Climate Models for Lawyers(judithcurry.com)
judithcurry.com
Climate Models for Lawyers
https://judithcurry.com/2016/11/12/climate-models-for-lawyers/
53 comments
Worth noting that although this analysis is a good one, and helps calm down the knee-jerk responses of "global warming is a fraud", your comment does not contradict the linked article, which does not argue that climate change is not real, but rather than GCMs are a tool of limited utility for predicting climate change or forming policy guidance around mitigating climate change.
The article does not discount the utility of GCMs in furthering our understanding of the climate in general, but reaches the conclusion that existing models are of limited utility when attempting to forecast the affect of policy changes (or the lack thereof) on climate trends.
The article does not discount the utility of GCMs in furthering our understanding of the climate in general, but reaches the conclusion that existing models are of limited utility when attempting to forecast the affect of policy changes (or the lack thereof) on climate trends.
This is slightly misleading. What we've understood for a century is the thermal forcing due to CO2, which is a logarithmic function of the CO2 concentration (ie, forcing == O(log n) in CO2 concentration).
What we don't understand (unless we decide GCMs are predictive and can be validated) is the impact of a given thermal forcing on planetary temperature. This is the "climate sensitivity." Unfortunately, this is the number we actually care about.
If climate sensitivity is low (negative feedback), Earth is thermally buffered and we have to worry less. If climate sensitivity is high (positive feedback), the opposite.
(Note also that Arrhenius, the discoverer of this effect, and pretty much everyone through the '60s, assumed that global warming was a positive side effect of burning fossil fuel, just from the preindustrial assumption that warm winters and high crop yields are good for humanity.)
What we don't understand (unless we decide GCMs are predictive and can be validated) is the impact of a given thermal forcing on planetary temperature. This is the "climate sensitivity." Unfortunately, this is the number we actually care about.
If climate sensitivity is low (negative feedback), Earth is thermally buffered and we have to worry less. If climate sensitivity is high (positive feedback), the opposite.
(Note also that Arrhenius, the discoverer of this effect, and pretty much everyone through the '60s, assumed that global warming was a positive side effect of burning fossil fuel, just from the preindustrial assumption that warm winters and high crop yields are good for humanity.)
Just to add to that, we know the increase in the atmosphere is mostly due to fossil fuels because that co2 source has unique isotope signatures compared to other sources like rotting plants and forest fires, and we know the basic plexiglass box scenario is actually playing out from satellite observations, which directly observe that it is co2 (and methane) spectra of heat specifically that is being blocked, not other wavelengths, and that the degree of change is in accordance with what would be expected given the amount of co2 we have added.
In other words everything is very clear, it all adds up, it has added up and been clear since the early 1990s.
In other words everything is very clear, it all adds up, it has added up and been clear since the early 1990s.
Is this how we ended up shifting from "global warming" to "climate change"? Improved models showing that things won't just get warmer, they'll go all kinds of sideways?
The change in terminology doesn't have scientific significance, it was done to try to improve public understanding.
Basically "warming" in popular usage means "I can take my jacket off now", whereas warming in scientific usage means "increasing the heat energy stored in a given volume."
Scientists have known for a long time that global warming (increasing the heat stored in the atmosphere) would create both local heating in some areas and local cooling in others (it's chaotic). But when a regular person hears "warming" and then the temperature goes down, they're confused. Hence "climate change."
Incidentally, predicting the local effects of warming is a major goal of GCMs, and one for which no other tool will do. But it's damn hard (again: it's chaotic).
Basically "warming" in popular usage means "I can take my jacket off now", whereas warming in scientific usage means "increasing the heat energy stored in a given volume."
Scientists have known for a long time that global warming (increasing the heat stored in the atmosphere) would create both local heating in some areas and local cooling in others (it's chaotic). But when a regular person hears "warming" and then the temperature goes down, they're confused. Hence "climate change."
Incidentally, predicting the local effects of warming is a major goal of GCMs, and one for which no other tool will do. But it's damn hard (again: it's chaotic).
When do you think this shift took place? The IPCC was established in the 80's.
NASA climatologist Gavin Schmidt on Curry (Google cache):
My reading of the evidence suggests clearly that the IPCC conclusions are an accurate assessment of the issue. I have tried to follow the proposed logic of Judith’s points here, but unfortunately each one of these arguments is either based on a misunderstanding, an unfamiliarity with what is actually being done or is a red herring associated with shorter-term variability. If Judith is interested in why her arguments are not convincing to others, perhaps this can give her some clues.
http://webcache.googleusercontent.com/search?q=cache:pLrHr9q...
