I used to do research on climate change, specifically on combining land, sea, and air models together and getting them to run on a massive cluster. It was very important to the other researches that the models produce the 'right' predictions which at the time was runaway global warming. When the models didn't show this it was presumed that the models were wrong so hyper-parameters were tuned to try to torture the models to produce the 'right' result. When even that didn't work they went so far as future pollute the data. Disillusioned with academia I left to work in industry.

My question is this; How qualified and experienced do I need to be in order to be able to legitimately and completely distrust the climate change 'experts'? Because I feel like I've earned that right.

> When the models didn't show this it was presumed that the models were wrong so hyper-parameters were tuned to try to torture the models to produce the 'right' result. When even that didn't work they went so far as future pollute the data.

Please name and shame. I've also done work in the field, and this kind of behavior was never acceptable - and should not be.

If you let the bad actors hide in obscurity, they will continue to practice bad science.

Like a #metoo movement for scientists. AFAIK Hyper-parameter tuning is fairly normal and necessary given how easy it is for the models to become unstable on their own and future polluting is often accidental. It can come down to judgement calls and difference of opinions as to what degree of intervention is acceptable which leaves a lot of wiggle room If you removed all future pollution and and left hyperparameters at the initial best guess you often end up with crazy results in backtesting. E.g. if our past predictions were correct then we should be living on Venus right now which obviously we're not so we must need different hyperparameters. My former colleagues were trying their best and even they knew their adjustments were going beyond reasonable. They never signed off on the final results so the project was politically useless and subsequently killed. They've all since left the climate change industry disillusioned as well.

> . if our past predictions were correct then we should be living on Venus right now which obviously we're not so we must need different hyperparameters

I would like to know hat models showed runaway warming and were publishing because I don't remember anything like that.

I was talking about backtesting of the models to see if they would have predicted the past correctly. I.e. You run the model from 1970 to today and measure how close the model prediction is with the actual measurements. If it's too far off then obviously the model is wrong and changes are made to try to improve it.

> It was very important to the other researches that the models produce the 'right' predictions which at the time was runaway global warming. When the models didn't show this it was presumed that the models were wrong

Sorry, you have claimed that the scientists wanted the 'right' predictions, that was runaway warming.

I repeat, can you link to any scientists saying in 2006-2007 that the most probable outcome was runaway warming?

What is the climate change industry?

Wait, so the terrible science you're talking about was never actually published, yet you still distrust the rest of the field?

The group leaders were pushed things too far for me to accept as legitimate but not far enough to produce the results needed. We were aware of others that pushed things even further and they got to continue working. This adds a selection criteria bias to those still doing the research which has me trusting them even less. And this was before ClimateGate which made the shenanigans done by other groups public.

Your reference to and unreserved use of the term "ClimateGate" makes me question your agenda here. Wasn't "ClimateGate" determined to be a smear campaign? I'm asking rhetorically as I can see the discussion devolving.

I generally keep my eyes open for climate change news and didn't see this. Do you have any reasonable references that explain that ClimateGate was a smear campaign? I thought it was a small number of committed researchers making some mistakes and straying from strict scientific protocols; I never saw that it was a smear campaign.

Sounds like we have a similar background. How long ago was this? How many models did you work with?

I had access to a few models and it was trivial to cause runaway warming. It was naturally something everyone tried when they were handed the keys to the servers. I recall causing the oceans boil within a few centuries.

~2006-2007, and it was a continuous stream of models. I was between the modellers and the cluster so I would rewrite the models to work on cluster.

I think in order to make the claim that climate change isn't happening, you need to be able to explain how a massive change in CO2 and other greenhouse gasses in the atmosphere will not result in warming.

There is fundamental data that does not depend on climate models that tells us we're in danger. Atmosphere composition in one of them. Ocean ph is another.

If you have specific criticisms against how climate models are being run, then the place for that debate is within the scientific community, with scientific arguments. Apparently you have decided that is not for you, though.

I make no claim that climate change isn't happening. Being between the modeler and the results meant it was my job to explain the result to the modeler. So criticizing climate change models within the scientific community was my job for over a year and a half.

Yes; but it seems your answer to my question is that I must also have several decades of experience.

