The Instigator
Pro (for)
7 Points
The Contender
Con (against)
0 Points

Resolved: Climate change is, on balance, anthropogenic in origin

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Voting Style: Open with Elo Restrictions Point System: Select Winner
Started: 5/10/2015 Category: Science
Updated: 2 years ago Status: Post Voting Period
Viewed: 2,133 times Debate No: 75088
Debate Rounds (4)
Comments (21)
Votes (2)




Select winner. 2k. 2 weeks.

== Definitions ==

Global warming: The average increase in temperatures since the late 19th century.

Man-Made: The literal definition is fairly obvious. In terms of this debate, man-made factors to climate change would be the emission of greenhouse gasses. Or, as the IPCC would describe man-made forcing, "changes in the concentrations of radiatively active species (e.g., CO2, aerosols)" [1].

To clarify "on balance", I am not arguing that climate change is entirely man made. But that it is predominately (50% or more) human caused.


R1: Acceptance
R2: Present case.
R3: Rebuttals
R4: Rebuttals and conclusion

== Some abbreviations ==

AGW -- Anthropogenic global warming
[G]CR -- [galactic] cosmic rays
TSI -- Total solar irradiation
MWP -- Medieval warm period
LIA -- Little ice age

== Rules ==

1. No forfeits
2. Nullifying the traditional rule 2 bsh uses. Sources can be put in outside links. For this topic I sometimes need the room :P
3. No new arguments in the final round
4. Maintain a civil and decorous atmosphere
5. No trolling
6. No "kritiks" of the topic (i.e. arguments that challenge an assumption in the resolution)
7. No semantics; debaters will adhere to the common/average understanding of the topic
8. The BOP is Shared; Pro must argue for independence and Con must argue against
9. Pro must present their case in round one
10. Violation of any of these rules or of any of the R1 set-up merits a loss



"I actually support ...the Spanish inquisition, the murder of natives and so much more."

Debate Round No. 1


C1) Climate sensitivity is likely high

Climate sensitivity is the key argument to this debate. Everyone agrees that CO2 has some direct effect, at least 1 degree C per doubling of CO2 concentration. This is what former climate modeler turned skeptic David Evans argues. “[All] serious skeptical scientists have always agreed with the government climate scientists about the direct effect of CO2. The argument is entirely about the feedbacks.” [1]

What are feedbacks? Feedbacks are important because they tell us how much warming we will have in the future. They amplify -- or dampen -- the warming effect of CO2. Changes in albedo, cloud cover, water vapor, and greenage can all affect warming. If sensitivity is 2-3 degrees C, CO2 can explain most of the warming since the late 70s. If it is lower it still causes a significant amount. My opponent needs to pretty much argue that the amplification effects are under one in order to win.

Let us assume that climate sensitivity is low. Say, feedbacks are around zero (no positive or negative feedbacks); every doubling of CO2 leads to roughly 1.1 degrees C increase in temperature. Even this unrealistically low climate sensitivity does not harm the AGW hypothesis. Nir Al Shaviv, a skeptical physicist, wrote a paper assuming the feedback effect was 1.1 degrees. He calculated that CO2 actually caused slightly over half of the modern warming trend [2] (about 57%). The famous Lindzen and Choi (and Spencer) results are really the only ones which cast doubt on the fact that CO2 is responsible for the warming. But Nir Al Shaviv told me in an email, “[m]y best estimate is that the sensitivity is higher than Lindzen and Choi, actually closed to no net amplifier, with the 50% of the CO2 doubling, the Anthropogenic contribution is also around 50%.” [3] Essentially, he verified what I sent to him in an email with calculations I had done assuming the amplifier was flat. My data found that it caused about 49.5% of the warming, but I failed to take into account the logarithmic effect of CO2, which makes the effect over 50%.

Even then, these assumptions are incorrect. Sensitivity is higher, and if it is, CO2 pretty much causes far more than 50% of the warming, but both estimates are enough to win me the debate. Research by Patrick Michaels, now a libertarian, CATO scholar found the amplifier to be 1.6 degrees C [4]. More than the 1.1 above. This puts the man made contribution to global warming above 50%, and certainly above 57%. This is not even including other gases which amplify the greenhouse effect.

The burgeoning evidence suggests that the net amplifier is around 2-3 degrees C. Based on multiple lines of evidence, stemming from volcanic eruptions, instrumental records, paleoclimatology, and more, the mean sensitivity sits firmly at about 3 degrees C. The following picture demonstrates the evidence.

