Some interesting assertions and misunderstandings cropping up in this discussion:
Originally Posted by sr2012
Originally Posted by jazzguru
A fantasy world like one in which the entire planet's climate is controlled by regulating the emission of a single trace gas?
Right. CO2 is a "trace" gas? Doesn't seem too "trace" and unimportant to me...
Agreed - to state that a trace gas concentration cannot have a significant effect on climate is to misunderstand the stability of complex systems. It is entirely possible that such an effect could exist, although it is not yet proven (IMO). Just as a related example, consider atmospheric ozone, which overall is present in the bulk of the atmosphere at far lower concentrations than CO2 (by a factor of 500 or so at less than 1 ppm) and even in the ozone layer at less than 10 ppm. Despite that, it plays a critical role in regulating UV irradiation at ground level, and without it the earth would not support life as we know it. What we don't know is how stable the climate is to variations in CO2 level; we know that it is a "greenhouse" gas, in that it partially inhibits planetary radiative cooling, but we don't really know how self-correcting the system is.
Originally Posted by SDW2001
Originally Posted by svnipp
One question I have for those who are convinced about man made global warming... According to the data from the Wiki link CO2 has gone up by something like 40% over the past 100 or so years. Shouldn't we have seen a more dramatic temperature increase than the .6C or whatever the number is for the past 100 or so years? I'm actually fairly agnostic on this particular issue, though I lean toward not believing the global warming argument. The biggest reason I have for doubt is that there are still planetary systems/cycles that we don't know enough about and how those impact global climate as well as similar lack of knowledge regarding that giant fusion reactor in the sky. That said, we know a LOT more about these things today than we did 100 years ago, or even 20 years ago and I think we will continue to advance that knowledge. However, I'm afraid that for the foreseeable future the sheer complexity of our global climate makes this science at least somewhat skeptical.
The short answer: No. Why? Because C02 does not cause warming, at least in the sense it doesn't predicate it. C02 levels historically lag warming.
That's possibly true, but potentially misleading. In the past we have not had a significant independent source of CO2. Increases in level followed warming primarily, I believe, because the major reservoir of CO2 is the oceans, and because gas solubility in water is a fairly strong inverse function of temperature. As a result, when temperatures rose due to other factors, the oceans became warmer and more CO2 came out of solution. Whether that produced a temporary positive feedback cycle is part of the debate, but either way, the observation itself does not prove, or even provide evidence for the assertion that CO2 itself is not a factor to cause warming.
As to whether the rise that we may have observed is large enough given the rise in CO2 levels, if CO2 is the culprit - we don't know, because we don't fully understand the entire system. But, it is most unlikely to be a simple linear effect, if it is occurring.