My answer is - you need to actually understand the thing you're criticizing, not just feel like you do. Another prerequisite is a lack of agenda or bias.

> you need to be able to explain how a massive change in CO2 and other greenhouse gasses in the atmosphere will not result in warming.

It's not so easy to be sure about the warning produced by the CO2 because a very big part is the "Climate Sensibility". And there is no straightforward way to calculate the climate sensibility, you must use climate models. From https://en.wikipedia.org/wiki/Climate_sensitivity#Radiative_...

> CO2 climate sensitivity has a component directly due to radiative forcing by CO2, and a further contribution arising from climate feedbacks, both positive and negative. "Without any feedbacks, a doubling of CO2 (which amounts to a forcing of 3.7 W/m2) would result in 1 °C global warming, which is easy to calculate and is undisputed. The remaining uncertainty is due entirely to feedbacks in the system, namely, the water vapor feedback, the ice-albedo feedback, the cloud feedback, and the lapse rate feedback";[14] addition of these feedbacks leads to a value of the sensitivity to CO2 doubling of approximately 3 °C ± 1.5 °C, which corresponds to a value of λ of 0.8 K/(W/m2).

> "Without any feedbacks, a doubling of CO2 (which amounts to a forcing of 3.7 W/m2) would result in 1 °C global warming, which is easy to calculate and is undisputed.

We're going to get warmer, to find out how much warmer, you need more complex models.

No one is making the claim that "change isn't happening". The skeptical view point isn't even "warming isn't happening". The skeptical view is that catastrophic warming isn't an accurate prediction of future temperature trends.

I believe the primary difference between the "consensus crowd" and the "skeptic crowd" is that the consensus crowd is confident in the predictive value of models that have a net positive feedback sensitivity to temperature increase while the skeptics argue that we don't actually know what the feedback mechanisms well enough to be confident in the models and in fact basic physical principles argue for a negative net feedback to temperature increases (to avoid runaway warming).

As for possibile negative feedback loops, increased CO2 might increase clouds, which increases the earth's albedo resulting in less energy input from the sun, which reduces temperature.

> The skeptical view point isn't even "warming isn't happening".

What the heck?

Let me clarify. There is a difference between warming and catastrophic warming. Serious skeptics are arguing against catastrophic warming as predicted by the models.

There is another level of debate, less foundational, regarding the quality of our temperature observations and the amount of warming (not catastrophic warming) that is a result of natural variation, human activity, measurement errors, data adjustments and the like.

Observational warming has in general been less than that predicted by the models suggesting that the extrapolation into the future by the models may not be accurate.

> Serious skeptics are arguing against catastrophic warming as predicted by the models.

What catastrophic warming? Or better, define catastrophic warming

And by the way, 90% of skeptics still say that there is no warming.

> Observational warming has in general been less than that predicted by the models suggesting that the extrapolation into the future by the models may not be accurate.

Source for that?

I'm using the phrase 'catastrophic warming' to refer to the warming predicted by climate models as opposed to the warming directly observed today and in the historical record.

Anthropomorphic global warming theory is roughly two connected claims. 1) rising CO2 levels caused by human activity results in a rise in the average global temperature and 2) the climate system has a feedback mechanism (sensitivity) that magnifies this CO2 induced warming.

Basic physics can be used to determine the warming caused by increased CO2. There are no serious skeptics in regards to these physical properties of CO2. My understanding is that the IPCC reports have consistently reported this warming as 1-1.5 degrees for every doubling of CO2 concentration in the atmosphere.

But that temperature rise isn't enough to create the catastrophic side effects that you see reported. That rise has to be magnified by the climate system through a variety of feedback mechanisms. This magnification/sensitivity can't be measured. It is the output of the climate models not one of the input parameters. Credible skeptics argue that a positive sensitivity is incorrect and that the climate system (as with most natural systems) has a negative sensitivity.

Here is what seems to be a reasonable review of predictions vs observations using a variety of methodologies most showing observations trending towards the lower half of the predicted ranges of the models (as opposed to trending toward the center line of the predictions): https://judithcurry.com/2017/09/26/are-climate-models-overst...

I'd be really interested in reading more about your findings, anywhere I should start in particular?