My reading of the evidence suggests clearly that the IPCC conclusions are an accurate assessment of the issue. I have tried to follow the proposed logic of Judith’s points here, but unfortunately each one of these arguments is either based on a misunderstanding, an unfamiliarity with what is actually being done or is a red herring associated with shorter-term variability. If Judith is interested in why her arguments are not convincing to others, perhaps this can give her some clues.
http://webcache.googleusercontent.com/search?q=cache:pLrHr9q...
This quote from Gavin Schmidt is two years old. I'm not sure what is has to do with this blog post by Curry about what climate models are.
Note that this blog post is not "about what climate models are". It seems she's been making the same types of arguments in the past, and this blog post is no different, so the past criticisms are still relevant.
You're not sure what a quote from someone criticizing the stances the author of the post takes, on a submission about the stances the author is taking?
"Scientists that evaluate climate models, develop physical process parameterizations, and utilize climate model results are convinced (at least to some degree) of the usefulness of climate models for their research. They are convinced because of the model’s relation to theory and physical understanding of the processes involved, consistency of the simulated responses among different models and different model versions, and the ability of the model and model components to simulate historical observations."
Anyone can create a model that behaves consistently when it is trained on historical data to predict historical data.
How do they overcome the problem of overfitting and why should anyone have any confidence in it until it shows accuracy going forward?
Anyone can create a model that behaves consistently when it is trained on historical data to predict historical data.
How do they overcome the problem of overfitting and why should anyone have any confidence in it until it shows accuracy going forward?
I think the key is in the last quoted sentence: there isn't one model. There are many, and they are generated in different ways with differing emphasis on different data sets. They gain confidence when these seem to agree with each other and the acceptable physical knowledge already understood. They also check the sanity of the model to make sure that it is consistent with what has already been observed. In that way anyone may gain confidence that multiple approaches are converging on similar results.
That, and there are metric crap-tonnes of data to work with of all sorts. Just ungodly amounts of it.
That, and there are metric crap-tonnes of data to work with of all sorts. Just ungodly amounts of it.
In other news:
http://www.realclimate.org/index.php/archives/2016/11/record...
There was a lot of crowing about sunspots a couple years back by Judith Curry et al. The Earth's heating can be explained by reaching a solar maximum! Etc.
But now the situation is reversed--the sun is cooling--and despite that we're on track for yet another record year of heating. Third in a row.
Her points about model uncertainty and overfitting have some limited level of validity. But it's hard to read her blog and not come away with the accurate takeaway of she'll say whatever she can to provide a cover story for not doing anything about AGW.
http://www.realclimate.org/index.php/archives/2016/11/record...
There was a lot of crowing about sunspots a couple years back by Judith Curry et al. The Earth's heating can be explained by reaching a solar maximum! Etc.
But now the situation is reversed--the sun is cooling--and despite that we're on track for yet another record year of heating. Third in a row.
Her points about model uncertainty and overfitting have some limited level of validity. But it's hard to read her blog and not come away with the accurate takeaway of she'll say whatever she can to provide a cover story for not doing anything about AGW.
Having skimmed the final paper and without being aware of Judith Curry or her reputation, my initial reaction while reading was "This seems to be a white paper in the school of 'here's something you can cite to justify why nothing should be done about climate change/global warming/CO2 emissions/etc.'"
Looking her up afterwards, it seems to me that this may also be her push for a significant position in the Trump administration. Seems that Judith Curry is the scientist who says "Well, they've revised the likely range so clearly they don't know what's likely and maybe it's too expensive to do anything right now."
I won't bother linking, a simple search based on her name will turn up a wide variety of links to her history, people bemoaning her stances, and people refuting some of the arguments she uses.
Looking her up afterwards, it seems to me that this may also be her push for a significant position in the Trump administration. Seems that Judith Curry is the scientist who says "Well, they've revised the likely range so clearly they don't know what's likely and maybe it's too expensive to do anything right now."
I won't bother linking, a simple search based on her name will turn up a wide variety of links to her history, people bemoaning her stances, and people refuting some of the arguments she uses.
Yeah it's kind of sad actually. I started reading this as serious piece and then sent it to a professor I had during my undergrad for a class on climate change. So embarrassing!!
The broad points about training data and non-linearities are important- but on a second pass it's hard to believe that people who spend their lives building GCMs don't think deeply about these challenges.
The broad points about training data and non-linearities are important- but on a second pass it's hard to believe that people who spend their lives building GCMs don't think deeply about these challenges.
I think the worrying thing is that it's not hard to believe, she's pointing out the breakdown of the scientific process.
She cops a lot of flack and hysteria, just for raising reasonable doubts!
If climate science is solid, then it shouldn't feel the need to vilify anyone who questions it. If it isn't solid then it should be subject to as much scrutiny as possible given the derived policy will have tremendous impacts to life.
