Quote:
|
Originally Posted by Ken G
I must apologize for not being up on all your arguments in this vein, and I would not ask you to repeat them here. But my question was what is your estimate of the *probability* (a rough guess, of course, if you feel it possible) that CO2 might be a climate factor, not your opinion of the majority likelihood. The latter is already clear.
|
There is no evidence that CO2 is a forcer of climate change. If there was solid evidence that CO2 is a climate forcer, then the probability would be 100%. In the absense of any good evidence for CO2 as a climate forcer a rough guess is not possible. Should I estimate 10^-1, 10^-3, 10^-6? What is the value of rough probability estimate? Either you have the data needed to calculate a probability or you don't.
Quote:
|
OK, this is a constructive issue toward reaching consensus.
|
Consensus is irrelevant.
Quote:
|
But note that you must also consider a criteria in the presence of solar cycle strengthening or staying the same, or else you are saying you cannot be convinced unless the Sun does something particular. You would be hamstrung to reach a conclusion half the time if the Sun's influence was actually of minimal importance.
|
You asked for a criteria that would be compelling to me. You're right - if the solar cycle strengthens and warming occurs, then its going to be much harder to make a compelling case for CO2 induced warming. But you're not just facing the current crop if climate data in this issue. I've discussed in the other threads specific evidence in the climate record contradicting the notion of CO2 as a climate forcer. There is the 1940-1970 cooling trend that corresponds with a reduction in solar activity even as CO2 levels were increasing. There is also the 800 year gap between the increases in temperature and the increases in CO2 revealed in the ice cores with the CO2 increases lagging behind the temperature increases.
There is the growing body of evidence on all observable time scales that climate change has been directed by solar variations.
Quote:
|
Yes, and what I am wondering is, what is the probability that the uncertainties in the analysis could result in the true answer being only 1/3, or 1/6?
|
If you will take the time to read the threads you will encounter the link, but I'll provide it
again . If you want to look at it those terms, the 1 sigma bounds on the warming and the model provide you with lower bound of 36% and upper bound >100% of the warming can be accounted for by solar influences.
Of course this study only accounts for direct solar irradiance changes as well as the cosmic ray influence. There is still a possibility that interstellar dust is modulated by the solar wind and provides another influence. So even the 2/3 estimate is possibly an incomplete accounting of the solar influence on climate.
Quote:
|
We can all agree it is frustratingly hard to use science to set policy when the science is in its infancy. Under those circumstances, the greatest strength of science, it's own tolerance for being wrong, becomes its greatest weakness. To me, the fact that CO2 level rise is caused by human intervention, and the fact that it has a potential mechanism for climate change even if unproven, is worthy of attention.
|
No, its not just unproven, CO2 forcing is contradicted by evidence already published. Having evidence that contradicts a hypothesis is very different from simply lacking evidence that "proves" a hypothesis. We can dream up all sorts of mechanisms. Should we initiate public policy based upon every potential threat that someone invents?
Ebola originates in Africa. We know that people that travel there run a greater risk of being exposed to it. Should we stop all citizens from going there in order to prevent a worldwide outbreak? After all, it only takes one infected person on an airliner to tranport that disease.
Quote:
|
What it does is to give us a good reason to sit down and actually come up with a worldwide fossil-fuel energy policy, which we're going to need anyway as fossil fuels become less abundant, although that's equally much an issue of greed versus fairness. Your claim that this is a purely scientific question is an internally inconsistent position, because science in its purest form has no rules for interfacing with public policy.
|
Can you show me where I claimed this is a purely scientific question? I specifically said I was not going to get into another pointless debate on economics. You're right, science has no rules for interfacing with public policy - which is why I don't see the point in talking public policy on this board. The science of AAGW is a matter of evidence and predictions that can be tested against that evidence. That is concrete within the uncertainty of the data.
Public policy is largely driven by political philosophy and belief. I'm not going to engage in those sorts of pointless discussion. I can engage in a discussion of the evidence - but why would I waste my time debating someone about their political philosophy.
Now how does the climate issue relate to public policy? The scientific evidence must first establish that there is a need for action. The points I find worth discussing involve that aspect. If it can be scientifically shown that the CO2 increases will in fact lead to catastrophic climate change and that there are plausible actions we could take to mitigate the threat, then its time to talk public policy.
Quote:
|
The AGW debate is inherently something a little different from science, because we're not allowed to be wrong here, if one cares about stewardship. It is much closer to the relationship that a doctor has with his/her patient, and we do well to remember their highest mission: do no harm.
|
Which is why it must be scientifically established that harm is being done.