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I have a question for the anthropogenic climate change doubters and deniers out there. You say either that it is certain that human activity is not having a si

I have a question for the anthropogenic climate change doubters and deniers out there. You say either that it is certain that human activity is not having a significant influence on the climate, or it is not certain whether or not it is. My question is, it there any sort of scientific evidence that might be discovered in the future that would lead you to change your mind, and if so what would it be? Or is you view simply fixed for now and the future?

sathackr 10y ago
For a long time I was in the "we don't have enough information to make a conclusion" camp, and dismissed anyone "jumping" to conclusions as alarmist. This xkcd changed my mind: https://xkcd.com/1732/ https://xkcd.com/1732/
- goodcanadian 10y ago
  The graph that convinced me (many years ago) was this one: http://www.jeremyrhammond.com/wp-content/uploads/2016/03/mauna-loa-co2-619x484.jpg http://www.jeremyrhammond.com/wp-content/uploads/2016/03/mau... It is simple physics as to how CO2 works as a greenhouse gas. Seeing the clear trend of increasing CO2 in the atmosphere makes warming sort of obvious (at least to me). All of the complex second order effects (how much warming, how climate and weather patterns will react, and so on) are much more complicated and therefore less clear. Nevertheless, we are having a strong clear effect on the atmosphere which is going to warm the planet. The rest is details (though those details are getting a lot scarier, recently).
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- eric_h 10y ago
  Much as I like Randall Munroe and xkcd, I don't see any sources cited in that comic. I don't know that we know, precisely, how fucked we are yet, but I do think it's clear that humans are having an effect, and we know very convincing reasons for why we're having an effect, so we should work to reduce that effect regardless of whether we're fucked in 100 years if we continue this way, or if it will take 1000.
  - throwaway6556 10y ago
    > regardless of whether we're fucked in 100 years if we continue this way, or if it will take 1000. But how are we to make money then?! Do you want Elon Musk to keep all off it for himself? Why do you hate America?
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  - sathackr 10y ago
    He cites his sources on the right near the top. > SHAKUN ET.AL. (2012), MARCOTT ET.AL.(2013), ANNAN AND HARGRAVES (2013), HADCRUT4, IPCC
    - eric_h 10y ago
      I stand corrected. Thanks.
- civility 10y ago
  I would've liked that comic illustration much more if he had gone back 400,000 years instead of only 20,000.
wtvanhest 10y ago
I am not a "denier", but I do struggle with the evidence I have read as most of it has too much subjectivity or is based on meta studies where all underlying papers are highly subjective. What is missing from the debate is 2-3 papers that are agreed on to be the clearest evidence that temperatures are changing due to human inputs. Calling people 'deniers' is an ad hominen attack that doesn't prove anything, and most importantly doesn't help change people's minds.
- eric_h 10y ago
  > Calling people 'deniers' is an ad hominen attack that doesn't prove anything, and most importantly doesn't help change people's minds. This is true, but the people who are, in fact, deniers likely won't change their minds anyway and likely will not be alive long enough to see any undeniable evidence that could. It's the same thing with discussing religion, I learned long ago to keep my mouth shut about it when talking to anyone who didn't express even a touch of an open mind about it. I agree that the magnitude of the effect has not been demonstrably measured by anyone yet, but I don't see that as any reason to not take action to at least try to reduce whatever damage we might have done, are currently doing, and might do in the future.
  - wtvanhest 10y ago
    There are major costs associated with cutting carbon emmissions before we have better technology. That is why people are questioning the 'science' of global warming. If we as a species are wrong about global warming in either direction, that is a big problem.
    - woodandsteel 10y ago
      >There are major costs associated with cutting carbon emmissions before we have better technology. But the technology has been rapidly getting more economical, and in some ways is now actually cheaper than fossil fuels (which also has many negative externalities of its own). And this has been happening only because there has been an enormous investment in renewable energy. The idea that the scientists all on their own will work for decades and come up with fully-ready technologies that then will be put into full production is just not how these things actually work.
stillsut 10y ago
