Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

What's Really Warming the World?

bloomberg.com

Post reply on HN
Print view View original

351–360 of 549 posts

Re: What's Really Warming the World?

#351

Post by sgt101 »

wnewman wrote: post #60
jasonkester wrote: post #3

Cool visualization. It's worth keeping in mind that the modeled data lines up with reality because it's supposed to. That's how you calibrate your model, by making sure it fits reality. The real trick is to see how well your model extrapolates from the data you have out into the future. As in, if you feed it data up to, say, 1990, will it correctly spit out 2015 temperatures that fit the reality of 2015, or will it s…

"The real trick is to see how well your model extrapolates from the data you have out into the future." That is the most common way to show the modeller is not shamelessly overfitting.:-| Another way, though, is less common but not vanishingly uncommon: the model may be so much simpler than the data it fits that overfitting is not a plausible explanation. (Roughly there are too many bits of entropy in the match to th…

Well - that's true apart from co-incidence. You can have a very simple theory which says "x is directly caused by y" and there is a lot of good data, and a great fit. But it's kist a co-incidence and breaks down immediately.

Occam's razor is a rule of thumb and an aesthetic boon, but nothing more.

The real test is that you have a theory that is meaningful and has explanatory power. If it grants insight on the mechanisms that are driving the relationships or generating the data and these make sense - you are pretty golden.

Another one is that the theory makes unexpected predictions that you can then test. This is a real winner, and why complex physics is so well regarded.

Re: What's Really Warming the World?

#352

Post by merpnderp »

ocschwar wrote: post #257
merpnderp wrote: post #210

Earlier quoted context omitted.

How do you use decadal moving averages from satellite data that has only existed since 1979? You'll get roughly the same trend as the full data set. Even so, the last two decades would still be flat, or very nearly so.

Hint: decades don't have to start with year 10*n+0.

We already know the full data set has a 1.2K/century trend (this is annual trend most commonly used to represent the data). Decadal moving averages aren't going to shed more light than that. We also know that if you just grab the last 19 years and 6 months, or any smaller subset of that, you'll see 0 to negative trends.

Re: What's Really Warming the World?

#353

Post by cholantesh »

marcus_holmes wrote: post #246
cholantesh wrote: post #133

Earlier quoted context omitted.

I wouldn't call a paper whose lead author is a well-established denier with no scientific training ( https://en.wikipedia.org/wiki/Christopher_Monckton,_3rd_Visc... ), and which is co-authored by a known practitioner of large-scale scientific fraud for pay ( http://rationalwiki.org/wiki/Willie_Soon ) particularly reputable.

ad-hominem. Who cares who wrote it, what does it say?

Really? You think it doesn't matter that the primary author on a paper about climate science doesn't even have an undergraduate-level education in the subject? That the second one credited has a history of accepting large sums of money to write papers endorsing spurious claims DIRECTLY RELATING to climate change?

Re: What's Really Warming the World?

#354

Post by phaemon »

merpnderp wrote: post #341
phaemon wrote: post #300

Earlier quoted context omitted.

Can I ask you two questions? What does your R script attempt to show? What is your null hypothesis? Thanks!

My R script merely finds the first time the temperature trend turns positive since last data point. My null hypothesis is when does the trend turn positive since the last data point. I'm not trying to be a smart ass, I'm just wanting to make clear I'm not making any grand claims, except that the most rigorous data, with the tightest confidence intervals (measured in fractions of K instead of multiple K's), says that…

> My null hypothesis is when does the trend turn positive since the last data point. I'm not trying to be a smart ass

I'm sure you're not, and certainly you seem to be making a good faith effort to analyse the data, but I'm afraid you're just doing it wrong. You can't just keep testing up to x data points till you hit a significance level and then say "this proves x-1 doesn't show the trend".

Imagine you were measuring the height of waves on a beach as the tide comes in. After 20 measurements, you can see a significant height difference, showing the tide is indeed rising. Now imagine if your stated conclusion was, "the tide hasn't been coming in for the last 19 waves".

It would be ridiculous, right? That's pretty much what you're doing here. If adding more data makes your conclusion worse, you're doing it wrong.

The correct way to test this is to say, "30 years of data shows a rising trend. Is the past 19 years significantly different to this?". Then your null hypothesis is that the trend remains the same and when you add more data your conclusion (either way) becomes stronger.

Since you've shown enough interest to create an R script to test this data, I sincerely hope you'll have enough interest now to test it properly and share what you find. Good luck!

Re: What's Really Warming the World?

