[lbsnake7]

I’m a climate change skeptic almost entirely because I don’t trust models. I believe there are too many dynamic things happening in the world for anyone to be able to predict accurately say the next 100 years (solar, earthquakes, volcanoes etc). One way to make me a believer though is an experiment: if I were to give you a 100 year stretch of history and you were able to accurately predict with the models what exactly happened in those 100 years.

The article talks about it a little bit about how the models are used to predict the 19th century to see if they are correct. But the models use the last 100 years as input so of course it will give you accurate output. But the real challenge of the models would be to accurately predict things that are not part of the inputs into the model. I don’t believe that these models can do this and are thus an exercise in straight extrapolation based on very complex and interconnected inputs.

[hannob]

The best thing we can do to see if the models work is to look how they performed compared to reality in the decades since we have climate models. Turns out: They worked really, really well. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/201...

[koheripbal]

Right, but again this goes back to OP's point that there is a survivorship bias in the models which tends the community to accept the models that both "predict" the past as well as reinforce the narrative that temperatures will continue to increase.

Having said that, the reality remains that, even without the models, the CO2 levels are increasing, they are well correlated to temperature increases, and they are expected to increase further - so VERY PROBABLY - climate change is a very serious massive problem. This is all true even without the models.

When it comes to the reliability of models, the devil is in the details. ...but, of course, no one should assume that a model turning out to be wrong or biased suddenly negates all the other evidence we have. Models are just one piece of a probability decision tree we need to navigate.

[mistermann]

> Turns out: They worked really, really well.

Does "they" refer to all models?

The main article's set of models are different than the ones referred to in another link someone in this thread provided, and I suspect the article you've linked will also use yet another unique set.

If it was me trying to persuade people, and all historic climate change models did indeed work really, really well, I'd make an authoritative web page that lists all of these models including their inputs and outputs, and show a detailed quantitative comparison of their outputs. I would think this approach would be more persuasive in multiple ways than hundreds of separate articles written in a narrative style, lacking numbers and consistency in sets of models.

[jknoepfler]

So if I asked you to bet at 50/50 odds that next year would be colder on average than this year, you'd take the bet?

[KevinEldon]

It seems people do take a variation of this bet quite often; they keep moving to and investing in coastal cities and regions.

[protanopia]

Are you asking about the weather in one specific year? Weather is not climate.

[jknoepfler]

I'm well aware of the distinction between weather and climate. I was asking if the climate change skeptic would take a bet that the global mean temperature (operationalized in some acceptable way) would decline in 2021 compared to 2020. If they believe that the earth is not, on average, getting hotter, then they should be indifferent to this bet (inter-year variation should be random around a fixed point).

I don't think any intellectually honest person is indifferent to this bet. Everyone believes there is a solid chance that the climate is actually getting warmer, and almost no one would wager serious money at even odds on a globally colder 2021.

If you wouldn't bet against the climate getting warmer, then I don't think you have any place calling yourself a "climate change skeptic"

In a similar vein, I invest in index funds because I'm not a market skeptic. The market (at the moment) tends to grow year over year. I put my money where my mouth is in the market, I'd do the same on global temperature, and I'd win (on average, if I bet year over year, unless something changes dramatically).

[lazyjones]

> If you wouldn't bet against the climate getting warmer, then I don't think you have any place calling yourself a "climate change skeptic"

The climate isn't getting warmer or colder just because next year's temperature does.

[jknoepfler]

sure, but if I believe the climate is getting warmer or colder, I know where to place my bets. feel free to propose a better or more precisely defined bet.

[bannable]

Yes, weather is climate. But that isn't what OP said.

[protanopia]

Climate is long term patterns. Weather is what is happening at a specific time. If the distinction wasn't made then someone could argue that a cold winter day disproves warming.

[jknoepfler]

that is not relevant to the wager I proposed, which still stands.

[lazyjones]

That's not what climate is about. Also, it depends on location, in many places it was colder in 2019 than in 2018. If you're talking about some calculated "global" temperature, it doesn't exist in a valid form.

[bannable]

Are you claiming that it is not possible to find a trend in a mean temperature of a great many points across the globe, over a long period of time?

What makes such a measurement an "invalid form"?

