Robin van Spaandonk wrote:
> An effect originating in complex phenomena may, in turn, cause >a simple, predictable secondary effect. [snip] The secondary effect is only predictable in the sense that one can say A will cause B. It is not predictable in the sense that one can say A will happen at such and such a time, and consequently B will happen also. This is because A arises out of complexity, and is thus inherently unpredictable without certain knowledge of the future. That means that in the time sense, B is also unpredictable.
Correct! However, in this case we are talking about a mixture of causes including one that is quite simple and predictable, and a secondary effect that is probably well understood. Let us be specific:
1. CO2 is being pumped into the atmosphere by human beings. We know this for a fact. We can estimate how much is being added by tallying up the amount of fossil fuel being burned. We can measure how much is appearing in the atmosphere by monitoring CO2 concentration. CO2 mixes throughout the atmosphere so concentration will not vary from one location to another. That makes it easy to measure. The techniques used to measure it are accurate and reliable, and they are precise enough to correlate the increased amount with fossil fuel. That is, we can confirm that present increases come from fossil fuel.
2. CO2 is also being pumped into the atmosphere by bacteria and other species, and removed by plants and algae. In contrast to the CO2 from fossil fuels, this is complex and difficult to predict. It may suddenly increase. Or, plant life may bloom unexpectedly and it may decrease. We cannot predict what may happen in the future. But we can say with certainty what is happening: CO2 concentration is increasing, and the increase correlates roughly to the amount added by fossil fuels. At present, biological processes are not having a significant effect on CO2 concentration.
3. Our models of the atmosphere are increasingly accurate, as shown by weather prediction (as I said). These models predict that increased CO2 concentration should have already increased average temperatures. This has been confirmed by actual measurements. The models also predict that the problem will get worse in the future as the concentration increases. It is argued by skeptics that the models are not dependable. That is not in evidence; they are working already. It is argued that they cannot work because they are extremely complex, but (as I said) they are no more complex than models in other areas of science which are proven to work.
4. Skeptics argue that the models are not reliable because they describe phenomena on a large scale (a planetary scale). This is faulty reasoning. The scale of a phenomenon has no bearing on whether it is predictable or not, or whether it can be modeled or not. Equally complex models about large-scale phenomena in nature such as the behavior of stars and galaxies are reliable. Going down a similar number of orders of magnitude away from common experience, we find that models describing subatomic particles also work quite well. There is simply no reason to think that models about the entire earth's atmosphere are somehow unreliable because the Earth is large.
5. I reiterate that once the CO2 enters the atmosphere, the model of what happens next becomes relatively simple, and it is well tested and confirmed (unfortunately).
6. Perhaps some enhanced biological process may arise that removes CO2: something like an unexpected plant bloom, or what Russ George is trying to with iron oxide in the ocean. However, we cannot count on this occurring. It would be foolhardy to do nothing and hope that some biological process comes along and rescues us, or that some beneficial feedback mechanism is already at work. Obviously there will be some beneficial feedback and some plant blooms, but there is no evidence that a sufficiently large beneficial feedback mechanism exists. And there is some evidence that the opposite kind of feedback mechanism may arise which makes the problem much worse.
- Jed
