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Comment by Karunamon | Hacker News Reader

Kind of an open question here. I am not a climatologist and neither are most people. Climate science is subtle and easy to misinterpret (and hence, spin) on the mater of anthropogenic climate change, or ACC.

To the average person, myself included, the arguments made by both "sides" (ACC exists, ACC does not exist) are equally convincing. That is, both seem logical and well-argued at the superficial level we can understand without training.

To the average person, myself included, both "sides" have a profit motive in fudging the numbers. (If ACC exists, the energy industry will fight because it ultimately harms their profits. If ACC doesn't exist, the academic lobby will fight for their prestige and grants)

Both sides are, ultimately, dirty, due to politicization if nothing else.

Both sides, ultimately, cannot be simultaneously correct.

And so I ask: Who should be trusted, why, and how, given the limited number of hours in the day available to people who aren't directly involved in climatology as their day job?

For bonus points, do any of the answers to those questions not boil down to the genetic or appeal to authority fallacies?

(The snark below in response to a legitimate, good-faith question is leading me to believe this topic cannot be discussed among reasonable people)

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You assert that both sides have a profit motive, but there is a huge disparity in the quantity of profit. The fossil fuel energy companies profit to the tune of hundreds of billions of dollars. The academic lobby grants 1) are minuscule in comparison and 2) most of the concerned academics have plenty of other things they'd rather be studying - climate change is what they choose now because of its existential nature.

I don't see how that matters - if you trained your whole life for one branch of science (or one career), you're a lot more likely to stay where you are rather than spend years starting from zero to move where you think more money might be.

That's a risk many are not willing to take.

Why they should move to another career?

"Climate Scientists" did not train their entire life to be climate scientists they come to it from a general background in geology, environmental science or physics with a two-three class "focus" during undergrad, another two to three class focus during grad school and maybe a phd.

Maybe.

Some of them just wound up there because they were the only people in the department with the Fortran chops to get the models working.

Climate scientists could deal with long-term weather prediction and other stuff. They don't need climate change to stay relevant.

>To the average person, myself included, both "sides" have a profit motive in fudging the numbers.

Yeah, this is almost entirely wrong. I'm sure there is slightly more public funding available in the Earth sciences because of the urgency of climate change, but not much- NSF funds for Earth science projects have been pretty steady for the last 20 years [0] and before that too. If climate change simply didn't exist, researchers would just get grants to work on the plethora of other important Earth science issues- human water usage, the ozone layer, ocean acidification, forest fires, coral bleaching, agricultural runoff, glacier retreat. There was no shortage of important Earth science problems- why on Earth would researchers go to such (impossible) lengths to fabricate one? The idea that international researchers have created some conspiracy to increase funding in their field is bizarre and incoherent and just demonstrates a lack of understanding of how science funding works. It also doesn't explain the international consensus on climate change- how has every major scientific organization and metereological society agreed upon it, when all of them have completely different funding situations? And if they have, well then surely they would have realized that this plan has not drastically increased their public funding in 20 years and given up on it by now! But in all seriousness, this idea is just insulting to the scientists and the fact that it's popular amongst American conservatives is pretty telling of how scientifically ignorant that ideology is.

[0] https://www.aaas.org/sites/default/files/CJS%20NSF%2015hc.jp...

> To the average person, myself included, the arguments made by both "sides" (ACC exists, ACC does not exist) are equally convincing. That is, both seem logical and well-argued at the superficial level we can understand without training.

Understanding climate change requires high degrees of expertise, the collection of large amounts of data, the use of large mathematical models, and the cooperation of a large number of scientists. A large number of scientists work very hard to track the state of climate change, and their assessment is that "climate-warming trends over the past century are extremely likely due to human activities" [0].

> If ACC doesn't exist, the academic lobby will fight for their prestige ang grants)

Please see the list of scientific bodies and their statements on climate change [1]. The idea that a large majority of all scientists with knowledge pertaining to climate science in the world would be corrupted, falsify results, and make false statements over many years to fund further studies seems exceedingly unlikely.

> And so I ask: Who should be trusted, why, and how, given the limited number of hours in the day available to people who aren't directly involved in climatology as their day job?

You should trust what 97% (or more) of all climate scientists agree upon. Arguing that a group of experts of a domain should be trusted is not logically fallacious.

[0] http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048...