[lazyjones]

It is not possible if there aren't valid temperature measurements available for all points throughout the measured period of time, so that many temperatures are "interpolated", estimated etc.

[bannable]

Except that we do have a massive number of recorded temperatures across a massive number of locations in the last 100 years. Climate models, some dating back to the 1970s, have correctly predicted global temperature changes in the 50 years since based on this data.

The measurements are real, and there is an established history of the models being generally correct (if not in specific details) by now. Climate study is not the new science you seem to think it is.

[lazyjones]

> Climate models, some dating back to the 1970s, have correctly predicted global temperature changes in the 50 years since based on this data.

Can you point me to one such model? One that actually predicted temperatures correctly back in the 1970s and not after various recent "adaptations" like "corrected" emission data?

> The measurements are real

Yes, measurements are real. Interpolations, resulting "global" temperatures and predictions aren't.

[jknoepfler]

On a crude first pass, I will accept any combination of the following datasets, assuming they are updated in 2020 and 2021:

HadCRUT4 (from UK Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit)

GISTEMP from the NASA GISS

MLOST from the NOAA

JMA from the Japan Meteorological Agency

I'm open to other datasets. I'm not choosy.

[lazyjones]

So, you would have lost the bet in 2016 and 2017. Did climate get colder?

[jknoepfler]

no, a noisy measure around a globally increasing trend line went down.

I believe that the noisy measure goes up, on average, because it is (noisily) measuring a warming climate. I'll make that bet every year, and I will come out ahead...

using the trend line, you could set odds at which the betting on a colder 2021 would be the correct bet - but it isn't 50/50, which it would be if the process were random noise.

as a professional poker player I'm not surprised by this argument, but I am saddened.

edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.

[lazyjones]

> * I'll make that bet every year, and I will come out ahead...*

Good luck with that, but you first asked about one year (next year), which is a different matter altogether.

> (edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.

I completely understand your point and how you are trying to move the goalpost from an easily refutable argument to something more useful. Perhaps your "professional poker player" mind doesn't understand that recent increases/decreases in temperature averages affect next year's weather, whereas past poker games don't affect your current one.

[jknoepfler]

you can, in fact, compute a mean temperature for the globe. and you can, in fact, plot a trend line over that mean. and that mean is, in fact, meaningful.

[tzs]

> I’m a climate change skeptic almost entirely because I don’t trust models.

We don't need any climate models to know that Earth is warming. We can tell that just from what we know of: how electromagnetic radiation works, the basic thermodynamics of gases, determining isotope ratios of the carbon making up a sample of CO2, how much solar energy falls on the Earth, the mechanisms by which energy can leave the Earth, the amount of energy leaving Earth as measured by satellites.

That's enough to allow verifying that:

(1) a net heating of the Earth taking place,

(2) this is mostly caused by humans (mostly be emission of greenhouse gases from fossil fuels) (and yes, we can tell the difference because emissions from burning fossil fuels have a different carbon isotope ratio than other sources), and

(3) it is getting more extreme.

All you need climate models for is to try to figure out where the extra heat will end up and what it will do there.

[DennisP]

People use models to try to nail down the details, not to see whether climate change from CO2 emissions is a real thing. That's well established by physics and geological history. A good presentation of this evidence is in a couple chapters of Hansen's Storms of My Grandchildren.

[chrisco255]

Could you point me to the academic, empirical research that quantifies the influence of CO2 on climate? Not a book, but from an academic publication.

[AsusFan]

Assuming that you asking honestly, and not just trying to derail the conversation...

Start here: https://skepticalscience.com/empirical-evidence-for-co2-enha...

Then proceed to intermediate and advanced. There are a TON of citations for your perusal. After your are done with that, the comments have some additional insights.

Have fun. This is quite the rabbit hole to dive into.

[chrisco255]

Skeptical Science is not an academic publication. It's a blog.

What was the CO2 ppm in the early Holocene? Why was the early Holocene so much warmer than today in spite of lower CO2 concentrations?

Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Svalbard Lakes

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...

[DennisP]

> There are a TON of citations

Here's one of them from that page, chosen at random: https://www.tandfonline.com/doi/abs/10.5589/m04-044

A blog page linking a bunch of academic papers is as good as a hackernews comment linking a bunch of academic papers.