For most lukewarmists it is certain that humans (GHG emissions) are causing the global temperature to increase. But how much? About +0.5C since pre-industrial times. Everybody also understands there's some natural variation, year-to-year noise which is 20x greater than the human caused warming signal. The trend over the past century is +1.0C / century. Or +0.2C / decade in the second half. So lukewarmists believe humans are responsible for about half of the observed warming this century (0.5 out of 1.0), the other half is noise which will cancel out in the long run. That implies the projection for future warming is small. The alarmist position is the opposite: believing that the noise was probably saving us from more warming, and that other mechanisms have acted to keep the observed warming down. In this view, humans are maybe responsible for over a 100% of the warming. This implies that the noise which has kept things manageable will eventually cancel out and we'll see a sharp increase in the rate of warming in the next two decades. So yes, I think skeptics, lukewarmists, and alarmists are all interested in GMT through 2030 to get a better idea for how much warming we'll get this century.
- woodandsteel 10y ago
  >I think skeptics, lukewarmists, and alarmists are all interested in GMT through 2030 to get a better idea for how much warming we'll get this century. So in term of the question I asked, you are saying that skeptics and lukewarmists would change their minds if GMT went up significantly more than their present views predict? And is this something they explicitly state, and all of them? Also, I was directing my question to deniers and skeptics, so let me ask what is your position.
  - stillsut 10y ago
    > you are saying that skeptics and lukewarmists would change their minds if GMT went up significantly more than their present views predict? Yes, absolutely. One thing which makes this seemingly completely empirical topic difficult though is the ~20x noise-to-signal ratio and the "red noise" inherent in the process. This means end points for the analysis make a huge difference. Both skeptics and alarmists will cherry-pick when they can, and will reflexively dismiss each others trend lines as cherry picked. My view is the "two sides" act as the prosecution and defense in an adversarial courtroom. Neither should be expected to raise evidence or lines of reasoning which detract from their own agenda. And both will constantly try to get the other side's evidence thrown out, even if they know it would get the general public closer to the truth.
Mendenhall 10y ago
I would say I 100 percent know people change the climate. How much I do not know. I have yet to see any scientific proof as to what percentage of change will be man made, or what degree the earth will change without human intervention. I dont think of myself as a denier but I do think of myself as someone who likes facts. In the research I have done when I have dug deeper it turns up a lot of assumptions\models. I think the science has to develope more to answer those type of questions accurately. I am not jumping to a conclusion of severity, I just want more facts so the correct action can be taken.
- woodandsteel 10y ago
  > I just want more facts so the correct action can be taken. So you do think your mind could be persuaded by more scientific evidence, but you don't state specifically what sort of evidence it would take to do it.
- woodandsteel 10y ago
  >I would say I 100 percent know people change the climate. No, there are lots of people who deny the climate is changing and that it is due at least in part to humans. They argue for instance, that the temperature data is inaccurate, or that any temperature rise we have seen recently is just random, or that it is systematic but due to increased solar radiation. I am rather surprised you aren't aware of these views.
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woodandsteel 10y ago
Thinking some more, I am realizing that, as someone who believes in anthropogenic climate change, I ought to be open to the possibility that in the future further evidence will disprove it. That said, at present that seems to me pretty unlikely.
Tycho 10y ago
The problem with "climate science" is that so many things about it set off my internal BS detector. But on specifics, it would be good to get a clear answer to the question - how come CO2 concentration was much higher in several past periods and it didn't turn the Earth into a desert?
- woodandsteel 10y ago
  >But on specifics, it would be good to get a clear answer to the question - how come CO2 concentration was much higher in several past periods and it didn't turn the Earth into a desert? So are you saying that if you got a persuasive answer to that question, you would then be persuaded that human activity is causing global warming, at least to a considerable degree?
  - Tycho 10y ago
    If there is not a good answer to that question, then I would reject the hypothesis outright. If there is a good answer, then I would accept it as a working hypothesis, unless any other screaming contradictions come up. I would also find it persuasive to see people with skin-in-the-game make informed decisions. For instance, selling off desirable waterfront properties because they believe rising sea levels will make them worthless within a century. But let's say 10 or 20 or 30 years from now, we have not observed any additional warming or maybe we've even had cooling. I would not be surprised. Whereas I imagine there would be a lot of people walking around thinking "How could 97% of scientists have been so wrong? How could so much well funded research produce the wrong conclusion?" They would struggle to integrate it into their worldview. (although I guess they would probably just say it's a temporary pause or something)
    - Oletros 10y ago