She cops a lot of flack and hysteria, just for raising reasonable doubts!
If climate science is solid, then it shouldn't feel the need to vilify anyone who questions it. If it isn't solid then it should be subject to as much scrutiny as possible given the derived policy will have tremendous impacts to life.
People who spend their lives building models in other sciences, say psychology, have missed gaps in their model... their whole approach, actually. Why is it inconceivable that climatology had equally glaring gaps?
Why not bother linking if the things she has said are so obviously wrong?
Because if I link to specific articles, it becomes about those articles, how the writers of them have their own axes to grind (e.g. William M. Connolley in http://scienceblogs.com/stoat/2016/11/14/judith-curry-wtf/ or http://www.realclimate.org/index.php/archives/2014/08/ipcc-a...), how the magazines and websites involved are all liberal mouthpieces (e.g. Scientific American via Nature.com, http://www.nature.com/news/2010/101101/full/news.2010.577.ht...).
Perhaps the most balanced article easily found is this one from the commie pinko NPR: http://www.npr.org/2013/08/22/213894792/uncertain-science-ju...
Re: William M. Connolley, see https://en.wikipedia.org/wiki/William_Connolley as a starting point to differentiate from many others with slight name variations.
edit: link in the wrong place
Perhaps the most balanced article easily found is this one from the commie pinko NPR: http://www.npr.org/2013/08/22/213894792/uncertain-science-ju...
Re: William M. Connolley, see https://en.wikipedia.org/wiki/William_Connolley as a starting point to differentiate from many others with slight name variations.
edit: link in the wrong place
Could someone with domain knowledge give feedback on the specifics she brings up? As I take it, the backbone of her argument is:
1) "If climate sensitivity is high, then we can expect substantial warming in the coming century as emissions continue to increase. If climate sensitivity is low, then future warming will be substantially lower."
2) "In fact, it seems that uncertainty about values of ECS has been increasing. The bottom of the ‘likely’ range has been lowered from 2 to 1.5oC in the AR5, whereas the AR4 stated that ECS is very unlikely to be less than 1.5oC. It is also significant that the AR5 does not cite a best estimate, whereas the AR4 cites a best estimate of 3oC. The stated reason for not citing a best estimate in the AR5 is the substantial discrepancy between observation-based estimates of ECS (lower), versus estimates from climate models (higher).
3) "If the climate sensitivity is on the low end of the range of estimates, and natural internal variability is on the strong side of the distribution of climate models, different conclusions are drawn about the relative importance of human causes to the 20th century warming."
4) "Whether or not human caused global warming is dangerous or not depends critically on whether the ECS value is closer to 1.5oC or 4.5oC."
5) "Given the uncertainties in equilibrium climate sensitivity and the magnitude and phasing of natural internal variability on decadal to century timescales, combined with the failure of climate models to explain the early 20th century warming and the mid-century cooling, I conclude that the climate models are not fit for the purpose of identifying with high confidence the proportional amount of natural versus human causes to the 20th century warming."
Is this an accurate summary of facts? Do we have good evidence about the true value of ECS that she does not mention? Is there evidence for scenarios where a 'low end' Equilibrium Climate Sensitivity still results in a dangerous warming? Or are there indeed values for ECS that would be considered 'likely' but do not result in dangerous warming?
Lack of knowledge about the true value of ECS is not an excuse to avoid precautionary measures, but it would seem to raise questions about the suitability of current climate models as predictors for future climate. At the least, it would imply that determining the true ECS should be a very high priority while other mitigation measures are taken.
1) "If climate sensitivity is high, then we can expect substantial warming in the coming century as emissions continue to increase. If climate sensitivity is low, then future warming will be substantially lower."
2) "In fact, it seems that uncertainty about values of ECS has been increasing. The bottom of the ‘likely’ range has been lowered from 2 to 1.5oC in the AR5, whereas the AR4 stated that ECS is very unlikely to be less than 1.5oC. It is also significant that the AR5 does not cite a best estimate, whereas the AR4 cites a best estimate of 3oC. The stated reason for not citing a best estimate in the AR5 is the substantial discrepancy between observation-based estimates of ECS (lower), versus estimates from climate models (higher).
3) "If the climate sensitivity is on the low end of the range of estimates, and natural internal variability is on the strong side of the distribution of climate models, different conclusions are drawn about the relative importance of human causes to the 20th century warming."
4) "Whether or not human caused global warming is dangerous or not depends critically on whether the ECS value is closer to 1.5oC or 4.5oC."
5) "Given the uncertainties in equilibrium climate sensitivity and the magnitude and phasing of natural internal variability on decadal to century timescales, combined with the failure of climate models to explain the early 20th century warming and the mid-century cooling, I conclude that the climate models are not fit for the purpose of identifying with high confidence the proportional amount of natural versus human causes to the 20th century warming."
