I noticed that both sides of this argument were each saying to the other that this or some other paper or papers on the subject refutes the other while saying that listing papers that take a stand on the subject can’t be used to prove a point.

I would be very cautious about denying global warming and equally cautious about overstating the role of people in the process.

It could be shown ultimately that things are worse or not as bad depending on the natural processes that mask the human impact.

But it merits keeping up with the science. Some of the global warming changes are potentially very rapid… 20 years to ice age like cold snap in Europe due to shutting down the saline-thermal conveyor from the tropics. Or rapid loss of water supply from the glaciers (then a cold snap). Or methyl hydrate release and greater warming. It would be nice to know ahead of time if any of these scenarios is likely to play out!

The computer models used to predict global warming generate multiple “scenarios” or “parallel universes”. The hysteria is generated by the consequences of the worst case scenarios. However, we only have a single real world scenario, and for 2008 we are down at the other end of the spectrum. This outcome was predicted by the sunspot cycle model and by the Farmer’s Almanac model. So the question arises as to whether the CO2 “polluters” should be held financially responsible for damages in other parallel universes?
OK, my argument is tongue-in-cheek. However, there are many well respected scientists, such as David Deutsh, who argue that certain phenomena, such as single-photon interference patterns can only be explained in terms of “parallel universes”.
So the question I am asking here is to what extent we consider the scenarios produced from climate simulation models to be reality?

Stanley
I understand your point. However, in no-arbitrage scenarios forecast “prices” do not have to be realized. (Example – what is the one year forward price of IBM – ignoring the dividend, it does not depend on where I expect IBM to be trading in 1 year.)
Incidentally, your experiment has already taken place in Santa Barbara. The town council voted to paint a line where the ocean would come to if global warming predictions of ocean levels rising came true. The net result was a drop in value for ocean front properties. Realtors quickly took advantage of the situation to hype the values of the “new oceanfront properties”. The city council then dropped the plan!

SailDog: “However the modeling has become surprisingly accurate.”

I don’t think that is accurate. As Walt wrote above, the models are all over the place. And the models have never been validated. The current models fit the data well, and the creators are happy with that. But that doesn’t mean they can forecast well. The climate models don’t use statistical techniques, but the problem is similar. In statistics, when you create a model, such as a regression model, you first fit the model to the data. Then you validate the model by attempting to predict a different data set than the one on which you built your model. For climate modelers, they would need to build their model on say the data from the first half of the 20th century and try to predict the climate for the second half. They tried that back in the 1980′s when climate modeling first got started and the models failed miserably in their predictions even though the models fit the training data set very well. As far as I have been able to determine, they have never tried again. Fit is sufficient for them, but it shouldn’t be.

In addition, all of the variables in the models are highly correlated. In statistics, that means you can’t tell which variable is really the cause of the effect. For example, CO2 levels are highly correlated with temperature and the activity of the sun. Climate modelers have chosen to assign cause to CO2 levels because it fits their theory, even though temp increases lead CO2 levels instead of lagging behind them as one would expect.

In the historical datat, temperatures rise before CO2 levels rise, indicating that higher temperatures cause increases in CO2 levels, which makes sense because warmer climates encourage animal life. But then the climate scientists are left without a cause for rising temperatures. Until very recently, they refused to include solar activity in their models because they were fixated on CO2. Some now include limited Solar data, usually the 11-yr cycle, just enough to declare it insufficient as a cause. I’m confident that when scientists honestly model solar activity, especially the roughly 300-yr cycle, they will find that solar activity explains temperature increases better than do GHGs.

BTW, those who fear melting of the ice caps should find a book called “Maps of the Ancient Sea Kings.” It contains maps of Greenland and Antarctica before they were ice covered, including detailed drawings of rivers and mountain ranges that we have been able to discover through the ice only very recently with advanced technology.

” It’s widely accepted that the Ordovician period (510-438 million years ago) was characterized by atmospheric CO2 levels of 4,000-5,000 ppmv. I’d like to know why the earth climate-system didn’t self-destruct then? Anyone have a good link to any reasonable explanations?”
Brian T. – this is correct. However, the continents had not yet formed in the Ordovician period – there were no polar ice caps to melt! I’m sure that if you plugged 4,000 ppm into the computer models it would predict huge temperatures.
However, you are probably wasting your time making a scientific argument to the AGW crowd – they believe that the earth was formed on October 24th 4004 BC at 9:00 am (GMT?) or some other young earth hypothesis. From their point of view, you are talking about something that happened 400-500 million years before the earth was formed.
The AGW crowd has the same consensus argument as the Keynesians. It is an undisputed fact that the majority of mainstream economists are Keynesian. However, that does not mean that they are anything other than wrong. It reminds me of the old bumper sticker “Eat horse manure – a billion flies can’t all be wrong!.