As seen, the average never dips below 2 degrees C. The mean is 2 - 4.5 degrees C, all of which are enough for me to win the debate. 2 degrees C probably puts you around 70% of the warming is due to CO2, and 3 at nearly 100%, though I have not done the math (yet…). Some studies find fairly high sensitivity, around 4 degrees C. JD Annan, a leading climatologist, uses a Bayesian statistical technique, the predominant methodology in both the skeptic and realist literature. He found a mean sensitivity of 3 degrees C, with upper estimates at 4 degrees C, though still possible, but very unlikely below 3 degrees C [5].

The following graph [6], which I like because since I have used it pretty much everyone else has stolen it, shows the results from 3 leading studies. Although the results are uncertain, they are certain in that sensitivity is above 2 degrees C.

A new paper, published in 2012, actually went against the consensus and found low sensitivity. Despite this, their results concluded that “[h]umanity is . . . responsible for the most recent period of warming from 1976 to 2010.” [7]

Sensitivity is high. That means I win the debate. If it is low, I still win the debate because it caused 50% of more of the modern warm period.

C2) Evidence from paleoclimatology

I love paleoclimatology. I like geology and come from a family of geologists who are also oil entrepenueres (maybe why I still have skeptic leanings). And pretty solid evidence in the paleoclimatological record actually shows a strong CO2 effect. I am just going to c/p my debate with Roy.

There is significant evidence from paleoclimate records that CO2 can have an effect on changes in the climate. Climate skeptic and paleoclimatologist Bob Carter emphasizes the importance of paleoclimate data. He compares climate to a piece of string. The current instrumental data (1850 – present) is a very short period of time, according to Carter. And when the ‘string’ is lengthened, we see a lot of climactic variability. Instead of looking at the recent past, we should look at the entire temperature record in order to get an accurate picture of the climate [8]. I will provide evidenc, contrary to what Carter believes, lengthening the string supports AGW theory.

Over the Cenozoic Era, which began 66 million years ago, we see clear warming and cooling cycles caused by changes in CO2 concentrations. The sun increased slightly over that time period, whereas temperatures cooled. CO2, however, fell steadily through that time period. Plate tectonics was also accounted for. With natural forcings an unlikely cause, “CO2 was the dominant climate forcing in the Cenozoic” [9].

When you lengthen the ‘string’ over the course of the entire Phanerozoic (500 million years; begins at the Cambrian) there is still evidence of CO2 driving multiple climate changes. The GEOCARB study, published in 2001, is one of the definitive proxy records for CO2 concentrations within the last 500 million years. The study notes that “over the long term there is indeed a correlation between CO2 and paleotemperature” [10].

Evidence from the Vostok ice cores (specifically 240,000 before present), proves that CO2 has had an effect on temperatures. Although the initial forcing was orbital changes in the sun, CO2 “plays . . . a key role in amplifying the initial orbital forcing” and “the CO2 increase clearly precedes the Northern Hemisphere deglaciation”. The study also notes that these forcings “are also at work for the present-day and future climate” [11].

There is also proof that it is warmer now than it has been since the MWP. In fact, it is warmer now than any year since 1400 AD [12]. Newer reconstructions continue to support this finding, and even extends the dataset. It finds that the Roman warm period (RWP) and the MWP as much cooler than today, and claims to have replicated previous ‘hockey stick’ studies [19]. The results are depicted below.

Looking into the geologic past, we see strong evidence in favor of the idea that carbon dioxide can increase temperature. It logically follows that if humans continue to emit CO2, and other greenhouse gasses, that human emissions will increase temperatures.

C3) Consensus

Before I continue, I would like to note this argument in and of itself does not prove that global warming is caused by man. Actual evidence should be the driving force behind this debate. The reason I chose to put this in my argument is simple: the science is not clear because of consensus, but a consensus exists because the evidence is clear. This evidence will be discussed later.

A study published in Science reviewed the ISI web of science in order to take a survey of relevant climate literature as to what the causes of climate change are. The study failed to find a single paper which was in opposition to the consensus position, that the main driver of climate change is anthropogenic. 75% of the papers supported the consensus position, whereas 25% had no position (they were focused on things other than forgings, like impacts or paleoclimate) [14]. The study also noted how many organizations have come out supporting the idea of anthropogenic climate change. The IPCC, the American Meteorological Society, American Geophysical Union, and the American Association for the Advancement of Science have all concluded that the evidence for AGW is overwhelming [15].

