ocean. This “replacement” time is directly measured by the 14C “bomb” curve which peaked in 1964, and dropped by 1/2 in 10 years. This is the same curve as the so-called “e-folding” time which is how long it would take for an exogenous CO2 addition to the atmosphere to be removed into the deep sinks. Also called “Tau” is point in time for the added CO2 to drop to 1/e of the start time, a 10 year half-life is identical to a Tau of 18 years.
        A simple rough model for this is a rapidly flowing river where the center of the river flows more rapidly than the water near the shore. Adding exogenous buckets of tinted water the the center of the river has the same fate as water added at the shore, both are removed but at somewhat different rates. No matter, water added to a river never accumulates. If you add a small stream to the river at a rate of 1 percent, the amount water from the small stream remains at 1 percent at all points downstream in the main river.
        If the anthropogenic fraction of atmospheric CO2 flow into the atmosphere is 4 percent of the “permanent” or “natural” flow, then the amount of anthropogenic CO2 in the atmosphere is 4 percent of 400 ppm, or 16 ppm. If all sources of CO2 to the atmosphere were instantly stopped, the remaining CO2 in the atmosphere would drop to 200 ppm in 10 years, 100 ppm in 20 years, 50 ppm in 30 years and 25ppm in 40 years. All due to deep sinks that never stop.

    • Golly, that sure is real magnanimous​ and open minded of you, Tony!
      I am pretty sure that to a hardcore warmista you are now squarely in the camp of being a filthy den!alist skeptic,
      Although to any serious person, that crap you’re spouting is still a bunch of nitwit warmista jackassery, your allowance that at least part of man’s time on Earth has not been diabolically evil planet killing, means your heart is possibly not completely a blackened cinder of self-hate. Perhaps in the same general area as the Grinch’s was around the time he ran into Cindy Lou Who.
      But I think it’s going to be a while yet before you are carving the Skeptical Roast Beast.
      Keep at it, you don’t want to give up 5 minutes before the miracle.
      Although I’m guessing any warmista epiphany has to be a somber one, what with embarrassment of realizing how incredibly wrong one has been about so much for so long on zero actual evidence.

      • Oh.
        Well, if Tonyb is not a warmista, I recommend practicing the warmista art of transference, and applying the above to any of your favorite trolls.
        With my regrets and apology.

  6. Dr. Mann
    Only facts are substance of science, anything else at best is an educated guess moving downwards via inconsequence to at the worst malicious attempt to mislead.

  7. For atmospheric concentrations IPCC considers 1750 to be the “pre-industrial” year, but we don’t know what the “global temperature” is in 1750, and we *do* know that the “global temperature” wasn’t constant during pre-industrial temperature times. This paper will give us some model estimates for 1400-1800, but the model guesses can’t be validated at all and there’s no reason to expect them to perform better than they have in current years.
    But that shouldn’t be relevant at all to the “carbon budget”. If there is any good reason for the politicians to set a 2C warming target from “pre-industrial” in the first place (questionable at best), surely the reason is to avoid a *specific* amount of *future* warming. That’s the change that will actually affect society, not a differential from an *unknown* figure at an arbitrary point in the past.
    Of course, the admission that we’ve already warmed 1.2C from an arbitrary guessed-at point in the past without anything catastrophic happening — or without anyone noticing any real harm at all — should call into question the idea that preventing the next ~1C of warming is all that important.

    • Any good reason for the politicians to set a 2C warming target from “pre-industrial” in the first place? It’s only a matter of time before they notice the coincidence of the end of the late glacial maximum and the beginning of of the Holocene 11,700 years ago and the beginning of slash and burn agriculture.
      Who cares about causation when it’s only “the cause” that matters?