[1] https://climate.nasa.gov/scientific-consensus/

It doesn't have to be knowingly false, though - you think that all of the studies in psychology that wound up being non-reproducible were all submitted by pathological liars?

Keep in mind that I never even mentioned deception, that was something you just set up and knocked down on your own. I have no doubt that most climatologists are doing exactly what they should be doing and aren't Saturday morning cartoon villains,

But if there's a more meta issue involved, such as bad data, I argue that it'll never see the light of day given the political incentives.

(In other words, the politicians are the villains, not the scientists running the data)

> It doesn't have to be knowingly false, though - you think that all of the studies in psychology that wound up being non-reproducible were all submitted by pathological liars?

> But if there's a more meta issue involved, such as bad data, I argue that it'll never see the light of day given the political incentives.

This is why single studies alone should not be the basis for large changes in policy. The current consensus in climate science is based on a large number of studies from different universities, science bodies, countries, using different sources of data, using different methods, and over a period of time. All of these factors makes it likely that the consensus is something which we should believe, and which should guide our policies.

> Keep in mind that I never even mentioned deception, that was something you just set up and knocked down on your own.

You stated that scientists have a profit motive for fudging their numbers, which if they did would be deceptive behavior.

> If ACC doesn't exist, the academic lobby will fight for their prestige ang grants

It would be better for "the academic lobby" to peddle the idea that climate science is unsettled, which would create more of a need for grants to study the issue.

Correct. Academic's job is to study, it doesn't matter what the outcome is, they have grants either way.

It is not always true. Imagine the system, where the government is a primary source of grants. There is a possibility that government will prefer funding the scientists whose work supports government's political agenda.

Neither we nor our politicians should adjudicate scientific results and pick and choose what makes sense to us. We are not qualified. Scientists have a process as well as peer review which determines valid vs invalid results.

I subscribe to 'Science' magazine which is one of the most respected publications among scientists (along with 'Nature' magazine). The consensus among scientists is settled: ACC is real. ACC deniers do not get published in respected science magazines because their peers do not respect their results.

Scientific results should be settled by the peer group of scientists, not by politicians or the general public (see vaccine conspiracies for example).

How is consensus settled, when there are renowned scientists out there who object the CAGW hypothesis? Roy Spencer, Richard Lindzen, Judith Curry, Freeman Dyson - are they all bought and paid for by oil industry?

consensus as in general agreement, as in a majority. Pointing out that some minority group exists is hardly a refutation. Would you not say there is a consensus the Earth is round?

Why should one trust majority, and not minority, if "minority" people are also qualified and respected (Spencer, Curry)? There were episodes in the history of science, when the majority turned out to be wrong.

Here's one example:

https://www.insidescience.org/news/scientific-consensus-almo...

I won't object to the fact that majorities can be wrong. There are many examples, ancient and recent. But that is a different argument from your other comment.

I trust majority in science because it is rarely wrong. I'd need a bit more than "majorities have been wrong before!" to switch sides.

Well, I'd need a bit more than "minorities are rarely right" to switch sides.

Which part of the science do you find unconvincing? We have great ice core data going back 1000's of years, the greenhouse effect itself is universally agreed upon and understood, we have a measurable rise in global average temperature over the last 2 centuries, and we see that people are spewing greenhouse gases into the atmosphere. Solar cycles, volcanoes, and other non-human sources have been refuted and disproved time and time again. only scientists paid to lobby on behalf of the source of warming disagree with the cause. What's missing that could ever convince you?

Convincing part stops at cloud feedback for me.

The CAGW builds upon following argument: increased concentration of CO2 reduces the EM radiation's emission in frequencies that CO2 absorbs, ergo the surface temperature should rise in order to keep Earth's thermodynamic balance.

Increased temperature clearly affects the formation of clouds which have both positive and negative effects: they deflect incoming solar radiation, but also deflect surface radiation. The net effect is unclear, unfortunately.

I'm also quite puzzled by apparent lag between CO2 and temperatures in Vostok ice core data. Contrary to CAGW, temperature rises first, and CO2 follows.

My layman understanding is quite limited, of course, that's why eventually I go to the scientists for their expertise. I don't believe that all opponents of CAGW theory are shills; some of them are very respected people: Lindzen, Spencer, etc. My only conclusion is that science is not settled and CAGW is still an unconfirmed hypothesis.

