Global Warming Models

[ponderingturtle]

While I have no doubt there are endless agenda-driven web sites containing all sorts of gibberish, I'm wondering if you can point to examples of "seemingly random numbers" published by known, seemingly credible sources?

What makes a credible source? Yes if I got involved and studied the papers published on the topic in peer reviewed sources that might make it easer to validate the strenght of the statements.

BUt from the normal media, well they have enough problems with fortune tellers and spirit diviners and so on and not calling bunk on them, so I have no way of knowing anything about the credibility of statements made by these kinds of things.

It is not easy for the lay audince to tell a crank from a serious scientist.

 

[Cuddles]

I was specificaly refering to the greenhouse effect, not how that effect will change the climate. I got the impression that there was a difference between the two.



The other problem is that alot of enviromentalism are not making arguements from a scientific perspecitive. They both have lots of woo involved it is just classical woo vs newage woo.

Evolution has been around and tested for longer as well, and that is a seperate issue. And I do see that while details of one are not quite rated the same between them

Example

Evolution
Basic Premise-Species change into new species
Detail-Cats and Dogs sperated as groups 50 million years ago

Climate Change
Basic Premise-The climate can undergo drastic changes
Detail- In 100 years the sealevel will be 10 feet higher than now

The basic premise of evolution is what people have problems with, and while the details change it does not change the basic premise

The basic premise of climate change poeple do not generaly have issues with, but the detailed predictions and such are where the discrepencies occur.

So compairing the two and the issues they have in the popular media is not accurate. I was questioning a detailed part of the theory regarding predicting climate change. It would be like say questioning when the last common ancestor that humans and chimps have is 3 million years ago or 7 million years ago. If one could be shown it would change the details of evolutionary theory but not the basic premise, but with climate change it is the details we are interested in.

When I said this hasn't been proved, I meant the general theory. The fact is that people do have a problem with the basic premise of climate change. Although now most people think CO2 increases global temperature, 30 years ago they thought the Earth was cooling. Virtually all the evidence that CO2 will heat things up is observations that CO2 levels increased at the same time as global temperatures. This does not prove anything, it could just mean that both were caused by another effect we haven't thought of, or even that global warming caused increased CO2. Without predicting the general outcome and observing things for at least a couple of centuries we cannot be sure that we have even the general principles of climate change, let alone the specific details.

For the record, I believe that we are causing global warming. This does not change the fact that it is far from proven. I think there are far too many claims of things that are caused by global warming when many of them could have, or are known to have, other causes. I think there should be much more attention on the obvious effects of pollution rather than focussing on an effect which can't be reliably proven until it is much too late to do anything about it.

 

[Cuddles]

So why do we never hear confidence numbers on global warming predictions? That would make me more apt to trust the seemingly random numbers spouted by various groups.

We don't here confidence numbers for the simple reason that no predictions have come true. Even if the current model is 100% accurate, we won't know this for several more decades. Climate change happens on too slow a time scale and with too much natural variation for us to confirm things on the timescale we are used to.

 

[ponderingturtle]

When I said this hasn't been proved, I meant the general theory. The fact is that people do have a problem with the basic premise of climate change.

Please show me the ice age deniers then. The only ones I can see doing that are the creationists

 

[Cuddles]

Sorry, I assumed you meant human induced climate change, which you probably didn't now I look back. I would still say that there are many people who deny climate change has happened, or can happen, over the course of human history. Most people would accept the ice ages, but can't accept that the world as we see it now can ever change significantly, hence the refusal to lower pollution and save the whales, etc..

I think this actually comes from exactly the same place as the problem with evolution. People can't see something happening in their own lifetime and therefore deny it could happen at all. With evolution the religious beliefs provide an alternative explanation, whereas with climate change people don't even see an explanation as needed, so religion is not involved.

 

[ponderingturtle]

Sorry, I assumed you meant human induced climate change, which you probably didn't now I look back. I would still say that there are many people who deny climate change has happened, or can happen, over the course of human history. Most people would accept the ice ages, but can't accept that the world as we see it now can ever change significantly, hence the refusal to lower pollution and save the whales, etc..

Failing to see how the climate can change on its own to create massive problems is also then a problem.

I think this actually comes from exactly the same place as the problem with evolution. People can't see something happening in their own lifetime and therefore deny it could happen at all. With evolution the religious beliefs provide an alternative explanation, whereas with climate change people don't even see an explanation as needed, so religion is not involved.

Hey there are those flood based geologists and such.

 

[a_unique_person]

So why do we never hear confidence numbers on global warming predictions? That would make me more apt to trust the seemingly random numbers spouted by various groups.

AFAIK, there are, in the scientific papers. You won't see them in the popular press, but at the in depth, scientific level, such data is present. Most people would not ask for such information.

I have a friend who works for the CSIRO in this area, and he is currently peer reviewing work for the next IPCC report. He said he couldn't believe there were papers being submitted that didn't have such information in them. That is, graphs that did not provide the margin for error in their predictions, for example. The scientific process of peer review at work.

 

[lenny]

You do not need to predict the future to test a model, just increase the data set in any fashion.

it depends on what you want to test; testing the ability of large nonlinear models to extrapolate is just hard. if you can afford to wait, out of sample prediction is a "better", but if you are then going to continue to extrapolate there is a fundamental uncertainty which will never go away.

climate models are only tested in-sample: this does not violate the rules of statistical good practice when it is required by the nature of the scientific question being addressed.

 

[lenny]

So why do we never hear confidence numbers on global warming predictions? That would make me more apt to trust the seemingly random numbers spouted by various groups

AFAIK, there are, in the scientific papers. You won't see them in the popular press, but at the in depth, scientific level, such data is present. Most people would not ask for such information.

in fact, it is very difficult to produce any user-relevant "error bars". the best you might do (if willing to invest the computer resources required) is to quantify the uncertainty in the forecast assuming the model is effectively perfect. for our state-of-the-art models, this assumption is not viable: so what would "uncertatiny bars" really mean?

this is no excuse for inaction, of course; but to deny it would allow nay-sayers to find a dispute amoung scientists, and then divert the argument in irrelevant directions.