      > If there is not a good answer to that question, then I would reject the hypothesis outright. If there is a good answer, then I would accept it as a working hypothesis, unless any other screaming contradictions come up. So, you won't accept it in any case
bkirkby 10y ago
the short answer is "science," specifically "observation." the long answer is that my skepticism comes from climate being a classic complexity issue where trying to isolate a single factor (carbon) as being the main forcing for climate change requires a lot of real evidence. i'd turn the question back around on you by asking "why do you believe in CAGW?" when i asked myself that question (because i was like most people and believed the standard news reports before i tried to really understand it), i discovered two main pieces of observational data that were overwhelming for why the increased carbon is going to lead to run-away warming: 1. the correlation of atmospheric carbon and temperature in the geologic record (ice core samples and tree ring data). it's very clear looking at those records that atmospheric carbon and temperature are correlated. but, when i dug into it i found out that in the geologic record the temperature increase PRECEEDS atmospheric CO2 by hundreds of years. if we were going to infer causation by correlation, then it would have to be the other way around. so that strong piece of evidence turned out not to be actual evidence. when i sought answers for this from the global warming alarmist scientists, what they had to say was "yes, it's true. what we know is that the temperature increases for some unknown reason, then carbon is released because of the temperature, which then causes the temperature to increase more and a positive feedback loop is created." but, if this were really how it happened and co2 is the overwhelmingly main forcing for temperature increase, then why wasn't the planet already destroyed back when we had 10x+ the amount of carbon in the atmosphere than what we are doing today? 2. after #1 melted away, i realized that the strongest evidence for CAGW was rooted in the predictions of climate models. it wasn't being proven by geologic or current observations, so what do the models tell us? well, the models are very interesting because they are mechanisms we use to try to understand a classic complexity problem. these are notoriously difficult problems to fully understand down to it's constituent components. add on top of it the timeframes we are talking about with the models, and it becomes very difficult to understand it right now. the models predict noticeable temperature increase in the 100s of years timeframe, not in the decadal timeframe. so to be able to actually observe the predictions of the models, we'd have to wait 100s of years. so, i wondered if there were other things that the models predicted that were more in the annual/decadal timeframe that we could observe to be happening. as it happens, the answer is yes. all models that predicted runaway warming due to the co2 greenhouse effect ALSO predicted a warming of the atmosphere at a greater rate than a warming of the surface. (which makes sense based on the theory) so all we'd have to do, is show that the atmosphere is heating up at an accelerated rate than the surface, and that would be a significant data point. but what we actually observe is the opposite. the surface temperature is increasing at a faster rate than the atmospheric temperature. so the observed data appears to be going against the theory. now, to be clear, i don't disagree that the planet is warming. i'm just skeptical that an increase in co2 is the main culprit. with that in mind, i'd love to hear other people's observational evidence that backs the theory up. that's what will convince me. and to make it clear, what will not convince me are fear mongering about "what if the theory is right?!" or the quasi-religious appeals to authority by saying "all these smart people believe different than you." i want predictions made by the theory that show observational corroboration (with, preferably, an elimination of other explanations for the outcome).
robotiamsowhat 10y ago
Perhaps a honest discussion would do? First things first - I would not call me a denier, but I would call me understander. An outcome from what I have read somewhere was that, if Sun increased its output by 1% (and kept it so for some years) it would cause equivalent warming to the one observed now. As far as I can say, Sun's activity was never constant. There may be other factors as well. On few occassions I showed this page to believers: https://en.wikipedia.org/wiki/Milankovitch_cycles https://en.wikipedia.org/wiki/Milankovitch_cycles - I do not remember getting any answer. The question was simple: what caused previous global warmings? What made the last glaciation melt down? I have searched for Milankovitch on HN and this was posted few times, but always zero comments from what I can see.
- woodandsteel 10y ago
  So in terms of my question, are you saying that if you were presented with persuasive evidence that it is not the case that the global warming we observe is being caused by increasing solar radiation, would you then be persuaded it is instead being caused at least to a considerable degree by human activity?
  - robotiamsowhat 10y ago