ACC doesn't build upon the hypothesis that CO2 reduces the energy emission. The underpinning is the greenhouse effect whereby gasses, particularly CO2 prevent heat absorbed by the Earth's surface from radiating back out into space. Only about 26% of the Sun's energy is reflected by clouds or the atmosphere. CO2 concentration increases heat retention but not cloud albedo(reflectiveness) nor atmospheric reflectiveness.

Cloud formation is not related to CO2. CO2 is the primary factor driving the greenhouse effect. In fact research is beginning to show that a warmer planet may have lower cloud cover [1][2]. There is no cloud controversy, you are literally making that up.

[1] https://content.time.com/time/health/article/0,8599,1912448,... [2]https://www.nsf.gov/news/special_reports/clouds/question.jsp

It does build on the fact that increased concentration of CO2 reduces EM waves emission (in the parts of frequency spectrum that can be absorbed by CO2) from Earth to space. Earth is presumed to maintain thermodynamic balance (i.e. energy received should be equal to energy lost). To compensate for reduced emission caused by CO2, Earth's surface warms up and restores the balance. This is global warming 101, I believe.

Have you read your links?

"One of the biggest questions in climate sensitivity has been the role of low-level cloud cover. Low-altitude clouds reflect some of the sun's radiation back into the atmosphere, cooling the earth. It's not yet known whether global warming will dissipate clouds, which would effectively speed up the process of climate change, or increase cloud cover, which would slow it down.

But a new study published in the July 24 issue of Science is clearing the haze. A group of researchers from the University of Miami and the Scripps Institute of Oceanography studied cloud data of the northeast Pacific Ocean — both from satellites and from the human eye — over the past 50 years and combined that with climate models. They found that low-level clouds tend to dissipate as the ocean warms — which means a warmer world could well have less cloud cover. "That would create positive feedback, a reinforcing cycle that continues to warm the climate," says Amy Clement, a climate scientist at the University of Miami and the lead author of the Science study."

That's one study that recorded the cloud data for subset of Earth.

Read about clouds feedback issue here, it's very pro-CO2-CAGW site: https://www.skepticalscience.com/clouds-negative-feedback.ht...

I did read the links, they both point to positive feedback cycles, and you cherry picked that quote to obfuscate that point.

Your first statement is proving my point, CO2 contributes to the greenhouse effect, causing warming on average. Human activity is the cause of historically high CO2 levels.

"Point to" is not confident enough. Even skepticalscience, the "alarmist"-side site, admits that "While clouds remain an uncertainty, the evidence is building that clouds will probably cause the planet to warm even further".

"A group of researchers from the University of Miami and the Scripps Institute of Oceanography studied cloud data of the northeast Pacific Ocean"

Study from your first link recorded cloud cover data over subset of Earth's atmosphere. It doesn't say anything about whether clouds feedback is positive, or negative. Local data is not very useful evidence, global data would be preferable.

Here is an explanation of what is cloud feedback: increase of temperature has effects on cloud formation. If feedback from changes in cloud formation is positive, it will lead to even more warming. Negative feedback would mean that changed cloud formation actually reduces warming.

  cloud data of the northeast Pacific Ocean — both from satellites and from the human eye

What methodology did they use to turn eyeballed guesstimates into data?

This 'consensus' approach is biased from the start, because it automatically gives a benefit to the so-called "scientists" as if they are somehow more wise or knowledgable about anything any more than a soothsayer or even pulling a few stones out of the ground and interpreting the residual dirt in their cracks while intoxicated on some brewed concoction of plants.

Nope. The IPCC consensus has been reached through a lot of hard, unpaid or very poorly paid, work by people passionate about helping others, that all the time know they could easily get bought to spread falsehoods and reap large rewards.

Freeman Dyson is not a climate scientist at all and never has been. Roy Spencer isn't a "renowned scientist"; he's a paid oil-industry shill. Lindzen used to be a scientist; now he's retired and gets paid to be a Cato Institute shill. Judith Curry also used to be a scientist and quit her academic job; presumably being a shill pays WAY better.

So, basically, yes, they are all bought and paid for, or, they simply have no credentials or knowledge of the field in question.

This is exactly what I meant by fallacies. Either their research is legitimate or it is not. And that legitimacy is not a factor of the employer - if their science sucks, it'll manifest in the data, analysis, or conclusions, regardless of who's paying for it.

"Shills" is an insult, not an argument.

Are you qualified to decipher the data? Honest question.

They aren't doing any "research".