Your linked paper is about arctic temperatures, not global average temperatures.

[anonuser123456]

>I’m a climate change skeptic almost entirely because I don’t trust models.

You don't have to believe the models:

https://www.fooledbyrandomness.com/climateletter.pdf

[lbsnake7]

My argument to this would be that changing our world because of a faulty model system would be disastrous. Because of the advancements of the last two centuries more people have had food and water and basic necessities being met then at any time in history (and yet we still have billions suffering). Worsening their lives over something that might not happen is not a good way to run the world. The models being accurate is important so that if we do implement policy that end up worsening people’s lives we have proof that it is worth it.

[fencepost]

The models being accurate is important so that if we do implement policy that end up worsening people’s lives we have proof that it is worth it.

The models differ in the scale of how bad it's going to be, not on whether it's going to be bad. Your stance is kind of like saying "Well doc, you're telling me I have sepsis, but you can't tell me how bad that's going to be so I'm refusing treatment until you can improve your models."

[bannable]

The current consensus on the impact of climate is NOT "something that might not happen".

Climate change is happening right now, with effects that are observable as trends across the globe. Even the most optimistic model is predicting widespread catastrophe.

[gus_massa]

That is essentially the same argument than in the Pascal's wager https://en.wikipedia.org/wiki/Pascal%27s_wager

[anonuser123456]

Not really.

Pascal's wager has no information. You know nothing of the state of god's existence.

The precautionary principle uses current equalibrium as the default.

The current working equalibrium embeds information.

The precautionary principle does not state it will result in the best outcome. Only that it's more likely to not have the worst.

[fencepost]

are thus an exercise in straight extrapolation based on very complex and interconnected inputs

If I throw a ball to you, your ability to put your hand approximately where it's going to be and catch it is "extrapolation based on very complex and interconnected inputs," and as it gets closer you're able to improve based on additional input.

Sure the models could all be wrong, we could be on the brink of a new ice age, and that ball could suddenly take a sharp right turn and accelerate. I wouldn't recommend putting all your money on either of those as a bet.

[tasty_freeze]

History is dominated by the vagaries of human behavior.

Climate is a physical phenomenon which can be modeled. One problem is that humans have an effect on the climate, so models can't predict how much effort humanity is going to put into averting that change. Since that aspect can't be modeled, they produce different projections for multiple cases of human behavior: business as usual, modest efforts to change, aggressive efforts to change.

[WhompingWindows]

Even if you ignore the statistical forecasting models, look at the natural disasters occurring every season, and the massive changes happening in glaciers and arctic regions. Forget future projections, what's wrong with acknowledging many historical records are being smashed here and now? Isn't that evidence of climactic change to you?

[IanSanders]

There being no accurate model doesn't imply climate not changing

[protanopia]

But is does imply that implementing specific policies to counteract what specific models predict might not be the best idea.

[rezeroed]

What are the downsides of going along with it, and finding out it was wrong?

[born_a_skeptic]

And who builds those models, people probably have a hidden agenda, because everyone has one.

[djsumdog]

I question a lot the models as well. I think pollution is a big problem in general, but CO2 is totally the wrong focus; like focusing on the sniffles and ignoring the flu. The real issue is consumerism and consumption. We cannot buy our way out of environmental disaster, but the CO2 camp is trying to offer that option: buy green, electric cars, etc.

In realize, we need fewer cars, more trains, better transport options, cell phones that last 8 years and that are repairable rather than 1.5 year planned obsolescence Internet of Trash devices.

The debate over climate/CO2 is a religious ideology at this point, and a very unhelpful one at that.

[cultus]

No, there's no debate in science this reality. You are just anti-science.

[djsumdog]

ah yes, that anti-science. I have four publications in Geography journals and hold a BS and MS in CompSci. Your "Science" is a religious ideology of its own.

[cultus]

I've got a PhD in geophysics. I'm telling you the state of the field. You can assume I'm lying or in on the climate scam it if you want.

[pinkfoot]

Wont you be kind enough to tell us which of the thousands of peer reviewed papers on the IPCCH website (ipcch.ch) website your data disputes.

Taliban