Is this an accurate summary of facts? Do we have good evidence about the true value of ECS that she does not mention? Is there evidence for scenarios where a 'low end' Equilibrium Climate Sensitivity still results in a dangerous warming? Or are there indeed values for ECS that would be considered 'likely' but do not result in dangerous warming?
Lack of knowledge about the true value of ECS is not an excuse to avoid precautionary measures, but it would seem to raise questions about the suitability of current climate models as predictors for future climate. At the least, it would imply that determining the true ECS should be a very high priority while other mitigation measures are taken.
It sounds like she's advocating for a political policy of doing nothing, because of "uncertainty". Consider our position on risk/uncertainty when it comes to minor disasters like an airplane hijacking. Now consider the appropriate response to the risk of a nation-destroying disaster. Is it reasonable to take the do-nothing policy?
While there is probably a legitimate fear that others will use her evidence to claim that , I see her as making a more limited claim in this piece: current GCM's cannot reliably be used to make definitive claims about climate a century out, and therefore should not be relied on for policy decisions unless their true uncertainty (model risk) is accounted for. Which quotes from this piece do you read as a "call to inaction"?
That said, it's true that she does write elsewhere about her belief that uncertainty does not necessarily increase the urgency of action: https://judithcurry.com/2016/01/05/climate-models-and-precau.... I haven't read many of the linked posts, but it would seem fair to summarize her position as something like "we don't yet have sufficient understanding of the problem to justify taking actions that will cause definite harm".
That said, it's true that she does write elsewhere about her belief that uncertainty does not necessarily increase the urgency of action: https://judithcurry.com/2016/01/05/climate-models-and-precau.... I haven't read many of the linked posts, but it would seem fair to summarize her position as something like "we don't yet have sufficient understanding of the problem to justify taking actions that will cause definite harm".
If "definite harm" includes moderate financial cost, that's a disastrous policy.
Depends on the risk. The chances of some calamity may be so low that the cost of prevention is not worth it.
Of course. But that isn't the case here.
I'm not sure how you know that, given that none but the most doctor ozish of climate scientists (Hansen and ilk) will claim the doomsday scenarios are likely. Even then, other climate scientists will quickly repudiate such claims. As they have.
All fields have their attention whores and serial exaggerators. They are better ignored.
Or perhaps you are referring to the opinions of advocates or true believers? Those opinions, unfortunately, saturate the media.
As with any controversial science, a reading of the contrasting opinions of phds would do you far better.
All fields have their attention whores and serial exaggerators. They are better ignored.
Or perhaps you are referring to the opinions of advocates or true believers? Those opinions, unfortunately, saturate the media.
As with any controversial science, a reading of the contrasting opinions of phds would do you far better.
I suppose that depends on what you view as doomsday. Since a huge portion of the world's population lives on the coast, close to sea level, any significant sea level rise seems like a doomsday to me.
Further, even with a more strict definition of "doomsday", how likely does it need to be before taking it seriously? I've been in a car thousands of times without crashing, but I always wear a seatbelt.
Further, even with a more strict definition of "doomsday", how likely does it need to be before taking it seriously? I've been in a car thousands of times without crashing, but I always wear a seatbelt.
Did you read those opposing phd opinions yet?
Did you consider my argument yet?
And yes, I have read much of the literature over the last decade. I'm not sure why you are emphasizing simply a PhD as credibility. I prefer to judge research on its own terms.
And yes, I have read much of the literature over the last decade. I'm not sure why you are emphasizing simply a PhD as credibility. I prefer to judge research on its own terms.
What argument? You asked me what the likelihood would need to be.
You mean the seat belt argument? The cost to society of reducing co2 emissions exceeds the cost of a seatbelt by a factor of several billion.. even trillion.
A nearby star could explode and kill us all. Should we figure out how likely that is before spending trillions to fix it?
Did you mean answer your question about what the odds would need to be? I would first need to see the rhetoric tuned down a bit, some listening to minority researchers first. Considering the effort spent in silencing them, the whole thing stinks to high hell.
Who else but phds have credibility in climate science, other than perhaps phds in another hard science? Some citizen advocate? Please. If we had this nonsense in medical science eggs would be illegal by now.
You mean the seat belt argument? The cost to society of reducing co2 emissions exceeds the cost of a seatbelt by a factor of several billion.. even trillion.
A nearby star could explode and kill us all. Should we figure out how likely that is before spending trillions to fix it?
Did you mean answer your question about what the odds would need to be? I would first need to see the rhetoric tuned down a bit, some listening to minority researchers first. Considering the effort spent in silencing them, the whole thing stinks to high hell.