Dyson is a renowned physicist interested in climate science. I believe that his physics/math skills and general intelligence allow him to be quite competent in climate issues.

Lindzen retired only in 2013. I don't see how this makes his opinion about CAGW less valuable, especially given the fact that he was skeptical about CAGW hypothesis for a long time.

"Judith Curry also used to be a scientist and quit her academic job; presumably being a shill pays WAY better." - where's the proof that she is a "shill"?

Roy Spencer is a renowned scientist in my book: "Roy Warren Spencer is a meteorologist, a principal research scientist at the University of Alabama in Huntsville, and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA's Aqua satellite. He has served as senior scientist for climate studies at NASA's Marshall Space Flight Center."

Again, where is the proof that he is oil industry's shill?

To my knowledge, Freeman Dyson has no peer reviewed research contributions in the climate literature. That should be the price of entry, otherwise there is nothing of substance to critique.

So basically, anyone who is a respectable scientist who disagrees with this is a shill?

Even by the late '90s there were renowned medical scientists who disagreed with the consensus around the "HIV causes AIDS" hypothesis, despite ample evidence.

https://en.m.wikipedia.org/wiki/HIV/AIDS_denialism

Climate change denialism is no different from AIDS denialism.

Ok, the minority view was wrong in this particular case. Minority views were also right in some other cases.

"Climate change denialism" - what's this? Is there any scientist out there who thinks that Earth's climate is stable in the long run?

Climate changes anyway, so why do anything about it? People die anyway, so who cares what causes AIDS?

Call it "climate science denialism" if you prefer. It's no different from AIDS denialism.

Thabo Mbeki, President of South Africa in 1999-2008, listened to the denialists' views about the AIDS outbreak. He had an AIDS advisory panel staffed with consensus critics -- just like Trump and Pruitt are doing. The estimated number of premature deaths due to Mbeki's counterproductive actions is around 300,000.

You asked how there could be "consensus" on the existence of ACC when some scientists dispute its existence.

The parent post gave an example of a case where some credentialed scientists continued to dispute the HIV-AIDS link well after the balance of evidence was against them.

Many people would say there was a "consensus" on the HIV-AIDS link despite the continued skepticism of some scientists, and that this scenario has parallels with climate science.

Can you offer a counter example, where a holdout group of scientists who disagreed with consensus in their field were proved right?

@swampangel: https://www.insidescience.org/news/scientific-consensus-almo...

here you go

The article is about paradigm shifts in science. Obviously those happen, but not every minority opinion is such a shift. They are notable because they are so very rare.

What do you see as the paradigm shift that turns climate science on its head and proves the consensus wrong?

Suppose that new discovery in natural climate variability provides IPCC with better models, and these models show that CO2 has only minor influence on global warming and climate overall. "Paradigm shift" would be a good description for this development.

Do, you don't accept the science because you think that perhaps in the furute it will be proven wrong.

Good thing, isn't?

Roy Spencer is a satellite observation expert, who has reversed his opinion of satellite measurements, and now believes that warming is about as described by the traditional thermometer datasets.

Judith Curry doesn't disagree with AGW, she disagrees with the scale predicted. That would mean less immediate, strict action, but action nevertheless.

Freeman Dyson isn't a climatologist, he also says himself "[m]y objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have." He also believes in AGW.

It's good to have sceptics, and in particular being sceptical about the scale of AGW is very reasonable. The IPCC predictions actually have a wide variance for these reasons. These scientists don't really speak against the moderate action currently proposed, they aren't backing for Trump's position.

I don't mind AGW at all (it's obvious that human activity influences the climate, and probably the effects of deforestation are as severe as effects from CO2 emissions), but I find CO2-CAGW (i.e. anthropogenic warming caused by CO2 emissions and leading to catastrophic consequences) unconvincing, to a lesser degree due to personal knowledge (uncertainty in clouds feedback, under appreciation of positive effects of higher CO2 concentration etc), and to a higher degree, due to views of Lindzen, Curry, Spencer Dyson, and other scientists.

Yes, Dyson's rhetoric on climate moved a bit towards "alarmist" side, but he still doesn't believe in catastrophic consequences:

"The good news is that the main effect of carbon dioxide … is to make the planet greener, [by] feeding the growth of green plants of all kinds [and] increasing the fertility of farms and fields and forests."

I've kind of lost faith in the peer review process after the reproduction crisis in psychology field broke, and it is quite believable that any study that arrives at the "wrong" (read: not acceptable politically) result will result in the paper not getting published, or worse.