I'm pretty sure I'm not allowed to have my own suspicions, so thanks for speaking up. If you're not trolling, really do consider writing under your real name and naming others involved. If it's too much of a risk to anyone's career or personal safety right now, you could always wait to publish until you're retired and/or old.

> Today, scientists still generally agree that it's impossible to attribute any individual weather phenomenon solely to climate change

Seems the actual science is the direct opposite of the headline once you read through the article.

At some point in the past, scientists have "generally agreed" things that were later found out to be wrong.

I don't see how the article contradicts the title at all. Certainly not 'direct opposite' as it even calls out specific scientists and specific papers that are in fact doing exactly what the headline says. It's not like the article headline says "All scientists now agree: Harvey caused by climate change" or something like that. The headline is very clear and very specific. It is fine.

"Scientists Can Now Blame Individual Natural Disasters on Climate Change"

There are two parts to that title:

1) "can now" implies that something significant in scientific understanding has changed 2) "blame individual natural disasters on climate change" is clear

#2 is flat out wrong because, see my quote above, the article makes it clear that the scientific consensus is still that individual events cannot be directly attributed to climate change.

#1 is wrong because nothing has changed.

Scientists can predict that the probability of extreme events in general is rising due to climate change but that is not proof that any specific event is attributable to climate change. That is not new. Nothing has changed in the consensus scientific position.

> Scientific consensus doesn't make something true

This is the same argument the denialist use. I am not sure how it is relevant to anything.

> making claims like "Storms cannot be blamed on climate change" is absolutely incorrect

Nobody made that claim.

There is an actual scientifically supportable position in between the two extremes you are proposing which is that in general the risk of extreme weather events is increasing due to climate change but no individual extreme weather event can be specifically attributed to climate change.

Yes, it seemed they buried the lede, kind of disingenuous journalism.

It's a bit redundant to say "disingenuous journalism" though, you could just say "journalism".

Oh fuck, got 'em!

"kind of"

Your statement is true that climate change could cause weather phenonmenon, but the headline reads "Scientists Can Now Blame Individual Natural Disasters on Climate Change". The line he quoted contradicts that headline.

Ok, we've changed the title to use more neutral language from the article text.

It's just standard HN moderation to replace baity titles with neutral ones, preferably using representative language from the article. We do this all the time, particularly with pop sci articles, where the headlines almost always oversell.

cryptoz is rate limited, but not for anything to do with this. We rate limit accounts when they either post too many low-quality-for-HN comments too quickly and/or have gotten into flamewars. We're happy to un-rate-limit accounts, and do so all the time, as long as we get a commitment from the user to abide by the intention of the site in the future. But it's best to email hn@ycombinator.com if you want us to do that. Same goes for any user of course.

> The whole science of event attribution developed so that we can provide scientifically robust answers to these questions. If we the experts don't do this, then there will be people who are not qualified who will go and fill in the gaps.

I don't think this will accomplish what these scientists hope. People fill gaps of trust more than gaps of fact. No amount of evidence or attribution is going to address that problem.

Agree. I think the butterfly effect is informally understood by the masses; I think most people will assume they have no control over specifc events. Pointing to a dry river bed and saying climate change is going to undermine the credibility of the scientists, whether or not the scientist is correct.

And people decide what they think we should actually do based on intuition and personal morals. Changing that gut feeling is massively difficult and data does not help.

Interesting article about assessing how much climate change actually increases the probability of extreme weather events. Unfortunately, the headline is clickbait that is repeatedly contradicted by the article itself.

It doesn't seem that way to me. The article even cites peer reviewed published papers where this exact thing is done, blaming a specific part or whole of a storm on climate change.

> Two separate studies published in December both found that climate change had influenced Harvey's record-breaking rainfall (Climatewire, Dec. 14, 2017).

I don't see anywhere in the article that even remotely comes close to contradicting the headline.

I'm a bit surprised that Scientific American is running chatty articles reprinted' from 'climatewire', an E&E website. https://www.eenews.net/eep/learn_more/

Can they predict individual extreme events, or does this only work retroactively?

They seem to have gone from saying "We can't attribute event X solely to climate change, but X is more likely due to climate change" to saying "X is more likely due to climate change".