Who else but phds have credibility in climate science, other than perhaps phds in another hard science? Some citizen advocate? Please. If we had this nonsense in medical science eggs would be illegal by now.
When considering insurance, one usually tries to estimate the cost of an event multiplied by the likelihood of an event. The insurance company needs to charge slightly more as a premium, but if it's not too much more, that's a good purchase. It's a good idea for individuals to trade a small amount of expected value for a big reduction in variance.
The odds of a nearby star exploding are fairly easy to calculate, as far as I know. I could inquire from a few astronomer friends if you'd like. It's probably on Wikipedia, too. The cost of avoiding a star explosion... I guess Elon Musk is working on it.
The US spends about $600 billion annually on defense. Investing a few billion in reducing the risk of catastrophic climate change sounds quite reasonable, since trillions of dollars are at stake. Heck, even the "non-catastrophic" result of only a couple feet of sea level rise would swallow hundreds of billions of dollars of land value.
I'm not sure what rhetoric needs to be tuned down, since I have already read much of the literature from "minority researchers". I guess not the recent stuff, as I've gotten tired of it. As far as I can tell, the effort spent silencing scientists is mostly the exertion of fossil fuel companies. Who stands to profit from restrictions on fossil fuel consumption? I guess some renewable energy companies do, but few others in the short term. I have a hard time understanding the theory of a vast left-wing conspiracy to get us all to... what? Where's the motivation? It clearly is an ineffective technique to gain political power. Much more plausible is the idea of a few businesses trying to spread uncertainty. We saw that before, with cigarettes.
When you say, "listening to" do you mean believing the analysis of? It's funny you seem to hold PhDs in such high esteem. Almost everyone I know has a doctorate. Well, about half of them. And many of those in "hard science" or specifically environmental studies. I respect them, of course (since they're my friends), but I also think about their claims critically. Many of them need some coaching with statistics and non-linear dynamics, but hey, we can't all be experts on everything.
The odds of a nearby star exploding are fairly easy to calculate, as far as I know. I could inquire from a few astronomer friends if you'd like. It's probably on Wikipedia, too. The cost of avoiding a star explosion... I guess Elon Musk is working on it.
The US spends about $600 billion annually on defense. Investing a few billion in reducing the risk of catastrophic climate change sounds quite reasonable, since trillions of dollars are at stake. Heck, even the "non-catastrophic" result of only a couple feet of sea level rise would swallow hundreds of billions of dollars of land value.
I'm not sure what rhetoric needs to be tuned down, since I have already read much of the literature from "minority researchers". I guess not the recent stuff, as I've gotten tired of it. As far as I can tell, the effort spent silencing scientists is mostly the exertion of fossil fuel companies. Who stands to profit from restrictions on fossil fuel consumption? I guess some renewable energy companies do, but few others in the short term. I have a hard time understanding the theory of a vast left-wing conspiracy to get us all to... what? Where's the motivation? It clearly is an ineffective technique to gain political power. Much more plausible is the idea of a few businesses trying to spread uncertainty. We saw that before, with cigarettes.
When you say, "listening to" do you mean believing the analysis of? It's funny you seem to hold PhDs in such high esteem. Almost everyone I know has a doctorate. Well, about half of them. And many of those in "hard science" or specifically environmental studies. I respect them, of course (since they're my friends), but I also think about their claims critically. Many of them need some coaching with statistics and non-linear dynamics, but hey, we can't all be experts on everything.
I supervise "hard" scientists for a living... or did, up until a couple of years ago. You'd be surprised what a few try to pull, without the aid of a vast conspiracy.
But there is one to silence climate moderates.
The evidence is abundant. You have to actually look for it though. It won't fall in your lap. And providing you with it will probably only get me more nonsequiturs and naysaying, as all you have to do is start with the parent link, which you have already summarily dismissed without qualifications.
When you stop guessing at your opposition's motivations and listen to them, I can resume this conversation with you. No more nonsequiturs and guesswork.
But there is one to silence climate moderates.
The evidence is abundant. You have to actually look for it though. It won't fall in your lap. And providing you with it will probably only get me more nonsequiturs and naysaying, as all you have to do is start with the parent link, which you have already summarily dismissed without qualifications.
When you stop guessing at your opposition's motivations and listen to them, I can resume this conversation with you. No more nonsequiturs and guesswork.
> When you stop guessing at your opposition's motivations and listen to them
I honestly hadn't even considered what your motivations are, but now I am wondering. At the risk of being accused of a non-sequitur, I'll mention an interview I heard this morning on NPR. The host spoke with a white supremacist. The last exchange was a bit frustrating. I'll paraphrase:
(Guest) Why do they [non-white immigrants] come here if they're treated so badly?
