How to Talk to a Climate Skeptic: Responses to the most common skeptical arguments on global warming A Grist Special Series

‘The CO2 rise is natural’—No skeptical argument has been more definitively disproven 12

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: It's clear from ice cores and other geological history that CO2 fluctuates naturally. It is bogus to assume today's rise is caused by humans.

Answer: We emit billions of tons of CO2 into the air and, lo and behold, there is more CO2 in the air. Surely it is not so difficult to believe that the CO2 rise is our fault. But if simple common sense is not enough, there is more to the case. (It is worth noting that investigation of this issue by the climate science community is a good indication that they are not taking things for granted or making any assumptions -- not even the reasonable ones!)

It is true that CO2 has gone up on its own in the past, most notably during the glacial-interglacial cycles. During this time, CO2 rose and fell by over 100 ppm, ranging between around 180 to 300ppm. But these rises, though they look steep over a 400Kyr timeframe, took 5K to 20Kyrs, depending on the glacial cycle.

By contrast, we have seen an equivalent rise of 100ppm in just 150 years! Check this plot for a dramatic juxtaposition of the slow glacial termination versus the industrial revolution.

There is still more to the case. By analyzing the isotopes of the carbon and oxygen atoms making up atmospheric CO2, in a process similar to carbon dating, scientists can and have detected a human "fingerprint." What they have found via the isotope signatures can be thought of as "old" carbon, which could only come from fossil fuel deposits, combined with "young" oxygen, as is found in the air all around us. So present day combustion of fossilized hydrocarbon deposits (natural gas, coal, and oil) is definitely the source of the CO2 currently accumulating -- just as common sense tells us.

For more of the nitty gritty technicalities straight from the climate scientists, including links to the actual research that established this, visit RealClimate's article on how we know the CO2 is ours.

Of all the pillars holding up the theory of anthropogenic global warming, this is one of the most unassailable.

Former musician, turned tree planter, turned software engineer. Same old story…

I have been blogging about climate change since 2006 at A Few Things Ill Considered.

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  1. ginin Posted 3:25 am
    29 Mar 2007

    CO2 Levels

    Hi, very interesting collection of information you have about GW. Most important, it's sourced to scientific data. But today I found something that disturbed me:

    http://www.freerepublic.com/focus/f-bloggers/1806245/post ...

    Is the data shown there valid? Has this paper been confirmed/rebutted? I will appreciate your input on this one. Thanks

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  2. Coby Beck's avatar

    Coby Beck Posted 7:43 pm
    01 Apr 2007

    bunk from beck

    Hi ginin,

    This stuff is really ridiculous.  I refered to an earlier and similar paper of his here:
    http://illconsidered.blogspot.com/2006/10/definately-not- ...

    In that article are links to more scientific opinions about his conclusions and methods.

    I would just add that if he were correct we would require a couple of pretty serious follow up explanations.  Firstly, if global CO2 really jumped all over the map as he claims occured in the early 20th century, why did it suddenly stop jumping and become so smooth and steady since?  Secondly, by what mechanism is CO2 so rapidly removed from the atmosphere?  Adding it is not such a problem, there are many places it can come from, but where did it go so rapidly?  CO2 spikes take centuries to flux out of the atmosphere.

    No, this is pure unadulterated bunk.

    Sorry for such a tardy reply.

    "The problem with people who have no vices is that they tend to have some pretty annoying virtues." -- [paraphrased] Elizabeth Taylor

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  3. theavenger Posted 7:11 am
    04 Apr 2007

    Newbie here

    Please indicate your scientific credentials that would compel one to believe your assessment of  the merit of that article rather than the views of the author.

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  4. Coby Beck's avatar

    Coby Beck Posted 6:50 pm
    04 Apr 2007

    you want credentials?

    If you want scientific credentials I refer you to the fine and highly qualified people who have authored the IPCC chapters on atmospheric CO2.  I apologize for not producing a link but I am out of town, busy, and without my bookmarks.

    I ask no one to take my word for anything, but I do think a little common sense of your own should dispatch 95% of the contrarian talking points out there, this one included.  The rest you must either think hard about or rely on the vast majority opinion of relevant experts.

    "The problem with people who have no vices is that they tend to have some pretty annoying virtues." -- [paraphrased] Elizabeth Taylor

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  5. MarkUK Posted 9:48 pm
    04 Apr 2007

    Alarm bells

    The alarm bells start going with parts like this:

    "Modern greenhouse hypothesis is based on the work of G.S. Callendar and C.D. Keeling, following S. Arrhenius, as latterly popularized by the IPCC. Review of available literature raise the question if these authors have systematically discarded a large number of valid technical papers and older atmospheric CO2 determinations because they did not fit their hypothesis? Obviously they use only a few carefully selected values from the older literature, invariably choosing results that are consistent with the hypothesis of an induced rise of CO2 in air caused by the burning of fossil fuel."