  8. Since we all know that correlation is not causation, and that we also don’t have, or possibly ever will have, a fixed number for ECS, what confidence do we have that any baseline we pick will be the most correct baseline? It seems a blindfolded monkey could throw a dart at a list of dates and be just as likely to be correct.
    Also, since we’re talking about CO2 levels, I haven’t seen anyone here talking about a recent paper with the conclusion that CO2 does not trap heat as has commonly been believed, and this therefore not a greenhouse gas at all. Their conclusion is that temperatures may be estimated by solar irradiance and total surface
    atmospheric pressure. Has anyone read this paper? Do the conclusions seem reasonable to anyone else?
    New Insights on the Physical Nature of the Atmospheric Greenhouse
    Effect Deduced from an Empirical Planetary Temperature Model
    Ned Nikolov* and Karl Zeller

    • I would be a little cautious. Papers overturning well accepted things do occur, but they are rare. This paper is based on a trebling of the greenhouse warming effect from 33K to 90K. This would be a major revolution in science. That does not make it wrong, but it is important to check the source.
      Is the journal in the Master Journals list? No, Environment, pollution and Climate change is not. Red flag. This means the journal is not accepted as a reliable source by libraries etc.
      What is the journal impact factor? There does not seem to be one, even on the journals host page – look down to the bottom, the journal is listed with a dash where the impact factor should be.
      I would say this paper looks like one of the vanity published ones in a “pay to play” journal. I would treat it with a large pinch of salt.

      • On the other hand, this is an interesting document which, if no-one can shoot holes in it, should win the authors a Nobel Prize. Briefly, the authors construct from first principles equations which, given known physical constants for the earth and various other planets and satellites, should enable the global surface temperature of any rocky planet to be calculated. Having done so, they find that the resultant equations are independent of any assumed warming from ‘greenhouse’ gases. Instead, they find the said temperatures are solely dependent on the amount of solar irradiance (ie, the heat received from the sun) and the surface atmospheric pressure. There
        are no ‘tipping points’ and there is no possibility of a runaway greenhouse scenario. Hence no “Catastrophic Anthropogenic Global Warming” and the present desire to limit carbon dioxide emission is seen as nonsense.
        The mathematics looks complicated, but seems logical. One does not need to understand the details of the construction of the various equations, but should be able to accept them on the basis that if they were wrong one of the authors would have told the other “There is a snag here.” and any problem would have been fixed. Similarly, at least one of the reviewers (one assumes it was properly peer reviewed) would have picked up on any incorrect mathematical derivations. One must also accept that they did not make a blunder in doing the regressions – should be a matter of putting in the various parameters they used into the standard regression
        analysis tool they used. Hence, their conclusions should be accepted as sound.
        Logically then they have driven a horse and cart through all the stuff pushed by so-called “climate scientists”, and accepted by politicians. And this means that all efforts to limit ‘global warming’ to two degrees Celsius are irrelevant at best, economically dangerous at worst, and should be abandoned.
        As I said, it will probably win them a Nobel Prize – only hope I live long enough to see them get it.
        I would love to see the comments from Stephen McIntyre and Ross McKitrick. I hope someone here can draw this to their attention.

      • I already posted this, but it did not appear and no “awaiting moderation message” so I will post the information again.
        This paper has been discussed here before . Anthony watts said of it “And I agree with Gavin, the paper itself is nonsense. Their work has been the same sort of “pressure rules the temperature of planetary atmospheres” nonsense that the irascible Doug Cotton pushes…under multiple fake names to try to get attention, here and elsewhere. Now they seem to have followed his lead.”
        Willis has many, many criticisms here:

      • “On the other hand, this is an interesting document which, if no-one can shoot holes in it, should win the authors a Nobel Prize.”
        Willis Eschenbach knocked quite a few holes in it in WUWT a post called “Traveling Through Other Dimensions
        Willis Eschenbach / September 1, 2015”
        Posts with the links do not seem to appear.

      • ” Briefly, the authors construct from first principles equations which, given known physical constants for the earth and various other planets and satellites, should enable the global surface temperature of any rocky planet to be calculated.”
        This is very much not contructing equations from first principles. It does not use any physical theory at all, but fits the data to a variety of models. Nothing wrong with that necessarily, but do not mix up the two.

    • “Has anyone read this paper? Do the conclusions seem reasonable to anyone else?”
      I have, and they do seem reasonable. Their formula seems to apply to more than one planet/moon, which could be significant if confirmed. I believe they are trying to add to the list of planets and moons that might fit the formula. Time will tell if they fit. A general formula that works across numerous planetary bodies is not something to ignore.

  9. Michael Mann, distinguished professor of atmospheric science

    Distinguished is such a versatile adjective.
    The question of what the baseline should be depends on what you are trying to use as a control.
    If you are concerned about CO2 then it’s when CO2 emissions start to accelerate. That is either;
    A) 1900 (when anything can be observed).
    B) 1950 when it becomes an exponential rise.
    Neither are further back.