    Solar radiation, changes in Earth's orbit (it has been proved to be chaotic, longterm, AFAIK), microvawe from space hitting steam in atmosphere, volcanic production. There are few things that come to my head and might be connected to the problem. Some of this may sound as fringe. Nevertheless I would like to see credible debunking, using data and logic. May include calculus. If I see worth, I will relearn calculus. Heck, it may include whatever that will make me want to think about it - models, tables, photos. Given the gravity of the problem and weight on future if there is miscalculation, I claim this should be taken out of politicians' hands. Wikipedia style. The hockeystick scandal did not help, either. And last but not least: what made the last glaciation melt and what caused it in first place? Model, please. Something I can compile on my computer. Twenty five years ago, maybe twenty, it would have easily placed itself among first ten fastest supercomputers (if I am correct). I am sure this machine can handle some computation. Even if not, give me a source code and let me worry how to run it. EDIT: Ok, I would prefer a bunch of equation, differential too, rather than source code. EDIT2: As of "being caused at least to a considerable degree by human activity", I am already rather certain that humans did their best to be part of the problem. The question I am trying to answer is "to what degree", not "if".
woodandsteel 10y ago
Two hours after posting my original question, I am realizing that some skeptics and deniers might be persuaded by additional evidence, but others wouldn't. A next question then would be how many in the US are persuadable and how many not. I am pretty sure most are not, but it would be good to have some survey data. I am also struck that most of the skeptics and deniers either didn't answer the question as to whether they they could be persuaded, or at least implied they could, but didn't say what specific sort of evidence it would take.
thrw_skpt 10y ago
I see several things about the climate science that can be substantially improved. * general discourse. Whenever someone raises some objection, the response is not a thoughtful argument, but many times a quick dismissal. you are certainly not one to do that, it is much appreciated * unfalsifiability. scientific theories should be falsifiable. anything else is religion or politics. For example, what happens if there is a large volcano, or something like Saddam burning thousands of oil wells in Kuwait. I read somewhere that some climate models did check their predictions against the actual outcomes, and this is good. More evidence of this type would be great. * model and data validation, audit and oversight. I am a quant working with both data and models in finance. I know about model uncertainty, and how messy is real world data. The regulators demand a lot of model testing, documentation, validation, ongoing monitoring, and audit. Our bible is the supervisory letter SR 11-7. Banks are investing billions in this and regulators hired hundreds of people to beef up their oversight. I don't see a similar scrutiny over the climate models that arguably are more important for the humanity * all results in climate science can be spun to align to the climate change thesis. If there is a large uncertainty about the results, one picks the worse outcome and the result is presented as "new research show that the [melting of Antarctica, let's say] may be happening much faster than previously thought". Well, the same research show that the X thing may be also happening much slower, but who cares about that? If something completely new comes up (e.g. number of trees in the Amazon basin being off by a factor of 10), then more funding is needed. * the 97% or so consensus of the climate scientists. My perception is that most of them know their own piece, and they are scrupulous, but can't conclude from their area of research one way or another about the whole global warming. They don't contradict it either, so if asked they say that global warming is most likely real. But that's not really a strong consensus, it's a polite agreement to not disagree. Here's a recent example on Hacker News: and antarctic ice researcher did an AMA on HN when his research regarding some Larsen C breakage made waves in the media [1]. The media spin was obviously that the world is getting warmer, and this is new evidence to support that. When someone on HN asked what we can do to stop further ice breaks, his answer was this: "Nothing! This is a completely natural process - ice builds up over time in the shelf and it has to be lost somehow. The calving of the iceberg is, in itself, not a result of human activity. If you mean more broadly how can we help prevent the loss of ice from Antarctica, then I'm not a climate policy expert". This gentleman is clearly a climate scientist, but he does not consider himself a "climate policy expert" * Freeman Dyson [2] judges the climate models as having too much uncertainty: "The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world we live in ..." By the way, I'm not a shill of the oil/coal/car industry. I do have a STEM PhD from MIT, and I can continue with more scientific arguments, but this message is getting already too long. I'm using a throwaway account. [1] https://news.ycombinator.com/item?id=13365211 https://news.ycombinator.com/item?id=13365211 [2] https://en.wikipedia.org/wiki/Freeman_Dyson#Climate_change https://en.wikipedia.org/wiki/Freeman_Dyson#Climate_change