And it's not like this is some conspiracy theory. Unspoken social consequences don't require people getting together and stroking their goatees cartoon-villain style.

The "consensus among scientists", looking at the psychology thing, can and has been wrong, so holding the concept up as if it makes error impossible doesn't seem to wash.

You're comparing many unscientific or poorly structured psychology studies to rigorously recorded and analyzed climate data?

You might as well give up now if your entire view of reality has been up-ended as you claim...

Both are peer reviewed science at the end of the day. What's to say the climatology studies are "rigorously recorded and analyzed" any better than the psychology studies? Am I to trust climatologists more than neuropsychologists for some reason?

* Both are experts in their field

* Both have prestigious journals

* Both are supposed to have a peer review process that prevents bogosity from being published and accepted.

Yet in one field, the peer review process, the ultimate guard that's supposed to prevent junk science from being published, failed. Is failing. Repeatedly. For a long time. It's not one failure, it's a chain of systemic failures.

That tells me that the entire concept of peer review is not immune to degenerating. And if it can happen in one field, it can happen in another, especially one that's harshly politicized (which psychology isn't, at least not anywhere near the same insane degree).

I find it very telling that this comment, the root problem, was downvoted and remains unanswered.

Perhaps it has been downvoted because the OP doesn't have any argument.

When some of the ones talking about the irreproducibility can give any proof that climate science has the same problem, perhaps we can start to talk.

> That tells me that the entire concept of peer review is not immune to degenerating. And if it can happen in one field, it can happen in another, especially one that's harshly politicized (which psychology isn't, at least not anywhere near the same insane degree).

Politization occurs almost only in the US.

Are you accusing the scientists of being politized?

Do you have any argument for your claims of not reprodicibility in climate science?

Do you have any argument for doubting the data that has been used for more than 40 years?

Do you have any argument apart of your political views?

Are you saying scientists (or rather, the institutions that fund their research and publish their data) are immune to politicization?

Are you saying that climatology is immune to bunk being published despite peer review?

Your post is a lot of whataboutism that doesn't answer the questions posed.

Changes in temperature and sea-levels based on man made actions are harder to convince people of than other factors. My go-to in cases like this is ocean acidification. The following is a straightforward introduction to this part of climate change:

http://www.nationalgeographic.com/environment/oceans/critica...

The process seems fairly simple. Oceans absorb a high proportion of the carbon dioxide released into the atmosphere from burning fossil fuels. This changes the pH levels of oceans, which then alters the environment that marine animals live in, causing a necessity to adapt. You could perform water pH experiments to prove the effects on marine life if you needed to convince yourself (though I wouldn't want to promote animal testing if there was another way to reach clarity on this).

Couldn't you demonstrate that more acidic solutions break down calcium carbonate?

What would that result imply for living water-borne organisms?

Many of them have shells made of calcium carbonate of live in reefs, the structure of which is made of calcium carbonate.

> (If ACC exists, the energy industry will fight because it ultimately harms their profits. If ACC doesn't exist, the academic lobby will fight for their prestige and grants)

Why climate scientists won't have grants if there is no climate change?

Climate doesn't need to be studied?

> Both sides are, ultimately, dirty, due to politicization if nothing else

Please, give me examples of climate scientists dirty by politization.

> For bonus points, do any of the answers to those questions not boil down to the genetic or appeal to authority fallacies?

Well, if you think that Theory of Evolution is appeal to authority, yes.

When the big majority of a field have consensus, you have to look at the motives and arguments of the minority dissenting, not saying that the majority appeals to authority

If ACC doesn't exist, the future is much scarier. It suggest that the climate is changing, but that human kind isn't causing it, suggesting that it's much harder for us to revert, suggesting that we are much more likely to be screwed.

Of the data we have, climate change being human caused is MUCH more preferable. The alternative is that the climate is changing and we aren't responsible.

If this "alternative" were the case, would humanity best be served by not knowing it to be the case?

No. Lack of knowledge is never helpful.

Yep. Same point was raised by Scott Adams in some of his blogs, like [1].

[1] http://blog.dilbert.com/post/154082416051/the-non-expert-pro...

How in the world is listening to climate scientists an "appeal to authority" fallacy? How are people supposed to get information about anything if this is your argument? Most of our knowledge comes from experts and specialists...

