But Al Gore made an unforgivable mistake in his presentation.
On the board he drew up a curve showing how the carbon dioxide rate has varied in the atmosphere during the last 650'000 years. Underneath this curve he showed how the temperature has varied during the same 650'000 years. He pointed out that the curves followed each other quite well. Then he said: "When the concentration of carbon dioxide is high, the temperature goes up".
Then he went on to show where the carbon dioxide concentration was today, and where it would be in a near future, in less than 50 years. He put on a great show demonstrating how very, very high it was, by going up in a lift machine and complaining about his vertigo...
But they aren't. First of all, you can see already from the two curves that they don't always follow each other. They are similar to each other, but deviate sometimes for a few thousands of years. Secondly, and more importantly, it is so, according to all serious sources, that it is the carbon dioxide curve that follows the temperature curve, and not the other way around! This is among other things due to the permafrosts that thaw up when temperatures are high, releasing carbon dioxide that is otherwise bound there, and the reduced solubility of gases in water with higher temperature, making the oceans release more carbon dioxide otherwise dissolved there.
At a panel debate at Chalmers University of Technology where I studied, this was put forth from several in the audience (which consisted mostly of employees and students at the university). A representative of the IPCC in the panel then said that he could not understand what difference this would make! Because if we know that an increase in temperature leads to an increase in carbon dioxide rate AND that an increase in carbon dioxide rate leads to an increase in temperature, all the more reason to be concerned! Then the problem rather becomes even bigger than what Al Gore showed!
But that's of course not how it is. The direction of the causality makes a world of difference. Let me illustrate this with an example. It is as if I would say:
"If it rains the ground gets wet. Therefore, if I go out and pour a number of buckets of water on the ground it will start to rain!"
No, that's not the case! The first sentence is right, but the second one is wrong. The error occurs because the causality has the opposite direction, namely that it is the raining that leads to the wetness of the ground, not the wetness of the ground that leads to rain.
Now of course it may be so that there exists a causality in the other direction as well! If I pour out a very large amount of water on the ground perhaps the humidity of the air as the water evaporates is increased to much that it actually, in some cases, triggers some little rainfall. But even if that is so, the strength of this causality has nothing to do with the strength of the opposite causality. The rule rain => wet ground, is very strong, whereas the rule wet ground => rain, is very weak. And if nobody before has poured any water on the ground right here, so that all the wetness of the ground historically has come from rain, and you draw up curves of how the the ground wetness and the rainfall have varied here, you will be able to see how the curves follow each other very neatly historically. But the moment I start experimenting with pouring water on the ground from a different source, the curves will deviate from one another. There is no reason to believe that they would keep co-varying just as nicely, now that I've suddenly brought in a new phenomenon into the statistics, a whole new significant factor causing an increase in one of the parameters, wetness on the ground!
And this is exactly how it is in the case of carbon dioxide and temperature. The rule temperature => carbon dioxide is very strong. Historically the carbon dioxide curve has therefore followed the temperature curve well, if also not perfectly, as there are also other factors influencing the carbon dioxide rate. The rule carbon dioxide => temperature on the other hand doesn't at all need to be as strong. At least Al Gore doesn't present any data indicating that it is, since the data he does present, according to all the experts I've heard commenting on the two curves, is explained by the causality directed temperature => carbon dioxide. Now we know that we have introduced a new phenomenon into the statistics, namely anthropogenic, industrial production of carbon dioxide, the like of which has never been seen, and there is therefore no reason to believe that the temperature and carbon dioxide curves will continue following each other. Rather they should deviate from each other as from that moment. This makes Al Gore's little show with the lift machine and the vertigo fall flat.
All this due to the direction of causality. Therefore it worries me that a representative of the IPCC, by his own accord, cannot understand what difference the direction of the causality makes, in this case responsible for the historical congruence of the temperature and carbon dioxide curves, since we know that there is a causality in both directions anyway!... If he cannot understand this, he understands very little of how scientific data must be read, and then I don't give much for whatever else he might have to say.
Likewise, after such a presentation scam, I don't give much for whatever else Al Gore might have to say.