sathackr 10y ago

For a long time I was in the "we don't have enough information to make a conclusion" camp, and dismissed anyone "jumping" to conclusions as alarmist. This xkcd changed my mind: https://xkcd.com/1732/ https://xkcd.com/1732/

goodcanadian 10y ago
The graph that convinced me (many years ago) was this one: http://www.jeremyrhammond.com/wp-content/uploads/2016/03/mauna-loa-co2-619x484.jpg http://www.jeremyrhammond.com/wp-content/uploads/2016/03/mau... It is simple physics as to how CO2 works as a greenhouse gas. Seeing the clear trend of increasing CO2 in the atmosphere makes warming sort of obvious (at least to me). All of the complex second order effects (how much warming, how climate and weather patterns will react, and so on) are much more complicated and therefore less clear. Nevertheless, we are having a strong clear effect on the atmosphere which is going to warm the planet. The rest is details (though those details are getting a lot scarier, recently).
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eric_h 10y ago
Much as I like Randall Munroe and xkcd, I don't see any sources cited in that comic. I don't know that we know, precisely, how fucked we are yet, but I do think it's clear that humans are having an effect, and we know very convincing reasons for why we're having an effect, so we should work to reduce that effect regardless of whether we're fucked in 100 years if we continue this way, or if it will take 1000.
- throwaway6556 10y ago
  > regardless of whether we're fucked in 100 years if we continue this way, or if it will take 1000. But how are we to make money then?! Do you want Elon Musk to keep all off it for himself? Why do you hate America?
- deleted 10y ago
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- sathackr 10y ago
  He cites his sources on the right near the top. > SHAKUN ET.AL. (2012), MARCOTT ET.AL.(2013), ANNAN AND HARGRAVES (2013), HADCRUT4, IPCC
  - eric_h 10y ago
    I stand corrected. Thanks.
civility 10y ago
I would've liked that comic illustration much more if he had gone back 400,000 years instead of only 20,000.

wtvanhest 10y ago

I am not a "denier", but I do struggle with the evidence I have read as most of it has too much subjectivity or is based on meta studies where all underlying papers are highly subjective. What is missing from the debate is 2-3 papers that are agreed on to be the clearest evidence that temperatures are changing due to human inputs. Calling people 'deniers' is an ad hominen attack that doesn't prove anything, and most importantly doesn't help change people's minds.

eric_h 10y ago
> Calling people 'deniers' is an ad hominen attack that doesn't prove anything, and most importantly doesn't help change people's minds. This is true, but the people who are, in fact, deniers likely won't change their minds anyway and likely will not be alive long enough to see any undeniable evidence that could. It's the same thing with discussing religion, I learned long ago to keep my mouth shut about it when talking to anyone who didn't express even a touch of an open mind about it. I agree that the magnitude of the effect has not been demonstrably measured by anyone yet, but I don't see that as any reason to not take action to at least try to reduce whatever damage we might have done, are currently doing, and might do in the future.
- wtvanhest 10y ago
  There are major costs associated with cutting carbon emmissions before we have better technology. That is why people are questioning the 'science' of global warming. If we as a species are wrong about global warming in either direction, that is a big problem.
  - woodandsteel 10y ago
    >There are major costs associated with cutting carbon emmissions before we have better technology. But the technology has been rapidly getting more economical, and in some ways is now actually cheaper than fossil fuels (which also has many negative externalities of its own). And this has been happening only because there has been an enormous investment in renewable energy. The idea that the scientists all on their own will work for decades and come up with fully-ready technologies that then will be put into full production is just not how these things actually work.