    • M Courtney
      At the start of this interglacial CO2 stayed at 260ppm for the first 7000 years, then moved to 285pp.
      That movement signified the maturing of biospheres after 12,000 years of voracious biosphere growth.
      Temperature remained in a narrow band for the total interglacial.
      We have been in the mature phase of the interglacial for over 3000 years, and over the past 1000 years reduced active biospheres at an ever increasing rate. Plus emitting CO2 into that smaller biosphere.
      There is no reference point that is valid. It is all make believe and opinion based on what your objectives are.

  10. Go back to the STONE AGE not 1890!!!
    The correct time frame to return us to is .. the stone age, and that’s consistent with what the loons on the left hanker for:
    “We have wished, we ecofreaks, for a disaster… to bomb us into the stone age, where we might live like Indians.” -Stewart Brand, Whole Earth Catalogue
    Just go ahead with FULL scale de-development, as Obama’s Science Czar called for:
    “A massive campaign must be launched to de-develop the United States.” -John Holdren, 1973
    The former head of the United Nations Environmental Program had the right idea:
    “Isn’t the only hope for the planet that the industrialized civilizations collapse. Isn’t it our responsibility to bring that about?” -ex UNEP Director Maurice Strong
    Of course, a problem with Maurice Strong’s idea is that he really needs to concentrate exclusively on the evil United States (maybe also on the evil UK and Australia!)!
    And we should let China and our other possible military antagonists go hog wild with their emissions. Indeed, the following graph needs to be changed so that future US emissions goes down to near zero (stone age levels not 1890!) and China’s goes through the roof, so then we can be a vassal state (slave of) of China:

    • Well, even cavemen burned coal for heat, and the natives of the American southwest (who never advanced beyond the stone age) burned coal as well…the fools! [sarc]
      Doesn’t appear as though retreating to the stone age is far enough for Mann.

    • 7 billion dead bodies are going to create a whole lot of CO2 as they decompose. The survivors will never be able to make that much quicklime.

      • Yeah, but there are four times as many of them as us.
        Are we supposed to feel bad about creating the modern world, which everyone on earth quote logically wants a slice of?

      • Since the residence time for CO2 in the atmosphere is short. What happened more than a decade ago is of no concern.

      • MarkW has the right idea. It is irrelevant if there was slightly more human-derived CO2 in the atmosphere a couple of hundred years ago.
        And from the article: “0.2 degrees C”. This is how much more heat was added because of going back in time and making adjustments? It’s insignificant.
        What’s important is what is happening now, and that is CO2 is going up and the temperatures are not going up. Just the opposite of what the alarmists predicted. So Mann’s additional CO2 claim has made no difference to anything in the real world.

      • sorry, markw, but no.
        there will be more co2 in the atmosphere
        100K yrs from now because of
        the co2 emitted this very day.
        co2 is basically forever, on a human

      • ta: you need to learn about
        the science done last decade by
        david archer (u chicago) and others.
        we are altering the carbon cycle
        for the next 4000 generations.

  11. First he says temps are influenced by many factors…..then goes on to claim temps would have been static without man’s influence…..then goes back to claim a time before the LIA and implies we would still be freezing out cahonies off if we didn’t pollute

  12. So we have warmed 1-1.2 degrees C since pre-industrial times. Exactly what have been the catastrophic results of that warming? A larger wealthier population, a greener planet producing more food.
    Yet we are supposed to believe that a further 0.5-1 degree C warming will be catastrophic.
    Brought to you by “scientists” with no supporting evidence. When will politicians stop the rot?

  13. There are also natural phenomena that preclude defining a single unique value for pre-industrial average global temperature.

    Like the fact that the global average temperature bounced all over the place before the industrial age, just as it does today.

    • The long term trend over the Holocene is very slightly negative, but not statistically significantly so. At finer scales there are trends that stand out but they tend mark intense, short term fluctuations.

    • Added to which it is even more of an imaginary number than the square root of -1 – and considerably less useful.

  14. Yeah, let’s just move the starting point to the depths of the LIA, then we can claim even more warming. Brilliant! /sarc

  15. “The IPCC research community uses a definition of preindustrial that is likely underestimating the warming that has already taken place,” said Michael Mann, distinguished professor of atmospheric science and director, Earth System Science Center, Penn State. “That means we have less carbon to burn than we previously thought, if we are to avert the most dangerous changes in climate.”
    That indicates that Michal Mann is an inductivist and not a scientist.
    He is speculating about what can not, and was not measured in the past to predict the future.