#355

Post by TillE »

themgt wrote: post #346

Helpful when reading this thread to keep in mind Michael Mann's six stages of climate change denial: 1. CO2 is not actually increasing. 2. Even if it is, the increase has no impact on the climate since there is no convincing evidence of warming. 3. Even if there is warming, it is due to natural causes. 4. Even if the warming cannot be explained by natural causes, the human impact is small, and the impact of continued…

The first four stages have always baffled me. Anyone who knows basic chemistry understands how carbon dioxide interacts with infrared radiation. Combine that with the fact that human activity is releasing tens of billions of tons of CO2 every year, which does not magically disappear. In fact, it's quite measurable.

The climate is complex, but the basic facts of the situation are incredibly simple and unavoidable. And yet, people have still tried.

Re: What's Really Warming the World?

#356

Post by dang »

paulhauggis wrote: post #226
paulhauggis wrote: post #113

Earlier quoted context omitted.

I also question how we know the difference between nature/cycles and man-made pollution. Here is a good example: https://en.wikipedia.org/wiki/Little_Ice_Age "Several causes have been proposed: cyclical lows in solar radiation, heightened volcanic activity, changes in the ocean circulation, an inherent variability in global climate, or decreases in the human population." It seems we don't even know how the little ice…

I bring up some simple questions and I am immediately silenced. I guess I didn't realize HN was anti-science and anti-intellectual.

"Please resist commenting about being downvoted. It never does any good, and it makes boring reading."

https://news.ycombinator.com/newsguidelines.html

Re: What's Really Warming the World?

#357

Post by suprfnk »

TillE wrote: post #355
themgt wrote: post #346

Helpful when reading this thread to keep in mind Michael Mann's six stages of climate change denial: 1. CO2 is not actually increasing. 2. Even if it is, the increase has no impact on the climate since there is no convincing evidence of warming. 3. Even if there is warming, it is due to natural causes. 4. Even if the warming cannot be explained by natural causes, the human impact is small, and the impact of continued…

The first four stages have always baffled me. Anyone who knows basic chemistry understands how carbon dioxide interacts with infrared radiation. Combine that with the fact that human activity is releasing tens of billions of tons of CO2 every year, which does not magically disappear. In fact, it's quite measurable. The climate is complex, but the basic facts of the situation are incredibly simple and unavoidable. And…

> The first four stages have always baffled me. Anyone who knows basic chemistry

Well, there you go. A lot of people don't.

Re: What's Really Warming the World?

#358

Post by IvyMike »

rza wrote: post #342

This graphic really just plays into the hands of climate change deniers. No labelled axis, a timeline of only 100 years (you could also argue the dinosaurs caused global warming), and the quite proud declaration at the end the argument is really "no contest" under the assumption that correlation == causation. I could also make a graph that shows the increase in global temperature correlating with the rise in the Lati…

> under the assumption that correlation == causation

Except we do have a pretty good understanding of the chemisty/physics of the greenhouse effect, too. So there's a prediction ("increased CO2 will lead to warming") and a validation. What more do they want?

Re: What's Really Warming the World?

#359

Post by gnaritas »

tosseraccount wrote: post #317
bildung wrote: post #304

Earlier quoted context omitted.

> I want solid proof ... or , uh "almost proof". Proofs don't exist in sciences concerned with the physical world. For proofs to work in the real world, you'd need certainty that you have recognised and correctly measured every variable that could affect the outcome of an observation/experiment. The last philosophy of science that allowed proofs was positivism. For the natural sciences, it has been replaced by critic…

I'm curious. Gravity has not been proven to attract two masses, for instance?

As he already said, science doesn't do proofs; proof is something for Math, science does evidence, nothing is ever proven. Asking a scientist for proof merely shows you don't know what science is and thus aren't capable of using it to make decisions.

Re: What's Really Warming the World?

#360

Post by JimmaDaRustla »

suprfnk wrote: post #357
TillE wrote: post #355

Earlier quoted context omitted.

The first four stages have always baffled me. Anyone who knows basic chemistry understands how carbon dioxide interacts with infrared radiation. Combine that with the fact that human activity is releasing tens of billions of tons of CO2 every year, which does not magically disappear. In fact, it's quite measurable. The climate is complex, but the basic facts of the situation are incredibly simple and unavoidable. And…

> The first four stages have always baffled me. Anyone who knows basic chemistry Well, there you go. A lot of people don't.

The baffling part about it is how someone can ignorantly argue correlations of basic chemistry when they don't know basic chemistry.
Post reply on HN