NASA furthers this argument, noting “most of the leading scientific organizations worldwide have issued public statements endorsing this position”. They also argue “[n]inety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities” [16].

A 196 page report representing 13 governmental agencies, and written by 28 authors from scientific institutions, has stated “[t]he global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases” [17].



3. Personal Correspondence.





8. Bob Carter. Climate: The Counter Consensus (London: Stacey International, 2011).







15. Ibid.






This debate is about if Climate change is anthropomorphic (man made) in origin (the start). I am negating this.
Note: this is not semantics,as these are the common understandings of the topic.

To claim that changes in the climate from over 4000 years ago is caused by humans is quite ridiculous.

Climate change has been happening for millions of years. Saying it has on balance, been caused by humans is false.

We have only been around 200,000 years.

To put that into perspective, we have only been on Earth for a minute compared to total Earth time.


It is ridiculous to suggest we are responsible for change happening millions of years ago
Debate Round No. 2


In R1 global warming was defined as an average increase in temperature since the late 19th century. We have caused pretty much all of the warming since 1976 and a significant percent of the pre-1940 warming, with a cooling spell between the late 40s to early 70s because of human aerosol emissions and a decline in TSI.

King’s entire argument is… paleoclimate. But I don’t have to prove that we caused warming 500 million years ago, only since around 1870 or so. Paleoclimatology does have an application in this debate: whether or not CO2 causes (or doesn’t cause) past climate changes is important. It can prove whether or not CO2 has any influence on the climate. My opponent’s conclusion — that I have to prove changes before the industrial revolution — breaks rule 6, and warrants an automatic merit loss. I will refute the case anyway, but only the relevant details:

A) Phanerozoic temperature record

King shows us a graph plotting temperature and CO2 throughout the phanerozoic eon, and tells us that there is no correlation. For at least the last few thousand years, CO2 has had a strong impact on climate [1].

Unfortunately,King’s graph uses a study which I preempted. It must be noted that the graph my opponent uses does not show the error bars, so any correlation (or non correlation) is uncertain at best. And, as I argued last round, the man who made the graph (GEOCARB; Berner 2001) actually says that there exists a long term correlation between temperature and carbon dioxide [2].

Berner’s study also fails to take into account saturation effects. When this is accounted for, the correlation between CO2 and temperature is almost perfect [3].

So, the second graph my opponent uses is blatantly incorrect. Not only do the authors of the data say that I am correct, not only do the error bars tell us that the results are not really with my opponent, but a separate analysis *improving* the methodology finds a nearly *perfect* correlation between CO2 and temperature.

B) More recent temperature changes

The graph my opponent uses seems like a sketchy-tabloid esque graph. There is no reason to trust it. The data is not so cut and dry, especially because data exists showing that temperatures are warmer — not cooler — than temperatures within the past 1000 years [4].

And the timescale king uses is cherry picked. Using the past 65 million years, CO2 is the predominant climate forcing of temperature changes [5]. Research focusing on the past few interglacials — which includes king’s graph — has concluded that CO2 “plays . . . a key role in amplifying the initial orbital forcing.” [6]

Plus, the graph king uses does not take into account other forcings. Of course other factors exist in climate — I am not arguing that CO2 is the only one, only that is can be (and is) a forcing since about 1870. Climate changes in response to whatever forcing exists at that date and time. And today, CO2 is driving climate. Just like how short term (volcanoes) and long-term (GCR fluctuations) can all affect climate, CO2 has *always* played *some* role in climate. On some timescales, it is dominant [3][4]. Merely because climate has changed for other reasons does not mean that humans have no effect. Most of the time, it is not a gun which kills a person, but it would be wrong to conclude that guns do not kill. Just because climate has changed before does not necessarily mean that our change is natural.

C) Humans have only existed for 200,000 years










16kadams has misunderstood the debate. This debate is not whether modern climate change is due to humans. This debate is about whether the ORIGIN of climate change is due to humans. As I have proven and 16k not rebutted, climate change has been happening for millions of years, and we have only been here for 200,000 years, making it ridiculous that humans cause the earliest climate change.