(Host) The same reason people have immigrated for hundreds of years, for better opportunities.
(Guest) [laughs] You are so close-minded.
Somehow, it seems that both conversants think they are trying to honestly engage the other person, yet the other simply ignores what is said.
I honestly hadn't even considered what your motivations are, but now I am wondering. At the risk of being accused of a non-sequitur, I'll mention an interview I heard this morning on NPR. The host spoke with a white supremacist. The last exchange was a bit frustrating. I'll paraphrase:
(Guest) Why do they [non-white immigrants] come here if they're treated so badly?
(Host) The same reason people have immigrated for hundreds of years, for better opportunities.
(Guest) [laughs] You are so close-minded.
Somehow, it seems that both conversants think they are trying to honestly engage the other person, yet the other simply ignores what is said.
"I conclude that the climate models are not fit for the purpose"
Without any statistical treatment at all. And then later puts "expert opinion" of others in quotes.
At that point, I lost confidence in the analysis. Do some well known numerical and statistical tests of the models, and create a Bayesian based estimate based on all the models, and see where you end up instead!
Without any statistical treatment at all. And then later puts "expert opinion" of others in quotes.
At that point, I lost confidence in the analysis. Do some well known numerical and statistical tests of the models, and create a Bayesian based estimate based on all the models, and see where you end up instead!
Perhaps you missed her point about selection bias? Only models confirming climate change can be published, any analysis is just going to confirm that.
It's unfortunate because climate change could be happening, but we aren't going to learn much more about it because research can't be invalidated. We've killed the skepticism science needs to function.
She's not denying it's happening, she's just not buying the grandiose narrative. I'm glad to hear her view, even just to know that it's there.
It's unfortunate because climate change could be happening, but we aren't going to learn much more about it because research can't be invalidated. We've killed the skepticism science needs to function.
She's not denying it's happening, she's just not buying the grandiose narrative. I'm glad to hear her view, even just to know that it's there.
Ah, yes she is a bit of a skeptic- http://www.skepticalscience.com/Judith_Curry_arg.htm
One point that it looks like Curry takes aim with more generally is the degree to which there is a consensus about global warming among scientists. She says that 97% of scientists can't believe in it because they haven't studied it or built their own models, etc -- they have "second order belief"
That's an important epistemological point to make. I guess we should all make our own GCMs to confirm for ourselves that we believe in AGW?? Sure maybe if we all had unlimited time. In science we share a common set of methodological beliefs and assumptions-- maybe there's a breakdown for her there, but I'd like to think the at the research institutions and tools that exist help accurately propagate true findings to the public especially in a matter that's as pressing to our long term wellbeing as climate change!
That's an important epistemological point to make. I guess we should all make our own GCMs to confirm for ourselves that we believe in AGW?? Sure maybe if we all had unlimited time. In science we share a common set of methodological beliefs and assumptions-- maybe there's a breakdown for her there, but I'd like to think the at the research institutions and tools that exist help accurately propagate true findings to the public especially in a matter that's as pressing to our long term wellbeing as climate change!
Research institutions did a pretty poor job of telling us cholesterol consumption causes atherosclerosis. Largely because we discounted minority scientific opinion.
> One point that it looks like Curry takes aim with more generally is the degree to which there is a consensus about global warming among scientists. She says that 97% of scientists can't believe in it because they haven't studied it or built their own models, etc -- they have "second order belief"
In the post below, her primary complaint about the 97% stat is that it doesn't specify the amount of climate change that those people attributed to humans: "After discarding the abstracts that were judged to have taken no position, Cook (2013) reported a 97% consensus that anthropogenic GHGs were causing global warming. However, three-fourths of that consensus was judged to be implied and more than 98% of the agreement was expressed non-quantitatively. Consequently, no widespread consensus exists in these abstracts that humans are responsible for most of the global warming; only that humans are responsible for an unspecified amount of global warming."
https://judithcurry.com/2015/12/20/what-is-there-a-97-consen...
I think the 97% stat provides a useful opportunity for those of us who would like to get to truth of the matter but haven't studied climatology and have no interest in spending years studying the subject just to determine the truth of this particular issue. So much of the argument about the subject is "they're wrong, I'm right" followed by technical explanation that you cannot tell who to trust. But you can understand how the 97% claim was reached. It provides a useful opportunity to gauge who to trust on the subject, although admittedly still requires careful consideration and more time that most will commit.