stillsut 10y ago

For most lukewarmists it is certain that humans (GHG emissions) are causing the global temperature to increase. But how much? About +0.5C since pre-industrial times. Everybody also understands there's some natural variation, year-to-year noise which is 20x greater than the human caused warming signal. The trend over the past century is +1.0C / century. Or +0.2C / decade in the second half. So lukewarmists believe humans are responsible for about half of the observed warming this century (0.5 out of 1.0), the other half is noise which will cancel out in the long run. That implies the projection for future warming is small. The alarmist position is the opposite: believing that the noise was probably saving us from more warming, and that other mechanisms have acted to keep the observed warming down. In this view, humans are maybe responsible for over a 100% of the warming. This implies that the noise which has kept things manageable will eventually cancel out and we'll see a sharp increase in the rate of warming in the next two decades. So yes, I think skeptics, lukewarmists, and alarmists are all interested in GMT through 2030 to get a better idea for how much warming we'll get this century.

woodandsteel 10y ago
>I think skeptics, lukewarmists, and alarmists are all interested in GMT through 2030 to get a better idea for how much warming we'll get this century. So in term of the question I asked, you are saying that skeptics and lukewarmists would change their minds if GMT went up significantly more than their present views predict? And is this something they explicitly state, and all of them? Also, I was directing my question to deniers and skeptics, so let me ask what is your position.
- stillsut 10y ago
  > you are saying that skeptics and lukewarmists would change their minds if GMT went up significantly more than their present views predict? Yes, absolutely. One thing which makes this seemingly completely empirical topic difficult though is the ~20x noise-to-signal ratio and the "red noise" inherent in the process. This means end points for the analysis make a huge difference. Both skeptics and alarmists will cherry-pick when they can, and will reflexively dismiss each others trend lines as cherry picked. My view is the "two sides" act as the prosecution and defense in an adversarial courtroom. Neither should be expected to raise evidence or lines of reasoning which detract from their own agenda. And both will constantly try to get the other side's evidence thrown out, even if they know it would get the general public closer to the truth.

Mendenhall 10y ago

I would say I 100 percent know people change the climate. How much I do not know. I have yet to see any scientific proof as to what percentage of change will be man made, or what degree the earth will change without human intervention. I dont think of myself as a denier but I do think of myself as someone who likes facts. In the research I have done when I have dug deeper it turns up a lot of assumptions\models. I think the science has to develope more to answer those type of questions accurately. I am not jumping to a conclusion of severity, I just want more facts so the correct action can be taken.

woodandsteel 10y ago
> I just want more facts so the correct action can be taken. So you do think your mind could be persuaded by more scientific evidence, but you don't state specifically what sort of evidence it would take to do it.
woodandsteel 10y ago
>I would say I 100 percent know people change the climate. No, there are lots of people who deny the climate is changing and that it is due at least in part to humans. They argue for instance, that the temperature data is inaccurate, or that any temperature rise we have seen recently is just random, or that it is systematic but due to increased solar radiation. I am rather surprised you aren't aware of these views.

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woodandsteel 10y ago

Thinking some more, I am realizing that, as someone who believes in anthropogenic climate change, I ought to be open to the possibility that in the future further evidence will disprove it. That said, at present that seems to me pretty unlikely.

Tycho 10y ago

The problem with "climate science" is that so many things about it set off my internal BS detector. But on specifics, it would be good to get a clear answer to the question - how come CO2 concentration was much higher in several past periods and it didn't turn the Earth into a desert?

woodandsteel 10y ago
>But on specifics, it would be good to get a clear answer to the question - how come CO2 concentration was much higher in several past periods and it didn't turn the Earth into a desert? So are you saying that if you got a persuasive answer to that question, you would then be persuaded that human activity is causing global warming, at least to a considerable degree?
- Tycho 10y ago
  If there is not a good answer to that question, then I would reject the hypothesis outright. If there is a good answer, then I would accept it as a working hypothesis, unless any other screaming contradictions come up. I would also find it persuasive to see people with skin-in-the-game make informed decisions. For instance, selling off desirable waterfront properties because they believe rising sea levels will make them worthless within a century. But let's say 10 or 20 or 30 years from now, we have not observed any additional warming or maybe we've even had cooling. I would not be surprised. Whereas I imagine there would be a lot of people walking around thinking "How could 97% of scientists have been so wrong? How could so much well funded research produce the wrong conclusion?" They would struggle to integrate it into their worldview. (although I guess they would probably just say it's a temporary pause or something)
  - Oletros 10y ago
    > If there is not a good answer to that question, then I would reject the hypothesis outright. If there is a good answer, then I would accept it as a working hypothesis, unless any other screaming contradictions come up. So, you won't accept it in any case