I take this same "both sides" approach to gravitation in particular. Gravity is subtle and easy to misinterpret but to the average person, myself included, the arguments made by both "sides" are equally convincing.

I don't think this is a good argument.

Anyone who has passed a freshman physics class is equipped to (with significant effort) verify Newton's law of gravitation.

Any middle school student with a stopwatch and a tower can drop things off and determine that there are laws describing the ways that unsupported objects move downward.

Everyone who ever lived has been in a position to independently observe many of the properties of gravitation without needing to trust even a single statement or datapoint provided by another person.

In order to even understand the theory of ACC, much less test it, requires a person to first have a ton of education and then to navigate a substantial amount of academic literature.

It doesn't matter what you think. What are the other sides of the statements you make? We need to hear hear them out and debate them as well.

You assume that so-called "freshmen physics" is a legitimate source of material and that middle school students are being taught legitimate science to begin with, when it could all be part of a pro-science agenda put forth by academic science thumpers promoting self-interested concepts of scientific ideology so that these people can continue to be employed and earn upwards of $40,000 per year as science propagandists. Let's not ignore the fact there's a lot of money at stake on these issues here, and for the involved parties getting you to believe in concepts like middle school science of freshmen physics are entirely based on a monetary incentive, despite what the evidence may show and even against contradictory evidence.

Also you assume that gravitation is proven beyond a theory or a concept, which is demonstrating your pro-gravity bias. The understanding of so-called "gravity" is based on nothing more than a theory, but general relativity and quantum theory are entirely incompatible with one another which basically debunks the entire thing as many leading scientists would agree, but again this assumes that any of the so-called "science" or the basis of any of this is even legitimate in the first place.

Finally, and this is very important, all of this completely disregards what religions might say too, and we need to hear each of the arguments of each individual religion and belief system and what their opinions and thoughts are on so-called "gravity", which, by the way, is not even mentioned in any holy books or writings whatsoever. That "gravity" is left out of every religious teaching entirely is very telling, and it demonstrates that from a theological standpoint that "gravity" has absolutely no basis in truth whatsoever, otherwise it obviously would be a subject of these belief systems and written about endlessly if it were a real thing. Can you really dispute or discount the words of supreme beings, let alone every God and belief system?

> If ACC doesn't exist, the academic lobby will fight for their prestige and grants

"The academic lobby"? Christ. If ACC doesn't exist why wouldn't they just go and get grants to study something else?

The philosopher Karl Popper explained in 1934 that scientific theories need to be falsifiable in order to be considered scientific.

I would say that AGW theory has not yet met that standard.

How so? If you could demonstrate a natural process that accounted for the data, that would pretty well falsify the claim that human production of greenhouse gases is the leading cause of climate change.

Haven't there been some studies about sun output? That seems natural?

That's been pretty well refuted as well.[1] Basically, the solar cycle can affect ocean temperature in the pacific to the degree that it can change circulation and some weather patterns, but has been shown to not be the cause of observed average temperature increases over the past 50 years.

[1]https://science.nasa.gov/science-news/science-at-nasa/2013/0...

It doesn't work like that. The null hypothesis is that natural processes fully account for observed temperature data. In order to generate enough thrust to escape the gravity of the null hypothesis, you must do the following, according to Karl Popper (cribbed from here [1]):

1) Describe a difficulty or gap in scientific knowledge, a "general problem", clearly defined, and show that the problem needs to be addressed.

2) Formulate a hypothesis, a "tentative theory", addressing the general problem, stated as clearly as possible in the language of science, which is mathematics.

3) Try to invalidate the tentative theory, and apply a certain scientific ethic described by Richard Feynman in his famous essay "Cargo Cult Science"[2]

I'm not sure the "general problem" has even been established. From 1880 to 2015 the Earth's temperature has gone from 288 K to 288.8 K, a 0.3% increase. So first of all you need to prove that the Earth system is not able to keep the climate stable.

Then you need to prove that recent increases in temperature are fundamentally different from past increases in the same system, i.e. the current interglacial period of the last 10,000 years. Again, this is not conclusive at all.

Then you need to prove that CO2 plays a huge part in the recent temperature changes. Correlation does not imply causation. Two independent variables can both increase and you have not proven that they are causally linked (beyond the first-order effects of course). All we have so far are computer models which, so far, are no more than best-fit lines on observed data.