    • Being and inductivist and a scientist are not incompatible. Inductive reasoning is the basis of science.

      • It is an interesting discussion, and deductive reasoning is usually thought of as the basis of scientific method, so my phrasing was certainly imprecise. However, when we assume that Newton’s Laws will apply as well today as they did yesterday we are using inductive reasoning. And induction is used to construct hypotheses and conjectures.

      • Seaice
        Deductive reasoning is the basis of science. Induction is not reasoning, it is guessing and hoping there is proof to follow.
        This difference describes perfectly the inversion of science that Hansen is famous for. First claim calamity then spend decades looking for proof of it. There was no such proof, not even an inkling of it, in 1988.
        There is none now, not even an inkling of it. To guess that there will be one day is ‘inductive’ and that is why the guessing persists. It is not science. Science is deduction from evidence and replication.

      • Crispin, do you think tomorrow will come? If so that is induction. Do you think Newton’s Laws will apply tomorrow as well as they did today? Induction again. We simply cannot get by without it.

      • We deduce the sun will rise tomorrow because we have observed it happening in the past. We deduce the apple will fall from the tree because we have observed and measured the motion of apples that fell from the tree previously. Deductive reasoning. There is a place for inductive reasoning in science, stretching mathematics to see where it may lead us, to provide hypotheses to us to test with observation. But inductive reasoning is not the basis of science.

      • Pumpsump – why do you think the past is a reliable guide to the future? We cannot test the future, so we have to rely on induction. It has always been so, so we anticipate it will continue to be so. This is inductive reasoning. For all we know all physical laws will cease to operate tomorrow.

    • Mann’s stock and trade since he gained media attention in 1998 has been fabrication. If you read his original work, the one that got Al Gore all excited, he uses sparse tree ring data as a source of pre-industrial temperatures and doesn’t give any confidence limits for his “measurements”. It really is appallingly bad. I was frankly shocked when I read it. I couldn’t believe it got published. Here’s the kicker; I’d been a proponent of the AGW hypothesis since about 1986. It was like being kicked in the face.
      Mann is no scientists.

      • History will show that the scientific claims of the global warming house of cards began to fall in 2003, by McIntyre & McKitrick. For a starting point see
        Personally, I say that the year the entire global warming meme began to die is when the Al Gore freak show was released in 2005 and when he said the science was beyond debate.

      • sorry, no. mcI and McK’s claims were about
        the hockey
        which has nothing to do with the case
        for agw. you should at least understand
        that much.
        hockey sticks have now
        been found everywhere.
        for good reason — basic science.
        mcI and mcK were a blip in history
        and now
        forgotten. sorry to burst your

      • The Hockey stick was used as proof of AGW.
        It’s hardly surprising that disciples of Mann, using the same data and same methods also were able to create hockey sticks of their own.

      • cracker -> You are joking, right. Otherwise you have just stated the most obvious, unjustified fabrication I’ve seen here.

      • markw: no, the hockey
        stick has not been used as proof of agw,
        by anyone who knows what they
        are talking about.
        it’s a reconstruction of past temperatures.
        that’s all
        but it does beg the question of “why?”

      • markw: groups like pages 2k, tingley & huybers, and many
        others have found
        the same hockey stick shape
        using completely independent and different
        you should understand what
        you’re taking about before you
        dismiss any work.

  16. Apparently, Dr. Mann’s philosophy is when you find yourself in a hole of stupidity, keep digging.

      • Or possibly something along the lines of “Iffen you’re gonna be going full retard anyhow… in for a penny, in for a pound. Let’s get nuts!”

      • I don’t think you’re right about him being stupid at all. Any idea what he pulls down in salary and “honorariums”? No. Mike’s not stupid. He’s a household name.
        Mike is a performer and he’s paid well. I doubt he believe his own tripe any more than Rush Limbaugh believes his. He’s a very successful showman of world repute. He isn’t a scientist though. It actually takes more than a degree to be a scientist. Ths is proven by the fact scientists existed before degrees did.

  17. I choose 1AD as the preindustrial baseline to use. We have warmed a whopping -1 C (yes that is a minus sign) since then so obviously industrial activities cause a decline in global temperatures! Where is my grant!
    (Do I need /sarc?)