bkirkby 10y ago

the short answer is "science," specifically "observation." the long answer is that my skepticism comes from climate being a classic complexity issue where trying to isolate a single factor (carbon) as being the main forcing for climate change requires a lot of real evidence. i'd turn the question back around on you by asking "why do you believe in CAGW?" when i asked myself that question (because i was like most people and believed the standard news reports before i tried to really understand it), i discovered two main pieces of observational data that were overwhelming for why the increased carbon is going to lead to run-away warming: 1. the correlation of atmospheric carbon and temperature in the geologic record (ice core samples and tree ring data). it's very clear looking at those records that atmospheric carbon and temperature are correlated. but, when i dug into it i found out that in the geologic record the temperature increase PRECEEDS atmospheric CO2 by hundreds of years. if we were going to infer causation by correlation, then it would have to be the other way around. so that strong piece of evidence turned out not to be actual evidence. when i sought answers for this from the global warming alarmist scientists, what they had to say was "yes, it's true. what we know is that the temperature increases for some unknown reason, then carbon is released because of the temperature, which then causes the temperature to increase more and a positive feedback loop is created." but, if this were really how it happened and co2 is the overwhelmingly main forcing for temperature increase, then why wasn't the planet already destroyed back when we had 10x+ the amount of carbon in the atmosphere than what we are doing today? 2. after #1 melted away, i realized that the strongest evidence for CAGW was rooted in the predictions of climate models. it wasn't being proven by geologic or current observations, so what do the models tell us? well, the models are very interesting because they are mechanisms we use to try to understand a classic complexity problem. these are notoriously difficult problems to fully understand down to it's constituent components. add on top of it the timeframes we are talking about with the models, and it becomes very difficult to understand it right now. the models predict noticeable temperature increase in the 100s of years timeframe, not in the decadal timeframe. so to be able to actually observe the predictions of the models, we'd have to wait 100s of years. so, i wondered if there were other things that the models predicted that were more in the annual/decadal timeframe that we could observe to be happening. as it happens, the answer is yes. all models that predicted runaway warming due to the co2 greenhouse effect ALSO predicted a warming of the atmosphere at a greater rate than a warming of the surface. (which makes sense based on the theory) so all we'd have to do, is show that the atmosphere is heating up at an accelerated rate than the surface, and that would be a significant data point. but what we actually observe is the opposite. the surface temperature is increasing at a faster rate than the atmospheric temperature. so the observed data appears to be going against the theory. now, to be clear, i don't disagree that the planet is warming. i'm just skeptical that an increase in co2 is the main culprit. with that in mind, i'd love to hear other people's observational evidence that backs the theory up. that's what will convince me. and to make it clear, what will not convince me are fear mongering about "what if the theory is right?!" or the quasi-religious appeals to authority by saying "all these smart people believe different than you." i want predictions made by the theory that show observational corroboration (with, preferably, an elimination of other explanations for the outcome).

robotiamsowhat 10y ago

Perhaps a honest discussion would do? First things first - I would not call me a denier, but I would call me understander. An outcome from what I have read somewhere was that, if Sun increased its output by 1% (and kept it so for some years) it would cause equivalent warming to the one observed now. As far as I can say, Sun's activity was never constant. There may be other factors as well. On few occassions I showed this page to believers: https://en.wikipedia.org/wiki/Milankovitch_cycles https://en.wikipedia.org/wiki/Milankovitch_cycles - I do not remember getting any answer. The question was simple: what caused previous global warmings? What made the last glaciation melt down? I have searched for Milankovitch on HN and this was posted few times, but always zero comments from what I can see.