Walt D, Fundamentalist,
The model should have been run further back and we could have an exact birth date for the Creator.
If you want to site science there is Henry’s Law from the early eighteen hundreds which states that the higher the temperature of a two component gas-liquid system the higher the partial tension of the gas over the liquid. In layman terms: the warmer your solution the more gas it releases or by warming your soda you can get rid of the bubbly.
And carbon dioxide is not the worst greenhouse gas. It is water (and it is also ~100 fold more in air). So after greens get rid of CO2 they need to dry the planet.
Come on guys! That is where we get when we discuss religion.

“However the modeling has become surprisingly accurate. Input the data in for any particular year and the models accurately backwards predict the climate for that year. There is now a much higher probability they will true for the future as well.” – SailDog
Poptech – In all fairness he said he was surprised. Presumably, what he is saying that he is surprised that a bullshit model would give predictions that are accurate? Isn’t this just an example of the broken clock? In 2008 the climate model has returned to its expected behavior and has predicted results that are bullshit. Politicians are now getting the message. It is difficult to sell people on global warming when they are freezing their asses off (in Chicago and New York). I had a Christmas card from a friend in UK who said they had had the worst summer since 1966. It appears that the fact that we have had no sunspot activity is more predictive than CO2. The AGW frauds claimed that sunspot activity is tantamount to astrology -the change in solar flux in negligible. They attributed to high temperatures that occurred when we had very high sunspot activity to man made global warming. It now appears that they were wrong. In fact, in the AGW theory, no cooling can occur. Since man made CO2 increases then concentration of CO2 in the atmosphere, if solar flux changes are deemed to be insignificant, the only change that can occur from a thermodynamic perspective, in the absence of volcanic eruptions, is a monotonic increase in average global temperature.

Mike D said:

‘However, you are probably wasting your time making a scientific argument to the AGW crowd – they believe that the earth was formed on October 24th 4004 BC at 9:00 am (GMT?) or some other young earth hypothesis. From their point of view, you are talking about something that happened 400-500 million years before the earth was formed.’

Response – would that were true. But last time I looked, and if I may also generalise a bit, the ranks of agw DENIERS were chockfull of rabid young-earth creationists with scarcely two empirical facts to rub together. Conversely, the AGW-is-evil-and-we-gotta-do-something-about-it brigate is full of enthusiastic but misguided ‘earth scientists’ and biologists whose sentimentality about ‘unspoilt’ nature ( Not to mention their generally socialistic instincts which arise from the cognitive nexus between wellmeaning compassion and economic ignorance), blinds them to the difference between values and facts, oughts and izzes, and who have yet to understand that science yields no certainty, and that Grand Plans’ consequences always impose costs that always outweigh any benefits.

All of which makes things very awkward for rationalist, Darwinian AGW skeptics like myself – we have to work doubly hard to demonstrate that yes, there IS real, proper science backing up AGW skepticism, and no, its just coincidence that the ideology of the rightwing fundamentalist religious fascists just happens to support the same conclusion for polemical reasons of their own. O the shame!.

Speaking of fascists, I have a similar problem with the one-dimensional political left-right spectrum. As a principled libertarian, I have long objected to being classified as ‘right-wing’, and hence lumped in with ‘fascists’, ‘Nazis’, and (modern) republicans or neocons – all of whom represent the very antithesis of the libertarian values I believe in. Again, O the shame!

David C: “…rabid young-earth creationists with scarcely two empirical facts to rub together.”

Cleary you don’t know anything about young-earth creationists. The movement is all about scientific evidence and they have far more evidence for their position than do evolutionists. Check out creationscience.com/onlinebook for a small sample of the scientific evidence.

Just to make it clear I am a firm evolutionist. I do not support any religious doctrine over science.

Ron, yes the Arctic ice melting is irrelevant since floating ice displaces the same amount of water once melted. The great concerns are the Greenland and Western Antarctic Ice Sheets, neither of which will melt for thousands of years. Antarctica is actually getting colder and the ice sheets growing.

Researchers find Antarctic ice is thickening (USA Today)
http://www.usatoday.com/news/science/cold-science/2002-01-18-wais-thicker.htm

ERS Altimeter Survey Shows Growth of Greenland Ice Sheet Interior (ESA – European Space Agency)
http://www.esa.int/esaEO/SEMILF638FE_planet_0.html

fundamentalist,
True, the volume of water in ice is greater than that of liquid water, I believe that water’s maximum density is at 34F. However, all floating objects displace their mass in the equivalent volume of water. Assuming that no sublimation nor evaporation occur during the melting of ice, the volume of melted ice (water) is exactly equal to the volume of water previously displaced by the ice. The differences in density between ice and water is what allows for icebergs and icecaps to float and has no effect on the final displacement of water/ice combinations, unless the volume of water remaining is insufficient to buoy the mass of the ice. In that event, the “sea level” would fall when the ice melted.