    That's not the writing of scientific article but the kind of writing you find in conspiracy novels. Suggestive questions and huge leaps in conclusions followed by the conclusion that the entire scientific community has been wrong, devious or fraudulent. Extraordinary claims ask for extraordinary evidence.

    If there is one thing scientists like it is finding mistakes in each other's papers... I've been there. If scientists had really published such bad, bad research it would by now have been thrown out.

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  6. theavenger Posted 4:21 am
    05 Apr 2007

    Credentials in the hard sciences please?

    I see. You do not wish to answer a valid question asked by a new reader? Links would make no difference anyway. I asked about YOUR credentials that will make me want to believe your posts, not the credentials of others who do not offer their wisdom here.

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  7. Coby Beck's avatar

    Coby Beck Posted 6:39 pm
    06 Apr 2007

    if you want credentials

    read from the primary sources and the IPCC report.  You are clearly stating that you want credentials so that you will feel comfortable believing what you read.  I do not want you to just believe what I write, I want you to follow up on my sources.  I do not produce any research of my own on these issues, and you should not blindly trust in my (or anyone's) opinions.

    We all have two and only two choices in this issue: read alot and think hard or trust well established institutions.
    http://gristmill.grist.org/story/2006/11/13/221250/49

    "What if this weren't a hypothetical question?" -- unknown

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  8. GreyFlcn Posted 2:11 pm
    08 Apr 2007

    Here we go

    Sad we have stonewalling at this much of a fundamental point.

    Anyways this should solve things pretty easily:
    http://www.youtube.com/watch?v=rtNdVDom0GU

    Even Martin Durkin agrees that the CO2 rise is manmade.   :P

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  9. WWAGD?!'s avatar

    WWAGD?! Posted 3:34 am
    21 May 2007

    Isotopes, or Just Dopes?


    There is still more to the case. By analyzing the isotopes of the carbon and oxygen atoms making up atmospheric CO2, in a process similar to carbon dating, scientists can and have detected a human "fingerprint."

    The amount of CO2 released from permafrost is enourmous.

    Which isotope is it?  

    Second question.   If the CO2 from fossil fuel burning is not the same isotope as atmospheric CO2, how can you be sure it has the same greenhouse gas effect as the natural CO2?

    Maybe this is why the hockey stick for CO2 rise is not reflected in a parallel temperature rise.

    John Bailo, The "Denier Guy"
    You Read It Here First

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  10. WWAGD?!'s avatar

    WWAGD?! Posted 1:56 am
    24 May 2007

    Natural Beats Anthropogenic, Every Time!

    This article clinches it:

    The Holocene CO2 Rise: Anthropogenic or Natural
    http://www.climate.unibe.ch/~stocker/papers/broecker06eos ... ...

    It is evident that MIS11 was a long interglacial that was not brought to an end by the precession cycle nor will the Holocene be (MIS 1).   Hence the cause for the CO2 rise during the last 8000 years was natural and not anthropogenic.

    John Bailo, The "Denier Guy"
    You Read It Here First

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  11. WWAGD?!'s avatar

    WWAGD?! Posted 3:24 am
    24 May 2007

    CO2 Natural


    http://www.co2science.org/scripts/CO2ScienceB2C/articles/ ...

    Clearly, to repeat some of the concluding words of Broecker, "we can state with some confidence that natural Holocene temperature fluctuations have been on the same scale as the human-caused effects estimated to result from greenhouse gases."  Hence, as he continues, "we cannot assume that in the absence of human intervention, earth's temperatures would have remained stable."  It would thus appear to be our common conclusion that we cannot unequivocally attribute any of the temperature rise of the past century and a half to CO2-induced global warming.  And that is why, as Broecker states in an earlier paper (Broecker, 1999), there exists "adequate room for maneuvering ... for those who doubt that the buildup of carbon dioxide and other greenhouse gases constitutes a substantial threat."

    John Bailo, The "Denier Guy"
    You Read It Here First

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  12. Linda B Posted 6:49 am
    26 Feb 2008

    Interesting

    It was an interesting post well worth reading. We humans sure destroys very much when it comes to the environment. I just hope we'll improve and get better on this matter.

    Linda, IT Professional currently working on the 10 pounds to lose project.