This John Stuart Mill quote seems apt: "People more happily situated, who sometimes hear their opinions disputed, and are not wholly unused to be set right when they are wrong, place the same unbounded reliance only on such of their opinions as are shared by all who surround them, or to whom they habitually defer: for in proportion to a man's want of confidence in his own solitary judgement, does he usually repose, with implicit trust, on the infallibility of "the world" in general. And the world, to each individual, means the part of it with which he comes in contact; his party, his sect, his church, his class of society: the man may be called, by comparison, almost liberal and large-minded to whom it means anything so comprehensive as his own country or his own age. Nor is his faith in his collective authority at all shaken by his being aware that other ages, countries, sects, churches, classes, and parties have thought, and even now think, the exact reverse. He develops upon his own world the responsibility of being in the right against the dissentient worlds of other people; and it never troubles him that mere accident has decided which of these numerous worlds is the object of his reliance, and that the same cause which make him a Churchman in London, would have made him a Buddhist or a Confucian in Pekin."
In the post below, her primary complaint about the 97% stat is that it doesn't specify the amount of climate change that those people attributed to humans: "After discarding the abstracts that were judged to have taken no position, Cook (2013) reported a 97% consensus that anthropogenic GHGs were causing global warming. However, three-fourths of that consensus was judged to be implied and more than 98% of the agreement was expressed non-quantitatively. Consequently, no widespread consensus exists in these abstracts that humans are responsible for most of the global warming; only that humans are responsible for an unspecified amount of global warming."
https://judithcurry.com/2015/12/20/what-is-there-a-97-consen...
I think the 97% stat provides a useful opportunity for those of us who would like to get to truth of the matter but haven't studied climatology and have no interest in spending years studying the subject just to determine the truth of this particular issue. So much of the argument about the subject is "they're wrong, I'm right" followed by technical explanation that you cannot tell who to trust. But you can understand how the 97% claim was reached. It provides a useful opportunity to gauge who to trust on the subject, although admittedly still requires careful consideration and more time that most will commit.
This John Stuart Mill quote seems apt: "People more happily situated, who sometimes hear their opinions disputed, and are not wholly unused to be set right when they are wrong, place the same unbounded reliance only on such of their opinions as are shared by all who surround them, or to whom they habitually defer: for in proportion to a man's want of confidence in his own solitary judgement, does he usually repose, with implicit trust, on the infallibility of "the world" in general. And the world, to each individual, means the part of it with which he comes in contact; his party, his sect, his church, his class of society: the man may be called, by comparison, almost liberal and large-minded to whom it means anything so comprehensive as his own country or his own age. Nor is his faith in his collective authority at all shaken by his being aware that other ages, countries, sects, churches, classes, and parties have thought, and even now think, the exact reverse. He develops upon his own world the responsibility of being in the right against the dissentient worlds of other people; and it never troubles him that mere accident has decided which of these numerous worlds is the object of his reliance, and that the same cause which make him a Churchman in London, would have made him a Buddhist or a Confucian in Pekin."
This is, like, the worst, most unconvincing way to make the (legitimate) point that she's wrong on climate science.
If I wrote a long essay, seasoned with the same phrasing, terminology, and reasoning used by credible academics, that proclaimed the spaghetti monster was real, you would be wise to dismiss my argument out-of-hand without personally reading it unless you were persuaded otherwise by someone or something else. Wasting your time on the off-chance that I had something relevant and substantive to offer would be a poor gamble.
Ad hominem is an informal fallacy, not a logical fallacy. A logical fallacy always makes an argument invalid. An informal fallacy makes an argument extremely suspect, but context matters. Unless you can instantly read and criticize all the arguments published everyday, or unless you're immortal and don't care about timely application or responses to arguments, you must structure your approach to acquiring knowledge. Alternatively, you could go through life haphazardly, allowing coincidence or, more often, wealth and social station to dictate the ideas you're exposed to.
Your point would stand if climate skeptics were earnest and constructive participants. But they've shown themselves not to be.
In short, credibility matters. Climate skeptics as a group lack credibility, and climate skeptic arguments as a class lack prima facie credibility. In the context of climate change discourse, pointing out (with citation) that an author is a bone fide climate skeptic (a label and affiliation with substance in our times) is totally legitimate, IMO.
I appreciate that some people with idle time are willing to dive in and provide more substantive criticism. But such earnest people aren't always around, and even reading their analyses takes time. I think it's fair to argue credibility, just like it's fair to argue credibility wrt EmDrive without painstaking analysis of wild quantum mechanical hypotheses.
Ad hominem is an informal fallacy, not a logical fallacy. A logical fallacy always makes an argument invalid. An informal fallacy makes an argument extremely suspect, but context matters. Unless you can instantly read and criticize all the arguments published everyday, or unless you're immortal and don't care about timely application or responses to arguments, you must structure your approach to acquiring knowledge. Alternatively, you could go through life haphazardly, allowing coincidence or, more often, wealth and social station to dictate the ideas you're exposed to.