My rich text isn't working, but you can see form the graphs that global warming has been happening for over 550 million years. We have been around for 200,000 and could not have started that change from 550 million years ago.

P1: This debate is if climate change has started because of humans
P2: Climate change has been happening for over 550 million years
P3: Humans have been around for 200,000 years
Conclusion: We are not the origin of global warming

Defense of P1: See resolution
Defense of P2: See graphs
Defense of P3:


Everything 16kadams has said is irrelevant. We are not arguing about modern climate change; we are arguing if humans started climate change. Since climate change has started before humans were even on the earth, it is obvious we haven't started it.
Debate Round No. 3


- kingd breaks two rules in this debate. He breaks #6 -- no K's of the topic -- #7 -- no semantics -- and arguably #5. Based on rule #10, I win the debate.

- kingd drops both consensus and sensitivity, conceding them as true.

- I refuted paleoclimate, showing that past records actually support AGW and that he misrepresented his sources
> showed today was abnormally warm for this recent interglacial cycle
> king's graph shows correlation

- his whole argument is a semantical ploy on origin and climate change. But is fails.
>R1 established "global warming" (synonomous to "climate change" in the literature) was defined to the late 1800s - present.
> so the origin of that climate change was indeed mankind
> pro wins
> king assumes I am talking about change over the past 500 million years. R1 proved this to not be the case.

Con's debate strategy is immoral, unfair, and rule breaking. Not to mention incorrect. I should win because:
(1) it was demonstrated that mankind has caused recent climate changes
(2) my opponent breaks 2 rules, arguably 3
> merit loss
(3) my opponent's sources bolster (1)

Vote Pro.


Alleged Rule Violations:
5. No trolling

How hurtful!
trolling:make a deliberately offensive or provocative online posting with the aim of upsetting someone or eliciting an angry response from them. (Google)
I am not trying to offend anyone deliberately. If anything, you are offending me by accusing me of breaking rules.

6. No "kritiks" of the topic (i.e. arguments that challenge an assumption in the resolution)

The resolution is not about global warming, which was defined first round by 16k. The debate right now is about climate change, which since it has been undefined, I define as "a long-term change in the earth's climate, especially a change due to an increase in the average atmospheric temperature:" ( I assumed we were talking about climate change as the resolution stated so.
Even though he claims ">R1 established "global warming" (synonomous to "climate change" in the literature) ", climate change and global warming are completely different, the Little Ice age was an example of climate change but not global warming. Not all change = warming.
16k thinks climate change = global warming because global warming is an example of climate change and they are therefore the same. That would be like saying because all squares= rectangles are rectangles = squares.

7. No semantics; debaters will adhere to the common/average understanding of the topic

The common understanding of climate change is changes in the climate, not necessarily warming. The definition of origin is "the point or place where something begins, arises, or is derived. (google)", which basically means beginning of something, which means the start. The start of CLIMATE CHANGE dated back to millions of years ago.

"Con's debate strategy is immoral, unfair, and rule breaking. "

To what morality system? Back up your assertions. Unfair? Well you instigated it and made the resolution so, not I. I am adhering to the rules. I explained why I followed the rules.


Climate change (not the same thing as global warming) has been happening for millions of years before humanity was alive. To say that humans affected the climate so long ago is patently ridiculous. Vote Con based on arguments and conduct, as Pro makes unwarranted attacks on me (calling me a troll and such).
Debate Round No. 4
21 comments have been posted on this debate. Showing 1 through 10 records.
Posted by FourTrouble 2 years ago
Also, as for 16k's argument that it was a rule violation -- it wasn't. Applying plain meaning isn't semantics as far as I can tell, especially when the words clearly aren't defined in R1. And the "common understanding" always allows for arguments of plain meaning. The key was showing that scholarly meaning should be preferred to plain meaning, and unfortunately 16k didn't do this. This also isn't a kritik -- none of the assumptions in the resolution are challenged. In fact, nothing's challenged. Kingkd simply applies the plain meaning of the terms. 16k's best argument for a rule violation was trolling, but that was a stretch and it wasn't developed nearly enough to actually be extended. So as much as 16k feels the argument was unfair, and that it was a rule violation, I have to say the debate is tied. There's no mechanism given for weighing the competing definitions, so I literally cannot decide the debate any other way.

