Correlation does not imply causation. So how do we determine causation? This is not an easy task within the science community and that is why the Koch brothers cling so tightly to often having it repeated.
This will show some of the difficulties involved with determining causation from any correlation. - http://www.michaelnielsen.org/ddi/if-cor...
So did Al Gore try too hard to show a causation with the correlation? Certainly! Just as the denial industry tries to eliminate anthropogenic causation with their claims that since climate has changed before, even before mankind came into existence, then how can mankind be a causation this time? As if everything will always be a natural process and mankind will have no influence on this.
You can also look at the probability of any possibility that may exist. When it concerns our current changing climate The Laws of Physics, Chemistry and Thermodynamics will tell us that adding more greenhouse gases to our atmosphere will lead to a warming of our climate above and beyond the natural variations within our climate. To date, no one has been able to show that this is incorrect, in any manner.
It would be more accurate to say that correlation does not *prove* causation. It can imply it, but is not itself sufficient. Particularly when you're talking actual statistical correlation (A changes in a statistically significant way as B changes) rather than just what could be called casual correlation (such as "The last 2 times we tried to have a picnic, it rained").
It is true that you need to figure out the underlying mechanism, since if all you know is that A changes with B, it could be that A causes B, B causes A, or C causes both. So, finding a mechanism would strengthen your case, as would experiments where you change A and see if B changes or vice versa--not something we can do with the whole atmosphere, but something we can and have done on a much smaller scale.
Also, keep in mind, in a meaningful sense proof doesn't exist in science. Scientists--or, at least, good scientists--always keep in mind the possibility that they are, in fact, completely wrong about something. That doesn't mean that someone being "skeptical" in the sense of treating a scientific issue as undecided is necessarily being a better scientist than someone treating a scientific issue as essentially decided. We would, for example, justifiably mock someone claiming to be a true scientist who was skeptical about the Earth being round, or orbiting the sun. It just means that scientists must always be open to new evidence, and change their minds if that new evidence shows something completely different.
If, next week, scientists found some previously unknown natural forcing that explains the temperature record better than CO2 does, such that dropping CO2 as a forcing explains the temperature record better than including it, once it was confirmed by enough studies, scientists would drop AGW like a hot rock. But unless and until that happens, the smart money is on the prevailing scientific theory being more or less right.
Well, other people have given you a detailed answer but for me the issue comes down to Occam's razor - the simplest explanation is usually the correct one.
We dig up fossil fuels. We burn them. That produces CO2. CO2 is a greenhouse gas. Greenhouse gases trap heat. All of those are independently verifiable and are pretty much as close to 'fact' as science can get. Now you draw a hypothesis - the planet will warm because of the additional CO2. And this is supported by the evidence of both the CO2 rise and temperature increase.
Does that prove causation? No, but it is the simplest explanation for what we observe. We can disprove causation if some other cause is found that fits the data.
So, what I'm getting at is that there is another aspect to 'proving' causation. That's showing other causes can give rise to the same data. And since we have not found an alternative explanation, that simply means we can increase our confidence in the hypothesis.
Graphic Conception: You are misrepresenting your statements and your arguments. Henry's Law is for a static resource.
"At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid."
Le Chatelier's Principal is for a changing resource.
"If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established."
The thing is, is that the oceans are currently increasing in CO2 at the same time the atmosphere is. This is why the atmosphere is only increasing (15.6gt/y) at a rate of less than half of what human emissions are (33.5gt/y). If a change in the system in one way occurs then the opposite way must change in order to attempt to maintain equilibrium. This is why, as we add more CO2 from burning fossil fuels, more than half of that is absorbed by the oceans. something that would not occur under normal circumstances.
And to the original question: While it is true that correlation does not equal causation... there are many MANY more measurements showing that the mode of thinking isn't only due to your argument. Some of these include the changing isotopic and chemical components of the atmosphere, frequencies of outbound radiation and downward longwave radiation, and so on. You have to ignore all this data in order to keep your correlation vs causation argument intact. Instead of paying attention to An Inconvenient Truth how about looking at actual scientific studies?
Correlation cannot be proven to be causation, you are right. However there already exist mountains of additional evidence, obtained from thousands of scientific studies, that tend to point to CO2 being the most likely cause. The reasons are numerous and often independent of each other, and are based on both theory (what we would expect based on our knowledge of how physics works) and observation (what we actually see from measurements and simulations).
I think An Inconvenient Truth was intended to be a very general overview, 'dumbed down' a bit to make it accessible and interesting to the greatest possible audience. I think at best a project like that should have the goal of getting people interested in the topic and asking questions -- and, judging by your question at least, it looks like it worked.
Correlation does not prove causation, it may indeed imply it, however in the inconvenient truth, it was used in an untruthful way, because we know that CO2 actually lags behind temperature.
Also the graph shown in the film (the hockey stick) as been shown to be incorrect even fraudulent.
I think there have been too many studies, all with aim of blaming climate change on CO2, so far I have not seen one study that approaches this subject from an honest unbiased point of view.
Two things to study. CO2 lags temperature (ice core data) and the warming effect of CO2 logarithmically diminishes with concentrations. (a simple fact known by all climate scientist's but not one they ever mention)
Jeff M. Another deliberately misleading statement by you quote
The thing is, is that the oceans are currently increasing in CO2 at the same time the atmosphere is. This is why the atmosphere is only increasing (15.6gt/y) at a rate of less than half of what human emissions are (33.5gt/y).
It is all going into the oceans huh, how about the fact that plants are responding by absorbing CO2 at a much faster rate and plant biomass is increasing in amounts http://www.reuters.com/article/2011/09/2...
Correlation, by itself cannot prove causation.
If A correlates well with B then the options are:
? A caused B
? B caused A
? Both A & B were caused by something else
? Coincidence
A good explanation of the mechanism is crucial if you want to prove causation.
There are, in fact, several types of correlation. Statisticians will tell you about Spearman, Kendall and Pearson. As someone who once did time series analysis we also used lagged cross-correlations. The last will tell you what the delay is between one series of events and a correlated series.
In climate science the consensus view is that CO2 causes the atmosphere to warm. Sceptics will argue that there is a rival theory that says that most of the CO2 is in the oceans and if you warm the oceans then they will expel more CO2 to the atmosphere. (Henry's Law). So one says CO2 causes warming and the other says warming causes CO2.
In my opinion, another vital ingredient for proving causation is finding out which one happened first. Does hitting the keys on a piano cause the sound to be made or does the sound cause the keys to be struck?
In the case of CO2 and warming the warming always happens first and the CO2 follows. Go back to the part in An Inconvenient Truth where Big Al is explaining the correlation. He never actually says that CO2 causes warming. Instead he talks about coastlines matching on opposite sides of the Atlantic, then moves on to his oversized graph and says something like: "Are they related? I never heard anything so ridiculous."
So, correlation is a requirement and may point you to an area of research but mechanism and timing are vital.
Well that was the clue that led scientists to believe CO2 was driving the warming, and as CO2 kept rising, so did global temps and it is a small step to determine that CO2 was causing AGW
Both CO2 and Methane are driving AGW but CO2 is identified as the culprit and I think that is deserved
Coralation does not mean causation, period. No opinion on global warming.
I know that correlation dos not imply causation.
I know that modern global climate change is caused by humans.
I watched The Inconvenient Truth recently, and Al Gore seems to be arguing that the correlation of CO2 to Temperature implies causation.
So, my question:
How can correlation be proven to be causation? Do you need a convincing argument, like the greenhouse effect? Do you need a scientific study?