In order for a computer model to be a good enough piece of evidence to favor dropping the null hypothesis and accepting the basis of the model, you would have to leave the model alone and see how well it predicts climate going forward. So far the models have not done well predicting actual climate [3].

QED.

[1] https://www.scribd.com/document/23499288/Lord-Monckton-Caugh...

[2] http://calteches.library.caltech.edu/51/2/CargoCult.htm

[3] https://wattsupwiththat.com/2017/06/28/173948/

You're right, I oversimplified the null hypothesis.

Based on my best understanding climate scientists have pretty well proven that CO2 plays a huge part in the recent temperature changes. Perhaps an actual climate scientist lurking on the forum could weigh in.

I'm not sure that the average earth temperature is all that important here. The alarmism I hear usually relates to the biosphere either radically altering or collapsing outright due to sea level rise if the ice caps melt - which would take about 8 degrees Fahrenheit over a relatively small area of the planet.

My beef is with the alarmism based on observations of the last 100 or so years. We are talking about a climate system that has gone through at least four glacial periods in the last half million years. You would think that science would be very careful about making assertions based on such limited evidence, but that's not what's happening.

Though open, this is a fantastic question, and one that everyone who is not a climate scientist should ask. The answer inevitably will vary depending on what you are willing to take people's word for, and how much time you're willing to spend digesting enough evidence to be convinced one way or another.

As shorthand in the following I will say that everyone, on this issue, can be classified as an "agnostic", an "alarmist", or a "denier", and I will trust you not to take those labels to insinuate anything about who is right or wrong (I myself am mostly in the alarmist camp).

IMO, the alarmists win A LOT of points (maybe not quite the whole game) for having a coherent, universally accepted, physics-based theory of the temperature of planets which correctly predicts observations from a variety of planets and requires radiative forcing from greenhouse gases in order to do it, while the deniers (as far as I can tell) do not propose an alternative theory or even generally agree on which part of the alarmists' chain of inference is broken. In, fact, until I see such a theory presented by the deniers (why are the planets we know the temperatures that they are, and what is the relationship between those temperatures and atmospheric GHG concentrations?), I really think the only sane stances to take are that of the alarmist or that of the agnostic.

Now, if you doubt that people can agree on the current surface temperatures and atmospheric compositions of Venus, Earth, the moon, and Mars, and are unwilling to spend the time to convince yourself that they do, then you're likely doomed to agnosticism. Same deal if you doubt that we can agree on the amount of CO2 we're emitting as a species on an annual basis.

Even then, you'll have to remain agnostic unless (1) you're willing to accept an appeal to authority or (2) you're willing to spend tens (but probably not hundreds) of hours understanding the basic theory of ACC, which holds that a doubling of the earth's CO2 concentration will result in an increase of 3C (plus or minus 1.5C) in the Earth's equilibrium temperature.

If you want to spend those tens of hours, you could start with this article[1] or this video lecture[2] or the wikipedia articles on "Planetary Equilibrium Temperature", "Radiative Forcing", and "Climate Sensitivity". The trick to not spending more than tens of hours is to remain laser-focused on understanding what those three terms mean, how they're related, and how one can try to measure climate sensitivity. In particular, a lot of discussions about prehistoric climate, on feedback mechanisms, and on the specific effects of global warming on specific regions of the globe will lead you astray if you let them.

If you don't have even a few hours to dig in on climate science, all I can say is that appeals to authority become a lot less unpalatable when the authorities appealed to are sufficiently numerous. Even if you think it not unlikely that NASA, NOAA, the EPA (all of whom are definitively, officially in the alarmist camp according to their websites) are in conspiracy with faculty at dozens or hundreds of universities, what about the 197 nations that were engaged in negotiating the recent Paris Climate Accord, or the 84 signatories of the Kyoto Protocol?

Lastly, just out of curiosity, in what form do you tend to see the genetic fallacy applied for or against ACC? I'm not sure I've encountered it.

Lastly, just out of curiosity, in what form do you tend to see the genetic fallacy applied for or against ACC? I'm not sure I've encountered it.

Generally, a saying that because group X funded the study, or that person X that has Y beliefs did the study, that it's automatically invalid (without even trying to actually examine the claims in the paper).

You can see examples of that in this very thread. A variant of adhom, basically.

Shut up or put up: Come back when you have implemented your own model that reproduces the 21st century's climate to date without human CO2. This is the standard that scientists are judging themselves by. For bonus points predict 2003 based on 1800-2002.

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