  18. I’m not sure who to attribute this to, but the article has the statement, “They found that assuming the traditional late 19th-century baseline and using the highest future emissions scenario, by the middle of this century, the temperature rise will likely be about 4 degrees C (5 degrees F). ” Actually, 4.0 deg C rise is equivalent to 7.2 deg F. Or being precise with respect to the stated significant figures, 4 C = 7 F. Either way, the veracity of the claims is open to question.

  19. Did someone just realize that even at the economic levels of 1850, there were several thriving democracies? Must go back to at least 1700 to have their ideal world, where there are royalty, nobility, peasants, and slaves.

  20. The Holocene ‘climate optimum’ was about 1.5 C warmer than now 8,000 years ago. So the optimum temperature has already been determined and we still have about 1.5 degrees C to go. Fortunately it looks like we might be able to get there by doing — NOTHING.

  21. Didn’t Michael Mann “prove” that the temperature never changed between 1000AD and 1900? Correct me if I’m wrong about the dates. If that’s the case, why is it necessary to go further back than 1900 for a baseline?

    • Where meters are not exactly known for taking all the facts into account at once.
      They like each of their internally illogical and self-contradictory arguments to be “stand alone”, and not compared to anything else they may or may not have said in the past.
      You know, like how global warming causes more snow and less snow, warm Winters and cold Winters, more rain and less rain, more hurricanes and less hurricanes, less ice at one pole but more at the other…etc…

      • Doh…speech to text! *bumps palm to side of head*
        The first word should be “Warmistas”.
        Not Where meters.

      • Not carefully rereading speech to text before hitting send can be very dangerous, especially at, say…work!
        Although sometimes amusing and often nonsensical, it does occasionally produce a truly regrettable message.
        I really wish preview panes were universal.

    • The MWP is a problem for alarmists because the temperatures were at least as warm then as today and probably warmer. Because of that it is unlikely that we are near a tipping point that will send temperatures skyrocketing.
      Michael Mann used his hockey stick to erase the MWP and LIA. I suspect that, after M&M debunked the hockey stick, most honest scientists no longer support it.
      Here’s a paper that deals with the current rebound from the LIA. It concludes that natural variability predominates and that human caused global warming is overstated.

    • “Didn’t Michael Mann “prove” that the temperature never changed between 1000AD and 1900?”

      • Correct, seaice! He just TRIED to prove that! With his trademark cherry picked data and bogus math. But he was exposed, wasn’t he? It must be so hard, trying to claw ahead in Academia when you’re not very bright and you’re in an utterly bogus field. Good thing he had dishonesty going for him!

  22. I’m surprised they haven’t tried this sooner.
    If future “forcing” [spit] only increases as the logarithm of increasing CO2 concentration, per Beer-Lambert, then it makes sense for every concerned alarmist to push the start date back as far as possible, and then some more.
    It seems kinda lame that this is only just occurring to them.

    • …and anyone who thinks the temperature record from that time doesn’t concur, is now best described as naïve if they think those temperatures can’t be “adjusted” to make them concur.

      • No real need for adjustment if we take the baseline date back to before the invention of the thermometer. At that point we’re completely free to just make stuff up.

      • Warmistas apparently give themselves much more leeway, feeling free to make stuff up whenever the heck they darn well feel like it.

  23. From the FRANT Department (Facts Ruin A Nice Theory) see:
    The Italians had a standardised, distributed set of temperature recording stations a long, long time ago. Their records show little warming since, though the extremes of warm and cold have become greater.
    The true believers (the Church in this case) closed them down as they were associated with the heretic Galileo – sound familiar?

  24. It seems to me that the most logical base line should be the Holocene Optimum.
    It is referred to as the Optimum for a reason, and also this was prior to any large scale anthropocentric land change and mass farming.

