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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: neolib who wrote (19407)	1/7/2008 5:35:04 PM
From: TimF	Read Replies (1) \| Respond to of 36921

If I were comparing AGW & evolution I would equate the evolutionary claim of common descent from a single (or very few) original life form(s) to the AGW claim that current global temps are being forced up primarily by human actions. I would not. In order of decreasing importance. 1 - The "claim of descent from a single or very few original life forms" doesn't itself give a cause. AGW does. 2 - The claim of evolution from a single (or very few) original life forms is a claim about the past, based on evidence from the past (even if the evidence is indirect, its not like we have fossil evidence of the 1st life forms). The AGW claim is a claim that something is happening now, and its not the type of effect that really can be observed except in hindsight. 3 - The extra vagueness of "a single (or very few)", rather than just "a single", or "less than 5", or "between 2 and 10", or something more specific. Would 10 be very few in this context? Would 25? Even if I did accept them as being equivalent I would point out 1 - The claim that we are evolved from very few organisms (counting 1 as "very few") is reasonable and IMO likely, even very likely (its hard to imagine that many diverse organisms would result in the type of similarities we see in all genetic information) but I would not say its something we really know, and I would not say that people who don't consider it as established are being unreasonable, or consider the idea a point that should be ignored. 2 - Not accepting that claim is not enough by itself to make you a creationist, so analogies to creationists based on this specific analogy fall down. 2 - No one is trying to propose any massive expensive changes (expensive on the scale of whole economies, not just an individual's budget) based on the idea that we are descended from 1 or at most a very few original life forms. With AGW, there is zero doubt that increased CO2 causes higher temps (other things held constant) but there is room for speculation that when the other things change as a result, something might magically flip things in the reverse direction. An example which many bashers cling to is cloud cover. If more GHG's either directly through warming, or by some other means (chemistry?) induced more cloud cover, than the cloud effect might more than mitigate the CO2 temp rise. Or increased equitorial temps might drive more heat transport out through the poles. Things like that. I agree with that. And in uncertainties about how much of the CO2 stays in the atmosphere (and how much gets absorbed in to or released from CO2 sinks), the issues of solar forcing, volcanoes (which emit CO2 and other greenhouse gasses, but which also have emissions which normally cause a net decrease in temperature at least in the relatively short run), and other issues (including but not limited to issues with the temperature data collection, and the fact that the warming started before large scale human emission of CO2) lead me to say that AGW isn't sufficently established yet. Which doesn't mean I think AGW defined as "global temps are being forced up primarily by human actions" isn't true. In fact I think it is the best theory out there. I think it likely is true. But even if, for the sake of argument, we says its 100% certain to be true, it doesn't say how much we have warmed up from human emission of CO2. And establishing "global temps are being forced up primarily by human actions" doesn't lead you to any predictions about the future, and certainly doesn't provide any significant support behind any plans for action related to CO2.