    Permalink

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Series Intro
'There is no evidence' -- Yes, there is 59
'Mauna Loa is a volcano' -- CO2 rise is measured on top of a volcano! 8
'Warming is due to the Urban Heat Island effect' -- No, it isn't 25
'One hundred years is not enough'--Yes it is 18
'The scientists aren't even sure' -- No scientist ever is 33
'One record year is not global warming'--Luckily, there are plenty more years to consider 19
'Glaciers have always grown and receded'--A few glaciers melting does not mean global warming 14
'The temperature record is unreliable'--But temperature trends are clear and widely corroborated 8
'It's cold today in Wagga Wagga'--Weather and climate are different 2
'The satellites show cooling'--No, they don't 15
'What about mid-century cooling?'--No one said CO2 is the only climate influence 11
'Antarctic ice is growing'--Well, probably not, but even if it were, we are not off the hook 8
'Global warming stopped in 1998'--Only if you flagrantly cherry pick 170
'But the glaciers are not melting'--Except ... they are! 3
'Antarctic sea ice is increasing'--Yes, but ... 14
'Sea level in the Arctic is falling'--Sea level is a surprisingly complicated thing 11
'Climate sensitivity is not very high'--Thermal inertia of the oceans means the jury is still out 2
'Some sites show cooling'--But you can't draw global conclusions from individual sites 0
'Global warming is a hoax'--I wish James Inhofe were just a hoax ... 12
'There is no consensus'--If this is not consensus, what would consensus look like? 109
'Position statements hide debate'--True enough, but that is not the whole picture 5
'Consensus is collusion'--Is climate science maturing, or should we reach for our tinfoil hats? 8
'Peiser refuted Oreskes'--In a poor piece of work that has been retracted by its author 4
'Models don't account for clouds'--Clouds are complex and uncertain, but unlikely to stop warming 6
'Climate models are unproven'--Actually, GCM's have many confirmed successes under their belts 13
'Aerosols should mean more warming in the south'--More North. Hemisphere warming is well-understood 1
'We can't even predict the weather next week'--But weather is not climate 11
'Chaotic systems are not predictable'--Sure, but who says climate is chaotic? 13
Understanding what is happening right under our noses does not require paleoclimate perfection 1
'They predicted global cooling in the 70s'--But that didn't even remotely resemble today's consensus 29
'Hansen has been wrong before'--Maybe, but not about the climate! 13
'It was warmer during the Holocene Climatic Optimum'--This period was not global and not like today 4
'The Medieval Warm Period was just as warm as today'--Repeating this point does not make it true 216
'Greenland used to be green'--Don't judge a book by its cover, much less a land by its name 23
Yes, the last ice age started thawing over 20,000 years ago, but that stopped a long time ago 5
'The hockey stick is broken'--Well, no ... but who's playing hockey anyway? 6
'Vineland was full of grapes'--Or was it an early advertising campaign? 4
'Global warming is part of a natural cycle'--This idea is one short step above appealing to magic 39
'Mars and Pluto are warming too'--No they aren't -- and what if they were? 24
'Volcanoes emit more CO2 than humans'--Not even close ... 31
'The null hypothesis says warming is natural'--An inappropriate test, and one that would fail anyway 4
'Climate is always changing'--That doesn't mean it isn't different today 5
'Natural emissions dwarf human emissions'--But emissions are only one side of the equation 5
'The CO2 rise is natural'--No skeptical argument has been more definitively disproven 12
'We are just recovering from the LIA'--Why should we expect this to happen? 4
'Climate scientists dodge the subject of water vapor'--No, they really don't 4
Water vapor is indeed a powerful greenhouse gas, but there is plenty of room for CO2 to play a role 29
There is no proof in science, but there are mountains of evidence 78
'CO2 doesn't lead, it lags'--Turns out CO2 rise is both a cause and an effect of warming 43
'Geological history does not support CO2's importance'--Just not true 0
'Historically, CO2 never caused temperature change'--Not so 19
'It's the sun, stupid'--Very bright, yes, but not getting brighter 18
The problem is not how high the temperature may go, but how fast it is changing 14
'Kyoto is a big effort for almost nothing'--Kyoto is only in its first phase 16
China and India have joined Kyoto, they just have different obligations, as is morally appropriate 3
'Climate change mitigation would lead to disaster'--Not really, but this may be lesser of two evils 6
Only if you ignore fossil fuel emissions 10
In 2008, did temperatures drop as much as they rose over the whole 20th century? 71
Is the IPCC so wrong their theories contradict a basic laws of physics? 23
Is the American Physical Society a crack in the climate change consensus? 3
Summer ice in the Arctic has recovered--Was the Arctic ice retreat a climate anomaly? 7
'Global warming comes from within'--Is heat at the Earth's core the real cause of global warming? 10
Was there another breathless announcement of another phony record, and another quiet retraction? 1
Hansen wants the skeptics thrown in jail--Did James Hansen really want to try the climate skeptics? 6
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