  25. A classic political strategy. The original baseline we chose is allowing way too much CO2 emmissions. Ive had a new idea! – lets change the baseline back to the depths of the LIA. That way we can say man has warmed the climate more than we thought! And we can reduce the emissions target even more! Brilliant!
    Just make sure nobody mentions natural climate variation at all, as our new proposal will be sunk. /sarc

    • warming is proportional
      to total co2 emissions. it
      doesn’t matter when you start,
      but you
      might as well start before man
      started heavily emitting

      • No, it may be proportional to total GHG forcing (from all GHGs) but certainly not to CO2; the whole ln(C/Co) thing comes into play with CO2. All of which begs the important questions: the sensitivity to forcing, the magnitude of warming, and the consequences of warming. Noting that adding CO2 causes some surface warming is pretty much irrelevant in terms of public policy. Accurate quantification of costs and benefits is needed to formulate reasoned public policy… and ‘the science’ seems no closer to that quantification than it was in the Charney report. ‘The science’ seems to me not up to that task, nor does it appear to be making much progress.

      • no stevefitpatrick.
        total warming is
        proportional to total
        emissions. this is a fundamental result found several
        years ago by Damon Matthews.
        the proportionality is
        1.5 C of surface warming per trillion tonnes
        of carbon emitted, with 2sigma error bounds
        of 1.0-2.1.
        “The proportionality of global warming to cumulative carbon emissions,” H. Damon Matthews et al, Nature v459, 11 June 2009, pp 829-832.

      • ps — this is the simple relation
        used by all policy
        makers to determine how much
        carbon we have left to emit
        before we reach
        X degrees of warming.

  26. I gotta tell ya, I’m single-handedly doing my best to personally destroy the planet. I eat lunch in my car with the engine running and the AC on – I eat Taco Bell to maximize my methane emissions (or sometimes Carl’s Junior to maximize the cows) – I work out at night, go jogging, maximizing my personal C02 output. I use 100 watt light bulbs for reading. I don’t even recycle.
    I’m like Lex Luthor and Dr. Doom rolled into one.
    Cue the evil laughter.

  27. Mann is in complete denial of natural climate change and oscillation. Only such a totally fanatical denier of reality could repeatedly utter the self-evidently meaningless phrase “preindustrial”. He really does seem to have convinced himself that earth’s climate was an unchanging garden of Eden, continuously for 4 billion years up until the industrial revolution. (Or maybe he believes in a much shorter age of the earth?)

  28. Models upon models, model runs after model runs…
    Sure sounds like manniacal’s buddies are deep in mikey’s version of fantasyland. Run models until one finds runs that validate confirmation bias. Voilà.
    Lunacytunes for delirious climastrologists.

  29. This is a very clear demonstration of the “It’s better to remain silent and be thought a fool…” axiom.
    Has no one explained to Mike that each time he goes back to the well and comes up with a different answer from the one he concocted last time, he discredits his own past work? As if it needed help to begin with. What a dweeb.

  30. The Manniac needs to make up his mind. He was chastising Hawking’s ridiculous anti-reality nonsense ostensibly to keep the science credible.
    And then he comes out with this apocalyptic claptrap.
    So It seems more likely he was guarding his turf, not really insisting on reasonable calm science.

  31. “The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”
    H. L. Mencken
    Earth’s carbon cycle contains 46,713 Gt (E15 gr) +/- 850 Gt (+/- 1.8%) of stores and reservoirs with a couple hundred fluxes Gt/y (+/- ??) flowing among those reservoirs. Mankind’s gross contribution over 260 years was 555 Gt or 1.2%. (IPCC AR5 Fig 6.1) Mankind’s net contribution, 240 Gt or 0.53%, (dry labbed by IPCC to make the numbers work) to this bubbling, churning caldron of carbon/carbon dioxide is 4 Gt/y +/- 96%. (IPCC AR5 Table 6.1) Seems relatively trivial to me. IPCC et. al. says natural variations can’t explain the increase in CO2. With these tiny percentages and high levels of uncertainty how would anybody even know? BTW fossil fuel between 1750 and 2011 represented 0.34% of the biospheric carbon cycle.
    Per IPCC AR5 Figure 6.1 prior to year 1750 CO2 represented about 1.26% of the total biospheric carbon balance (589/46,713). After mankind’s contributions, 67 % fossil fuel and cement – 33% land use changes, atmospheric CO2 increased to about 1.77% of the total biosphere carbon balance (829/46,713). This represents a shift of 0.51% from all the collected stores, ocean outgassing, carbonates, carbohydrates, etc. not just mankind, to the atmosphere. A 0.51% rearrangement of 46,713 Gt of stores and 100s of Gt annual fluxes doesn’t impress me as measurable let alone actionable, attributable, or significant.
    IPCC just pulled all of these CO2/GHG numbers out of some thoroughly PhD papered BUTT!

