As we have explained in 2006, Vostok ice core records show that the carbon dioxide concentration averaged over a few centuries has been correlated with temperature at least for half a million of years. However, we know for sure that the temperature was the cause and the CO2 concentration was its consequence, not the other way around. It follows that the greenhouse effect hasn't been important in the last half a million of years.
There are many ways to see it. The 800-year lag is the most popular one, it has been featured in the Global Warming Swindle (especially in this two-minute-long segment), and we will discuss it below. However, there are other ways to see that the influence of temperature on the concentration of gases has been more important than any influence in the opposite direction. For example, the ice core records show that the concentration of methane was correlated with temperature, too. If the CO2 concentration were the primary cause, we would have no explanation why the CH4 concentration was also correlated. In fact, CO2 and CH4 play the very same role in the ice core records. If some combination of them determined the temperature, we would still have no explanation why these two concentrations were correlated with one another.
Moreover, easy reasoning can be used to show that the ability of oceans to store gases decreases with increasing temperature and this effect is clearly much stronger than the greenhouse effect.
The 800-year lag
However, the most popular - and the most straightforward - explanation of the direction of the causal relationship is the fact that in all cases, the CO2 concentration only changed its trend roughly 800 years after temperature had done the same thing. There have been many papers that showed this fact and incidentally, no one seems to disagree with it. For example, a recent paper by Lowell Stott et al. in Science (2007) showed that 19,000 ago, when the last ice age started to go away, CO2 lagged by about 1,000 years, too.
Every sane person knows that this detailed insight implies that the greenhouse effect couldn't have been among the most important effects. Not only the ice core data fails to provide us with evidence supporting the greenhouse theory of the climate; it provides us with strong evidence against it.
The greenhouse effect has been much less important than outgassing. Although we add more CO2 than what Earth has seen for millions of years, the small characteristic importance of the greenhouse effect probably wins.
For whatever reason, some people are not willing to accept this obvious conclusion. That's why they invent various bizarre verbal constructs to circumvent the otherwise inevitable conclusion. The whole "group" at RealClimate.ORG has agreed that there was a lag. But they say that in the first 800 years when the influence of temperature on CO2 is manifest, it was indeed temperature that drove the gases. But in the remaining 4200 years of the trend, it was surely the other way around: CO2 escalated the warming, they say.
Everyone who has basic understanding of feedback theory knows that what they talk about is a textbook example of a positive-feedback system, and if the climate were such a system, the mutually supportive interactions would lead to exponentially escalating temperatures in one of the possible directions. That's clearly not observed in the data and the positive-feedback hypothesis is thus falsified.
The list of people who understand basics of feedback theory includes Jeff who would like to believe the RealClimate.ORG guys except that he has found their rebuttal "incredibly lame, and, in [his] opinion, plain wrong." So he gave a detailed, technical version of my argument above. He also concluded that the hypothesis that CO2 actually helps to regulate the temperature is much more consistent with the data and he asked the owner of an alarmist blog called Reasic what's the answer and whether there is some other evidence for the greenhouse-driven theory of the climate that could replace this obviously wrong argument based on the ice core correlations.
What answer did he get? Reasic first mentions several rudimentary facts about the greenhouse effect and what kind of electromagnetic radiation it affects. These comments have clearly nothing to do with the direction of the causal relationship in the ice core records and with Jeff's rather sophisticated concerns. Reasic nevertheless adds a paragraph about the absence of any doubts. In my opinion, there can be no doubts that the reader who would think that the relevance of the greenhouse effect has been proven in this particular Reasic's paragraph should see her doctor.
But it gets even better. Reasic tries to answer the first paragraph that talks about the 800-year lag. The alarmist blog says:
- The idea that this lag somehow debunks the theory of anthropogenic global warming did not originate from the scientists who discovered the lag. It has come from right-wing pundits and skeptics.
Very relevant argument. I am sure that Jeff will be impressed. :-) This kind of "argument" could be good enough for something in between orangutans and chimpanzees. How does Reasic support the statement? Well, the website tells us that the paper that reported the lag contained the following sentence:
- ... is still in full agreement with the idea that CO2 plays, through its greenhouse effect, a key role in amplifying the initial orbital forcing ...
You have heard the holy word. Well, what Reasic fails to grasp is that science - including experiments, calculations, and arguments - must be reproducible. If an argument can be shown to be manifestly wrong by a careful analysis now, it really doesn't matter whether it's written in one paper or two. Also, it doesn't matter whether the authors of a flawed assertion have previously made some experimental discoveries. These two things have nothing to do with each other. When the Bible used to determine the ultimate truth, the rules of the game may have been different. But times have changed.
Sorry, Reasic. This sentence of that paper is manifestly wrong and one could even speculate that it was added to satisfy politically biased reviewers or co-authors of the article that revealed rather strong evidence against the greenhouse theory of the climate.Concerning Jeff's main comment about the unobserved positive feedback, Reasic says that he or she is no expert but he or she answers anyway:
- First, some unknown event triggers the warming (and there are several theories on what this event is).
Maybe it's Gaia. At any rate, the main observed features of the graphs and their causes are not what the politically correct people interested in the climate should look at. They should look at the featureless parts of the graphs :-) that carry no information but where Gaia can conveniently hide with all of Her theories and all of Her prophets and their disciples.
- Then, the warming triggers a mixing of the deep ocean, which releases CO2 (a process known as “outgassing”).
Well, if warming of the middle troposphere directly triggers motion in deep ocean, I suppose that this remarkable synchronization was organized by cell phones. ;-) But note that Reasic can spell "outgassing": that's really impressive!
- There is a finite amount of CO2 in the deep ocean, so CO2 cannot be released into the atmosphere indefinitely.
This is another really cute comment. Most kids in the kindergarden will agree with me that there is much more material in the ocean than in the atmosphere. Air is the light substance inside the bubbles from bubbly fu*k - how do I translate this Czech word into English? - while water is heavy. And some of the most educated kids will even know that the oceans contain 50 times more CO2 than the atmosphere. Search for 50 times at this page.
The idea that their hypothetical positive-feedback instability would stop growing because the ocean runs out of CO2 is really entertaining. It's like a very fat woman on a diet who has 50 cakes in her (rotating) fridge and who simply loves to eat cakes. The more she eats, the more she loves it. But after she eats one half of the first cake, she decides that she is running out of cakes and stops. While it's completely silly, Reasic offers us several more sentences with the very same content:
- Also, it is believed that the 800-year period is also the mixing time for the deep ocean, further solidifying this theory. So, there is a limit to the amount of natural CO2 that can be released, making a never-ending cycle of temperature increase unlikely.
And some of the alarmist readers are grateful for these great arguments! Well, one person's waste is another person's cake.
And that's the memo.
P.S.: Eric Steig has created another meaningless text composed of lies and fog about this topic. Unlike others, he even wants to question the fact that the lag is there. Instead, he argues that CO2 "leads" the temperature variations on "historical "timescales. I am pretty sure that he must realize that what he writes is a downright lie. There doesn't exist a single example of a correlation between CO2 concentration and temperature in which CO2 would "lead" temperature. Such an opposite relationship didn't occur in the glacials and interglacials and it was not a part of the modern history either. The modern, post-little-ice-age warming started well before significant emissions of CO2. I wonder how stupid the people who buy these obvious lies must be. The people who spread these lies - like Eric Steig - are criminals who should be arrested before it's too late.
Bonus climate articles on The Reference Frame