Your point would stand if climate skeptics were earnest and constructive participants. But they've shown themselves not to be.
In short, credibility matters. Climate skeptics as a group lack credibility, and climate skeptic arguments as a class lack prima facie credibility. In the context of climate change discourse, pointing out (with citation) that an author is a bone fide climate skeptic (a label and affiliation with substance in our times) is totally legitimate, IMO.
I appreciate that some people with idle time are willing to dive in and provide more substantive criticism. But such earnest people aren't always around, and even reading their analyses takes time. I think it's fair to argue credibility, just like it's fair to argue credibility wrt EmDrive without painstaking analysis of wild quantum mechanical hypotheses.
This would be fair if she wasn't arguing that the credibility of healthy skepticism shouldn't be tarnished in science.
"Climate believers" attack her credibility, she defends her credibility, but her arguments are invalid from the start because she's not credible?
The group of people who want to research the grandiose climate change narrative from a skeptical angle are attacked because of political reasons not because what they are doing is wrong scientifically.
Climate science should be thankful she exists, not offended.
"Climate believers" attack her credibility, she defends her credibility, but her arguments are invalid from the start because she's not credible?
The group of people who want to research the grandiose climate change narrative from a skeptical angle are attacked because of political reasons not because what they are doing is wrong scientifically.
Climate science should be thankful she exists, not offended.
Sorry? Sure, don't feel the need to believe any of their refutations, but you can follow their links to her statements and decide whether or not you agree with her take.
My point was that what you wrote was the opposite of convincing. If I start googling everything myself, then sure. I wouldn't have had any problem with your comment if you just wrote "here are her views, and here are the rebuttals", like the page you linked to does, and like the other commenters have already done in this thread. As it stands, your comment isn't ad hominem, but saying she is a bit of a skeptic is wrong-headed as a way to point out that she's wrong on climate science, it does less than nothing to advance that point.
Okay, that makes sense, I agree with you there. Thanks for making that point. What maybe would have been better and a less normative way to make the point is that she has as track record of writing and making statements that advance claims that are outside the mainstream of climate science.
They are not just outside the mainstream, but fundamentally not backed up by known physics and statistics.
This is an ad hominem attack and has no bearing on this specific article about what climate models are.
In an ideal situation for science writing, who someone is, their agenda, etc, shouldn't matter for interpretation right? But here having read the piece without that context, and then having someone point out who the author was really changed my interpretation- for better or for worse.
Many of the points she makes about statistical validity make sense - complex, non linear systems are difficult to predict, models need to be validated on data different from their training sets, etc. So those points, without digging into the real meat of how they're applied to these models specifically -- which she knows lawyers won't, serve to mislead.
I think what's also at the heart of this discussion though is whether what she's writing really is science or if it's opinion/has an agenda. When one puts oneself in the position of writing an overview like this, well then maybe it's one's responsibility to present (as well as complicate) the general consensus rather than present an argument that is not that mainstream as more of a consensus then it really is.
Many of the points she makes about statistical validity make sense - complex, non linear systems are difficult to predict, models need to be validated on data different from their training sets, etc. So those points, without digging into the real meat of how they're applied to these models specifically -- which she knows lawyers won't, serve to mislead.
I think what's also at the heart of this discussion though is whether what she's writing really is science or if it's opinion/has an agenda. When one puts oneself in the position of writing an overview like this, well then maybe it's one's responsibility to present (as well as complicate) the general consensus rather than present an argument that is not that mainstream as more of a consensus then it really is.
In fact, the opposite is true: it is skepticism of global warming that depends on the correctness of GCMs.
In the simplest model, which any kid can test in middle school, you take a plexiglass box full of air (representing the atmosphere), add some extra CO2 to it, and see if the temperature goes up. It does.
Well, since the mid-1800s, we have been adding CO2 to the atmosphere. We know that we've burned a lot of fossil fuels (that were underground), and we have directly measured an increase in the amount of CO2 in the atmosphere. So based on the simplest model, we'd expect to see the temperature going up. And we do! Yay, science works.
Of course there are a lot of ways to say that the simple model is wrong. But they all involve the construction of a more complex model. In order to see if anything will mitigate or compensate the basic physics of how more CO2 traps more heat, you have to add in additional factors.
So when someone goes on and on and on about the shortcomings of super-complex GCMs, remember this. GCMs are important tools for making detailed predictions and policy decisions, but we don't need them to predict the basic fact of global warming.
In fact the original hypothesis of global warming dates back to about 1900, well before anyone was using computers to model anything. The theory of global warming rests on basic thermodynamics, and it was first proposed not long after those basics were discovered.