woodandsteel 10y ago
So in terms of my question, are you saying that if you were presented with persuasive evidence that it is not the case that the global warming we observe is being caused by increasing solar radiation, would you then be persuaded it is instead being caused at least to a considerable degree by human activity?
- robotiamsowhat 10y ago
  Solar radiation, changes in Earth's orbit (it has been proved to be chaotic, longterm, AFAIK), microvawe from space hitting steam in atmosphere, volcanic production. There are few things that come to my head and might be connected to the problem. Some of this may sound as fringe. Nevertheless I would like to see credible debunking, using data and logic. May include calculus. If I see worth, I will relearn calculus. Heck, it may include whatever that will make me want to think about it - models, tables, photos. Given the gravity of the problem and weight on future if there is miscalculation, I claim this should be taken out of politicians' hands. Wikipedia style. The hockeystick scandal did not help, either. And last but not least: what made the last glaciation melt and what caused it in first place? Model, please. Something I can compile on my computer. Twenty five years ago, maybe twenty, it would have easily placed itself among first ten fastest supercomputers (if I am correct). I am sure this machine can handle some computation. Even if not, give me a source code and let me worry how to run it. EDIT: Ok, I would prefer a bunch of equation, differential too, rather than source code. EDIT2: As of "being caused at least to a considerable degree by human activity", I am already rather certain that humans did their best to be part of the problem. The question I am trying to answer is "to what degree", not "if".

woodandsteel 10y ago

Two hours after posting my original question, I am realizing that some skeptics and deniers might be persuaded by additional evidence, but others wouldn't. A next question then would be how many in the US are persuadable and how many not. I am pretty sure most are not, but it would be good to have some survey data. I am also struck that most of the skeptics and deniers either didn't answer the question as to whether they they could be persuaded, or at least implied they could, but didn't say what specific sort of evidence it would take.

thrw_skpt 10y ago

I see several things about the climate science that can be substantially improved. * general discourse. Whenever someone raises some objection, the response is not a thoughtful argument, but many times a quick dismissal. you are certainly not one to do that, it is much appreciated * unfalsifiability. scientific theories should be falsifiable. anything else is religion or politics. For example, what happens if there is a large volcano, or something like Saddam burning thousands of oil wells in Kuwait. I read somewhere that some climate models did check their predictions against the actual outcomes, and this is good. More evidence of this type would be great. * model and data validation, audit and oversight. I am a quant working with both data and models in finance. I know about model uncertainty, and how messy is real world data. The regulators demand a lot of model testing, documentation, validation, ongoing monitoring, and audit. Our bible is the supervisory letter SR 11-7. Banks are investing billions in this and regulators hired hundreds of people to beef up their oversight. I don't see a similar scrutiny over the climate models that arguably are more important for the humanity * all results in climate science can be spun to align to the climate change thesis. If there is a large uncertainty about the results, one picks the worse outcome and the result is presented as "new research show that the [melting of Antarctica, let's say] may be happening much faster than previously thought". Well, the same research show that the X thing may be also happening much slower, but who cares about that? If something completely new comes up (e.g. number of trees in the Amazon basin being off by a factor of 10), then more funding is needed. * the 97% or so consensus of the climate scientists. My perception is that most of them know their own piece, and they are scrupulous, but can't conclude from their area of research one way or another about the whole global warming. They don't contradict it either, so if asked they say that global warming is most likely real. But that's not really a strong consensus, it's a polite agreement to not disagree. Here's a recent example on Hacker News: and antarctic ice researcher did an AMA on HN when his research regarding some Larsen C breakage made waves in the media [1]. The media spin was obviously that the world is getting warmer, and this is new evidence to support that. When someone on HN asked what we can do to stop further ice breaks, his answer was this: "Nothing! This is a completely natural process - ice builds up over time in the shelf and it has to be lost somehow. The calving of the iceberg is, in itself, not a result of human activity. If you mean more broadly how can we help prevent the loss of ice from Antarctica, then I'm not a climate policy expert". This gentleman is clearly a climate scientist, but he does not consider himself a "climate policy expert" * Freeman Dyson [2] judges the climate models as having too much uncertainty: "The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world we live in ..." By the way, I'm not a shill of the oil/coal/car industry. I do have a STEM PhD from MIT, and I can continue with more scientific arguments, but this message is getting already too long. I'm using a throwaway account. [1] https://news.ycombinator.com/item?id=13365211 https://news.ycombinator.com/item?id=13365211 [2] https://en.wikipedia.org/wiki/Freeman_Dyson#Climate_change https://en.wikipedia.org/wiki/Freeman_Dyson#Climate_change