      • Nope…this be grade “A” deluxe high-falutin crap.
        They are refining their crap with every pass through their veg-o-matic slicer dicer, and will soon be producing pharmaceutical grade pure crap.
        Although crap being what it is, they will have then arrived pretty much where they started out.

  32. A serious question. Why would Mann et. al. be using the CMIP5 model ensemble to determine pre-industrial temperature? I thought the models were tuned to hindcast to match the historical record. Given that Mann claims to be able to reconstruct past global temperatures from various proxies, why do they need GCMs.

    • Well, that’s sort of complicated, but the short answer is no one believes Mann’s proxies after he published them last time. My guess is he figures hanging his hat on a whole bunch of failed climate models is better than relying on his own reputation for abject failure?

    • I took it to be a sort of “Any port in a storm” grasp at any straw they could grab.

  33. “global temperature averages could be held to 2 degrees C (3.6 degrees F) or to the preferred 1.5 degrees C (1.7 degrees F).”
    That would be 2.7 F, not 1.7. They were probably using the same method as always: Pulling wildly erroneous guesses out of their hysterical butts.

  34. Common sense and scientific integrity have been sacrificed on the alter of Carbon Dioxide

  35. Michael Mann = hot air. He can take his “carbon budget” & stick it in a private place – that is, if he is actually able to remove his head first.

  36. I am the only one who is becoming increasingly riled while reading each latest iteration of made up baloney?
    I am just truly sick of these arguments that use predetermined conclusions to derive ever more grave fantasy-land doomsday scenarios.
    There is no evidence in existence, not one shred, that CO2 is the temperature control knob of the atmosphere, and some desired temperature can be dialed in by any means whatsoever, let alone by policies that do not actually change anything.
    On top of that, how the hell have they brainwashed even a single soul into believing that the bitterly cold time of a few hundred years ago is a desirable prospect, and the clement warmth we now enjoy is a catastrophe?
    How the hell can anyone accept for a second that the deadly cold wastelands must be preserved at all and any costs?
    At this point I am actively wanting to see a sharp and deadly multi-year cool-off, to once and for all destroy the idea that warmista insanity makes a lick of sense.

    • DITTO !!!!!
      I’m totally sick of the lack of historic perspective from the AGW scammers.
      Arctic sea ice extent is above what it has been for some 90-95% of the Holocene,
      Greenland Ice mass is pretty much at its highest in 8000 years,
      Temperatures are but a tiny bump above the coldest period in 10,000 years.
      And I bet EVERY one of these AGW scammers lives in WARM places and uses heaps of fossil fuel energy for heating in winter., We know for certain that the high priests of the AGW agenda are full-on users of carbon based energy.
      It really is like some sort of mental disorder / manic brain-washing !!

    • Ditto. How often do you see in the MSM any discussion of the benefits of higher CO2? I don’t recall seeing one, ever. Greening of the earth seems to be a bad thing, not worthy of discussion in a positive light. You never see anything discussing what a 2C rise in temperatures will do for life expectancy or quality. No discussions about CO2 emissions reducing as it warms because we don’t need to heat as much. It is always about the coastal people having to move to the fly over country (god forbid) to escape sea level rise.

      • Jim Gorman
        Seldom has it been easier to disprove a comment on WUWT, and that is really saying something. Literally numbers 1 and 2 on a google search of “greening of earth” gives hits from those institutions so hated here, The Guardian and the BBC
        Please make some effort to substantiate your claims.

  37. CO2 is one of the two major building-blocked for ALL LIFE ON EARTH, and it has been desperately short for 100s of thousands of years.
    Finally human kind comes along, and through their ingenuity find ways of saving the planet from these desperately low CO2 levels.
    Then the very people who should be worshipping CO2, the environmentalists, band together and try to stop its production.
    Fortunately, their efforts so far have had minimal affect, and with China now funding a whole heap of coal fired power stations around the world, the ONLY people who are going to suffer are those who’s very gullible governments are cow-towing to this CO2 HATRED insanity/agenda.

  38. Isn’t “it’s worse than we thought” another way of saying that previous science studies that confirmed something were wrong?

  39. Is it possible there was less CO2 during the Little Ice Age because less plants were growing due to the cold?
    Non-scientist, just asking!

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