That said, I totally feel bad for 16k here, because it sucks when someone does what kingkd did. I think it's really just bad mannered.
Posted by FourTrouble 2 years ago
== RFD ==

This is a really sh!tty debate. The problem is the lack of definitions for "climate change" and "origin" in R1. Neither 16k nor kingkd defines them in R1. That means definitions for these words are open to debate. The outcome turns on how the words are defined. 16k defines "climate change" as "global warming," and "origin" as "cause." Under these definitions, 16k clearly wins. On the other hand, if I accept kingkd's definitions, kingkd wins. I buy kindkd's argument that most climate change historically, dating back to the beginning of Earth, isn't caused by humans. His argument honestly doesn't need much elaboration, and while 16k tries to refute kingkd's sources, that's just not enough to refute kindkd's point, because 16k drops the key fact that climate has been changing for millions of years. And even if CO2 has had a primary role in climate change over the past 65 million years, that doesn't change the fact that climate has been changing for 500,000 million years. Under kingkd's definitions, kindkd wins. That means the outcome turns on which definitions I accept as correct.

kingkd argues plain meaning of the words. But plain meaning alone doesn't mean I should prefer his definition. Words often acquire technical meanings. The question is whether to prefer plain meaning of technical meaning. So I turn to 16k's arguments. 16k argues based on R1, and because of how the words are defined in the scholarly literature (where "climate change" and "global warming" are used interchangeably). The problem is that R1 doesn't actually define "climate change" or "origin," so there's no reason to assume "global warming" is equivalent to "climate change" via R1. As for usage in the "scholarly literature," why should I prefer that to the plain meaning of the term? 16k doesn't really elaborate on this, which is why ultimately I don't know how to weigh these competing definitions. 16k had to give a reason to prefer scholarly definition to plain meaning. He didn't.
Posted by tejretics 2 years ago
I *knew* kingkd had reported the vote.
Posted by bluesteel 2 years ago
>Reported vote: tejretics // Passes moderation

Vote report: RFD misunderstands the resolution

[*Moderator reasoning*] The RFD says that Con engaged in semantics. Con did engage in semantics, arguing that "climate change" does not mean the common modern understanding, i.e. current global warming, but rather means any climate change that has ever occurred in the history of the Earth. A reasonable interpretation of the resolution and the no semantics rule is that Con violated it, so this vote is permissible.
Posted by tejretics 2 years ago
"Origin" is "the point or place where something begins, arises, or is derived." - note *is derived*.
Posted by tejretics 2 years ago
Not the *start*, "origin" can also mean *cause*, in any time period.
Posted by kingkd 2 years ago
The word "is" can also be used to define the past. For example, "The past is cool" means that at this current time, the past has a quality of being cool. The resolution "Climate is on balance man made in origin" means that on balance, at this current time, the beginning/start of climate change is man made, which I easily refuted in my entire case
Posted by Varrack 2 years ago
Well this went downhill.
Posted by kingkd 2 years ago
@tejretics, i am arguing that the origin climate change is not man made. THe resolution says that "Climate change is man made in its origin", so at its origin, climate change is not man made. You make a claim about "is" being present tense, but the word "is" is about climate change, at the origin. AT THE ORIGIN, climate change was and never was caused by humans.
Posted by kingkd 2 years ago
GG 16k. Interesting debate
2 votes have been placed for this debate. Showing 1 through 2 records.
Vote Placed by FourTrouble 2 years ago
Who won the debate:--
Reasons for voting decision: RFD in comments.
Vote Placed by tejretics 2 years ago
Who won the debate:Vote Checkmark-
Reasons for voting decision: Con breaks two rules -- no kritiks and no semantics. The primary confusion here is "origin", which Con *incorrectly* interprets to mean only "beginning". Since "is" is a *present tense* verb of the resolution, the resolution was TODAY's climate change is primarily anthropogenic in origin. Con repeatedly critiques this and says climate change was not "initially caused" by mankind. That is completely irrelevant. According to Rule 10, the violation of the rules deems a complete 7-point victory. Furthermore, S&G is to Pro because Con frequently replaces "anthropogenic" with "anthropomorphic". Thus, arguments and S&G would be awarded to Pro, and the violation of the rules allows me to award Pro the victory. In other words, Con accuses Pro of having no links and only impacts, but as a voter, I see that Pro has links and a proper impact calculus shows that Pro clearly illustrates CO2's impact on GW. As always, happy to clarify this RFD.